TTY/Serial driver updates for 5.17-rc1

Here is the big set of tty/serial driver updates for 5.17-rc1.
 
 Nothing major in here, just lots of good updates and fixes, including:
 	- more tty core cleanups from Jiri as well as mxser driver
 	  cleanups.  This is the majority of the core diffstat
 	- tty documentation updates from Jiri
 	- platform_get_irq() updates
 	- various serial driver updates for new features and hardware
 	- fifo usage for 8250 console, reducing cpu load a lot
 	- LED fix for keyboards, long-time bugfix that went through many
 	  revisions
 	- minor cleanups
 
 All have been in linux-next for a while with no reported problems.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'tty-5.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty/serial driver updates from Greg KH:
 "Here is the big set of tty/serial driver updates for 5.17-rc1.

  Nothing major in here, just lots of good updates and fixes, including:

   - more tty core cleanups from Jiri as well as mxser driver cleanups.
     This is the majority of the core diffstat

   - tty documentation updates from Jiri

   - platform_get_irq() updates

   - various serial driver updates for new features and hardware

   - fifo usage for 8250 console, reducing cpu load a lot

   - LED fix for keyboards, long-time bugfix that went through many
     revisions

   - minor cleanups

  All have been in linux-next for a while with no reported problems"

* tag 'tty-5.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (119 commits)
  serial: core: Keep mctrl register state and cached copy in sync
  serial: stm32: correct loop for dma error handling
  serial: stm32: fix flow control transfer in DMA mode
  serial: stm32: rework TX DMA state condition
  serial: stm32: move tx dma terminate DMA to shutdown
  serial: pl011: Drop redundant DTR/RTS preservation on close/open
  serial: pl011: Drop CR register reset on set_termios
  serial: pl010: Drop CR register reset on set_termios
  serial: liteuart: fix MODULE_ALIAS
  serial: 8250_bcm7271: Fix return error code in case of dma_alloc_coherent() failure
  Revert "serdev: BREAK/FRAME/PARITY/OVERRUN notification prototype V2"
  tty: goldfish: Use platform_get_irq() to get the interrupt
  serdev: BREAK/FRAME/PARITY/OVERRUN notification prototype V2
  tty: serial: meson: Drop the legacy compatible strings and clock code
  serial: pmac_zilog: Use platform_get_irq() to get the interrupt
  serial: bcm63xx: Use platform_get_irq() to get the interrupt
  serial: ar933x: Use platform_get_irq() to get the interrupt
  serial: vt8500: Use platform_get_irq() to get the interrupt
  serial: altera_jtaguart: Use platform_get_irq_optional() to get the interrupt
  serial: pxa: Use platform_get_irq() to get the interrupt
  ...

Documentation/devicetree/bindings/serial/amlogic,meson-uart.yaml

@@ -29,6 +29,7 @@ properties:
               - amlogic,meson8-uart
               - amlogic,meson8b-uart
               - amlogic,meson-gx-uart
+              - amlogic,meson-s4-uart
           - const: amlogic,meson-ao-uart
       - description: Everything-Else power domain UART controller
         enum:
@@ -36,6 +37,7 @@ properties:
           - amlogic,meson8-uart
           - amlogic,meson8b-uart
           - amlogic,meson-gx-uart
+          - amlogic,meson-s4-uart
 
   reg:
     maxItems: 1

Documentation/devicetree/bindings/serial/fsl-lpuart.yaml

@@ -21,9 +21,15 @@ properties:
           - fsl,ls1028a-lpuart
           - fsl,imx7ulp-lpuart
           - fsl,imx8qm-lpuart
+          - fsl,imxrt1050-lpuart
       - items:
-          - const: fsl,imx8qxp-lpuart
+          - enum:
+              - fsl,imx8qxp-lpuart
+              - fsl,imx8ulp-lpuart
           - const: fsl,imx7ulp-lpuart
+      - items:
+          - const: fsl,imx8qm-lpuart
+          - const: fsl,imx8qxp-lpuart
 
   reg:
     maxItems: 1

Documentation/devicetree/bindings/serial/renesas,sci.yaml

@@ -14,7 +14,15 @@ allOf:
 
 properties:
   compatible:
-    const: renesas,sci
+    oneOf:
+      - items:
+          - enum:
+              - renesas,r9a07g044-sci     # RZ/G2{L,LC}
+              - renesas,r9a07g054-sci     # RZ/V2L
+          - const: renesas,sci            # generic SCI compatible UART
+
+      - items:
+          - const: renesas,sci            # generic SCI compatible UART
 
   reg:
     maxItems: 1
@@ -54,18 +62,46 @@ required:
   - clocks
   - clock-names
 
+if:
+  properties:
+    compatible:
+      contains:
+        enum:
+          - renesas,r9a07g044-sci
+          - renesas,r9a07g054-sci
+then:
+  properties:
+    resets:
+      maxItems: 1
+
+    power-domains:
+      maxItems: 1
+
+  required:
+    - resets
+    - power-domains
+
 unevaluatedProperties: false
 
 examples:
   - |
+    #include <dt-bindings/clock/r9a07g044-cpg.h>
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+
     aliases {
             serial0 = &sci0;
     };
 
-    sci0: serial@ffff78 {
+    sci0: serial@1004d000 {
-            compatible = "renesas,sci";
+            compatible = "renesas,r9a07g044-sci", "renesas,sci";
-            reg = <0xffff78 8>;
+            reg = <0x1004d000 0x400>;
-            interrupts = <88 0>, <89 0>, <90 0>, <91 0>;
+            interrupts = <GIC_SPI 405 IRQ_TYPE_LEVEL_HIGH>,
-            clocks = <&fclk>;
+                         <GIC_SPI 406 IRQ_TYPE_LEVEL_HIGH>,
+                         <GIC_SPI 407 IRQ_TYPE_LEVEL_HIGH>,
+                         <GIC_SPI 408 IRQ_TYPE_LEVEL_HIGH>;
+            interrupt-names = "eri", "rxi", "txi", "tei";
+            clocks = <&cpg CPG_MOD R9A07G044_SCI0_CLKP>;
             clock-names = "fck";
+            power-domains = <&cpg>;
+            resets = <&cpg R9A07G044_SCI0_RST>;
     };

Documentation/devicetree/bindings/serial/renesas,scif.yaml

@@ -64,9 +64,21 @@ properties:
           - const: renesas,rcar-gen3-scif # R-Car Gen3 and RZ/G2
           - const: renesas,scif           # generic SCIF compatible UART
 
+      - items:
+          - enum:
+              - renesas,scif-r8a779f0     # R-Car S4-8
+          - const: renesas,rcar-gen4-scif # R-Car Gen4
+          - const: renesas,scif           # generic SCIF compatible UART
+
       - items:
           - enum:
               - renesas,scif-r9a07g044      # RZ/G2{L,LC}
+              - renesas,scif-r9a07g054      # RZ/V2L
+
+      - items:
+          - enum:
+              - renesas,scif-r9a07g054      # RZ/V2L
+          - const: renesas,scif-r9a07g044   # RZ/G2{L,LC} fallback for RZ/V2L
 
   reg:
     maxItems: 1
@@ -153,6 +165,9 @@ if:
         enum:
           - renesas,rcar-gen2-scif
           - renesas,rcar-gen3-scif
+          - renesas,rcar-gen4-scif
+          - renesas,scif-r9a07g044
+          - renesas,scif-r9a07g054
 then:
   required:
     - resets

Documentation/driver-api/serial/index.rst

@@ -9,7 +9,6 @@ Support for Serial devices
 
 
     driver
-    tty
 
 Serial drivers
 ==============

Documentation/driver-api/serial/n_gsm.rst

@@ -18,9 +18,12 @@ How to use it
 1.1 initialize the modem in 0710 mux mode (usually AT+CMUX= command) through
     its serial port. Depending on the modem used, you can pass more or less
     parameters to this command.
+
 1.2 switch the serial line to using the n_gsm line discipline by using
     TIOCSETD ioctl.
+
 1.3 configure the mux using GSMIOC_GETCONF / GSMIOC_SETCONF ioctl.
+
 1.4 obtain base gsmtty number for the used serial port.
 
 Major parts of the initialization program :
@@ -95,10 +98,13 @@ Major parts of the initialization program :
 
 2.1 receive string "AT+CMUX= command" through its serial port,initialize
     mux mode config
+
 2.2 switch the serial line to using the n_gsm line discipline by using
     TIOCSETD ioctl.
+
 2.3 configure the mux using GSMIOC_GETCONF / GSMIOC_SETCONF ioctl.
-2.4 obtain base gsmtty number for the used serial port,
+
+2.4 obtain base gsmtty number for the used serial port::
 
   #include <stdio.h>
   #include <stdint.h>

Documentation/driver-api/serial/tty.rst

@@ -1,328 +0,0 @@
-=================
-The Lockronomicon
-=================
-
-Your guide to the ancient and twisted locking policies of the tty layer and
-the warped logic behind them. Beware all ye who read on.
-
-
-Line Discipline
----------------
-
-Line disciplines are registered with tty_register_ldisc() passing the
-discipline number and the ldisc structure. At the point of registration the
-discipline must be ready to use and it is possible it will get used before
-the call returns success. If the call returns an error then it won't get
-called. Do not re-use ldisc numbers as they are part of the userspace ABI
-and writing over an existing ldisc will cause demons to eat your computer.
-After the return the ldisc data has been copied so you may free your own
-copy of the structure. You must not re-register over the top of the line
-discipline even with the same data or your computer again will be eaten by
-demons.
-
-In order to remove a line discipline call tty_unregister_ldisc().
-In ancient times this always worked. In modern times the function will
-return -EBUSY if the ldisc is currently in use. Since the ldisc referencing
-code manages the module counts this should not usually be a concern.
-
-Heed this warning: the reference count field of the registered copies of the
-tty_ldisc structure in the ldisc table counts the number of lines using this
-discipline. The reference count of the tty_ldisc structure within a tty
-counts the number of active users of the ldisc at this instant. In effect it
-counts the number of threads of execution within an ldisc method (plus those
-about to enter and exit although this detail matters not).
-
-Line Discipline Methods
------------------------
-
-TTY side interfaces
-^^^^^^^^^^^^^^^^^^^
-
-======================= =======================================================
-open()			Called when the line discipline is attached to
-			the terminal. No other call into the line
-			discipline for this tty will occur until it
-			completes successfully. Should initialize any
-			state needed by the ldisc, and set receive_room
-			in the tty_struct to the maximum amount of data
-			the line discipline is willing to accept from the
-			driver with a single call to receive_buf().
-			Returning an error will prevent the ldisc from
-			being attached. Can sleep.
-
-close()			This is called on a terminal when the line
-			discipline is being unplugged. At the point of
-			execution no further users will enter the
-			ldisc code for this tty. Can sleep.
-
-hangup()		Called when the tty line is hung up.
-			The line discipline should cease I/O to the tty.
-			No further calls into the ldisc code will occur.
-			Can sleep.
-
-read()			(optional) A process requests reading data from
-			the line. Multiple read calls may occur in parallel
-			and the ldisc must deal with serialization issues.
-			If not defined, the process will receive an EIO
-			error. May sleep.
-
-write()			(optional) A process requests writing data to the
-			line. Multiple write calls are serialized by the
-			tty layer for the ldisc. If not defined, the
-			process will receive an EIO error. May sleep.
-
-flush_buffer()		(optional) May be called at any point between
-			open and close, and instructs the line discipline
-			to empty its input buffer.
-
-set_termios()		(optional) Called on termios structure changes.
-			The caller passes the old termios data and the
-			current data is in the tty. Called under the
-			termios semaphore so allowed to sleep. Serialized
-			against itself only.
-
-poll()			(optional) Check the status for the poll/select
-			calls. Multiple poll calls may occur in parallel.
-			May sleep.
-
-ioctl()			(optional) Called when an ioctl is handed to the
-			tty layer that might be for the ldisc. Multiple
-			ioctl calls may occur in parallel. May sleep.
-
-compat_ioctl()		(optional) Called when a 32 bit ioctl is handed
-			to the tty layer that might be for the ldisc.
-			Multiple ioctl calls may occur in parallel.
-			May sleep.
-======================= =======================================================
-
-Driver Side Interfaces
-^^^^^^^^^^^^^^^^^^^^^^
-
-======================= =======================================================
-receive_buf()		(optional) Called by the low-level driver to hand
-			a buffer of received bytes to the ldisc for
-			processing. The number of bytes is guaranteed not
-			to exceed the current value of tty->receive_room.
-			All bytes must be processed.
-
-receive_buf2()		(optional) Called by the low-level driver to hand
-			a buffer of received bytes to the ldisc for
-			processing. Returns the number of bytes processed.
-
-			If both receive_buf() and receive_buf2() are
-			defined, receive_buf2() should be preferred.
-
-write_wakeup()		May be called at any point between open and close.
-			The TTY_DO_WRITE_WAKEUP flag indicates if a call
-			is needed but always races versus calls. Thus the
-			ldisc must be careful about setting order and to
-			handle unexpected calls. Must not sleep.
-
-			The driver is forbidden from calling this directly
-			from the ->write call from the ldisc as the ldisc
-			is permitted to call the driver write method from
-			this function. In such a situation defer it.
-
-dcd_change()		Report to the tty line the current DCD pin status
-			changes and the relative timestamp. The timestamp
-			cannot be NULL.
-======================= =======================================================
-
-
-Driver Access
-^^^^^^^^^^^^^
-
-Line discipline methods can call the following methods of the underlying
-hardware driver through the function pointers within the tty->driver
-structure:
-
-======================= =======================================================
-write()			Write a block of characters to the tty device.
-			Returns the number of characters accepted. The
-			character buffer passed to this method is already
-			in kernel space.
-
-put_char()		Queues a character for writing to the tty device.
-			If there is no room in the queue, the character is
-			ignored.
-
-flush_chars()		(Optional) If defined, must be called after
-			queueing characters with put_char() in order to
-			start transmission.
-
-write_room()		Returns the numbers of characters the tty driver
-			will accept for queueing to be written.
-
-ioctl()			Invoke device specific ioctl.
-			Expects data pointers to refer to userspace.
-			Returns ENOIOCTLCMD for unrecognized ioctl numbers.
-
-set_termios()		Notify the tty driver that the device's termios
-			settings have changed. New settings are in
-			tty->termios. Previous settings should be passed in
-			the "old" argument.
-
-			The API is defined such that the driver should return
-			the actual modes selected. This means that the
-			driver function is responsible for modifying any
-			bits in the request it cannot fulfill to indicate
-			the actual modes being used. A device with no
-			hardware capability for change (e.g. a USB dongle or
-			virtual port) can provide NULL for this method.
-
-throttle()		Notify the tty driver that input buffers for the
-			line discipline are close to full, and it should
-			somehow signal that no more characters should be
-			sent to the tty.
-
-unthrottle()		Notify the tty driver that characters can now be
-			sent to the tty without fear of overrunning the
-			input buffers of the line disciplines.
-
-stop()			Ask the tty driver to stop outputting characters
-			to the tty device.
-
-start()			Ask the tty driver to resume sending characters
-			to the tty device.
-
-hangup()		Ask the tty driver to hang up the tty device.
-
-break_ctl()		(Optional) Ask the tty driver to turn on or off
-			BREAK status on the RS-232 port.  If state is -1,
-			then the BREAK status should be turned on; if
-			state is 0, then BREAK should be turned off.
-			If this routine is not implemented, use ioctls
-			TIOCSBRK / TIOCCBRK instead.
-
-wait_until_sent()	Waits until the device has written out all of the
-			characters in its transmitter FIFO.
-
-send_xchar()		Send a high-priority XON/XOFF character to the device.
-======================= =======================================================
-
-
-Flags
-^^^^^
-
-Line discipline methods have access to tty->flags field containing the
-following interesting flags:
-
-======================= =======================================================
-TTY_THROTTLED		Driver input is throttled. The ldisc should call
-			tty->driver->unthrottle() in order to resume
-			reception when it is ready to process more data.
-
-TTY_DO_WRITE_WAKEUP	If set, causes the driver to call the ldisc's
-			write_wakeup() method in order to resume
-			transmission when it can accept more data
-			to transmit.
-
-TTY_IO_ERROR		If set, causes all subsequent userspace read/write
-			calls on the tty to fail, returning -EIO.
-
-TTY_OTHER_CLOSED	Device is a pty and the other side has closed.
-
-TTY_NO_WRITE_SPLIT	Prevent driver from splitting up writes into
-			smaller chunks.
-======================= =======================================================
-
-
-Locking
-^^^^^^^
-
-Callers to the line discipline functions from the tty layer are required to
-take line discipline locks. The same is true of calls from the driver side
-but not yet enforced.
-
-Three calls are now provided::
-
-	ldisc = tty_ldisc_ref(tty);
-
-takes a handle to the line discipline in the tty and returns it. If no ldisc
-is currently attached or the ldisc is being closed and re-opened at this
-point then NULL is returned. While this handle is held the ldisc will not
-change or go away::
-
-	tty_ldisc_deref(ldisc)
-
-Returns the ldisc reference and allows the ldisc to be closed. Returning the
-reference takes away your right to call the ldisc functions until you take
-a new reference::
-
-	ldisc = tty_ldisc_ref_wait(tty);
-
-Performs the same function as tty_ldisc_ref except that it will wait for an
-ldisc change to complete and then return a reference to the new ldisc.
-
-While these functions are slightly slower than the old code they should have
-minimal impact as most receive logic uses the flip buffers and they only
-need to take a reference when they push bits up through the driver.
-
-A caution: The ldisc->open(), ldisc->close() and driver->set_ldisc
-functions are called with the ldisc unavailable. Thus tty_ldisc_ref will
-fail in this situation if used within these functions. Ldisc and driver
-code calling its own functions must be careful in this case.
-
-
-Driver Interface
-----------------
-
-======================= =======================================================
-open()			Called when a device is opened. May sleep
-
-close()			Called when a device is closed. At the point of
-			return from this call the driver must make no
-			further ldisc calls of any kind. May sleep
-
-write()			Called to write bytes to the device. May not
-			sleep. May occur in parallel in special cases.
-			Because this includes panic paths drivers generally
-			shouldn't try and do clever locking here.
-
-put_char()		Stuff a single character onto the queue. The
-			driver is guaranteed following up calls to
-			flush_chars.
-
-flush_chars()		Ask the kernel to write put_char queue
-
-write_room()		Return the number of characters that can be stuffed
-			into the port buffers without overflow (or less).
-			The ldisc is responsible for being intelligent
-			about multi-threading of write_room/write calls
-
-ioctl()			Called when an ioctl may be for the driver
-
-set_termios()		Called on termios change, serialized against
-			itself by a semaphore. May sleep.
-
-set_ldisc()		Notifier for discipline change. At the point this
-			is done the discipline is not yet usable. Can now
-			sleep (I think)
-
-throttle()		Called by the ldisc to ask the driver to do flow
-			control.  Serialization including with unthrottle
-			is the job of the ldisc layer.
-
-unthrottle()		Called by the ldisc to ask the driver to stop flow
-			control.
-
-stop()			Ldisc notifier to the driver to stop output. As with
-			throttle the serializations with start() are down
-			to the ldisc layer.
-
-start()			Ldisc notifier to the driver to start output.
-
-hangup()		Ask the tty driver to cause a hangup initiated
-			from the host side. [Can sleep ??]
-
-break_ctl()		Send RS232 break. Can sleep. Can get called in
-			parallel, driver must serialize (for now), and
-			with write calls.
-
-wait_until_sent()	Wait for characters to exit the hardware queue
-			of the driver. Can sleep
-
-send_xchar()	  	Send XON/XOFF and if possible jump the queue with
-			it in order to get fast flow control responses.
-			Cannot sleep ??
-======================= =======================================================

Documentation/index.rst

@@ -137,6 +137,7 @@ needed).
    misc-devices/index
    scheduler/index
    mhi/index
+   tty/index
 
 Architecture-agnostic documentation
 -----------------------------------

Documentation/tty/index.rst

@@ -0,0 +1,63 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+===
+TTY
+===
+
+Teletypewriter (TTY) layer takes care of all those serial devices. Including
+the virtual ones like pseudoterminal (PTY).
+
+TTY structures
+==============
+
+There are several major TTY structures. Every TTY device in a system has a
+corresponding struct tty_port. These devices are maintained by a TTY driver
+which is struct tty_driver. This structure describes the driver but also
+contains a reference to operations which could be performed on the TTYs. It is
+struct tty_operations. Then, upon open, a struct tty_struct is allocated and
+lives until the final close. During this time, several callbacks from struct
+tty_operations are invoked by the TTY layer.
+
+Every character received by the kernel (both from devices and users) is passed
+through a preselected :doc:`tty_ldisc` (in
+short ldisc; in C, struct tty_ldisc_ops). Its task is to transform characters
+as defined by a particular ldisc or by user too. The default one is n_tty,
+implementing echoes, signal handling, jobs control, special characters
+processing, and more. The transformed characters are passed further to
+user/device, depending on the source.
+
+In-detail description of the named TTY structures is in separate documents:
+
+.. toctree::
+   :maxdepth: 2
+
+   tty_driver
+   tty_port
+   tty_struct
+   tty_ldisc
+   tty_buffer
+   n_tty
+   tty_internals
+
+Writing TTY Driver
+==================
+
+Before one starts writing a TTY driver, they must consider
+:doc:`Serial <../driver-api/serial/driver>` and :doc:`USB Serial
+<../usb/usb-serial>` layers
+first. Drivers for serial devices can often use one of these specific layers to
+implement a serial driver. Only special devices should be handled directly by
+the TTY Layer. If you are about to write such a driver, read on.
+
+A *typical* sequence a TTY driver performs is as follows:
+
+#. Allocate and register a TTY driver (module init)
+#. Create and register TTY devices as they are probed (probe function)
+#. Handle TTY operations and events like interrupts (TTY core invokes the
+   former, the device the latter)
+#. Remove devices as they are going away (remove function)
+#. Unregister and free the TTY driver (module exit)
+
+Steps regarding driver, i.e. 1., 3., and 5. are described in detail in
+:doc:`tty_driver`. For the other two (devices handling), look into
+:doc:`tty_port`.

Documentation/tty/n_tty.rst

@@ -0,0 +1,22 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=====
+N_TTY
+=====
+
+.. contents:: :local:
+
+The default (and fallback) :doc:`TTY line discipline <tty_ldisc>`. It tries to
+handle characters as per POSIX.
+
+External Functions
+==================
+
+.. kernel-doc:: drivers/tty/n_tty.c
+   :export:
+
+Internal Functions
+==================
+
+.. kernel-doc:: drivers/tty/n_tty.c
+   :internal:

Documentation/tty/tty_buffer.rst

@@ -0,0 +1,46 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+==========
+TTY Buffer
+==========
+
+.. contents:: :local:
+
+Here, we document functions for taking care of tty buffer and their flipping.
+Drivers are supposed to fill the buffer by one of those functions below and
+then flip the buffer, so that the data are passed to :doc:`line discipline
+<tty_ldisc>` for further processing.
+
+Flip Buffer Management
+======================
+
+.. kernel-doc:: drivers/tty/tty_buffer.c
+   :identifiers: tty_prepare_flip_string tty_insert_flip_string_fixed_flag
+           tty_insert_flip_string_flags __tty_insert_flip_char
+           tty_flip_buffer_push tty_ldisc_receive_buf
+
+----
+
+Other Functions
+===============
+
+.. kernel-doc:: drivers/tty/tty_buffer.c
+   :identifiers: tty_buffer_space_avail tty_buffer_set_limit
+
+----
+
+Buffer Locking
+==============
+
+These are used only in special circumstances. Avoid them.
+
+.. kernel-doc:: drivers/tty/tty_buffer.c
+   :identifiers: tty_buffer_lock_exclusive tty_buffer_unlock_exclusive
+
+----
+
+Internal Functions
+==================
+
+.. kernel-doc:: drivers/tty/tty_buffer.c
+   :internal:

Documentation/tty/tty_driver.rst

@@ -0,0 +1,128 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=============================
+TTY Driver and TTY Operations
+=============================
+
+.. contents:: :local:
+
+Allocation
+==========
+
+The first thing a driver needs to do is to allocate a struct tty_driver. This
+is done by tty_alloc_driver() (or __tty_alloc_driver()). Next, the newly
+allocated structure is filled with information. See `TTY Driver Reference`_ at
+the end of this document on what actually shall be filled in.
+
+The allocation routines expect a number of devices the driver can handle at
+most and flags. Flags are those starting ``TTY_DRIVER_`` listed and described
+in `TTY Driver Flags`_ below.
+
+When the driver is about to be freed, tty_driver_kref_put() is called on that.
+It will decrements the reference count and if it reaches zero, the driver is
+freed.
+
+For reference, both allocation and deallocation functions are explained here in
+detail:
+
+.. kernel-doc:: drivers/tty/tty_io.c
+   :identifiers: __tty_alloc_driver tty_driver_kref_put
+
+TTY Driver Flags
+----------------
+
+Here comes the documentation of flags accepted by tty_alloc_driver() (or
+__tty_alloc_driver()):
+
+.. kernel-doc:: include/linux/tty_driver.h
+   :doc: TTY Driver Flags
+
+----
+
+Registration
+============
+
+When a struct tty_driver is allocated and filled in, it can be registered using
+tty_register_driver(). It is recommended to pass ``TTY_DRIVER_DYNAMIC_DEV`` in
+flags of tty_alloc_driver(). If it is not passed, *all* devices are also
+registered during tty_register_driver() and the following paragraph of
+registering devices can be skipped for such drivers. However, the struct
+tty_port part in `Registering Devices`_ is still relevant there.
+
+.. kernel-doc:: drivers/tty/tty_io.c
+   :identifiers: tty_register_driver tty_unregister_driver
+
+Registering Devices
+-------------------
+
+Every TTY device shall be backed by a struct tty_port. Usually, TTY drivers
+embed tty_port into device's private structures. Further details about handling
+tty_port can be found in :doc:`tty_port`. The driver is also recommended to use
+tty_port's reference counting by tty_port_get() and tty_port_put(). The final
+put is supposed to free the tty_port including the device's private struct.
+
+Unless ``TTY_DRIVER_DYNAMIC_DEV`` was passed as flags to tty_alloc_driver(),
+TTY driver is supposed to register every device discovered in the system
+(the latter is preferred). This is performed by tty_register_device(). Or by
+tty_register_device_attr() if the driver wants to expose some information
+through struct attribute_group. Both of them register ``index``'th device and
+upon return, the device can be opened. There are also preferred tty_port
+variants described in `Linking Devices to Ports`_ later. It is up to driver to
+manage free indices and choosing the right one. The TTY layer only refuses to
+register more devices than passed to tty_alloc_driver().
+
+When the device is opened, the TTY layer allocates struct tty_struct and starts
+calling operations from :c:member:`tty_driver.ops`, see `TTY Operations
+Reference`_.
+
+The registration routines are documented as follows:
+
+.. kernel-doc:: drivers/tty/tty_io.c
+   :identifiers: tty_register_device tty_register_device_attr
+        tty_unregister_device
+
+----
+
+Linking Devices to Ports
+------------------------
+As stated earlier, every TTY device shall have a struct tty_port assigned to
+it. It must be known to the TTY layer at :c:member:`tty_driver.ops.install()`
+at latest.  There are few helpers to *link* the two. Ideally, the driver uses
+tty_port_register_device() or tty_port_register_device_attr() instead of
+tty_register_device() and tty_register_device_attr() at the registration time.
+This way, the driver needs not care about linking later on.
+
+If that is not possible, the driver still can link the tty_port to a specific
+index *before* the actual registration by tty_port_link_device(). If it still
+does not fit, tty_port_install() can be used from the
+:c:member:`tty_driver.ops.install` hook as a last resort. The last one is
+dedicated mostly for in-memory devices like PTY where tty_ports are allocated
+on demand.
+
+The linking routines are documented here:
+
+.. kernel-doc::  drivers/tty/tty_port.c
+   :identifiers: tty_port_link_device tty_port_register_device
+        tty_port_register_device_attr
+
+----
+
+TTY Driver Reference
+====================
+
+All members of struct tty_driver are documented here. The required members are
+noted at the end. struct tty_operations are documented next.
+
+.. kernel-doc:: include/linux/tty_driver.h
+   :identifiers: tty_driver
+
+----
+
+TTY Operations Reference
+========================
+
+When a TTY is registered, these driver hooks can be invoked by the TTY layer:
+
+.. kernel-doc:: include/linux/tty_driver.h
+   :identifiers: tty_operations
+

Documentation/tty/tty_internals.rst

@@ -0,0 +1,31 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=============
+TTY Internals
+=============
+
+.. contents:: :local:
+
+Kopen
+=====
+
+These functions serve for opening a TTY from the kernelspace:
+
+.. kernel-doc:: drivers/tty/tty_io.c
+      :identifiers: tty_kopen_exclusive tty_kopen_shared tty_kclose
+
+----
+
+Exported Internal Functions
+===========================
+
+.. kernel-doc:: drivers/tty/tty_io.c
+   :identifiers: tty_release_struct tty_dev_name_to_number tty_get_icount
+
+----
+
+Internal Functions
+==================
+
+.. kernel-doc:: drivers/tty/tty_io.c
+   :internal:

Documentation/tty/tty_ldisc.rst

@@ -0,0 +1,85 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+===================
+TTY Line Discipline
+===================
+
+.. contents:: :local:
+
+TTY line discipline process all incoming and outgoing character from/to a tty
+device. The default line discipline is :doc:`N_TTY <n_tty>`. It is also a
+fallback if establishing any other discipline for a tty fails. If even N_TTY
+fails, N_NULL takes over. That never fails, but also does not process any
+characters -- it throws them away.
+
+Registration
+============
+
+Line disciplines are registered with tty_register_ldisc() passing the ldisc
+structure. At the point of registration the discipline must be ready to use and
+it is possible it will get used before the call returns success. If the call
+returns an error then it won’t get called. Do not re-use ldisc numbers as they
+are part of the userspace ABI and writing over an existing ldisc will cause
+demons to eat your computer. You must not re-register over the top of the line
+discipline even with the same data or your computer again will be eaten by
+demons. In order to remove a line discipline call tty_unregister_ldisc().
+
+Heed this warning: the reference count field of the registered copies of the
+tty_ldisc structure in the ldisc table counts the number of lines using this
+discipline. The reference count of the tty_ldisc structure within a tty counts
+the number of active users of the ldisc at this instant. In effect it counts
+the number of threads of execution within an ldisc method (plus those about to
+enter and exit although this detail matters not).
+
+.. kernel-doc:: drivers/tty/tty_ldisc.c
+   :identifiers: tty_register_ldisc tty_unregister_ldisc
+
+Other Functions
+===============
+
+.. kernel-doc:: drivers/tty/tty_ldisc.c
+   :identifiers: tty_set_ldisc tty_ldisc_flush
+
+Line Discipline Operations Reference
+====================================
+
+.. kernel-doc:: include/linux/tty_ldisc.h
+   :identifiers: tty_ldisc_ops
+
+Driver Access
+=============
+
+Line discipline methods can call the methods of the underlying hardware driver.
+These are documented as a part of struct tty_operations.
+
+TTY Flags
+=========
+
+Line discipline methods have access to :c:member:`tty_struct.flags` field. See
+:doc:`tty_struct`.
+
+Locking
+=======
+
+Callers to the line discipline functions from the tty layer are required to
+take line discipline locks. The same is true of calls from the driver side
+but not yet enforced.
+
+.. kernel-doc:: drivers/tty/tty_ldisc.c
+   :identifiers: tty_ldisc_ref_wait tty_ldisc_ref tty_ldisc_deref
+
+While these functions are slightly slower than the old code they should have
+minimal impact as most receive logic uses the flip buffers and they only
+need to take a reference when they push bits up through the driver.
+
+A caution: The :c:member:`tty_ldisc_ops.open()`,
+:c:member:`tty_ldisc_ops.close()` and :c:member:`tty_driver.set_ldisc()`
+functions are called with the ldisc unavailable. Thus tty_ldisc_ref() will fail
+in this situation if used within these functions.  Ldisc and driver code
+calling its own functions must be careful in this case.
+
+Internal Functions
+==================
+
+.. kernel-doc:: drivers/tty/tty_ldisc.c
+   :internal:

Documentation/tty/tty_port.rst

@@ -0,0 +1,70 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+========
+TTY Port
+========
+
+.. contents:: :local:
+
+The TTY drivers are advised to use struct tty_port helpers as much as possible.
+If the drivers implement :c:member:`tty_port.ops.activate()` and
+:c:member:`tty_port.ops.shutdown()`, they can use tty_port_open(),
+tty_port_close(), and tty_port_hangup() in respective
+:c:member:`tty_struct.ops` hooks.
+
+The reference and details are contained in the `TTY Port Reference`_ and `TTY
+Port Operations Reference`_ sections at the bottom.
+
+TTY Port Functions
+==================
+
+Init & Destroy
+--------------
+
+.. kernel-doc::  drivers/tty/tty_port.c
+   :identifiers: tty_port_init tty_port_destroy
+        tty_port_get tty_port_put
+
+Open/Close/Hangup Helpers
+-------------------------
+
+.. kernel-doc::  drivers/tty/tty_port.c
+   :identifiers: tty_port_install tty_port_open tty_port_block_til_ready
+        tty_port_close tty_port_close_start tty_port_close_end tty_port_hangup
+        tty_port_shutdown
+
+TTY Refcounting
+---------------
+
+.. kernel-doc::  drivers/tty/tty_port.c
+   :identifiers: tty_port_tty_get tty_port_tty_set
+
+TTY Helpers
+-----------
+
+.. kernel-doc::  drivers/tty/tty_port.c
+   :identifiers: tty_port_tty_hangup tty_port_tty_wakeup
+
+
+Modem Signals
+-------------
+
+.. kernel-doc::  drivers/tty/tty_port.c
+   :identifiers: tty_port_carrier_raised tty_port_raise_dtr_rts
+        tty_port_lower_dtr_rts
+
+----
+
+TTY Port Reference
+==================
+
+.. kernel-doc:: include/linux/tty_port.h
+   :identifiers: tty_port
+
+----
+
+TTY Port Operations Reference
+=============================
+
+.. kernel-doc:: include/linux/tty_port.h
+   :identifiers: tty_port_operations

Documentation/tty/tty_struct.rst

@@ -0,0 +1,81 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+==========
+TTY Struct
+==========
+
+.. contents:: :local:
+
+struct tty_struct is allocated by the TTY layer upon the first open of the TTY
+device and released after the last close. The TTY layer passes this structure
+to most of struct tty_operation's hooks. Members of tty_struct are documented
+in `TTY Struct Reference`_ at the bottom.
+
+Initialization
+==============
+
+.. kernel-doc:: drivers/tty/tty_io.c
+   :identifiers: tty_init_termios
+
+Name
+====
+
+.. kernel-doc:: drivers/tty/tty_io.c
+   :identifiers: tty_name
+
+Reference counting
+==================
+
+.. kernel-doc:: include/linux/tty.h
+   :identifiers: tty_kref_get
+
+.. kernel-doc:: drivers/tty/tty_io.c
+   :identifiers: tty_kref_put
+
+Install
+=======
+
+.. kernel-doc:: drivers/tty/tty_io.c
+   :identifiers: tty_standard_install
+
+Read & Write
+============
+
+.. kernel-doc:: drivers/tty/tty_io.c
+   :identifiers: tty_put_char
+
+Start & Stop
+============
+
+.. kernel-doc:: drivers/tty/tty_io.c
+   :identifiers: start_tty stop_tty
+
+Wakeup
+======
+
+.. kernel-doc:: drivers/tty/tty_io.c
+   :identifiers: tty_wakeup
+
+Hangup
+======
+
+.. kernel-doc:: drivers/tty/tty_io.c
+   :identifiers: tty_hangup tty_vhangup tty_hung_up_p
+
+Misc
+====
+
+.. kernel-doc:: drivers/tty/tty_io.c
+   :identifiers: tty_do_resize
+
+TTY Struct Flags
+================
+
+.. kernel-doc:: include/linux/tty.h
+   :doc: TTY Struct Flags
+
+TTY Struct Reference
+====================
+
+.. kernel-doc:: include/linux/tty.h
+   :identifiers: tty_struct

arch/alpha/kernel/srmcons.c

@@ -59,7 +59,7 @@ srmcons_do_receive_chars(struct tty_port *port)
 	} while((result.bits.status & 1) && (++loops < 10));
 
 	if (count)
-		tty_schedule_flip(port);
+		tty_flip_buffer_push(port);
 
 	return count;
 }

arch/arm/include/debug/pl01x.S

@@ -8,13 +8,6 @@
 */
 #include <linux/amba/serial.h>
 
-#ifdef CONFIG_DEBUG_ZTE_ZX
-#undef UART01x_DR
-#undef UART01x_FR
-#define UART01x_DR     0x04
-#define UART01x_FR     0x14
-#endif
-
 #ifdef CONFIG_DEBUG_UART_PHYS
 		.macro	addruart, rp, rv, tmp
 		ldr	\rp, =CONFIG_DEBUG_UART_PHYS

drivers/accessibility/speakup/spk_ttyio.c

@@ -88,7 +88,7 @@ static int spk_ttyio_receive_buf2(struct tty_struct *tty,
 	}
 
 	if (!ldisc_data->buf_free)
-		/* ttyio_in will tty_schedule_flip */
+		/* ttyio_in will tty_flip_buffer_push */
 		return 0;
 
 	/* Make sure the consumer has read buf before we have seen
@@ -312,7 +312,7 @@ static unsigned char ttyio_in(struct spk_synth *in_synth, int timeout)
 	mb();
 	ldisc_data->buf_free = true;
 	/* Let TTY push more characters */
-	tty_schedule_flip(tty->port);
+	tty_flip_buffer_push(tty->port);
 
 	return rv;
 }

drivers/bluetooth/hci_ldisc.c

@@ -739,14 +739,13 @@ static int hci_uart_set_flags(struct hci_uart *hu, unsigned long flags)
  * Arguments:
  *
  *    tty        pointer to tty instance data
- *    file       pointer to open file object for device
  *    cmd        IOCTL command code
  *    arg        argument for IOCTL call (cmd dependent)
  *
  * Return Value:    Command dependent
  */
-static int hci_uart_tty_ioctl(struct tty_struct *tty, struct file *file,
+static int hci_uart_tty_ioctl(struct tty_struct *tty, unsigned int cmd,
-			      unsigned int cmd, unsigned long arg)
+			      unsigned long arg)
 {
 	struct hci_uart *hu = tty->disc_data;
 	int err = 0;

drivers/input/serio/serport.c

@@ -207,8 +207,8 @@ static void serport_set_type(struct tty_struct *tty, unsigned long type)
  * serport_ldisc_ioctl() allows to set the port protocol, and device ID
  */
 
-static int serport_ldisc_ioctl(struct tty_struct *tty, struct file *file,
+static int serport_ldisc_ioctl(struct tty_struct *tty, unsigned int cmd,
-			       unsigned int cmd, unsigned long arg)
+			       unsigned long arg)
 {
 	if (cmd == SPIOCSTYPE) {
 		unsigned long type;
@@ -226,7 +226,6 @@ static int serport_ldisc_ioctl(struct tty_struct *tty, struct file *file,
 #ifdef CONFIG_COMPAT
 #define COMPAT_SPIOCSTYPE	_IOW('q', 0x01, compat_ulong_t)
 static int serport_ldisc_compat_ioctl(struct tty_struct *tty,
-				       struct file *file,
 				       unsigned int cmd, unsigned long arg)
 {
 	if (cmd == COMPAT_SPIOCSTYPE) {

drivers/net/can/slcan.c

@@ -673,8 +673,8 @@ static void slcan_hangup(struct tty_struct *tty)
 }
 
 /* Perform I/O control on an active SLCAN channel. */
-static int slcan_ioctl(struct tty_struct *tty, struct file *file,
+static int slcan_ioctl(struct tty_struct *tty, unsigned int cmd,
-		       unsigned int cmd, unsigned long arg)
+		       unsigned long arg)
 {
 	struct slcan *sl = (struct slcan *) tty->disc_data;
 	unsigned int tmp;

drivers/net/hamradio/6pack.c

@@ -681,8 +681,8 @@ static void sixpack_close(struct tty_struct *tty)
 }
 
 /* Perform I/O control on an active 6pack channel. */
-static int sixpack_ioctl(struct tty_struct *tty, struct file *file,
+static int sixpack_ioctl(struct tty_struct *tty, unsigned int cmd,
-	unsigned int cmd, unsigned long arg)
+		unsigned long arg)
 {
 	struct sixpack *sp = sp_get(tty);
 	struct net_device *dev;

drivers/net/hamradio/mkiss.c

@@ -806,8 +806,8 @@ static void mkiss_close(struct tty_struct *tty)
 }
 
 /* Perform I/O control on an active ax25 channel. */
-static int mkiss_ioctl(struct tty_struct *tty, struct file *file,
+static int mkiss_ioctl(struct tty_struct *tty, unsigned int cmd,
-	unsigned int cmd, unsigned long arg)
+		unsigned long arg)
 {
 	struct mkiss *ax = mkiss_get(tty);
 	struct net_device *dev;

drivers/net/ppp/ppp_async.c

@@ -281,8 +281,7 @@ ppp_asynctty_write(struct tty_struct *tty, struct file *file,
  */
 
 static int
-ppp_asynctty_ioctl(struct tty_struct *tty, struct file *file,
+ppp_asynctty_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
-		   unsigned int cmd, unsigned long arg)
 {
 	struct asyncppp *ap = ap_get(tty);
 	int err, val;

drivers/net/ppp/ppp_synctty.c

@@ -274,8 +274,7 @@ ppp_sync_write(struct tty_struct *tty, struct file *file,
 }
 
 static int
-ppp_synctty_ioctl(struct tty_struct *tty, struct file *file,
+ppp_synctty_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
-		  unsigned int cmd, unsigned long arg)
 {
 	struct syncppp *ap = sp_get(tty);
 	int __user *p = (int __user *)arg;

drivers/net/slip/slip.c

@@ -1072,8 +1072,8 @@ static void slip_unesc6(struct slip *sl, unsigned char s)
 #endif /* CONFIG_SLIP_MODE_SLIP6 */
 
 /* Perform I/O control on an active SLIP channel. */
-static int slip_ioctl(struct tty_struct *tty, struct file *file,
+static int slip_ioctl(struct tty_struct *tty, unsigned int cmd,
-					unsigned int cmd, unsigned long arg)
+		unsigned long arg)
 {
 	struct slip *sl = tty->disc_data;
 	unsigned int tmp;

drivers/s390/char/keyboard.h

@@ -56,7 +56,7 @@ static inline void
 kbd_put_queue(struct tty_port *port, int ch)
 {
 	tty_insert_flip_char(port, ch, 0);
-	tty_schedule_flip(port);
+	tty_flip_buffer_push(port);
 }
 
 static inline void
@@ -64,5 +64,5 @@ kbd_puts_queue(struct tty_port *port, char *cp)
 {
 	while (*cp)
 		tty_insert_flip_char(port, *cp++, 0);
-	tty_schedule_flip(port);
+	tty_flip_buffer_push(port);
 }

drivers/tty/goldfish.c

@@ -151,7 +151,7 @@ static irqreturn_t goldfish_tty_interrupt(int irq, void *dev_id)
 	address = (unsigned long)(void *)buf;
 	goldfish_tty_rw(qtty, address, count, 0);
 
-	tty_schedule_flip(&qtty->port);
+	tty_flip_buffer_push(&qtty->port);
 	return IRQ_HANDLED;
 }
 
@@ -298,7 +298,7 @@ static int goldfish_tty_probe(struct platform_device *pdev)
 	struct resource *r;
 	struct device *ttydev;
 	void __iomem *base;
-	u32 irq;
+	int irq;
 	unsigned int line;
 
 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -313,14 +313,12 @@ static int goldfish_tty_probe(struct platform_device *pdev)
 		return -ENOMEM;
 	}
 
-	r = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+	irq = platform_get_irq(pdev, 0);
-	if (!r) {
+	if (irq < 0) {
-		pr_err("goldfish_tty: No IRQ resource available!\n");
+		ret = irq;
 		goto err_unmap;
 	}
 
-	irq = r->start;
-
 	mutex_lock(&goldfish_tty_lock);
 
 	if (pdev->id == PLATFORM_DEVID_NONE)

drivers/tty/mips_ejtag_fdc.c

@@ -955,19 +955,18 @@ static int mips_ejtag_fdc_tty_probe(struct mips_cdmm_device *dev)
 		mips_ejtag_fdc_con.tty_drv = driver;
 
 	init_waitqueue_head(&priv->waitqueue);
-	priv->thread = kthread_create(mips_ejtag_fdc_put, priv, priv->fdc_name);
-	if (IS_ERR(priv->thread)) {
-		ret = PTR_ERR(priv->thread);
-		dev_err(priv->dev, "Couldn't create kthread (%d)\n", ret);
-		goto err_destroy_ports;
-	}
 	/*
 	 * Bind the writer thread to the right CPU so it can't migrate.
 	 * The channels are per-CPU and we want all channel I/O to be on a
 	 * single predictable CPU.
 	 */
-	kthread_bind(priv->thread, dev->cpu);
+	priv->thread = kthread_run_on_cpu(mips_ejtag_fdc_put, priv,
-	wake_up_process(priv->thread);
+					  dev->cpu, "ttyFDC/%u");
+	if (IS_ERR(priv->thread)) {
+		ret = PTR_ERR(priv->thread);
+		dev_err(priv->dev, "Couldn't create kthread (%d)\n", ret);
+		goto err_destroy_ports;
+	}
 
 	/* Look for an FDC IRQ */
 	priv->irq = get_c0_fdc_int();
@@ -1095,15 +1094,14 @@ static int mips_ejtag_fdc_tty_cpu_up(struct mips_cdmm_device *dev)
 	}
 
 	/* Restart the kthread */
-	priv->thread = kthread_create(mips_ejtag_fdc_put, priv, priv->fdc_name);
+	/* Bind it back to the right CPU and set it off */
+	priv->thread = kthread_run_on_cpu(mips_ejtag_fdc_put, priv,
+					  dev->cpu, "ttyFDC/%u");
 	if (IS_ERR(priv->thread)) {
 		ret = PTR_ERR(priv->thread);
 		dev_err(priv->dev, "Couldn't re-create kthread (%d)\n", ret);
 		goto out;
 	}
-	/* Bind it back to the right CPU and set it off */
-	kthread_bind(priv->thread, dev->cpu);
-	wake_up_process(priv->thread);
 out:
 	return ret;
 }

drivers/tty/moxa.c

@@ -1683,7 +1683,7 @@ static int moxa_poll_port(struct moxa_port *p, unsigned int handle,
 		if (inited && !tty_throttled(tty) &&
 				MoxaPortRxQueue(p) > 0) { /* RX */
 			MoxaPortReadData(p);
-			tty_schedule_flip(&p->port);
+			tty_flip_buffer_push(&p->port);
 		}
 	} else {
 		clear_bit(EMPTYWAIT, &p->statusflags);
@@ -1708,7 +1708,7 @@ static int moxa_poll_port(struct moxa_port *p, unsigned int handle,
 
 	if (tty && (intr & IntrBreak) && !I_IGNBRK(tty)) { /* BREAK */
 		tty_insert_flip_char(&p->port, 0, TTY_BREAK);
-		tty_schedule_flip(&p->port);
+		tty_flip_buffer_push(&p->port);
 	}
 
 	if (intr & IntrLine)

drivers/tty/mxser.c

@@ -159,14 +159,32 @@
 #define MXSER_BAUD_BASE		921600
 #define MXSER_CUSTOM_DIVISOR	(MXSER_BAUD_BASE * 16)
 
-#define PCI_DEVICE_ID_POS104UL	0x1044
+#define PCI_DEVICE_ID_MOXA_RC7000	0x0001
-#define PCI_DEVICE_ID_CB108	0x1080
+#define PCI_DEVICE_ID_MOXA_CP102	0x1020
-#define PCI_DEVICE_ID_CP102UF	0x1023
+#define PCI_DEVICE_ID_MOXA_CP102UL	0x1021
-#define PCI_DEVICE_ID_CP112UL	0x1120
+#define PCI_DEVICE_ID_MOXA_CP102U	0x1022
-#define PCI_DEVICE_ID_CB114	0x1142
+#define PCI_DEVICE_ID_MOXA_CP102UF	0x1023
-#define PCI_DEVICE_ID_CP114UL	0x1143
+#define PCI_DEVICE_ID_MOXA_C104		0x1040
-#define PCI_DEVICE_ID_CB134I	0x1341
+#define PCI_DEVICE_ID_MOXA_CP104U	0x1041
-#define PCI_DEVICE_ID_CP138U	0x1380
+#define PCI_DEVICE_ID_MOXA_CP104JU	0x1042
+#define PCI_DEVICE_ID_MOXA_CP104EL	0x1043
+#define PCI_DEVICE_ID_MOXA_POS104UL	0x1044
+#define PCI_DEVICE_ID_MOXA_CB108	0x1080
+#define PCI_DEVICE_ID_MOXA_CP112UL	0x1120
+#define PCI_DEVICE_ID_MOXA_CT114	0x1140
+#define PCI_DEVICE_ID_MOXA_CP114	0x1141
+#define PCI_DEVICE_ID_MOXA_CB114	0x1142
+#define PCI_DEVICE_ID_MOXA_CP114UL	0x1143
+#define PCI_DEVICE_ID_MOXA_CP118U	0x1180
+#define PCI_DEVICE_ID_MOXA_CP118EL	0x1181
+#define PCI_DEVICE_ID_MOXA_CP132	0x1320
+#define PCI_DEVICE_ID_MOXA_CP132U	0x1321
+#define PCI_DEVICE_ID_MOXA_CP134U	0x1340
+#define PCI_DEVICE_ID_MOXA_CB134I	0x1341
+#define PCI_DEVICE_ID_MOXA_CP138U	0x1380
+#define PCI_DEVICE_ID_MOXA_C168		0x1680
+#define PCI_DEVICE_ID_MOXA_CP168U	0x1681
+#define PCI_DEVICE_ID_MOXA_CP168EL	0x1682
 
 #define MXSER_NPORTS(ddata)		((ddata) & 0xffU)
 #define MXSER_HIGHBAUD			0x0100
@@ -194,32 +212,32 @@ static const struct {
 /* driver_data correspond to the lines in the structure above
    see also ISA probe function before you change something */
 static const struct pci_device_id mxser_pcibrds[] = {
-	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_MOXA_C168),	.driver_data = 8 },
+	{ PCI_DEVICE_DATA(MOXA, C168,		8) },
-	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_MOXA_C104),	.driver_data = 4 },
+	{ PCI_DEVICE_DATA(MOXA, C104,		4) },
-	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_MOXA_CP132),	.driver_data = 2 },
+	{ PCI_DEVICE_DATA(MOXA, CP132,		2) },
-	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_MOXA_CP114),	.driver_data = 4 },
+	{ PCI_DEVICE_DATA(MOXA, CP114,		4) },
-	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_MOXA_CT114),	.driver_data = 4 },
+	{ PCI_DEVICE_DATA(MOXA, CT114,		4) },
-	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_MOXA_CP102),	.driver_data = 2 | MXSER_HIGHBAUD },
+	{ PCI_DEVICE_DATA(MOXA, CP102,		2 | MXSER_HIGHBAUD) },
-	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_MOXA_CP104U),	.driver_data = 4 },
+	{ PCI_DEVICE_DATA(MOXA, CP104U,		4) },
-	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_MOXA_CP168U),	.driver_data = 8 },
+	{ PCI_DEVICE_DATA(MOXA, CP168U,		8) },
-	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_MOXA_CP132U),	.driver_data = 2 },
+	{ PCI_DEVICE_DATA(MOXA, CP132U,		2) },
-	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_MOXA_CP134U),	.driver_data = 4 },
+	{ PCI_DEVICE_DATA(MOXA, CP134U,		4) },
-	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_MOXA_CP104JU),.driver_data = 4 },
+	{ PCI_DEVICE_DATA(MOXA, CP104JU,	4) },
-	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_MOXA_RC7000),	.driver_data = 8 }, /* RC7000 */
+	{ PCI_DEVICE_DATA(MOXA, RC7000,		8) }, /* RC7000 */
-	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_MOXA_CP118U),	.driver_data = 8 },
+	{ PCI_DEVICE_DATA(MOXA, CP118U,		8) },
-	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_MOXA_CP102UL),.driver_data = 2 },
+	{ PCI_DEVICE_DATA(MOXA, CP102UL,	2) },
-	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_MOXA_CP102U),	.driver_data = 2 },
+	{ PCI_DEVICE_DATA(MOXA, CP102U,		2) },
-	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_MOXA_CP118EL),.driver_data = 8 },
+	{ PCI_DEVICE_DATA(MOXA, CP118EL,	8) },
-	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_MOXA_CP168EL),.driver_data = 8 },
+	{ PCI_DEVICE_DATA(MOXA, CP168EL,	8) },
-	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_MOXA_CP104EL),.driver_data = 4 },
+	{ PCI_DEVICE_DATA(MOXA, CP104EL,	4) },
-	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_CB108),	.driver_data = 8 },
+	{ PCI_DEVICE_DATA(MOXA, CB108,		8) },
-	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_CB114),	.driver_data = 4 },
+	{ PCI_DEVICE_DATA(MOXA, CB114,		4) },
-	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_CB134I),	.driver_data = 4 },
+	{ PCI_DEVICE_DATA(MOXA, CB134I,		4) },
-	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_CP138U),	.driver_data = 8 },
+	{ PCI_DEVICE_DATA(MOXA, CP138U,		8) },
-	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_POS104UL),	.driver_data = 4 },
+	{ PCI_DEVICE_DATA(MOXA, POS104UL,	4) },
-	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_CP114UL),	.driver_data = 4 },
+	{ PCI_DEVICE_DATA(MOXA, CP114UL,	4) },
-	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_CP102UF),	.driver_data = 2 },
+	{ PCI_DEVICE_DATA(MOXA, CP102UF,	2) },
-	{ PCI_VDEVICE(MOXA, PCI_DEVICE_ID_CP112UL),	.driver_data = 2 },
+	{ PCI_DEVICE_DATA(MOXA, CP112UL,	2) },
 	{ }
 };
 MODULE_DEVICE_TABLE(pci, mxser_pcibrds);
@@ -251,8 +269,6 @@ struct mxser_port {
 	u8 MCR;			/* Modem control register */
 	u8 FCR;			/* FIFO control register */
 
-	bool ldisc_stop_rx;
-
 	struct async_icount icount; /* kernel counters for 4 input interrupts */
 	unsigned int timeout;
 
@@ -262,7 +278,6 @@ struct mxser_port {
 	unsigned int xmit_head;
 	unsigned int xmit_tail;
 	unsigned int xmit_cnt;
-	int closing;
 
 	spinlock_t slock;
 };
@@ -684,27 +699,34 @@ static void mxser_change_speed(struct tty_struct *tty, struct ktermios *old_term
 	outb(cval, info->ioaddr + UART_LCR);
 }
 
-static void mxser_check_modem_status(struct tty_struct *tty,
+static u8 mxser_check_modem_status(struct tty_struct *tty,
-				struct mxser_port *port, int status)
+				struct mxser_port *port)
 {
+	u8 msr = inb(port->ioaddr + UART_MSR);
+
+	if (!(msr & UART_MSR_ANY_DELTA))
+		return msr;
+
 	/* update input line counters */
-	if (status & UART_MSR_TERI)
+	if (msr & UART_MSR_TERI)
 		port->icount.rng++;
-	if (status & UART_MSR_DDSR)
+	if (msr & UART_MSR_DDSR)
 		port->icount.dsr++;
-	if (status & UART_MSR_DDCD)
+	if (msr & UART_MSR_DDCD)
 		port->icount.dcd++;
-	if (status & UART_MSR_DCTS)
+	if (msr & UART_MSR_DCTS)
 		port->icount.cts++;
 	wake_up_interruptible(&port->port.delta_msr_wait);
 
-	if (tty_port_check_carrier(&port->port) && (status & UART_MSR_DDCD)) {
+	if (tty_port_check_carrier(&port->port) && (msr & UART_MSR_DDCD)) {
-		if (status & UART_MSR_DCD)
+		if (msr & UART_MSR_DCD)
 			wake_up_interruptible(&port->port.open_wait);
 	}
 
 	if (tty_port_cts_enabled(&port->port))
-		mxser_handle_cts(tty, port, status);
+		mxser_handle_cts(tty, port, msr);
+
+	return msr;
 }
 
 static void mxser_disable_and_clear_FIFO(struct mxser_port *info)
@@ -801,6 +823,20 @@ static int mxser_activate(struct tty_port *port, struct tty_struct *tty)
 	return 0;
 }
 
+/*
+ * To stop accepting input, we disable the receive line status interrupts, and
+ * tell the interrupt driver to stop checking the data ready bit in the line
+ * status register.
+ */
+static void mxser_stop_rx(struct mxser_port *info)
+{
+	info->IER &= ~UART_IER_RLSI;
+	if (info->board->must_hwid)
+		info->IER &= ~MOXA_MUST_RECV_ISR;
+
+	outb(info->IER, info->ioaddr + UART_IER);
+}
+
 /*
  * This routine will shutdown a serial port
  */
@@ -811,6 +847,8 @@ static void mxser_shutdown_port(struct tty_port *port)
 
 	spin_lock_irqsave(&info->slock, flags);
 
+	mxser_stop_rx(info);
+
 	/*
 	 * clear delta_msr_wait queue to avoid mem leaks: we may free the irq
 	 * here so the queue might never be waken up
@@ -874,64 +912,9 @@ static void mxser_flush_buffer(struct tty_struct *tty)
 	tty_wakeup(tty);
 }
 
-
-static void mxser_close_port(struct tty_port *port)
-{
-	struct mxser_port *info = container_of(port, struct mxser_port, port);
-	unsigned long timeout;
-	/*
-	 * At this point we stop accepting input.  To do this, we
-	 * disable the receive line status interrupts, and tell the
-	 * interrupt driver to stop checking the data ready bit in the
-	 * line status register.
-	 */
-	info->IER &= ~UART_IER_RLSI;
-	if (info->board->must_hwid)
-		info->IER &= ~MOXA_MUST_RECV_ISR;
-
-	outb(info->IER, info->ioaddr + UART_IER);
-	/*
-	 * Before we drop DTR, make sure the UART transmitter
-	 * has completely drained; this is especially
-	 * important if there is a transmit FIFO!
-	 */
-	timeout = jiffies + HZ;
-	while (!(inb(info->ioaddr + UART_LSR) & UART_LSR_TEMT)) {
-		schedule_timeout_interruptible(5);
-		if (time_after(jiffies, timeout))
-			break;
-	}
-}
-
-/*
- * This routine is called when the serial port gets closed.  First, we
- * wait for the last remaining data to be sent.  Then, we unlink its
- * async structure from the interrupt chain if necessary, and we free
- * that IRQ if nothing is left in the chain.
- */
 static void mxser_close(struct tty_struct *tty, struct file *filp)
 {
-	struct mxser_port *info = tty->driver_data;
+	tty_port_close(tty->port, tty, filp);
-	struct tty_port *port = &info->port;
-
-	if (info == NULL)
-		return;
-	if (tty_port_close_start(port, tty, filp) == 0)
-		return;
-	info->closing = 1;
-	mutex_lock(&port->mutex);
-	mxser_close_port(port);
-	mxser_flush_buffer(tty);
-	if (tty_port_initialized(port) && C_HUPCL(tty))
-		tty_port_lower_dtr_rts(port);
-	mxser_shutdown_port(port);
-	tty_port_set_initialized(port, 0);
-	mutex_unlock(&port->mutex);
-	info->closing = 0;
-	/* Right now the tty_port set is done outside of the close_end helper
-	   as we don't yet have everyone using refcounts */	
-	tty_port_close_end(port, tty);
-	tty_port_tty_set(port, NULL);
 }
 
 static int mxser_write(struct tty_struct *tty, const unsigned char *buf, int count)
@@ -940,9 +923,6 @@ static int mxser_write(struct tty_struct *tty, const unsigned char *buf, int cou
 	struct mxser_port *info = tty->driver_data;
 	unsigned long flags;
 
-	if (!info->port.xmit_buf)
-		return 0;
-
 	while (1) {
 		c = min_t(int, count, min(SERIAL_XMIT_SIZE - info->xmit_cnt - 1,
 					  SERIAL_XMIT_SIZE - info->xmit_head));
@@ -973,9 +953,6 @@ static int mxser_put_char(struct tty_struct *tty, unsigned char ch)
 	struct mxser_port *info = tty->driver_data;
 	unsigned long flags;
 
-	if (!info->port.xmit_buf)
-		return 0;
-
 	if (info->xmit_cnt >= SERIAL_XMIT_SIZE - 1)
 		return 0;
 
@@ -993,7 +970,7 @@ static void mxser_flush_chars(struct tty_struct *tty)
 {
 	struct mxser_port *info = tty->driver_data;
 
-	if (!info->xmit_cnt || tty->flow.stopped || !info->port.xmit_buf ||
+	if (!info->xmit_cnt || tty->flow.stopped ||
 			(tty->hw_stopped && !mxser_16550A_or_MUST(info)))
 		return;
 
@@ -1153,25 +1130,24 @@ static int mxser_get_lsr_info(struct mxser_port *info,
 static int mxser_tiocmget(struct tty_struct *tty)
 {
 	struct mxser_port *info = tty->driver_data;
-	unsigned char control, status;
+	unsigned char control;
 	unsigned long flags;
+	u8 msr;
 
 	if (tty_io_error(tty))
 		return -EIO;
 
 	spin_lock_irqsave(&info->slock, flags);
 	control = info->MCR;
-	status = inb(info->ioaddr + UART_MSR);
+	msr = mxser_check_modem_status(tty, info);
-	if (status & UART_MSR_ANY_DELTA)
-		mxser_check_modem_status(tty, info, status);
 	spin_unlock_irqrestore(&info->slock, flags);
 
 	return ((control & UART_MCR_RTS) ? TIOCM_RTS : 0) |
 		    ((control & UART_MCR_DTR) ? TIOCM_DTR : 0) |
-		    ((status & UART_MSR_DCD) ? TIOCM_CAR : 0) |
+		    ((msr & UART_MSR_DCD) ? TIOCM_CAR : 0) |
-		    ((status & UART_MSR_RI) ? TIOCM_RNG : 0) |
+		    ((msr & UART_MSR_RI) ? TIOCM_RNG : 0) |
-		    ((status & UART_MSR_DSR) ? TIOCM_DSR : 0) |
+		    ((msr & UART_MSR_DSR) ? TIOCM_DSR : 0) |
-		    ((status & UART_MSR_CTS) ? TIOCM_CTS : 0);
+		    ((msr & UART_MSR_CTS) ? TIOCM_CTS : 0);
 }
 
 static int mxser_tiocmset(struct tty_struct *tty,
@@ -1326,11 +1302,14 @@ static int mxser_get_icount(struct tty_struct *tty,
 	return 0;
 }
 
-static void mxser_stoprx(struct tty_struct *tty)
+/*
+ * This routine is called by the upper-layer tty layer to signal that
+ * incoming characters should be throttled.
+ */
+static void mxser_throttle(struct tty_struct *tty)
 {
 	struct mxser_port *info = tty->driver_data;
 
-	info->ldisc_stop_rx = true;
 	if (I_IXOFF(tty)) {
 		if (info->board->must_hwid) {
 			info->IER &= ~MOXA_MUST_RECV_ISR;
@@ -1349,21 +1328,11 @@ static void mxser_stoprx(struct tty_struct *tty)
 	}
 }
 
-/*
- * This routine is called by the upper-layer tty layer to signal that
- * incoming characters should be throttled.
- */
-static void mxser_throttle(struct tty_struct *tty)
-{
-	mxser_stoprx(tty);
-}
-
 static void mxser_unthrottle(struct tty_struct *tty)
 {
 	struct mxser_port *info = tty->driver_data;
 
 	/* startrx */
-	info->ldisc_stop_rx = false;
 	if (I_IXOFF(tty)) {
 		if (info->x_char)
 			info->x_char = 0;
@@ -1409,7 +1378,7 @@ static void mxser_start(struct tty_struct *tty)
 	unsigned long flags;
 
 	spin_lock_irqsave(&info->slock, flags);
-	if (info->xmit_cnt && info->port.xmit_buf)
+	if (info->xmit_cnt)
 		__mxser_start_tx(info);
 	spin_unlock_irqrestore(&info->slock, flags);
 }
@@ -1442,15 +1411,25 @@ static void mxser_set_termios(struct tty_struct *tty, struct ktermios *old_termi
 	}
 }
 
+static bool mxser_tx_empty(struct mxser_port *info)
+{
+	unsigned long flags;
+	u8 lsr;
+
+	spin_lock_irqsave(&info->slock, flags);
+	lsr = inb(info->ioaddr + UART_LSR);
+	spin_unlock_irqrestore(&info->slock, flags);
+
+	return !(lsr & UART_LSR_TEMT);
+}
+
 /*
  * mxser_wait_until_sent() --- wait until the transmitter is empty
  */
 static void mxser_wait_until_sent(struct tty_struct *tty, int timeout)
 {
 	struct mxser_port *info = tty->driver_data;
-	unsigned long orig_jiffies, char_time;
+	unsigned long expire, char_time;
-	unsigned long flags;
-	int lsr;
 
 	if (info->type == PORT_UNKNOWN)
 		return;
@@ -1458,7 +1437,6 @@ static void mxser_wait_until_sent(struct tty_struct *tty, int timeout)
 	if (info->xmit_fifo_size == 0)
 		return;		/* Just in case.... */
 
-	orig_jiffies = jiffies;
 	/*
 	 * Set the check interval to be 1/5 of the estimated time to
 	 * send a single character, and make it at least 1.  The check
@@ -1473,6 +1451,9 @@ static void mxser_wait_until_sent(struct tty_struct *tty, int timeout)
 		char_time = 1;
 	if (timeout && timeout < char_time)
 		char_time = timeout;
+
+	char_time = jiffies_to_msecs(char_time);
+
 	/*
 	 * If the transmitter hasn't cleared in twice the approximate
 	 * amount of time to send the entire FIFO, it probably won't
@@ -1485,18 +1466,15 @@ static void mxser_wait_until_sent(struct tty_struct *tty, int timeout)
 	if (!timeout || timeout > 2 * info->timeout)
 		timeout = 2 * info->timeout;
 
-	spin_lock_irqsave(&info->slock, flags);
+	expire = jiffies + timeout;
-	while (!((lsr = inb(info->ioaddr + UART_LSR)) & UART_LSR_TEMT)) {
+
-		spin_unlock_irqrestore(&info->slock, flags);
+	while (mxser_tx_empty(info)) {
-		schedule_timeout_interruptible(char_time);
+		msleep_interruptible(char_time);
-		spin_lock_irqsave(&info->slock, flags);
 		if (signal_pending(current))
 			break;
-		if (timeout && time_after(jiffies, orig_jiffies + timeout))
+		if (time_after(jiffies, expire))
 			break;
 	}
-	spin_unlock_irqrestore(&info->slock, flags);
-	set_current_state(TASK_RUNNING);
 }
 
 /*
@@ -1531,8 +1509,7 @@ static int mxser_rs_break(struct tty_struct *tty, int break_state)
 	return 0;
 }
 
-static bool mxser_receive_chars_new(struct tty_struct *tty,
+static bool mxser_receive_chars_new(struct mxser_port *port, u8 status)
-		struct mxser_port *port, u8 status)
 {
 	enum mxser_must_hwid hwid = port->board->must_hwid;
 	u8 gdl;
@@ -1546,12 +1523,10 @@ static bool mxser_receive_chars_new(struct tty_struct *tty,
 	if (hwid == MOXA_MUST_MU150_HWID)
 		gdl &= MOXA_MUST_GDL_MASK;
 
-	if (gdl >= tty->receive_room && !port->ldisc_stop_rx)
-		mxser_stoprx(tty);
-
 	while (gdl--) {
 		u8 ch = inb(port->ioaddr + UART_RX);
-		tty_insert_flip_char(&port->port, ch, 0);
+		if (!tty_insert_flip_char(&port->port, ch, 0))
+			port->icount.buf_overrun++;
 	}
 
 	return true;
@@ -1561,10 +1536,8 @@ static u8 mxser_receive_chars_old(struct tty_struct *tty,
 		                struct mxser_port *port, u8 status)
 {
 	enum mxser_must_hwid hwid = port->board->must_hwid;
-	int recv_room = tty->receive_room;
 	int ignored = 0;
 	int max = 256;
-	int cnt = 0;
 	u8 ch;
 
 	do {
@@ -1599,14 +1572,10 @@ static u8 mxser_receive_chars_old(struct tty_struct *tty,
 					port->icount.overrun++;
 				}
 			}
-			tty_insert_flip_char(&port->port, ch, flag);
+			if (!tty_insert_flip_char(&port->port, ch, flag)) {
-			cnt++;
+				port->icount.buf_overrun++;
-			if (cnt >= recv_room) {
-				if (!port->ldisc_stop_rx)
-					mxser_stoprx(tty);
 				break;
 			}
-
 		}
 
 		if (hwid)
@@ -1621,10 +1590,7 @@ static u8 mxser_receive_chars_old(struct tty_struct *tty,
 static u8 mxser_receive_chars(struct tty_struct *tty,
 		struct mxser_port *port, u8 status)
 {
-	if (tty->receive_room == 0 && !port->ldisc_stop_rx)
+	if (!mxser_receive_chars_new(port, status))
-		mxser_stoprx(tty);
-
-	if (!mxser_receive_chars_new(tty, port, status))
 		status = mxser_receive_chars_old(tty, port, status);
 
 	tty_flip_buffer_push(&port->port);
@@ -1634,7 +1600,7 @@ static u8 mxser_receive_chars(struct tty_struct *tty,
 
 static void mxser_transmit_chars(struct tty_struct *tty, struct mxser_port *port)
 {
-	int count, cnt;
+	int count;
 
 	if (port->x_char) {
 		outb(port->x_char, port->ioaddr + UART_TX);
@@ -1643,27 +1609,22 @@ static void mxser_transmit_chars(struct tty_struct *tty, struct mxser_port *port
 		return;
 	}
 
-	if (port->port.xmit_buf == NULL)
-		return;
-
 	if (!port->xmit_cnt || tty->flow.stopped ||
 			(tty->hw_stopped && !mxser_16550A_or_MUST(port))) {
 		__mxser_stop_tx(port);
 		return;
 	}
 
-	cnt = port->xmit_cnt;
 	count = port->xmit_fifo_size;
 	do {
 		outb(port->port.xmit_buf[port->xmit_tail++],
 			port->ioaddr + UART_TX);
-		port->xmit_tail = port->xmit_tail & (SERIAL_XMIT_SIZE - 1);
+		port->xmit_tail &= SERIAL_XMIT_SIZE - 1;
+		port->icount.tx++;
 		if (!--port->xmit_cnt)
 			break;
 	} while (--count > 0);
 
-	port->icount.tx += (cnt - port->xmit_cnt);
-
 	if (port->xmit_cnt < WAKEUP_CHARS)
 		tty_wakeup(tty);
 
@@ -1674,7 +1635,7 @@ static void mxser_transmit_chars(struct tty_struct *tty, struct mxser_port *port
 static bool mxser_port_isr(struct mxser_port *port)
 {
 	struct tty_struct *tty;
-	u8 iir, msr, status;
+	u8 iir, status;
 	bool error = false;
 
 	iir = inb(port->ioaddr + UART_IIR);
@@ -1683,7 +1644,7 @@ static bool mxser_port_isr(struct mxser_port *port)
 
 	iir &= MOXA_MUST_IIR_MASK;
 	tty = tty_port_tty_get(&port->port);
-	if (!tty || port->closing || !tty_port_initialized(&port->port)) {
+	if (!tty) {
 		status = inb(port->ioaddr + UART_LSR);
 		outb(port->FCR | UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT,
 				port->ioaddr + UART_FCR);
@@ -1707,9 +1668,7 @@ static bool mxser_port_isr(struct mxser_port *port)
 			status = mxser_receive_chars(tty, port, status);
 	}
 
-	msr = inb(port->ioaddr + UART_MSR);
+	mxser_check_modem_status(tty, port);
-	if (msr & UART_MSR_ANY_DELTA)
-		mxser_check_modem_status(tty, port, msr);
 
 	if (port->board->must_hwid) {
 		if (iir == 0x02 && (status & UART_LSR_THRE))
@@ -1836,7 +1795,6 @@ static void mxser_initbrd(struct mxser_board *brd, bool high_baud)
 		tty_port_init(&info->port);
 		info->port.ops = &mxser_port_ops;
 		info->board = brd;
-		info->ldisc_stop_rx = false;
 
 		/* Enhance mode enabled here */
 		if (brd->must_hwid != MOXA_OTHER_UART)

drivers/tty/n_gsm.c

@@ -2074,8 +2074,6 @@ static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
 /**
  *	gsm_error		-	handle tty error
  *	@gsm: ldisc data
- *	@data: byte received (may be invalid)
- *	@flag: error received
  *
  *	Handle an error in the receipt of data for a frame. Currently we just
  *	go back to hunting for a SOF.
@@ -2083,8 +2081,7 @@ static void gsm1_receive(struct gsm_mux *gsm, unsigned char c)
  *	FIXME: better diagnostics ?
  */
 
-static void gsm_error(struct gsm_mux *gsm,
+static void gsm_error(struct gsm_mux *gsm)
-				unsigned char data, unsigned char flag)
 {
 	gsm->state = GSM_SEARCH;
 	gsm->io_error++;
@@ -2504,7 +2501,7 @@ static void gsmld_receive_buf(struct tty_struct *tty, const unsigned char *cp,
 		case TTY_BREAK:
 		case TTY_PARITY:
 		case TTY_FRAME:
-			gsm_error(gsm, *cp, flags);
+			gsm_error(gsm);
 			break;
 		default:
 			WARN_ONCE(1, "%s: unknown flag %d\n",
@@ -2690,8 +2687,8 @@ static __poll_t gsmld_poll(struct tty_struct *tty, struct file *file,
 	return mask;
 }
 
-static int gsmld_ioctl(struct tty_struct *tty, struct file *file,
+static int gsmld_ioctl(struct tty_struct *tty, unsigned int cmd,
-		       unsigned int cmd, unsigned long arg)
+		       unsigned long arg)
 {
 	struct gsm_config c;
 	struct gsm_mux *gsm = tty->disc_data;

drivers/tty/n_hdlc.c

@@ -593,14 +593,13 @@ static ssize_t n_hdlc_tty_write(struct tty_struct *tty, struct file *file,
 /**
  * n_hdlc_tty_ioctl - process IOCTL system call for the tty device.
  * @tty: pointer to tty instance data
- * @file: pointer to open file object for device
  * @cmd: IOCTL command code
  * @arg: argument for IOCTL call (cmd dependent)
  *
  * Returns command dependent result.
  */
-static int n_hdlc_tty_ioctl(struct tty_struct *tty, struct file *file,
+static int n_hdlc_tty_ioctl(struct tty_struct *tty, unsigned int cmd,
-			    unsigned int cmd, unsigned long arg)
+			    unsigned long arg)
 {
 	struct n_hdlc *n_hdlc = tty->disc_data;
 	int error = 0;

drivers/tty/n_tty.c

@@ -189,14 +189,13 @@ static void tty_copy(struct tty_struct *tty, void *to, size_t tail, size_t n)
  * n_tty_kick_worker - start input worker (if required)
  * @tty: terminal
  *
- *	Re-schedules the flip buffer work if it may have stopped
+ * Re-schedules the flip buffer work if it may have stopped.
  *
- *	Caller holds exclusive termios_rwsem
+ * Locking:
- *	   or
+ *  * Caller holds exclusive %termios_rwsem, or
- *	n_tty_read()/consumer path:
+ *  * n_tty_read()/consumer path:
- *		holds non-exclusive termios_rwsem
+ *	holds non-exclusive %termios_rwsem
  */
-
 static void n_tty_kick_worker(struct tty_struct *tty)
 {
 	struct n_tty_data *ldata = tty->disc_data;
@@ -233,11 +232,9 @@ static ssize_t chars_in_buffer(struct tty_struct *tty)
  * n_tty_write_wakeup	-	asynchronous I/O notifier
  * @tty: tty device
  *
- *	Required for the ptys, serial driver etc. since processes
+ * Required for the ptys, serial driver etc. since processes that attach
- *	that attach themselves to the master and rely on ASYNC
+ * themselves to the master and rely on ASYNC IO must be woken up.
- *	IO must be woken up
  */
-
 static void n_tty_write_wakeup(struct tty_struct *tty)
 {
 	clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
@@ -306,10 +303,10 @@ static void n_tty_check_unthrottle(struct tty_struct *tty)
  *
  * Add a character to the tty read_buf queue.
  *
- *	n_tty_receive_buf()/producer path:
+ * Locking:
- *		caller holds non-exclusive termios_rwsem
+ *  * n_tty_receive_buf()/producer path:
+ *	caller holds non-exclusive %termios_rwsem
  */
-
 static inline void put_tty_queue(unsigned char c, struct n_tty_data *ldata)
 {
 	*read_buf_addr(ldata, ldata->read_head) = c;
@@ -320,13 +317,13 @@ static inline void put_tty_queue(unsigned char c, struct n_tty_data *ldata)
  * reset_buffer_flags	-	reset buffer state
  * @ldata: line disc data to reset
  *
- *	Reset the read buffer counters and clear the flags.
+ * Reset the read buffer counters and clear the flags. Called from
- *	Called from n_tty_open() and n_tty_flush_buffer().
+ * n_tty_open() and n_tty_flush_buffer().
  *
- *	Locking: caller holds exclusive termios_rwsem
+ * Locking:
- *		 (or locking is not required)
+ *  * caller holds exclusive %termios_rwsem, or
+ *  * (locking is not required)
  */
-
 static void reset_buffer_flags(struct n_tty_data *ldata)
 {
 	ldata->read_head = ldata->canon_head = ldata->read_tail = 0;
@@ -354,16 +351,15 @@ static void n_tty_packet_mode_flush(struct tty_struct *tty)
  * n_tty_flush_buffer	-	clean input queue
  * @tty: terminal device
  *
- *	Flush the input buffer. Called when the tty layer wants the
+ * Flush the input buffer. Called when the tty layer wants the buffer flushed
- *	buffer flushed (eg at hangup) or when the N_TTY line discipline
+ * (eg at hangup) or when the %N_TTY line discipline internally has to clean
- *	internally has to clean the pending queue (for example some signals).
+ * the pending queue (for example some signals).
  *
- *	Holds termios_rwsem to exclude producer/consumer while
+ * Holds %termios_rwsem to exclude producer/consumer while buffer indices are
- *	buffer indices are reset.
+ * reset.
  *
- *	Locking: ctrl.lock, exclusive termios_rwsem
+ * Locking: %ctrl.lock, exclusive %termios_rwsem
  */
-
 static void n_tty_flush_buffer(struct tty_struct *tty)
 {
 	down_write(&tty->termios_rwsem);
@@ -379,11 +375,10 @@ static void n_tty_flush_buffer(struct tty_struct *tty)
  * is_utf8_continuation	-	utf8 multibyte check
  * @c: byte to check
  *
- *	Returns true if the utf8 character 'c' is a multibyte continuation
+ * Returns: true if the utf8 character @c is a multibyte continuation
- *	character. We use this to correctly compute the on screen size
+ * character. We use this to correctly compute the on-screen size of the
- *	of the character when printing
+ * character when printing.
  */
-
 static inline int is_utf8_continuation(unsigned char c)
 {
 	return (c & 0xc0) == 0x80;
@@ -394,10 +389,9 @@ static inline int is_utf8_continuation(unsigned char c)
  * @c: byte to check
  * @tty: terminal device
  *
- *	Returns true if the utf8 character 'c' is a multibyte continuation
+ * Returns: true if the utf8 character @c is a multibyte continuation character
- *	character and the terminal is in unicode mode.
+ * and the terminal is in unicode mode.
  */
-
 static inline int is_continuation(unsigned char c, struct tty_struct *tty)
 {
 	return I_IUTF8(tty) && is_utf8_continuation(c);
@@ -409,22 +403,19 @@ static inline int is_continuation(unsigned char c, struct tty_struct *tty)
  * @tty: terminal device
  * @space: space available in tty driver write buffer
  *
- *	This is a helper function that handles one output character
+ * This is a helper function that handles one output character (including
- *	(including special characters like TAB, CR, LF, etc.),
+ * special characters like TAB, CR, LF, etc.), doing OPOST processing and
- *	doing OPOST processing and putting the results in the
+ * putting the results in the tty driver's write buffer.
- *	tty driver's write buffer.
  *
- *	Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY
+ * Note that Linux currently ignores TABDLY, CRDLY, VTDLY, FFDLY and NLDLY.
- *	and NLDLY.  They simply aren't relevant in the world today.
+ * They simply aren't relevant in the world today. If you ever need them, add
- *	If you ever need them, add them here.
+ * them here.
  *
- *	Returns the number of bytes of buffer space used or -1 if
+ * Returns: the number of bytes of buffer space used or -1 if no space left.
- *	no space left.
  *
- *	Locking: should be called under the output_lock to protect
+ * Locking: should be called under the %output_lock to protect the column state
- *		 the column state and space left in the buffer
+ * and space left in the buffer.
  */
-
 static int do_output_char(unsigned char c, struct tty_struct *tty, int space)
 {
 	struct n_tty_data *ldata = tty->disc_data;
@@ -492,14 +483,13 @@ static int do_output_char(unsigned char c, struct tty_struct *tty, int space)
  * @tty: terminal device
  *
  * Output one character with OPOST processing.
- *	Returns -1 when the output device is full and the character
- *	must be retried.
  *
- *	Locking: output_lock to protect column state and space left
+ * Returns: -1 when the output device is full and the character must be
- *		 (also, this is called from n_tty_write under the
+ * retried.
- *		  tty layer write lock)
+ *
+ * Locking: %output_lock to protect column state and space left (also, this is
+ *called from n_tty_write() under the tty layer write lock).
  */
-
 static int process_output(unsigned char c, struct tty_struct *tty)
 {
 	struct n_tty_data *ldata = tty->disc_data;
@@ -524,18 +514,17 @@ static int process_output(unsigned char c, struct tty_struct *tty)
  * @nr: number of bytes to output
  *
  * Output a block of characters with OPOST processing.
- *	Returns the number of characters output.
  *
- *	This path is used to speed up block console writes, among other
+ * This path is used to speed up block console writes, among other things when
- *	things when processing blocks of output data. It handles only
+ * processing blocks of output data. It handles only the simple cases normally
- *	the simple cases normally found and helps to generate blocks of
+ * found and helps to generate blocks of symbols for the console driver and
- *	symbols for the console driver and thus improve performance.
+ * thus improve performance.
  *
- *	Locking: output_lock to protect column state and space left
+ * Returns: the number of characters output.
- *		 (also, this is called from n_tty_write under the
+ *
- *		  tty layer write lock)
+ * Locking: %output_lock to protect column state and space left (also, this is
+ * called from n_tty_write() under the tty layer write lock).
  */
-
 static ssize_t process_output_block(struct tty_struct *tty,
 				    const unsigned char *buf, unsigned int nr)
 {
@@ -596,30 +585,27 @@ break_out:
 }
 
 /**
- *	process_echoes	-	write pending echo characters
+ * __process_echoes	-	write pending echo characters
  * @tty: terminal device
  *
- *	Write previously buffered echo (and other ldisc-generated)
+ * Write previously buffered echo (and other ldisc-generated) characters to the
- *	characters to the tty.
+ * tty.
  *
- *	Characters generated by the ldisc (including echoes) need to
+ * Characters generated by the ldisc (including echoes) need to be buffered
- *	be buffered because the driver's write buffer can fill during
+ * because the driver's write buffer can fill during heavy program output.
- *	heavy program output.  Echoing straight to the driver will
+ * Echoing straight to the driver will often fail under these conditions,
- *	often fail under these conditions, causing lost characters and
+ * causing lost characters and resulting mismatches of ldisc state information.
- *	resulting mismatches of ldisc state information.
  *
- *	Since the ldisc state must represent the characters actually sent
+ * Since the ldisc state must represent the characters actually sent to the
- *	to the driver at the time of the write, operations like certain
+ * driver at the time of the write, operations like certain changes in column
- *	changes in column state are also saved in the buffer and executed
+ * state are also saved in the buffer and executed here.
- *	here.
  *
- *	A circular fifo buffer is used so that the most recent characters
+ * A circular fifo buffer is used so that the most recent characters are
- *	are prioritized.  Also, when control characters are echoed with a
+ * prioritized. Also, when control characters are echoed with a prefixed "^",
- *	prefixed "^", the pair is treated atomically and thus not separated.
+ * the pair is treated atomically and thus not separated.
  *
- *	Locking: callers must hold output_lock
+ * Locking: callers must hold %output_lock.
  */
-
 static size_t __process_echoes(struct tty_struct *tty)
 {
 	struct n_tty_data *ldata = tty->disc_data;
@@ -834,7 +820,6 @@ static void flush_echoes(struct tty_struct *tty)
  *
  * Add a character or operation byte to the echo buffer.
  */
-
 static inline void add_echo_byte(unsigned char c, struct n_tty_data *ldata)
 {
 	*echo_buf_addr(ldata, ldata->echo_head) = c;
@@ -848,7 +833,6 @@ static inline void add_echo_byte(unsigned char c, struct n_tty_data *ldata)
  *
  * Add an operation to the echo buffer to move back one column.
  */
-
 static void echo_move_back_col(struct n_tty_data *ldata)
 {
 	add_echo_byte(ECHO_OP_START, ldata);
@@ -859,10 +843,9 @@ static void echo_move_back_col(struct n_tty_data *ldata)
  * echo_set_canon_col	-	add operation to set the canon column
  * @ldata: n_tty data
  *
- *	Add an operation to the echo buffer to set the canon column
+ * Add an operation to the echo buffer to set the canon column to the current
- *	to the current column.
+ * column.
  */
-
 static void echo_set_canon_col(struct n_tty_data *ldata)
 {
 	add_echo_byte(ECHO_OP_START, ldata);
@@ -877,13 +860,11 @@ static void echo_set_canon_col(struct n_tty_data *ldata)
  *
  * Add an operation to the echo buffer to erase a tab.
  *
- *	Called by the eraser function, which knows how many character
+ * Called by the eraser function, which knows how many character columns have
- *	columns have been used since either a previous tab or the start
+ * been used since either a previous tab or the start of input. This
- *	of input.  This information will be used later, along with
+ * information will be used later, along with canon column (if applicable), to
- *	canon column (if applicable), to go back the correct number
+ * go back the correct number of columns.
- *	of columns.
  */
-
 static void echo_erase_tab(unsigned int num_chars, int after_tab,
 			   struct n_tty_data *ldata)
 {
@@ -906,11 +887,10 @@ static void echo_erase_tab(unsigned int num_chars, int after_tab,
  * @ldata: line disc data
  *
  * Echo user input back onto the screen. This must be called only when
- *	L_ECHO(tty) is true. Called from the driver receive_buf path.
+ * L_ECHO(tty) is true. Called from the &tty_driver.receive_buf() path.
  *
  * This variant does not treat control characters specially.
  */
-
 static void echo_char_raw(unsigned char c, struct n_tty_data *ldata)
 {
 	if (c == ECHO_OP_START) {
@@ -927,12 +907,11 @@ static void echo_char_raw(unsigned char c, struct n_tty_data *ldata)
  * @tty: terminal device
  *
  * Echo user input back onto the screen. This must be called only when
- *	L_ECHO(tty) is true. Called from the driver receive_buf path.
+ * L_ECHO(tty) is true. Called from the &tty_driver.receive_buf() path.
  *
- *	This variant tags control characters to be echoed as "^X"
+ * This variant tags control characters to be echoed as "^X" (where X is the
- *	(where X is the letter representing the control char).
+ * letter representing the control char).
  */
-
 static void echo_char(unsigned char c, struct tty_struct *tty)
 {
 	struct n_tty_data *ldata = tty->disc_data;
@@ -951,7 +930,6 @@ static void echo_char(unsigned char c, struct tty_struct *tty)
  * finish_erasing	-	complete erase
  * @ldata: n_tty data
  */
-
 static inline void finish_erasing(struct n_tty_data *ldata)
 {
 	if (ldata->erasing) {
@@ -965,14 +943,13 @@ static inline void finish_erasing(struct n_tty_data *ldata)
  * @c: character input
  * @tty: terminal device
  *
- *	Perform erase and necessary output when an erase character is
+ * Perform erase and necessary output when an erase character is present in the
- *	present in the stream from the driver layer. Handles the complexities
+ * stream from the driver layer. Handles the complexities of UTF-8 multibyte
- *	of UTF-8 multibyte symbols.
+ * symbols.
  *
- *	n_tty_receive_buf()/producer path:
+ * Locking: n_tty_receive_buf()/producer path:
- *		caller holds non-exclusive termios_rwsem
+ *	caller holds non-exclusive %termios_rwsem
  */
-
 static void eraser(unsigned char c, struct tty_struct *tty)
 {
 	struct n_tty_data *ldata = tty->disc_data;
@@ -1091,20 +1068,6 @@ static void eraser(unsigned char c, struct tty_struct *tty)
 		finish_erasing(ldata);
 }
 
-/**
- *	isig		-	handle the ISIG optio
- *	@sig: signal
- *	@tty: terminal
- *
- *	Called when a signal is being sent due to terminal input.
- *	Called from the driver receive_buf path so serialized.
- *
- *	Performs input and output flush if !NOFLSH. In this context, the echo
- *	buffer is 'output'. The signal is processed first to alert any current
- *	readers or writers to discontinue and exit their i/o loops.
- *
- *	Locking: ctrl.lock
- */
 
 static void __isig(int sig, struct tty_struct *tty)
 {
@@ -1115,6 +1078,20 @@ static void __isig(int sig, struct tty_struct *tty)
 	}
 }
 
+/**
+ * isig			-	handle the ISIG optio
+ * @sig: signal
+ * @tty: terminal
+ *
+ * Called when a signal is being sent due to terminal input. Called from the
+ * &tty_driver.receive_buf() path, so serialized.
+ *
+ * Performs input and output flush if !NOFLSH. In this context, the echo
+ * buffer is 'output'. The signal is processed first to alert any current
+ * readers or writers to discontinue and exit their i/o loops.
+ *
+ * Locking: %ctrl.lock
+ */
 static void isig(int sig, struct tty_struct *tty)
 {
 	struct n_tty_data *ldata = tty->disc_data;
@@ -1154,15 +1131,14 @@ static void isig(int sig, struct tty_struct *tty)
  * n_tty_receive_break	-	handle break
  * @tty: terminal
  *
- *	An RS232 break event has been hit in the incoming bitstream. This
+ * An RS232 break event has been hit in the incoming bitstream. This can cause
- *	can cause a variety of events depending upon the termios settings.
+ * a variety of events depending upon the termios settings.
  *
- *	n_tty_receive_buf()/producer path:
+ * Locking: n_tty_receive_buf()/producer path:
  *	caller holds non-exclusive termios_rwsem
  *
- *	Note: may get exclusive termios_rwsem if flushing input buffer
+ * Note: may get exclusive %termios_rwsem if flushing input buffer
  */
-
 static void n_tty_receive_break(struct tty_struct *tty)
 {
 	struct n_tty_data *ldata = tty->disc_data;
@@ -1184,15 +1160,12 @@ static void n_tty_receive_break(struct tty_struct *tty)
  * n_tty_receive_overrun	-	handle overrun reporting
  * @tty: terminal
  *
- *	Data arrived faster than we could process it. While the tty
+ * Data arrived faster than we could process it. While the tty driver has
- *	driver has flagged this the bits that were missed are gone
+ * flagged this the bits that were missed are gone forever.
- *	forever.
  *
- *	Called from the receive_buf path so single threaded. Does not
+ * Called from the receive_buf path so single threaded. Does not need locking
- *	need locking as num_overrun and overrun_time are function
+ * as num_overrun and overrun_time are function private.
- *	private.
  */
-
 static void n_tty_receive_overrun(struct tty_struct *tty)
 {
 	struct n_tty_data *ldata = tty->disc_data;
@@ -1211,11 +1184,11 @@ static void n_tty_receive_overrun(struct tty_struct *tty)
  * @tty: terminal device
  * @c: character
  *
- *	Process a parity error and queue the right data to indicate
+ * Process a parity error and queue the right data to indicate the error case
- *	the error case if necessary.
+ * if necessary.
  *
- *	n_tty_receive_buf()/producer path:
+ * Locking: n_tty_receive_buf()/producer path:
- *		caller holds non-exclusive termios_rwsem
+ * 	caller holds non-exclusive %termios_rwsem
  */
 static void n_tty_receive_parity_error(struct tty_struct *tty, unsigned char c)
 {
@@ -1247,19 +1220,6 @@ n_tty_receive_signal_char(struct tty_struct *tty, int signal, unsigned char c)
 		process_echoes(tty);
 }
 
-/**
- *	n_tty_receive_char	-	perform processing
- *	@tty: terminal device
- *	@c: character
- *
- *	Process an individual character of input received from the driver.
- *	This is serialized with respect to itself by the rules for the
- *	driver above.
- *
- *	n_tty_receive_buf()/producer path:
- *		caller holds non-exclusive termios_rwsem
- *		publishes canon_head if canonical mode is active
- */
 static void n_tty_receive_char_special(struct tty_struct *tty, unsigned char c)
 {
 	struct n_tty_data *ldata = tty->disc_data;
@@ -1394,6 +1354,18 @@ handle_newline:
 	put_tty_queue(c, ldata);
 }
 
+/**
+ * n_tty_receive_char	-	perform processing
+ * @tty: terminal device
+ * @c: character
+ *
+ * Process an individual character of input received from the driver.  This is
+ * serialized with respect to itself by the rules for the driver above.
+ *
+ * Locking: n_tty_receive_buf()/producer path:
+ *	caller holds non-exclusive %termios_rwsem
+ *	publishes canon_head if canonical mode is active
+ */
 static void n_tty_receive_char(struct tty_struct *tty, unsigned char c)
 {
 	struct n_tty_data *ldata = tty->disc_data;
@@ -1597,34 +1569,33 @@ static void __receive_buf(struct tty_struct *tty, const unsigned char *cp,
  * n_tty_receive_buf_common	-	process input
  * @tty: device to receive input
  * @cp: input chars
- *	@fp: flags for each char (if NULL, all chars are TTY_NORMAL)
+ * @fp: flags for each char (if %NULL, all chars are %TTY_NORMAL)
  * @count: number of input chars in @cp
  * @flow: enable flow control
  *
- *	Called by the terminal driver when a block of characters has
+ * Called by the terminal driver when a block of characters has been received.
- *	been received. This function must be called from soft contexts
+ * This function must be called from soft contexts not from interrupt context.
- *	not from interrupt context. The driver is responsible for making
+ * The driver is responsible for making calls one at a time and in order (or
- *	calls one at a time and in order (or using flush_to_ldisc)
+ * using flush_to_ldisc()).
  *
- *	Returns the # of input chars from @cp which were processed.
+ * Returns: the # of input chars from @cp which were processed.
  *
- *	In canonical mode, the maximum line length is 4096 chars (including
+ * In canonical mode, the maximum line length is 4096 chars (including the line
- *	the line termination char); lines longer than 4096 chars are
+ * termination char); lines longer than 4096 chars are truncated. After 4095
- *	truncated. After 4095 chars, input data is still processed but
+ * chars, input data is still processed but not stored. Overflow processing
- *	not stored. Overflow processing ensures the tty can always
+ * ensures the tty can always receive more input until at least one line can be
- *	receive more input until at least one line can be read.
+ * read.
  *
- *	In non-canonical mode, the read buffer will only accept 4095 chars;
+ * In non-canonical mode, the read buffer will only accept 4095 chars; this
- *	this provides the necessary space for a newline char if the input
+ * provides the necessary space for a newline char if the input mode is
- *	mode is switched to canonical.
+ * switched to canonical.
  *
- *	Note it is possible for the read buffer to _contain_ 4096 chars
+ * Note it is possible for the read buffer to _contain_ 4096 chars in
- *	in non-canonical mode: the read buffer could already contain the
+ * non-canonical mode: the read buffer could already contain the maximum canon
- *	maximum canon line of 4096 chars when the mode is switched to
+ * line of 4096 chars when the mode is switched to non-canonical.
- *	non-canonical.
  *
- *	n_tty_receive_buf()/producer path:
+ * Locking: n_tty_receive_buf()/producer path:
- *		claims non-exclusive termios_rwsem
+ *	claims non-exclusive %termios_rwsem
  *	publishes commit_head or canon_head
  */
 static int
@@ -1714,15 +1685,13 @@ static int n_tty_receive_buf2(struct tty_struct *tty, const unsigned char *cp,
  * @tty: terminal
  * @old: previous data
  *
- *	Called by the tty layer when the user changes termios flags so
+ * Called by the tty layer when the user changes termios flags so that the line
- *	that the line discipline can plan ahead. This function cannot sleep
+ * discipline can plan ahead. This function cannot sleep and is protected from
- *	and is protected from re-entry by the tty layer. The user is
+ * re-entry by the tty layer. The user is guaranteed that this function will
- *	guaranteed that this function will not be re-entered or in progress
+ * not be re-entered or in progress when the ldisc is closed.
- *	when the ldisc is closed.
  *
- *	Locking: Caller holds tty->termios_rwsem
+ * Locking: Caller holds @tty->termios_rwsem
  */
-
 static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
 {
 	struct n_tty_data *ldata = tty->disc_data;
@@ -1811,12 +1780,10 @@ static void n_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
  * n_tty_close		-	close the ldisc for this tty
  * @tty: device
  *
- *	Called from the terminal layer when this line discipline is
+ * Called from the terminal layer when this line discipline is being shut down,
- *	being shut down, either because of a close or becsuse of a
+ * either because of a close or becsuse of a discipline change. The function
- *	discipline change. The function will not be called while other
+ * will not be called while other ldisc methods are in progress.
- *	ldisc methods are in progress.
  */
-
 static void n_tty_close(struct tty_struct *tty)
 {
 	struct n_tty_data *ldata = tty->disc_data;
@@ -1834,12 +1801,10 @@ static void n_tty_close(struct tty_struct *tty)
  * n_tty_open		-	open an ldisc
  * @tty: terminal to open
  *
- *	Called when this line discipline is being attached to the
+ * Called when this line discipline is being attached to the terminal device.
- *	terminal device. Can sleep. Called serialized so that no
+ * Can sleep. Called serialized so that no other events will occur in parallel.
- *	other events will occur in parallel. No further open will occur
+ * No further open will occur until a close.
- *	until a close.
  */
-
 static int n_tty_open(struct tty_struct *tty)
 {
 	struct n_tty_data *ldata;
@@ -1879,19 +1844,18 @@ static inline int input_available_p(struct tty_struct *tty, int poll)
  * @kbp: data
  * @nr: size of data
  *
- *	Helper function to speed up n_tty_read.  It is only called when
+ * Helper function to speed up n_tty_read(). It is only called when %ICANON is
- *	ICANON is off; it copies characters straight from the tty queue.
+ * off; it copies characters straight from the tty queue.
  *
- *	Called under the ldata->atomic_read_lock sem
+ * Returns: true if it successfully copied data, but there is still more data
+ * to be had.
  *
- *	Returns true if it successfully copied data, but there is still
+ * Locking:
- *	more data to be had.
+ *  * called under the @ldata->atomic_read_lock sem
- *
+ *  * n_tty_read()/consumer path:
- *	n_tty_read()/consumer path:
+ *		caller holds non-exclusive %termios_rwsem;
- *		caller holds non-exclusive termios_rwsem
  *		read_tail published
  */
-
 static bool copy_from_read_buf(struct tty_struct *tty,
 				      unsigned char **kbp,
 				      size_t *nr)
@@ -1931,23 +1895,22 @@ static bool copy_from_read_buf(struct tty_struct *tty,
  * @kbp: data
  * @nr: size of data
  *
- *	Helper function for n_tty_read.  It is only called when ICANON is on;
+ * Helper function for n_tty_read(). It is only called when %ICANON is on; it
- *	it copies one line of input up to and including the line-delimiting
+ * copies one line of input up to and including the line-delimiting character
- *	character into the result buffer.
+ * into the result buffer.
  *
- *	NB: When termios is changed from non-canonical to canonical mode and
+ * Note: When termios is changed from non-canonical to canonical mode and the
- *	the read buffer contains data, n_tty_set_termios() simulates an EOF
+ * read buffer contains data, n_tty_set_termios() simulates an EOF push (as if
- *	push (as if C-d were input) _without_ the DISABLED_CHAR in the buffer.
+ * C-d were input) _without_ the %DISABLED_CHAR in the buffer. This causes data
- *	This causes data already processed as input to be immediately available
+ * already processed as input to be immediately available as input although a
- *	as input although a newline has not been received.
+ * newline has not been received.
  *
- *	Called under the atomic_read_lock mutex
+ * Locking:
- *
+ *  * called under the %atomic_read_lock mutex
- *	n_tty_read()/consumer path:
+ *  * n_tty_read()/consumer path:
- *		caller holds non-exclusive termios_rwsem
+ *	caller holds non-exclusive %termios_rwsem;
  *	read_tail published
  */
-
 static bool canon_copy_from_read_buf(struct tty_struct *tty,
 				     unsigned char **kbp,
 				     size_t *nr)
@@ -2019,15 +1982,15 @@ static bool canon_copy_from_read_buf(struct tty_struct *tty,
  * @tty: tty
  * @file: file handle
  *
- *	Perform job control management checks on this file/tty descriptor
+ * Perform job control management checks on this @file/@tty descriptor and if
- *	and if appropriate send any needed signals and return a negative
+ * appropriate send any needed signals and return a negative error code if
- *	error code if action should be taken.
+ * action should be taken.
  *
- *	Locking: redirected write test is safe
+ * Locking:
- *		 current->signal->tty check is safe
+ *  * redirected write test is safe
- *		 ctrl.lock to safely reference tty->ctrl.pgrp
+ *  * current->signal->tty check is safe
+ *  * ctrl.lock to safely reference @tty->ctrl.pgrp
  */
-
 static int job_control(struct tty_struct *tty, struct file *file)
 {
 	/* Job control check -- must be done at start and after
@@ -2046,21 +2009,22 @@ static int job_control(struct tty_struct *tty, struct file *file)
  * n_tty_read		-	read function for tty
  * @tty: tty device
  * @file: file object
- *	@buf: userspace buffer pointer
+ * @kbuf: kernelspace buffer pointer
  * @nr: size of I/O
+ * @cookie: if non-%NULL, this is a continuation read
+ * @offset: where to continue reading from (unused in n_tty)
  *
- *	Perform reads for the line discipline. We are guaranteed that the
+ * Perform reads for the line discipline. We are guaranteed that the line
- *	line discipline will not be closed under us but we may get multiple
+ * discipline will not be closed under us but we may get multiple parallel
- *	parallel readers and must handle this ourselves. We may also get
+ * readers and must handle this ourselves. We may also get a hangup. Always
- *	a hangup. Always called in user context, may sleep.
+ * called in user context, may sleep.
  *
  * This code must be sure never to sleep through a hangup.
  *
- *	n_tty_read()/consumer path:
+ * Locking: n_tty_read()/consumer path:
- *		claims non-exclusive termios_rwsem
+ *	claims non-exclusive termios_rwsem;
  *	publishes read_tail
  */
-
 static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
 			  unsigned char *kbuf, size_t nr,
 			  void **cookie, unsigned long offset)
@@ -2238,19 +2202,17 @@ more_to_be_read:
  * @buf: userspace buffer pointer
  * @nr: size of I/O
  *
- *	Write function of the terminal device.  This is serialized with
+ * Write function of the terminal device. This is serialized with respect to
- *	respect to other write callers but not to termios changes, reads
+ * other write callers but not to termios changes, reads and other such events.
- *	and other such events.  Since the receive code will echo characters,
+ * Since the receive code will echo characters, thus calling driver write
- *	thus calling driver write methods, the output_lock is used in
+ * methods, the %output_lock is used in the output processing functions called
- *	the output processing functions called here as well as in the
+ * here as well as in the echo processing function to protect the column state
- *	echo processing function to protect the column state and space
+ * and space left in the buffer.
- *	left in the buffer.
  *
  * This code must be sure never to sleep through a hangup.
  *
  * Locking: output_lock to protect column state and space left
- *		 (note that the process_output*() functions take this
+ *	 (note that the process_output*() functions take this lock themselves)
- *		  lock themselves)
  */
 
 static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
@@ -2346,14 +2308,14 @@ break_out:
  * @file: file accessing it
  * @wait: poll table
  *
- *	Called when the line discipline is asked to poll() for data or
+ * Called when the line discipline is asked to poll() for data or for special
- *	for special events. This code is not serialized with respect to
+ * events. This code is not serialized with respect to other events save
- *	other events save open/close.
+ * open/close.
  *
  * This code must be sure never to sleep through a hangup.
- *	Called without the kernel lock held - fine
+ *
+ * Locking: called without the kernel lock held -- fine.
  */
-
 static __poll_t n_tty_poll(struct tty_struct *tty, struct file *file,
 							poll_table *wait)
 {
@@ -2400,8 +2362,8 @@ static unsigned long inq_canon(struct n_tty_data *ldata)
 	return nr;
 }
 
-static int n_tty_ioctl(struct tty_struct *tty, struct file *file,
+static int n_tty_ioctl(struct tty_struct *tty, unsigned int cmd,
-		       unsigned int cmd, unsigned long arg)
+		       unsigned long arg)
 {
 	struct n_tty_data *ldata = tty->disc_data;
 	int retval;

drivers/tty/serial/8250/8250.h

@@ -241,16 +241,8 @@ static inline int serial8250_in_MCR(struct uart_8250_port *up)
 	return mctrl;
 }
 
-#if defined(__alpha__) && !defined(CONFIG_PCI)
+bool alpha_jensen(void);
-/*
+void alpha_jensen_set_mctrl(struct uart_port *port, unsigned int mctrl);
- * Digital did something really horribly wrong with the OUT1 and OUT2
- * lines on at least some ALPHA's.  The failure mode is that if either
- * is cleared, the machine locks up with endless interrupts.
- */
-#define ALPHA_KLUDGE_MCR  (UART_MCR_OUT2 | UART_MCR_OUT1)
-#else
-#define ALPHA_KLUDGE_MCR 0
-#endif
 
 #ifdef CONFIG_SERIAL_8250_PNP
 int serial8250_pnp_init(void);

drivers/tty/serial/8250/8250_alpha.c

@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+#include <asm/machvec.h>
+#include "8250.h"
+
+bool alpha_jensen(void)
+{
+	return !strcmp(alpha_mv.vector_name, "Jensen");
+}
+
+void alpha_jensen_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+	/*
+	 * Digital did something really horribly wrong with the OUT1 and OUT2
+	 * lines on Alpha Jensen.  The failure mode is that if either is
+	 * cleared, the machine locks up with endless interrupts.
+	 */
+	mctrl |= TIOCM_OUT1 | TIOCM_OUT2;
+
+	serial8250_do_set_mctrl(port, mctrl);
+}

drivers/tty/serial/8250/8250_bcm7271.c

@@ -941,7 +941,7 @@ static int brcmuart_probe(struct platform_device *pdev)
 	struct brcmuart_priv *priv;
 	struct clk *baud_mux_clk;
 	struct uart_8250_port up;
-	struct resource *irq;
+	int irq;
 	void __iomem *membase = NULL;
 	resource_size_t mapbase = 0;
 	u32 clk_rate = 0;
@@ -952,11 +952,9 @@ static int brcmuart_probe(struct platform_device *pdev)
 		"uart", "dma_rx", "dma_tx", "dma_intr2", "dma_arb"
 	};
 
-	irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+	irq = platform_get_irq(pdev, 0);
-	if (!irq) {
+	if (irq < 0)
-		dev_err(dev, "missing irq\n");
+		return irq;
-		return -EINVAL;
-	}
 	priv = devm_kzalloc(dev, sizeof(struct brcmuart_priv),
 			GFP_KERNEL);
 	if (!priv)
@@ -1044,7 +1042,7 @@ static int brcmuart_probe(struct platform_device *pdev)
 	up.port.dev = dev;
 	up.port.mapbase = mapbase;
 	up.port.membase = membase;
-	up.port.irq = irq->start;
+	up.port.irq = irq;
 	up.port.handle_irq = brcmuart_handle_irq;
 	up.port.regshift = 2;
 	up.port.iotype = of_device_is_big_endian(np) ?
@@ -1076,15 +1074,19 @@ static int brcmuart_probe(struct platform_device *pdev)
 		priv->rx_bufs = dma_alloc_coherent(dev,
 						   priv->rx_size,
 						   &priv->rx_addr, GFP_KERNEL);
-		if (!priv->rx_bufs)
+		if (!priv->rx_bufs) {
+			ret = -ENOMEM;
 			goto err;
+		}
 		priv->tx_size = UART_XMIT_SIZE;
 		priv->tx_buf = dma_alloc_coherent(dev,
 						  priv->tx_size,
 						  &priv->tx_addr, GFP_KERNEL);
-		if (!priv->tx_buf)
+		if (!priv->tx_buf) {
+			ret = -ENOMEM;
 			goto err;
 		}
+	}
 
 	ret = serial8250_register_8250_port(&up);
 	if (ret < 0) {
@@ -1097,6 +1099,7 @@ static int brcmuart_probe(struct platform_device *pdev)
 	if (priv->dma_enabled) {
 		dma_irq = platform_get_irq_byname(pdev,  "dma");
 		if (dma_irq < 0) {
+			ret = dma_irq;
 			dev_err(dev, "no IRQ resource info\n");
 			goto err1;
 		}
@@ -1116,7 +1119,7 @@ err1:
 err:
 	brcmuart_free_bufs(dev, priv);
 	brcmuart_arbitration(priv, 0);
-	return -ENODEV;
+	return ret;
 }
 
 static int brcmuart_remove(struct platform_device *pdev)

drivers/tty/serial/8250/8250_core.c

@@ -509,11 +509,10 @@ static void __init serial8250_isa_init_ports(void)
 
 		up->ops = &univ8250_driver_ops;
 
-		/*
+		if (IS_ENABLED(CONFIG_ALPHA_JENSEN) ||
-		 * ALPHA_KLUDGE_MCR needs to be killed.
+		    (IS_ENABLED(CONFIG_ALPHA_GENERIC) && alpha_jensen()))
-		 */
+			port->set_mctrl = alpha_jensen_set_mctrl;
-		up->mcr_mask = ~ALPHA_KLUDGE_MCR;
+
-		up->mcr_force = ALPHA_KLUDGE_MCR;
 		serial8250_set_defaults(up);
 	}
 

drivers/tty/serial/8250/8250_pci.c

@@ -1278,7 +1278,7 @@ static int pci_quatech_init(struct pci_dev *dev)
 			outl(inl(base + 0x38) | 0x00002000, base + 0x38);
 			tmp = inl(base + 0x3c);
 			outl(tmp | 0x01000000, base + 0x3c);
-			outl(tmp &= ~0x01000000, base + 0x3c);
+			outl(tmp & ~0x01000000, base + 0x3c);
 		}
 	}
 	return 0;
@@ -1318,89 +1318,6 @@ static int pci_default_setup(struct serial_private *priv,
 
 	return setup_port(priv, port, bar, offset, board->reg_shift);
 }
-static void
-pericom_do_set_divisor(struct uart_port *port, unsigned int baud,
-			       unsigned int quot, unsigned int quot_frac)
-{
-	int scr;
-	int lcr;
-
-	for (scr = 16; scr > 4; scr--) {
-		unsigned int maxrate = port->uartclk / scr;
-		unsigned int divisor = max(maxrate / baud, 1U);
-		int delta = maxrate / divisor - baud;
-
-		if (baud > maxrate + baud / 50)
-			continue;
-
-		if (delta > baud / 50)
-			divisor++;
-
-		if (divisor > 0xffff)
-			continue;
-
-		/* Update delta due to possible divisor change */
-		delta = maxrate / divisor - baud;
-		if (abs(delta) < baud / 50) {
-			lcr = serial_port_in(port, UART_LCR);
-			serial_port_out(port, UART_LCR, lcr | 0x80);
-			serial_port_out(port, UART_DLL, divisor & 0xff);
-			serial_port_out(port, UART_DLM, divisor >> 8 & 0xff);
-			serial_port_out(port, 2, 16 - scr);
-			serial_port_out(port, UART_LCR, lcr);
-			return;
-		}
-	}
-}
-static int pci_pericom_setup(struct serial_private *priv,
-		  const struct pciserial_board *board,
-		  struct uart_8250_port *port, int idx)
-{
-	unsigned int bar, offset = board->first_offset, maxnr;
-
-	bar = FL_GET_BASE(board->flags);
-	if (board->flags & FL_BASE_BARS)
-		bar += idx;
-	else
-		offset += idx * board->uart_offset;
-
-
-	maxnr = (pci_resource_len(priv->dev, bar) - board->first_offset) >>
-		(board->reg_shift + 3);
-
-	if (board->flags & FL_REGION_SZ_CAP && idx >= maxnr)
-		return 1;
-
-	port->port.set_divisor = pericom_do_set_divisor;
-
-	return setup_port(priv, port, bar, offset, board->reg_shift);
-}
-
-static int pci_pericom_setup_four_at_eight(struct serial_private *priv,
-		  const struct pciserial_board *board,
-		  struct uart_8250_port *port, int idx)
-{
-	unsigned int bar, offset = board->first_offset, maxnr;
-
-	bar = FL_GET_BASE(board->flags);
-	if (board->flags & FL_BASE_BARS)
-		bar += idx;
-	else
-		offset += idx * board->uart_offset;
-
-	if (idx==3)
-		offset = 0x38;
-
-	maxnr = (pci_resource_len(priv->dev, bar) - board->first_offset) >>
-		(board->reg_shift + 3);
-
-	if (board->flags & FL_REGION_SZ_CAP && idx >= maxnr)
-		return 1;
-
-	port->port.set_divisor = pericom_do_set_divisor;
-
-	return setup_port(priv, port, bar, offset, board->reg_shift);
-}
 
 static int
 ce4100_serial_setup(struct serial_private *priv,
@@ -1886,42 +1803,6 @@ pci_moxa_setup(struct serial_private *priv,
 #define PCIE_DEVICE_ID_WCH_CH384_8S	0x3853
 #define PCIE_DEVICE_ID_WCH_CH382_2S	0x3253
 
-#define PCI_VENDOR_ID_ACCESIO			0x494f
-#define PCI_DEVICE_ID_ACCESIO_PCIE_COM_2SDB	0x1051
-#define PCI_DEVICE_ID_ACCESIO_MPCIE_COM_2S	0x1053
-#define PCI_DEVICE_ID_ACCESIO_PCIE_COM_4SDB	0x105C
-#define PCI_DEVICE_ID_ACCESIO_MPCIE_COM_4S	0x105E
-#define PCI_DEVICE_ID_ACCESIO_PCIE_COM232_2DB	0x1091
-#define PCI_DEVICE_ID_ACCESIO_MPCIE_COM232_2	0x1093
-#define PCI_DEVICE_ID_ACCESIO_PCIE_COM232_4DB	0x1099
-#define PCI_DEVICE_ID_ACCESIO_MPCIE_COM232_4	0x109B
-#define PCI_DEVICE_ID_ACCESIO_PCIE_COM_2SMDB	0x10D1
-#define PCI_DEVICE_ID_ACCESIO_MPCIE_COM_2SM	0x10D3
-#define PCI_DEVICE_ID_ACCESIO_PCIE_COM_4SMDB	0x10DA
-#define PCI_DEVICE_ID_ACCESIO_MPCIE_COM_4SM	0x10DC
-#define PCI_DEVICE_ID_ACCESIO_MPCIE_ICM485_1	0x1108
-#define PCI_DEVICE_ID_ACCESIO_MPCIE_ICM422_2	0x1110
-#define PCI_DEVICE_ID_ACCESIO_MPCIE_ICM485_2	0x1111
-#define PCI_DEVICE_ID_ACCESIO_MPCIE_ICM422_4	0x1118
-#define PCI_DEVICE_ID_ACCESIO_MPCIE_ICM485_4	0x1119
-#define PCI_DEVICE_ID_ACCESIO_PCIE_ICM_2S	0x1152
-#define PCI_DEVICE_ID_ACCESIO_PCIE_ICM_4S	0x115A
-#define PCI_DEVICE_ID_ACCESIO_PCIE_ICM232_2	0x1190
-#define PCI_DEVICE_ID_ACCESIO_MPCIE_ICM232_2	0x1191
-#define PCI_DEVICE_ID_ACCESIO_PCIE_ICM232_4	0x1198
-#define PCI_DEVICE_ID_ACCESIO_MPCIE_ICM232_4	0x1199
-#define PCI_DEVICE_ID_ACCESIO_PCIE_ICM_2SM	0x11D0
-#define PCI_DEVICE_ID_ACCESIO_PCIE_COM422_4	0x105A
-#define PCI_DEVICE_ID_ACCESIO_PCIE_COM485_4	0x105B
-#define PCI_DEVICE_ID_ACCESIO_PCIE_COM422_8	0x106A
-#define PCI_DEVICE_ID_ACCESIO_PCIE_COM485_8	0x106B
-#define PCI_DEVICE_ID_ACCESIO_PCIE_COM232_4	0x1098
-#define PCI_DEVICE_ID_ACCESIO_PCIE_COM232_8	0x10A9
-#define PCI_DEVICE_ID_ACCESIO_PCIE_COM_4SM	0x10D9
-#define PCI_DEVICE_ID_ACCESIO_PCIE_COM_8SM	0x10E9
-#define PCI_DEVICE_ID_ACCESIO_PCIE_ICM_4SM	0x11D8
-
-
 #define	PCI_DEVICE_ID_MOXA_CP102E	0x1024
 #define	PCI_DEVICE_ID_MOXA_CP102EL	0x1025
 #define	PCI_DEVICE_ID_MOXA_CP104EL_A	0x1045
@@ -2198,16 +2079,6 @@ static struct pci_serial_quirk pci_serial_quirks[] = {
 		.setup		= pci_default_setup,
 		.exit		= pci_plx9050_exit,
 	},
-	/*
-	 * Pericom (Only 7954 - It have a offset jump for port 4)
-	 */
-	{
-		.vendor		= PCI_VENDOR_ID_PERICOM,
-		.device		= PCI_DEVICE_ID_PERICOM_PI7C9X7954,
-		.subvendor	= PCI_ANY_ID,
-		.subdevice	= PCI_ANY_ID,
-		.setup		= pci_pericom_setup_four_at_eight,
-	},
 	/*
 	 * PLX
 	 */
@@ -2238,125 +2109,7 @@ static struct pci_serial_quirk pci_serial_quirks[] = {
 		.setup		= pci_default_setup,
 		.exit		= pci_plx9050_exit,
 	},
-	{
+	/*
-		.vendor     = PCI_VENDOR_ID_ACCESIO,
-		.device     = PCI_DEVICE_ID_ACCESIO_PCIE_COM_4SDB,
-		.subvendor  = PCI_ANY_ID,
-		.subdevice  = PCI_ANY_ID,
-		.setup      = pci_pericom_setup_four_at_eight,
-	},
-	{
-		.vendor     = PCI_VENDOR_ID_ACCESIO,
-		.device     = PCI_DEVICE_ID_ACCESIO_MPCIE_COM_4S,
-		.subvendor  = PCI_ANY_ID,
-		.subdevice  = PCI_ANY_ID,
-		.setup      = pci_pericom_setup_four_at_eight,
-	},
-	{
-		.vendor     = PCI_VENDOR_ID_ACCESIO,
-		.device     = PCI_DEVICE_ID_ACCESIO_PCIE_COM232_4DB,
-		.subvendor  = PCI_ANY_ID,
-		.subdevice  = PCI_ANY_ID,
-		.setup      = pci_pericom_setup_four_at_eight,
-	},
-	{
-		.vendor     = PCI_VENDOR_ID_ACCESIO,
-		.device     = PCI_DEVICE_ID_ACCESIO_MPCIE_COM232_4,
-		.subvendor  = PCI_ANY_ID,
-		.subdevice  = PCI_ANY_ID,
-		.setup      = pci_pericom_setup_four_at_eight,
-	},
-	{
-		.vendor     = PCI_VENDOR_ID_ACCESIO,
-		.device     = PCI_DEVICE_ID_ACCESIO_PCIE_COM_4SMDB,
-		.subvendor  = PCI_ANY_ID,
-		.subdevice  = PCI_ANY_ID,
-		.setup      = pci_pericom_setup_four_at_eight,
-	},
-	{
-		.vendor     = PCI_VENDOR_ID_ACCESIO,
-		.device     = PCI_DEVICE_ID_ACCESIO_MPCIE_COM_4SM,
-		.subvendor  = PCI_ANY_ID,
-		.subdevice  = PCI_ANY_ID,
-		.setup      = pci_pericom_setup_four_at_eight,
-	},
-	{
-		.vendor     = PCI_VENDOR_ID_ACCESIO,
-		.device     = PCI_DEVICE_ID_ACCESIO_MPCIE_ICM422_4,
-		.subvendor  = PCI_ANY_ID,
-		.subdevice  = PCI_ANY_ID,
-		.setup      = pci_pericom_setup_four_at_eight,
-	},
-	{
-		.vendor     = PCI_VENDOR_ID_ACCESIO,
-		.device     = PCI_DEVICE_ID_ACCESIO_MPCIE_ICM485_4,
-		.subvendor  = PCI_ANY_ID,
-		.subdevice  = PCI_ANY_ID,
-		.setup      = pci_pericom_setup_four_at_eight,
-	},
-	{
-		.vendor     = PCI_VENDOR_ID_ACCESIO,
-		.device     = PCI_DEVICE_ID_ACCESIO_PCIE_ICM232_4,
-		.subvendor  = PCI_ANY_ID,
-		.subdevice  = PCI_ANY_ID,
-		.setup      = pci_pericom_setup_four_at_eight,
-	},
-	{
-		.vendor     = PCI_VENDOR_ID_ACCESIO,
-		.device     = PCI_DEVICE_ID_ACCESIO_PCIE_ICM_4S,
-		.subvendor  = PCI_ANY_ID,
-		.subdevice  = PCI_ANY_ID,
-		.setup      = pci_pericom_setup_four_at_eight,
-	},
-	{
-		.vendor     = PCI_VENDOR_ID_ACCESIO,
-		.device     = PCI_DEVICE_ID_ACCESIO_MPCIE_ICM232_4,
-		.subvendor  = PCI_ANY_ID,
-		.subdevice  = PCI_ANY_ID,
-		.setup      = pci_pericom_setup_four_at_eight,
-	},
-	{
-		.vendor     = PCI_VENDOR_ID_ACCESIO,
-		.device     = PCI_DEVICE_ID_ACCESIO_PCIE_COM422_4,
-		.subvendor  = PCI_ANY_ID,
-		.subdevice  = PCI_ANY_ID,
-		.setup      = pci_pericom_setup_four_at_eight,
-	},
-	{
-		.vendor     = PCI_VENDOR_ID_ACCESIO,
-		.device     = PCI_DEVICE_ID_ACCESIO_PCIE_COM485_4,
-		.subvendor  = PCI_ANY_ID,
-		.subdevice  = PCI_ANY_ID,
-		.setup      = pci_pericom_setup_four_at_eight,
-	},
-	{
-		.vendor     = PCI_VENDOR_ID_ACCESIO,
-		.device     = PCI_DEVICE_ID_ACCESIO_PCIE_COM232_4,
-		.subvendor  = PCI_ANY_ID,
-		.subdevice  = PCI_ANY_ID,
-		.setup      = pci_pericom_setup_four_at_eight,
-	},
-	{
-		.vendor     = PCI_VENDOR_ID_ACCESIO,
-		.device     = PCI_DEVICE_ID_ACCESIO_PCIE_COM_4SM,
-		.subvendor  = PCI_ANY_ID,
-		.subdevice  = PCI_ANY_ID,
-		.setup      = pci_pericom_setup_four_at_eight,
-	},
-	{
-		.vendor     = PCI_VENDOR_ID_ACCESIO,
-		.device     = PCI_DEVICE_ID_ACCESIO_PCIE_ICM_4SM,
-		.subvendor  = PCI_ANY_ID,
-		.subdevice  = PCI_ANY_ID,
-		.setup      = pci_pericom_setup_four_at_eight,
-	},
-	{
-		.vendor     = PCI_VENDOR_ID_ACCESIO,
-		.device     = PCI_ANY_ID,
-		.subvendor  = PCI_ANY_ID,
-		.subdevice  = PCI_ANY_ID,
-		.setup      = pci_pericom_setup,
-	},	/*
 	 * SBS Technologies, Inc., PMC-OCTALPRO 232
 	 */
 	{
@@ -2948,10 +2701,6 @@ enum pci_board_num_t {
 	pbn_wch382_2,
 	pbn_wch384_4,
 	pbn_wch384_8,
-	pbn_pericom_PI7C9X7951,
-	pbn_pericom_PI7C9X7952,
-	pbn_pericom_PI7C9X7954,
-	pbn_pericom_PI7C9X7958,
 	pbn_sunix_pci_1s,
 	pbn_sunix_pci_2s,
 	pbn_sunix_pci_4s,
@@ -3696,33 +3445,6 @@ static struct pciserial_board pci_boards[] = {
 		.uart_offset    = 8,
 		.first_offset   = 0x00,
 	},
-	/*
-	 * Pericom PI7C9X795[1248] Uno/Dual/Quad/Octal UART
-	 */
-	[pbn_pericom_PI7C9X7951] = {
-		.flags          = FL_BASE0,
-		.num_ports      = 1,
-		.base_baud      = 921600,
-		.uart_offset	= 0x8,
-	},
-	[pbn_pericom_PI7C9X7952] = {
-		.flags          = FL_BASE0,
-		.num_ports      = 2,
-		.base_baud      = 921600,
-		.uart_offset	= 0x8,
-	},
-	[pbn_pericom_PI7C9X7954] = {
-		.flags          = FL_BASE0,
-		.num_ports      = 4,
-		.base_baud      = 921600,
-		.uart_offset	= 0x8,
-	},
-	[pbn_pericom_PI7C9X7958] = {
-		.flags          = FL_BASE0,
-		.num_ports      = 8,
-		.base_baud      = 921600,
-		.uart_offset	= 0x8,
-	},
 	[pbn_sunix_pci_1s] = {
 		.num_ports	= 1,
 		.base_baud      = 921600,
@@ -3834,6 +3556,10 @@ static const struct pci_device_id blacklist[] = {
 	{ PCI_VDEVICE(EXAR, PCI_ANY_ID), },
 	{ PCI_VDEVICE(COMMTECH, PCI_ANY_ID), },
 
+	/* Pericom devices */
+	{ PCI_VDEVICE(PERICOM, PCI_ANY_ID), },
+	{ PCI_VDEVICE(ACCESSIO, PCI_ANY_ID), },
+
 	/* End of the black list */
 	{ }
 };
@@ -5027,127 +4753,6 @@ static const struct pci_device_id serial_pci_tbl[] = {
 	{	PCI_VENDOR_ID_DCI, PCI_DEVICE_ID_DCI_PCCOM8,
 		PCI_ANY_ID, PCI_ANY_ID, 0, 0,
 		pbn_b3_8_115200 },
-	/*
-	 * Pericom PI7C9X795[1248] Uno/Dual/Quad/Octal UART
-	 */
-	{   PCI_VENDOR_ID_PERICOM, PCI_DEVICE_ID_PERICOM_PI7C9X7951,
-		PCI_ANY_ID, PCI_ANY_ID,
-		0,
-		0, pbn_pericom_PI7C9X7951 },
-	{   PCI_VENDOR_ID_PERICOM, PCI_DEVICE_ID_PERICOM_PI7C9X7952,
-		PCI_ANY_ID, PCI_ANY_ID,
-		0,
-		0, pbn_pericom_PI7C9X7952 },
-	{   PCI_VENDOR_ID_PERICOM, PCI_DEVICE_ID_PERICOM_PI7C9X7954,
-		PCI_ANY_ID, PCI_ANY_ID,
-		0,
-		0, pbn_pericom_PI7C9X7954 },
-	{   PCI_VENDOR_ID_PERICOM, PCI_DEVICE_ID_PERICOM_PI7C9X7958,
-		PCI_ANY_ID, PCI_ANY_ID,
-		0,
-		0, pbn_pericom_PI7C9X7958 },
-	/*
-	 * ACCES I/O Products quad
-	 */
-	{	PCI_VENDOR_ID_ACCESIO, PCI_DEVICE_ID_ACCESIO_PCIE_COM_2SDB,
-		PCI_ANY_ID, PCI_ANY_ID, 0, 0,
-		pbn_pericom_PI7C9X7952 },
-	{	PCI_VENDOR_ID_ACCESIO, PCI_DEVICE_ID_ACCESIO_MPCIE_COM_2S,
-		PCI_ANY_ID, PCI_ANY_ID, 0, 0,
-		pbn_pericom_PI7C9X7952 },
-	{	PCI_VENDOR_ID_ACCESIO, PCI_DEVICE_ID_ACCESIO_PCIE_COM_4SDB,
-		PCI_ANY_ID, PCI_ANY_ID, 0, 0,
-		pbn_pericom_PI7C9X7954 },
-	{	PCI_VENDOR_ID_ACCESIO, PCI_DEVICE_ID_ACCESIO_MPCIE_COM_4S,
-		PCI_ANY_ID, PCI_ANY_ID, 0, 0,
-		pbn_pericom_PI7C9X7954 },
-	{	PCI_VENDOR_ID_ACCESIO, PCI_DEVICE_ID_ACCESIO_PCIE_COM232_2DB,
-		PCI_ANY_ID, PCI_ANY_ID, 0, 0,
-		pbn_pericom_PI7C9X7952 },
-	{	PCI_VENDOR_ID_ACCESIO, PCI_DEVICE_ID_ACCESIO_MPCIE_COM232_2,
-		PCI_ANY_ID, PCI_ANY_ID, 0, 0,
-		pbn_pericom_PI7C9X7952 },
-	{	PCI_VENDOR_ID_ACCESIO, PCI_DEVICE_ID_ACCESIO_PCIE_COM232_4DB,
-		PCI_ANY_ID, PCI_ANY_ID, 0, 0,
-		pbn_pericom_PI7C9X7954 },
-	{	PCI_VENDOR_ID_ACCESIO, PCI_DEVICE_ID_ACCESIO_MPCIE_COM232_4,
-		PCI_ANY_ID, PCI_ANY_ID, 0, 0,
-		pbn_pericom_PI7C9X7954 },
-	{	PCI_VENDOR_ID_ACCESIO, PCI_DEVICE_ID_ACCESIO_PCIE_COM_2SMDB,
-		PCI_ANY_ID, PCI_ANY_ID, 0, 0,
-		pbn_pericom_PI7C9X7952 },
-	{	PCI_VENDOR_ID_ACCESIO, PCI_DEVICE_ID_ACCESIO_MPCIE_COM_2SM,
-		PCI_ANY_ID, PCI_ANY_ID, 0, 0,
-		pbn_pericom_PI7C9X7952 },
-	{	PCI_VENDOR_ID_ACCESIO, PCI_DEVICE_ID_ACCESIO_PCIE_COM_4SMDB,
-		PCI_ANY_ID, PCI_ANY_ID, 0, 0,
-		pbn_pericom_PI7C9X7954 },
-	{	PCI_VENDOR_ID_ACCESIO, PCI_DEVICE_ID_ACCESIO_MPCIE_COM_4SM,
-		PCI_ANY_ID, PCI_ANY_ID, 0, 0,
-		pbn_pericom_PI7C9X7954 },
-	{	PCI_VENDOR_ID_ACCESIO, PCI_DEVICE_ID_ACCESIO_MPCIE_ICM485_1,
-		PCI_ANY_ID, PCI_ANY_ID, 0, 0,
-		pbn_pericom_PI7C9X7951 },
-	{	PCI_VENDOR_ID_ACCESIO, PCI_DEVICE_ID_ACCESIO_MPCIE_ICM422_2,
-		PCI_ANY_ID, PCI_ANY_ID, 0, 0,
-		pbn_pericom_PI7C9X7952 },
-	{	PCI_VENDOR_ID_ACCESIO, PCI_DEVICE_ID_ACCESIO_MPCIE_ICM485_2,
-		PCI_ANY_ID, PCI_ANY_ID, 0, 0,
-		pbn_pericom_PI7C9X7952 },
-	{	PCI_VENDOR_ID_ACCESIO, PCI_DEVICE_ID_ACCESIO_MPCIE_ICM422_4,
-		PCI_ANY_ID, PCI_ANY_ID, 0, 0,
-		pbn_pericom_PI7C9X7954 },
-	{	PCI_VENDOR_ID_ACCESIO, PCI_DEVICE_ID_ACCESIO_MPCIE_ICM485_4,
-		PCI_ANY_ID, PCI_ANY_ID, 0, 0,
-		pbn_pericom_PI7C9X7954 },
-	{	PCI_VENDOR_ID_ACCESIO, PCI_DEVICE_ID_ACCESIO_PCIE_ICM_2S,
-		PCI_ANY_ID, PCI_ANY_ID, 0, 0,
-		pbn_pericom_PI7C9X7952 },
-	{	PCI_VENDOR_ID_ACCESIO, PCI_DEVICE_ID_ACCESIO_PCIE_ICM_4S,
-		PCI_ANY_ID, PCI_ANY_ID, 0, 0,
-		pbn_pericom_PI7C9X7954 },
-	{	PCI_VENDOR_ID_ACCESIO, PCI_DEVICE_ID_ACCESIO_PCIE_ICM232_2,
-		PCI_ANY_ID, PCI_ANY_ID, 0, 0,
-		pbn_pericom_PI7C9X7952 },
-	{	PCI_VENDOR_ID_ACCESIO, PCI_DEVICE_ID_ACCESIO_MPCIE_ICM232_2,
-		PCI_ANY_ID, PCI_ANY_ID, 0, 0,
-		pbn_pericom_PI7C9X7952 },
-	{	PCI_VENDOR_ID_ACCESIO, PCI_DEVICE_ID_ACCESIO_PCIE_ICM232_4,
-		PCI_ANY_ID, PCI_ANY_ID, 0, 0,
-		pbn_pericom_PI7C9X7954 },
-	{	PCI_VENDOR_ID_ACCESIO, PCI_DEVICE_ID_ACCESIO_MPCIE_ICM232_4,
-		PCI_ANY_ID, PCI_ANY_ID, 0, 0,
-		pbn_pericom_PI7C9X7954 },
-	{	PCI_VENDOR_ID_ACCESIO, PCI_DEVICE_ID_ACCESIO_PCIE_ICM_2SM,
-		PCI_ANY_ID, PCI_ANY_ID, 0, 0,
-		pbn_pericom_PI7C9X7952 },
-	{	PCI_VENDOR_ID_ACCESIO, PCI_DEVICE_ID_ACCESIO_PCIE_COM422_4,
-		PCI_ANY_ID, PCI_ANY_ID, 0, 0,
-		pbn_pericom_PI7C9X7954 },
-	{	PCI_VENDOR_ID_ACCESIO, PCI_DEVICE_ID_ACCESIO_PCIE_COM485_4,
-		PCI_ANY_ID, PCI_ANY_ID, 0, 0,
-		pbn_pericom_PI7C9X7954 },
-	{	PCI_VENDOR_ID_ACCESIO, PCI_DEVICE_ID_ACCESIO_PCIE_COM422_8,
-		PCI_ANY_ID, PCI_ANY_ID, 0, 0,
-		pbn_pericom_PI7C9X7958 },
-	{	PCI_VENDOR_ID_ACCESIO, PCI_DEVICE_ID_ACCESIO_PCIE_COM485_8,
-		PCI_ANY_ID, PCI_ANY_ID, 0, 0,
-		pbn_pericom_PI7C9X7958 },
-	{	PCI_VENDOR_ID_ACCESIO, PCI_DEVICE_ID_ACCESIO_PCIE_COM232_4,
-		PCI_ANY_ID, PCI_ANY_ID, 0, 0,
-		pbn_pericom_PI7C9X7954 },
-	{	PCI_VENDOR_ID_ACCESIO, PCI_DEVICE_ID_ACCESIO_PCIE_COM232_8,
-		PCI_ANY_ID, PCI_ANY_ID, 0, 0,
-		pbn_pericom_PI7C9X7958 },
-	{	PCI_VENDOR_ID_ACCESIO, PCI_DEVICE_ID_ACCESIO_PCIE_COM_4SM,
-		PCI_ANY_ID, PCI_ANY_ID, 0, 0,
-		pbn_pericom_PI7C9X7954 },
-	{	PCI_VENDOR_ID_ACCESIO, PCI_DEVICE_ID_ACCESIO_PCIE_COM_8SM,
-		PCI_ANY_ID, PCI_ANY_ID, 0, 0,
-		pbn_pericom_PI7C9X7958 },
-	{	PCI_VENDOR_ID_ACCESIO, PCI_DEVICE_ID_ACCESIO_PCIE_ICM_4SM,
-		PCI_ANY_ID, PCI_ANY_ID, 0, 0,
-		pbn_pericom_PI7C9X7954 },
 	/*
 	 * Topic TP560 Data/Fax/Voice 56k modem (reported by Evan Clarke)
 	 */

drivers/tty/serial/8250/8250_pericom.c

@@ -0,0 +1,214 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Driver for Pericom UART */
+
+#include <linux/bits.h>
+#include <linux/module.h>
+#include <linux/overflow.h>
+#include <linux/pci.h>
+
+#include "8250.h"
+
+#define PCI_DEVICE_ID_ACCESSIO_PCIE_COM_2SDB	0x1051
+#define PCI_DEVICE_ID_ACCESSIO_MPCIE_COM_2S	0x1053
+#define PCI_DEVICE_ID_ACCESSIO_PCIE_COM422_4	0x105a
+#define PCI_DEVICE_ID_ACCESSIO_PCIE_COM485_4	0x105b
+#define PCI_DEVICE_ID_ACCESSIO_PCIE_COM_4SDB	0x105c
+#define PCI_DEVICE_ID_ACCESSIO_MPCIE_COM_4S	0x105e
+#define PCI_DEVICE_ID_ACCESSIO_PCIE_COM422_8	0x106a
+#define PCI_DEVICE_ID_ACCESSIO_PCIE_COM485_8	0x106b
+#define PCI_DEVICE_ID_ACCESSIO_PCIE_COM232_2DB	0x1091
+#define PCI_DEVICE_ID_ACCESSIO_MPCIE_COM232_2	0x1093
+#define PCI_DEVICE_ID_ACCESSIO_PCIE_COM232_4	0x1098
+#define PCI_DEVICE_ID_ACCESSIO_PCIE_COM232_4DB	0x1099
+#define PCI_DEVICE_ID_ACCESSIO_MPCIE_COM232_4	0x109b
+#define PCI_DEVICE_ID_ACCESSIO_PCIE_COM232_8	0x10a9
+#define PCI_DEVICE_ID_ACCESSIO_PCIE_COM_2SMDB	0x10d1
+#define PCI_DEVICE_ID_ACCESSIO_MPCIE_COM_2SM	0x10d3
+#define PCI_DEVICE_ID_ACCESSIO_PCIE_COM_4SM	0x10d9
+#define PCI_DEVICE_ID_ACCESSIO_PCIE_COM_4SMDB	0x10da
+#define PCI_DEVICE_ID_ACCESSIO_MPCIE_COM_4SM	0x10dc
+#define PCI_DEVICE_ID_ACCESSIO_PCIE_COM_8SM	0x10e9
+#define PCI_DEVICE_ID_ACCESSIO_MPCIE_ICM485_1	0x1108
+#define PCI_DEVICE_ID_ACCESSIO_MPCIE_ICM422_2	0x1110
+#define PCI_DEVICE_ID_ACCESSIO_MPCIE_ICM485_2	0x1111
+#define PCI_DEVICE_ID_ACCESSIO_MPCIE_ICM422_4	0x1118
+#define PCI_DEVICE_ID_ACCESSIO_MPCIE_ICM485_4	0x1119
+#define PCI_DEVICE_ID_ACCESSIO_PCIE_ICM_2S	0x1152
+#define PCI_DEVICE_ID_ACCESSIO_PCIE_ICM_4S	0x115a
+#define PCI_DEVICE_ID_ACCESSIO_PCIE_ICM232_2	0x1190
+#define PCI_DEVICE_ID_ACCESSIO_MPCIE_ICM232_2	0x1191
+#define PCI_DEVICE_ID_ACCESSIO_PCIE_ICM232_4	0x1198
+#define PCI_DEVICE_ID_ACCESSIO_MPCIE_ICM232_4	0x1199
+#define PCI_DEVICE_ID_ACCESSIO_PCIE_ICM_2SM	0x11d0
+#define PCI_DEVICE_ID_ACCESSIO_PCIE_ICM_4SM	0x11d8
+
+struct pericom8250 {
+	void __iomem *virt;
+	unsigned int nr;
+	int line[];
+};
+
+static void pericom_do_set_divisor(struct uart_port *port, unsigned int baud,
+				   unsigned int quot, unsigned int quot_frac)
+{
+	int scr;
+
+	for (scr = 16; scr > 4; scr--) {
+		unsigned int maxrate = port->uartclk / scr;
+		unsigned int divisor = max(maxrate / baud, 1U);
+		int delta = maxrate / divisor - baud;
+
+		if (baud > maxrate + baud / 50)
+			continue;
+
+		if (delta > baud / 50)
+			divisor++;
+
+		if (divisor > 0xffff)
+			continue;
+
+		/* Update delta due to possible divisor change */
+		delta = maxrate / divisor - baud;
+		if (abs(delta) < baud / 50) {
+			struct uart_8250_port *up = up_to_u8250p(port);
+			int lcr = serial_port_in(port, UART_LCR);
+
+			serial_port_out(port, UART_LCR, lcr | 0x80);
+			serial_dl_write(up, divisor);
+			serial_port_out(port, 2, 16 - scr);
+			serial_port_out(port, UART_LCR, lcr);
+			return;
+		}
+	}
+}
+
+static int pericom8250_probe(struct pci_dev *pdev, const struct pci_device_id *id)
+{
+	unsigned int nr, i, bar = 0, maxnr;
+	struct pericom8250 *pericom;
+	struct uart_8250_port uart;
+	int ret;
+
+	ret = pcim_enable_device(pdev);
+	if (ret)
+		return ret;
+
+	maxnr = pci_resource_len(pdev, bar) >> 3;
+
+	if (pdev->vendor == PCI_VENDOR_ID_PERICOM)
+		nr = pdev->device & 0x0f;
+	else if (pdev->vendor == PCI_VENDOR_ID_ACCESSIO)
+		nr = BIT(((pdev->device & 0x38) >> 3) - 1);
+	else
+		nr = 1;
+
+	pericom = devm_kzalloc(&pdev->dev, struct_size(pericom, line, nr), GFP_KERNEL);
+	if (!pericom)
+		return -ENOMEM;
+
+	pericom->virt = pcim_iomap(pdev, bar, 0);
+	if (!pericom->virt)
+		return -ENOMEM;
+
+	memset(&uart, 0, sizeof(uart));
+
+	uart.port.dev = &pdev->dev;
+	uart.port.irq = pdev->irq;
+	uart.port.private_data = pericom;
+	uart.port.iotype = UPIO_PORT;
+	uart.port.uartclk = 921600 * 16;
+	uart.port.flags = UPF_SKIP_TEST | UPF_BOOT_AUTOCONF | UPF_SHARE_IRQ | UPF_MAGIC_MULTIPLIER;
+	uart.port.set_divisor = pericom_do_set_divisor;
+	for (i = 0; i < nr && i < maxnr; i++) {
+		unsigned int offset = (i == 3 && nr == 4) ? 0x38 : i * 0x8;
+
+		uart.port.iobase = pci_resource_start(pdev, bar) + offset;
+
+		dev_dbg(&pdev->dev, "Setup PCI port: port %lx, irq %d, type %d\n",
+			uart.port.iobase, uart.port.irq, uart.port.iotype);
+
+		pericom->line[i] = serial8250_register_8250_port(&uart);
+		if (pericom->line[i] < 0) {
+			dev_err(&pdev->dev,
+				"Couldn't register serial port %lx, irq %d, type %d, error %d\n",
+				uart.port.iobase, uart.port.irq,
+				uart.port.iotype, pericom->line[i]);
+			break;
+		}
+	}
+	pericom->nr = i;
+
+	pci_set_drvdata(pdev, pericom);
+	return 0;
+}
+
+static void pericom8250_remove(struct pci_dev *pdev)
+{
+	struct pericom8250 *pericom = pci_get_drvdata(pdev);
+	unsigned int i;
+
+	for (i = 0; i < pericom->nr; i++)
+		serial8250_unregister_port(pericom->line[i]);
+}
+
+static const struct pci_device_id pericom8250_pci_ids[] = {
+	/*
+	 * Pericom PI7C9X795[1248] Uno/Dual/Quad/Octal UART
+	 * (Only 7954 has an offset jump for port 4)
+	 */
+	{ PCI_VDEVICE(PERICOM, PCI_DEVICE_ID_PERICOM_PI7C9X7951) },
+	{ PCI_VDEVICE(PERICOM, PCI_DEVICE_ID_PERICOM_PI7C9X7952) },
+	{ PCI_VDEVICE(PERICOM, PCI_DEVICE_ID_PERICOM_PI7C9X7954) },
+	{ PCI_VDEVICE(PERICOM, PCI_DEVICE_ID_PERICOM_PI7C9X7958) },
+
+	/*
+	 * ACCES I/O Products quad
+	 * (Only 7954 has an offset jump for port 4)
+	 */
+	{ PCI_VDEVICE(ACCESSIO, PCI_DEVICE_ID_ACCESSIO_PCIE_COM_2SDB) },
+	{ PCI_VDEVICE(ACCESSIO, PCI_DEVICE_ID_ACCESSIO_MPCIE_COM_2S) },
+	{ PCI_VDEVICE(ACCESSIO, PCI_DEVICE_ID_ACCESSIO_PCIE_COM422_4) },
+	{ PCI_VDEVICE(ACCESSIO, PCI_DEVICE_ID_ACCESSIO_PCIE_COM485_4) },
+	{ PCI_VDEVICE(ACCESSIO, PCI_DEVICE_ID_ACCESSIO_PCIE_COM_4SDB) },
+	{ PCI_VDEVICE(ACCESSIO, PCI_DEVICE_ID_ACCESSIO_MPCIE_COM_4S) },
+	{ PCI_VDEVICE(ACCESSIO, PCI_DEVICE_ID_ACCESSIO_PCIE_COM422_8) },
+	{ PCI_VDEVICE(ACCESSIO, PCI_DEVICE_ID_ACCESSIO_PCIE_COM485_8) },
+	{ PCI_VDEVICE(ACCESSIO, PCI_DEVICE_ID_ACCESSIO_PCIE_COM232_2DB) },
+	{ PCI_VDEVICE(ACCESSIO, PCI_DEVICE_ID_ACCESSIO_MPCIE_COM232_2) },
+	{ PCI_VDEVICE(ACCESSIO, PCI_DEVICE_ID_ACCESSIO_PCIE_COM232_4) },
+	{ PCI_VDEVICE(ACCESSIO, PCI_DEVICE_ID_ACCESSIO_PCIE_COM232_4DB) },
+	{ PCI_VDEVICE(ACCESSIO, PCI_DEVICE_ID_ACCESSIO_MPCIE_COM232_4) },
+	{ PCI_VDEVICE(ACCESSIO, PCI_DEVICE_ID_ACCESSIO_PCIE_COM232_8) },
+	{ PCI_VDEVICE(ACCESSIO, PCI_DEVICE_ID_ACCESSIO_PCIE_COM_2SMDB) },
+	{ PCI_VDEVICE(ACCESSIO, PCI_DEVICE_ID_ACCESSIO_MPCIE_COM_2SM) },
+	{ PCI_VDEVICE(ACCESSIO, PCI_DEVICE_ID_ACCESSIO_PCIE_COM_4SM) },
+	{ PCI_VDEVICE(ACCESSIO, PCI_DEVICE_ID_ACCESSIO_PCIE_COM_4SMDB) },
+	{ PCI_VDEVICE(ACCESSIO, PCI_DEVICE_ID_ACCESSIO_MPCIE_COM_4SM) },
+	{ PCI_VDEVICE(ACCESSIO, PCI_DEVICE_ID_ACCESSIO_PCIE_COM_8SM) },
+	{ PCI_VDEVICE(ACCESSIO, PCI_DEVICE_ID_ACCESSIO_MPCIE_ICM485_1) },
+	{ PCI_VDEVICE(ACCESSIO, PCI_DEVICE_ID_ACCESSIO_MPCIE_ICM422_2) },
+	{ PCI_VDEVICE(ACCESSIO, PCI_DEVICE_ID_ACCESSIO_MPCIE_ICM485_2) },
+	{ PCI_VDEVICE(ACCESSIO, PCI_DEVICE_ID_ACCESSIO_MPCIE_ICM422_4) },
+	{ PCI_VDEVICE(ACCESSIO, PCI_DEVICE_ID_ACCESSIO_MPCIE_ICM485_4) },
+	{ PCI_VDEVICE(ACCESSIO, PCI_DEVICE_ID_ACCESSIO_PCIE_ICM_2S) },
+	{ PCI_VDEVICE(ACCESSIO, PCI_DEVICE_ID_ACCESSIO_PCIE_ICM_4S) },
+	{ PCI_VDEVICE(ACCESSIO, PCI_DEVICE_ID_ACCESSIO_PCIE_ICM232_2) },
+	{ PCI_VDEVICE(ACCESSIO, PCI_DEVICE_ID_ACCESSIO_MPCIE_ICM232_2) },
+	{ PCI_VDEVICE(ACCESSIO, PCI_DEVICE_ID_ACCESSIO_PCIE_ICM232_4) },
+	{ PCI_VDEVICE(ACCESSIO, PCI_DEVICE_ID_ACCESSIO_MPCIE_ICM232_4) },
+	{ PCI_VDEVICE(ACCESSIO, PCI_DEVICE_ID_ACCESSIO_PCIE_ICM_2SM) },
+	{ PCI_VDEVICE(ACCESSIO, PCI_DEVICE_ID_ACCESSIO_PCIE_ICM_4SM) },
+	{ }
+};
+MODULE_DEVICE_TABLE(pci, pericom8250_pci_ids);
+
+static struct pci_driver pericom8250_pci_driver = {
+	.name           = "8250_pericom",
+	.id_table       = pericom8250_pci_ids,
+	.probe          = pericom8250_probe,
+	.remove         = pericom8250_remove,
+};
+module_pci_driver(pericom8250_pci_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Pericom UART driver");

drivers/tty/serial/8250/8250_port.c

@@ -2026,7 +2026,7 @@ void serial8250_do_set_mctrl(struct uart_port *port, unsigned int mctrl)
 
 	mcr = serial8250_TIOCM_to_MCR(mctrl);
 
-	mcr = (mcr & up->mcr_mask) | up->mcr_force | up->mcr;
+	mcr |= up->mcr;
 
 	serial8250_out_MCR(up, mcr);
 }
@@ -2056,10 +2056,7 @@ static void serial8250_break_ctl(struct uart_port *port, int break_state)
 	serial8250_rpm_put(up);
 }
 
-/*
+static void wait_for_lsr(struct uart_8250_port *up, int bits)
- *	Wait for transmitter & holding register to empty
- */
-static void wait_for_xmitr(struct uart_8250_port *up, int bits)
 {
 	unsigned int status, tmout = 10000;
 
@@ -2076,6 +2073,16 @@ static void wait_for_xmitr(struct uart_8250_port *up, int bits)
 		udelay(1);
 		touch_nmi_watchdog();
 	}
+}
+
+/*
+ *	Wait for transmitter & holding register to empty
+ */
+static void wait_for_xmitr(struct uart_8250_port *up, int bits)
+{
+	unsigned int tmout;
+
+	wait_for_lsr(up, bits);
 
 	/* Wait up to 1s for flow control if necessary */
 	if (up->port.flags & UPF_CONS_FLOW) {
@@ -3092,7 +3099,7 @@ static ssize_t rx_trig_bytes_show(struct device *dev,
 	if (rxtrig_bytes < 0)
 		return rxtrig_bytes;
 
-	return snprintf(buf, PAGE_SIZE, "%d\n", rxtrig_bytes);
+	return sysfs_emit(buf, "%d\n", rxtrig_bytes);
 }
 
 static int do_set_rxtrig(struct tty_port *port, unsigned char bytes)
@@ -3325,6 +3332,35 @@ static void serial8250_console_restore(struct uart_8250_port *up)
 	serial8250_out_MCR(up, UART_MCR_DTR | UART_MCR_RTS);
 }
 
+/*
+ * Print a string to the serial port using the device FIFO
+ *
+ * It sends fifosize bytes and then waits for the fifo
+ * to get empty.
+ */
+static void serial8250_console_fifo_write(struct uart_8250_port *up,
+					  const char *s, unsigned int count)
+{
+	int i;
+	const char *end = s + count;
+	unsigned int fifosize = up->port.fifosize;
+	bool cr_sent = false;
+
+	while (s != end) {
+		wait_for_lsr(up, UART_LSR_THRE);
+
+		for (i = 0; i < fifosize && s != end; ++i) {
+			if (*s == '\n' && !cr_sent) {
+				serial_out(up, UART_TX, '\r');
+				cr_sent = true;
+			} else {
+				serial_out(up, UART_TX, *s++);
+				cr_sent = false;
+			}
+		}
+	}
+}
+
 /*
  *	Print a string to the serial port trying not to disturb
  *	any possible real use of the port...
@@ -3340,7 +3376,7 @@ void serial8250_console_write(struct uart_8250_port *up, const char *s,
 	struct uart_8250_em485 *em485 = up->em485;
 	struct uart_port *port = &up->port;
 	unsigned long flags;
-	unsigned int ier;
+	unsigned int ier, use_fifo;
 	int locked = 1;
 
 	touch_nmi_watchdog();
@@ -3372,6 +3408,19 @@ void serial8250_console_write(struct uart_8250_port *up, const char *s,
 		mdelay(port->rs485.delay_rts_before_send);
 	}
 
+	use_fifo = (up->capabilities & UART_CAP_FIFO) &&
+		port->fifosize > 1 &&
+		(serial_port_in(port, UART_FCR) & UART_FCR_ENABLE_FIFO) &&
+		/*
+		 * After we put a data in the fifo, the controller will send
+		 * it regardless of the CTS state. Therefore, only use fifo
+		 * if we don't use control flow.
+		 */
+		!(up->port.flags & UPF_CONS_FLOW);
+
+	if (likely(use_fifo))
+		serial8250_console_fifo_write(up, s, count);
+	else
 		uart_console_write(port, s, count, serial8250_console_putchar);
 
 	/*

drivers/tty/serial/8250/Kconfig

@@ -498,6 +498,14 @@ config SERIAL_8250_MID
 	  present on the UART found on Intel Medfield SOC and various other
 	  Intel platforms.
 
+config SERIAL_8250_PERICOM
+	tristate "Support for Pericom and Acces I/O serial ports"
+	default SERIAL_8250
+	depends on SERIAL_8250 && PCI
+	help
+	  Selecting this option will enable handling of the extra features
+	  present on the Pericom and Acces I/O UARTs.
+
 config SERIAL_8250_PXA
 	tristate "PXA serial port support"
 	depends on SERIAL_8250

drivers/tty/serial/8250/Makefile

@@ -5,6 +5,8 @@
 
 obj-$(CONFIG_SERIAL_8250)		+= 8250.o 8250_base.o
 8250-y					:= 8250_core.o
+8250-$(CONFIG_ALPHA_GENERIC)		+= 8250_alpha.o
+8250-$(CONFIG_ALPHA_JENSEN)		+= 8250_alpha.o
 8250-$(CONFIG_SERIAL_8250_PNP)		+= 8250_pnp.o
 8250_base-y				:= 8250_port.o
 8250_base-$(CONFIG_SERIAL_8250_DMA)	+= 8250_dma.o
@@ -36,6 +38,7 @@ obj-$(CONFIG_SERIAL_8250_UNIPHIER)	+= 8250_uniphier.o
 obj-$(CONFIG_SERIAL_8250_INGENIC)	+= 8250_ingenic.o
 obj-$(CONFIG_SERIAL_8250_LPSS)		+= 8250_lpss.o
 obj-$(CONFIG_SERIAL_8250_MID)		+= 8250_mid.o
+obj-$(CONFIG_SERIAL_8250_PERICOM)	+= 8250_pericom.o
 obj-$(CONFIG_SERIAL_8250_PXA)		+= 8250_pxa.o
 obj-$(CONFIG_SERIAL_8250_TEGRA)		+= 8250_tegra.o
 obj-$(CONFIG_SERIAL_8250_BCM7271)	+= 8250_bcm7271.o

drivers/tty/serial/Kconfig

@@ -263,7 +263,7 @@ config SERIAL_SAMSUNG_UARTS
 
 config SERIAL_SAMSUNG_CONSOLE
 	bool "Support for console on Samsung SoC serial port"
-	depends on SERIAL_SAMSUNG=y
+	depends on SERIAL_SAMSUNG
 	select SERIAL_CORE_CONSOLE
 	select SERIAL_EARLYCON
 	help

drivers/tty/serial/altera_jtaguart.c

@@ -418,8 +418,9 @@ static int altera_jtaguart_probe(struct platform_device *pdev)
 	struct altera_jtaguart_platform_uart *platp =
 			dev_get_platdata(&pdev->dev);
 	struct uart_port *port;
-	struct resource *res_irq, *res_mem;
+	struct resource *res_mem;
 	int i = pdev->id;
+	int irq;
 
 	/* -1 emphasizes that the platform must have one port, no .N suffix */
 	if (i == -1)
@@ -438,9 +439,11 @@ static int altera_jtaguart_probe(struct platform_device *pdev)
 	else
 		return -ENODEV;
 
-	res_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+	irq = platform_get_irq_optional(pdev, 0);
-	if (res_irq)
+	if (irq < 0 && irq != -ENXIO)
-		port->irq = res_irq->start;
+		return irq;
+	if (irq > 0)
+		port->irq = irq;
 	else if (platp)
 		port->irq = platp->irq;
 	else

drivers/tty/serial/altera_uart.c

@@ -553,7 +553,6 @@ static int altera_uart_probe(struct platform_device *pdev)
 	struct altera_uart_platform_uart *platp = dev_get_platdata(&pdev->dev);
 	struct uart_port *port;
 	struct resource *res_mem;
-	struct resource *res_irq;
 	int i = pdev->id;
 	int ret;
 
@@ -577,9 +576,11 @@ static int altera_uart_probe(struct platform_device *pdev)
 	else
 		return -EINVAL;
 
-	res_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+	ret = platform_get_irq_optional(pdev, 0);
-	if (res_irq)
+	if (ret < 0 && ret != -ENXIO)
-		port->irq = res_irq->start;
+		return ret;
+	if (ret > 0)
+		port->irq = ret;
 	else if (platp)
 		port->irq = platp->irq;
 

drivers/tty/serial/amba-pl010.c

@@ -446,14 +446,11 @@ pl010_set_termios(struct uart_port *port, struct ktermios *termios,
 	if ((termios->c_cflag & CREAD) == 0)
 		uap->port.ignore_status_mask |= UART_DUMMY_RSR_RX;
 
-	/* first, disable everything */
 	old_cr = readb(uap->port.membase + UART010_CR) & ~UART010_CR_MSIE;
 
 	if (UART_ENABLE_MS(port, termios->c_cflag))
 		old_cr |= UART010_CR_MSIE;
 
-	writel(0, uap->port.membase + UART010_CR);
-
 	/* Set baud rate */
 	quot -= 1;
 	writel((quot & 0xf00) >> 8, uap->port.membase + UART010_LCRM);

drivers/tty/serial/amba-pl011.c

@@ -188,38 +188,6 @@ static struct vendor_data vendor_st = {
 	.get_fifosize		= get_fifosize_st,
 };
 
-static const u16 pl011_zte_offsets[REG_ARRAY_SIZE] = {
-	[REG_DR] = ZX_UART011_DR,
-	[REG_FR] = ZX_UART011_FR,
-	[REG_LCRH_RX] = ZX_UART011_LCRH,
-	[REG_LCRH_TX] = ZX_UART011_LCRH,
-	[REG_IBRD] = ZX_UART011_IBRD,
-	[REG_FBRD] = ZX_UART011_FBRD,
-	[REG_CR] = ZX_UART011_CR,
-	[REG_IFLS] = ZX_UART011_IFLS,
-	[REG_IMSC] = ZX_UART011_IMSC,
-	[REG_RIS] = ZX_UART011_RIS,
-	[REG_MIS] = ZX_UART011_MIS,
-	[REG_ICR] = ZX_UART011_ICR,
-	[REG_DMACR] = ZX_UART011_DMACR,
-};
-
-static unsigned int get_fifosize_zte(struct amba_device *dev)
-{
-	return 16;
-}
-
-static struct vendor_data vendor_zte = {
-	.reg_offset		= pl011_zte_offsets,
-	.access_32b		= true,
-	.ifls			= UART011_IFLS_RX4_8|UART011_IFLS_TX4_8,
-	.fr_busy		= ZX_UART01x_FR_BUSY,
-	.fr_dsr			= ZX_UART01x_FR_DSR,
-	.fr_cts			= ZX_UART01x_FR_CTS,
-	.fr_ri			= ZX_UART011_FR_RI,
-	.get_fifosize		= get_fifosize_zte,
-};
-
 /* Deals with DMA transactions */
 
 struct pl011_sgbuf {
@@ -262,7 +230,6 @@ struct uart_amba_port {
 	unsigned int		im;		/* interrupt mask */
 	unsigned int		old_status;
 	unsigned int		fifosize;	/* vendor-specific */
-	unsigned int		old_cr;		/* state during shutdown */
 	unsigned int		fixed_baud;	/* vendor-set fixed baud rate */
 	char			type[12];
 	bool			rs485_tx_started;
@@ -1837,8 +1804,8 @@ static int pl011_startup(struct uart_port *port)
 
 	spin_lock_irq(&uap->port.lock);
 
-	/* restore RTS and DTR */
+	cr = pl011_read(uap, REG_CR);
-	cr = uap->old_cr & (UART011_CR_RTS | UART011_CR_DTR);
+	cr &= UART011_CR_RTS | UART011_CR_DTR;
 	cr |= UART01x_CR_UARTEN | UART011_CR_RXE;
 
 	if (port->rs485.flags & SER_RS485_ENABLED) {
@@ -1915,7 +1882,6 @@ static void pl011_disable_uart(struct uart_amba_port *uap)
 	uap->port.status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS);
 	spin_lock_irq(&uap->port.lock);
 	cr = pl011_read(uap, REG_CR);
-	uap->old_cr = cr;
 	cr &= UART011_CR_RTS | UART011_CR_DTR;
 	cr |= UART01x_CR_UARTEN | UART011_CR_TXE;
 	pl011_write(cr, uap, REG_CR);
@@ -2105,9 +2071,7 @@ pl011_set_termios(struct uart_port *port, struct ktermios *termios,
 	if (port->rs485.flags & SER_RS485_ENABLED)
 		termios->c_cflag &= ~CRTSCTS;
 
-	/* first, disable everything */
 	old_cr = pl011_read(uap, REG_CR);
-	pl011_write(0, uap, REG_CR);
 
 	if (termios->c_cflag & CRTSCTS) {
 		if (old_cr & UART011_CR_RTS)
@@ -2183,32 +2147,13 @@ static const char *pl011_type(struct uart_port *port)
 	return uap->port.type == PORT_AMBA ? uap->type : NULL;
 }
 
-/*
- * Release the memory region(s) being used by 'port'
- */
-static void pl011_release_port(struct uart_port *port)
-{
-	release_mem_region(port->mapbase, SZ_4K);
-}
-
-/*
- * Request the memory region(s) being used by 'port'
- */
-static int pl011_request_port(struct uart_port *port)
-{
-	return request_mem_region(port->mapbase, SZ_4K, "uart-pl011")
-			!= NULL ? 0 : -EBUSY;
-}
-
 /*
  * Configure/autoconfigure the port.
  */
 static void pl011_config_port(struct uart_port *port, int flags)
 {
-	if (flags & UART_CONFIG_TYPE) {
+	if (flags & UART_CONFIG_TYPE)
 		port->type = PORT_AMBA;
-		pl011_request_port(port);
-	}
 }
 
 /*
@@ -2223,6 +2168,8 @@ static int pl011_verify_port(struct uart_port *port, struct serial_struct *ser)
 		ret = -EINVAL;
 	if (ser->baud_base < 9600)
 		ret = -EINVAL;
+	if (port->mapbase != (unsigned long) ser->iomem_base)
+		ret = -EINVAL;
 	return ret;
 }
 
@@ -2275,8 +2222,6 @@ static const struct uart_ops amba_pl011_pops = {
 	.flush_buffer	= pl011_dma_flush_buffer,
 	.set_termios	= pl011_set_termios,
 	.type		= pl011_type,
-	.release_port	= pl011_release_port,
-	.request_port	= pl011_request_port,
 	.config_port	= pl011_config_port,
 	.verify_port	= pl011_verify_port,
 #ifdef CONFIG_CONSOLE_POLL
@@ -2306,8 +2251,6 @@ static const struct uart_ops sbsa_uart_pops = {
 	.shutdown	= sbsa_uart_shutdown,
 	.set_termios	= sbsa_uart_set_termios,
 	.type		= pl011_type,
-	.release_port	= pl011_release_port,
-	.request_port	= pl011_request_port,
 	.config_port	= pl011_config_port,
 	.verify_port	= pl011_verify_port,
 #ifdef CONFIG_CONSOLE_POLL
@@ -2754,7 +2697,6 @@ static int pl011_setup_port(struct device *dev, struct uart_amba_port *uap,
 
 	index = pl011_probe_dt_alias(index, dev);
 
-	uap->old_cr = 0;
 	uap->port.dev = dev;
 	uap->port.mapbase = mmiobase->start;
 	uap->port.membase = base;
@@ -2975,11 +2917,6 @@ static const struct amba_id pl011_ids[] = {
 		.mask	= 0x00ffffff,
 		.data	= &vendor_st,
 	},
-	{
-		.id	= AMBA_LINUX_ID(0x00, 0x1, 0xffe),
-		.mask	= 0x00ffffff,
-		.data	= &vendor_zte,
-	},
 	{ 0, 0 },
 };
 

drivers/tty/serial/ar933x_uart.c

@@ -707,11 +707,11 @@ static int ar933x_uart_probe(struct platform_device *pdev)
 	struct ar933x_uart_port *up;
 	struct uart_port *port;
 	struct resource *mem_res;
-	struct resource *irq_res;
 	struct device_node *np;
 	unsigned int baud;
 	int id;
 	int ret;
+	int irq;
 
 	np = pdev->dev.of_node;
 	if (IS_ENABLED(CONFIG_OF) && np) {
@@ -730,11 +730,9 @@ static int ar933x_uart_probe(struct platform_device *pdev)
 	if (id >= CONFIG_SERIAL_AR933X_NR_UARTS)
 		return -EINVAL;
 
-	irq_res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+	irq = platform_get_irq(pdev, 0);
-	if (!irq_res) {
+	if (irq < 0)
-		dev_err(&pdev->dev, "no IRQ resource\n");
+		return irq;
-		return -EINVAL;
-	}
 
 	up = devm_kzalloc(&pdev->dev, sizeof(struct ar933x_uart_port),
 			  GFP_KERNEL);
@@ -766,7 +764,7 @@ static int ar933x_uart_probe(struct platform_device *pdev)
 
 	port->mapbase = mem_res->start;
 	port->line = id;
-	port->irq = irq_res->start;
+	port->irq = irq;
 	port->dev = &pdev->dev;
 	port->type = PORT_AR933X;
 	port->iotype = UPIO_MEM32;

drivers/tty/serial/atmel_serial.c

@@ -1004,6 +1004,13 @@ static void atmel_tx_dma(struct uart_port *port)
 		desc->callback = atmel_complete_tx_dma;
 		desc->callback_param = atmel_port;
 		atmel_port->cookie_tx = dmaengine_submit(desc);
+		if (dma_submit_error(atmel_port->cookie_tx)) {
+			dev_err(port->dev, "dma_submit_error %d\n",
+				atmel_port->cookie_tx);
+			return;
+		}
+
+		dma_async_issue_pending(chan);
 	}
 
 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
@@ -1258,6 +1265,13 @@ static int atmel_prepare_rx_dma(struct uart_port *port)
 	desc->callback_param = port;
 	atmel_port->desc_rx = desc;
 	atmel_port->cookie_rx = dmaengine_submit(desc);
+	if (dma_submit_error(atmel_port->cookie_rx)) {
+		dev_err(port->dev, "dma_submit_error %d\n",
+			atmel_port->cookie_rx);
+		goto chan_err;
+	}
+
+	dma_async_issue_pending(atmel_port->chan_rx);
 
 	return 0;
 
@@ -2479,7 +2493,7 @@ static int atmel_init_port(struct atmel_uart_port *atmel_port,
 	port->fifosize		= 1;
 	port->dev		= &pdev->dev;
 	port->mapbase		= mpdev->resource[0].start;
-	port->irq		= mpdev->resource[1].start;
+	port->irq		= platform_get_irq(mpdev, 0);
 	port->rs485_config	= atmel_config_rs485;
 	port->iso7816_config	= atmel_config_iso7816;
 	port->membase		= NULL;

drivers/tty/serial/bcm63xx_uart.c

@@ -804,7 +804,7 @@ static struct uart_driver bcm_uart_driver = {
  */
 static int bcm_uart_probe(struct platform_device *pdev)
 {
-	struct resource *res_mem, *res_irq;
+	struct resource *res_mem;
 	struct uart_port *port;
 	struct clk *clk;
 	int ret;
@@ -833,9 +833,10 @@ static int bcm_uart_probe(struct platform_device *pdev)
 	if (IS_ERR(port->membase))
 		return PTR_ERR(port->membase);
 
-	res_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+	ret = platform_get_irq(pdev, 0);
-	if (!res_irq)
+	if (ret < 0)
-		return -ENODEV;
+		return ret;
+	port->irq = ret;
 
 	clk = clk_get(&pdev->dev, "refclk");
 	if (IS_ERR(clk) && pdev->dev.of_node)
@@ -845,7 +846,6 @@ static int bcm_uart_probe(struct platform_device *pdev)
 		return -ENODEV;
 
 	port->iotype = UPIO_MEM;
-	port->irq = res_irq->start;
 	port->ops = &bcm_uart_ops;
 	port->flags = UPF_BOOT_AUTOCONF;
 	port->dev = &pdev->dev;

drivers/tty/serial/fsl_lpuart.c

@@ -247,6 +247,7 @@ enum lpuart_type {
 	LS1028A_LPUART,
 	IMX7ULP_LPUART,
 	IMX8QXP_LPUART,
+	IMXRT1050_LPUART,
 };
 
 struct lpuart_port {
@@ -310,6 +311,11 @@ static struct lpuart_soc_data imx8qxp_data = {
 	.iotype = UPIO_MEM32,
 	.reg_off = IMX_REG_OFF,
 };
+static struct lpuart_soc_data imxrt1050_data = {
+	.devtype = IMXRT1050_LPUART,
+	.iotype = UPIO_MEM32,
+	.reg_off = IMX_REG_OFF,
+};
 
 static const struct of_device_id lpuart_dt_ids[] = {
 	{ .compatible = "fsl,vf610-lpuart",	.data = &vf_data, },
@@ -317,6 +323,7 @@ static const struct of_device_id lpuart_dt_ids[] = {
 	{ .compatible = "fsl,ls1028a-lpuart",	.data = &ls1028a_data, },
 	{ .compatible = "fsl,imx7ulp-lpuart",	.data = &imx7ulp_data, },
 	{ .compatible = "fsl,imx8qxp-lpuart",	.data = &imx8qxp_data, },
+	{ .compatible = "fsl,imxrt1050-lpuart",	.data = &imxrt1050_data},
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, lpuart_dt_ids);
@@ -1793,8 +1800,8 @@ static void lpuart_dma_shutdown(struct lpuart_port *sport)
 	}
 
 	if (sport->lpuart_dma_tx_use) {
-		if (wait_event_interruptible(sport->dma_wait,
+		if (wait_event_interruptible_timeout(sport->dma_wait,
-			!sport->dma_tx_in_progress) != false) {
+			!sport->dma_tx_in_progress, msecs_to_jiffies(300)) <= 0) {
 			sport->dma_tx_in_progress = false;
 			dmaengine_terminate_all(sport->dma_tx_chan);
 		}
@@ -2626,6 +2633,7 @@ OF_EARLYCON_DECLARE(lpuart32, "fsl,ls1021a-lpuart", lpuart32_early_console_setup
 OF_EARLYCON_DECLARE(lpuart32, "fsl,ls1028a-lpuart", ls1028a_early_console_setup);
 OF_EARLYCON_DECLARE(lpuart32, "fsl,imx7ulp-lpuart", lpuart32_imx_early_console_setup);
 OF_EARLYCON_DECLARE(lpuart32, "fsl,imx8qxp-lpuart", lpuart32_imx_early_console_setup);
+OF_EARLYCON_DECLARE(lpuart32, "fsl,imxrt1050-lpuart", lpuart32_imx_early_console_setup);
 EARLYCON_DECLARE(lpuart, lpuart_early_console_setup);
 EARLYCON_DECLARE(lpuart32, lpuart32_early_console_setup);
 

drivers/tty/serial/imx.c

@@ -486,18 +486,21 @@ static void imx_uart_stop_tx(struct uart_port *port)
 static void imx_uart_stop_rx(struct uart_port *port)
 {
 	struct imx_port *sport = (struct imx_port *)port;
-	u32 ucr1, ucr2;
+	u32 ucr1, ucr2, ucr4;
 
 	ucr1 = imx_uart_readl(sport, UCR1);
 	ucr2 = imx_uart_readl(sport, UCR2);
+	ucr4 = imx_uart_readl(sport, UCR4);
 
 	if (sport->dma_is_enabled) {
 		ucr1 &= ~(UCR1_RXDMAEN | UCR1_ATDMAEN);
 	} else {
 		ucr1 &= ~UCR1_RRDYEN;
 		ucr2 &= ~UCR2_ATEN;
+		ucr4 &= ~UCR4_OREN;
 	}
 	imx_uart_writel(sport, ucr1, UCR1);
+	imx_uart_writel(sport, ucr4, UCR4);
 
 	ucr2 &= ~UCR2_RXEN;
 	imx_uart_writel(sport, ucr2, UCR2);
@@ -1544,7 +1547,7 @@ static void imx_uart_shutdown(struct uart_port *port)
 	imx_uart_writel(sport, ucr1, UCR1);
 
 	ucr4 = imx_uart_readl(sport, UCR4);
-	ucr4 &= ~(UCR4_OREN | UCR4_TCEN);
+	ucr4 &= ~UCR4_TCEN;
 	imx_uart_writel(sport, ucr4, UCR4);
 
 	spin_unlock_irqrestore(&sport->port.lock, flags);
@@ -2482,10 +2485,12 @@ static void imx_uart_enable_wakeup(struct imx_port *sport, bool on)
 
 	if (sport->have_rtscts) {
 		u32 ucr1 = imx_uart_readl(sport, UCR1);
-		if (on)
+		if (on) {
+			imx_uart_writel(sport, USR1_RTSD, USR1);
 			ucr1 |= UCR1_RTSDEN;
-		else
+		} else {
 			ucr1 &= ~UCR1_RTSDEN;
+		}
 		imx_uart_writel(sport, ucr1, UCR1);
 	}
 }

drivers/tty/serial/lantiq.c

@@ -16,8 +16,6 @@
 #include <linux/ioport.h>
 #include <linux/lantiq.h>
 #include <linux/module.h>
-#include <linux/of_address.h>
-#include <linux/of_irq.h>
 #include <linux/of_platform.h>
 #include <linux/serial.h>
 #include <linux/serial_core.h>
@@ -728,19 +726,23 @@ static struct uart_driver lqasc_reg = {
 static int fetch_irq_lantiq(struct device *dev, struct ltq_uart_port *ltq_port)
 {
 	struct uart_port *port = &ltq_port->port;
-	struct resource irqres[3];
+	struct platform_device *pdev = to_platform_device(dev);
-	int ret;
+	int irq;
 
-	ret = of_irq_to_resource_table(dev->of_node, irqres, 3);
+	irq = platform_get_irq(pdev, 0);
-	if (ret != 3) {
+	if (irq < 0)
-		dev_err(dev,
+		return irq;
-			"failed to get IRQs for serial port\n");
+	ltq_port->tx_irq = irq;
-		return -ENODEV;
+	irq = platform_get_irq(pdev, 1);
-	}
+	if (irq < 0)
-	ltq_port->tx_irq = irqres[0].start;
+		return irq;
-	ltq_port->rx_irq = irqres[1].start;
+	ltq_port->rx_irq = irq;
-	ltq_port->err_irq = irqres[2].start;
+	irq = platform_get_irq(pdev, 2);
-	port->irq = irqres[0].start;
+	if (irq < 0)
+		return irq;
+	ltq_port->err_irq = irq;
+
+	port->irq = ltq_port->tx_irq;
 
 	return 0;
 }
@@ -793,7 +795,7 @@ static int fetch_irq_intel(struct device *dev, struct ltq_uart_port *ltq_port)
 	struct uart_port *port = &ltq_port->port;
 	int ret;
 
-	ret = of_irq_get(dev->of_node, 0);
+	ret = platform_get_irq(to_platform_device(dev), 0);
 	if (ret < 0) {
 		dev_err(dev, "failed to fetch IRQ for serial port\n");
 		return ret;

drivers/tty/serial/liteuart.c

@@ -436,4 +436,4 @@ module_exit(liteuart_exit);
 MODULE_AUTHOR("Antmicro <www.antmicro.com>");
 MODULE_DESCRIPTION("LiteUART serial driver");
 MODULE_LICENSE("GPL v2");
-MODULE_ALIAS("platform: liteuart");
+MODULE_ALIAS("platform:liteuart");

drivers/tty/serial/lpc32xx_hs.c

@@ -341,7 +341,7 @@ static irqreturn_t serial_lpc32xx_interrupt(int irq, void *dev_id)
 		       LPC32XX_HSUART_IIR(port->membase));
 		port->icount.overrun++;
 		tty_insert_flip_char(tport, 0, TTY_OVERRUN);
-		tty_schedule_flip(tport);
+		tty_flip_buffer_push(tport);
 	}
 
 	/* Data received? */

drivers/tty/serial/meson_uart.c

@@ -622,10 +622,7 @@ meson_serial_early_console_setup(struct earlycon_device *device, const char *opt
 	device->con->write = meson_serial_early_console_write;
 	return 0;
 }
-/* Legacy bindings, should be removed when no more used */
+
-OF_EARLYCON_DECLARE(meson, "amlogic,meson-uart",
-		    meson_serial_early_console_setup);
-/* Stable bindings */
 OF_EARLYCON_DECLARE(meson, "amlogic,meson-ao-uart",
 		    meson_serial_early_console_setup);
 
@@ -668,25 +665,6 @@ static inline struct clk *meson_uart_probe_clock(struct device *dev,
 	return clk;
 }
 
-/*
- * This function gets clocks in the legacy non-stable DT bindings.
- * This code will be remove once all the platforms switch to the
- * new DT bindings.
- */
-static int meson_uart_probe_clocks_legacy(struct platform_device *pdev,
-					  struct uart_port *port)
-{
-	struct clk *clk = NULL;
-
-	clk = meson_uart_probe_clock(&pdev->dev, NULL);
-	if (IS_ERR(clk))
-		return PTR_ERR(clk);
-
-	port->uartclk = clk_get_rate(clk);
-
-	return 0;
-}
-
 static int meson_uart_probe_clocks(struct platform_device *pdev,
 				   struct uart_port *port)
 {
@@ -713,10 +691,11 @@ static int meson_uart_probe_clocks(struct platform_device *pdev,
 
 static int meson_uart_probe(struct platform_device *pdev)
 {
-	struct resource *res_mem, *res_irq;
+	struct resource *res_mem;
 	struct uart_port *port;
 	u32 fifosize = 64; /* Default is 64, 128 for EE UART_0 */
 	int ret = 0;
+	int irq;
 
 	if (pdev->dev.of_node)
 		pdev->id = of_alias_get_id(pdev->dev.of_node, "serial");
@@ -739,9 +718,9 @@ static int meson_uart_probe(struct platform_device *pdev)
 	if (!res_mem)
 		return -ENODEV;
 
-	res_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+	irq = platform_get_irq(pdev, 0);
-	if (!res_irq)
+	if (irq < 0)
-		return -ENODEV;
+		return irq;
 
 	of_property_read_u32(pdev->dev.of_node, "fifo-size", &fifosize);
 
@@ -754,19 +733,14 @@ static int meson_uart_probe(struct platform_device *pdev)
 	if (!port)
 		return -ENOMEM;
 
-	/* Use legacy way until all platforms switch to new bindings */
-	if (of_device_is_compatible(pdev->dev.of_node, "amlogic,meson-uart"))
-		ret = meson_uart_probe_clocks_legacy(pdev, port);
-	else
 	ret = meson_uart_probe_clocks(pdev, port);
-
 	if (ret)
 		return ret;
 
 	port->iotype = UPIO_MEM;
 	port->mapbase = res_mem->start;
 	port->mapsize = resource_size(res_mem);
-	port->irq = res_irq->start;
+	port->irq = irq;
 	port->flags = UPF_BOOT_AUTOCONF | UPF_LOW_LATENCY;
 	port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_MESON_CONSOLE);
 	port->dev = &pdev->dev;
@@ -804,9 +778,6 @@ static int meson_uart_remove(struct platform_device *pdev)
 }
 
 static const struct of_device_id meson_uart_dt_match[] = {
-	/* Legacy bindings, should be removed when no more used */
-	{ .compatible = "amlogic,meson-uart" },
-	/* Stable bindings */
 	{ .compatible = "amlogic,meson6-uart" },
 	{ .compatible = "amlogic,meson8-uart" },
 	{ .compatible = "amlogic,meson8b-uart" },

drivers/tty/serial/pmac_zilog.c

@@ -1702,17 +1702,21 @@ extern struct platform_device scc_a_pdev, scc_b_pdev;
 
 static int __init pmz_init_port(struct uart_pmac_port *uap)
 {
-	struct resource *r_ports, *r_irq;
+	struct resource *r_ports;
+	int irq;
 
 	r_ports = platform_get_resource(uap->pdev, IORESOURCE_MEM, 0);
-	r_irq = platform_get_resource(uap->pdev, IORESOURCE_IRQ, 0);
+	if (!r_ports)
-	if (!r_ports || !r_irq)
 		return -ENODEV;
 
+	irq = platform_get_irq(uap->pdev, 0);
+	if (irq < 0)
+		return irq;
+
 	uap->port.mapbase  = r_ports->start;
 	uap->port.membase  = (unsigned char __iomem *) r_ports->start;
 	uap->port.iotype   = UPIO_MEM;
-	uap->port.irq      = r_irq->start;
+	uap->port.irq      = irq;
 	uap->port.uartclk  = ZS_CLOCK;
 	uap->port.fifosize = 1;
 	uap->port.ops      = &pmz_pops;

drivers/tty/serial/pxa.c

@@ -842,14 +842,18 @@ static int serial_pxa_probe_dt(struct platform_device *pdev,
 static int serial_pxa_probe(struct platform_device *dev)
 {
 	struct uart_pxa_port *sport;
-	struct resource *mmres, *irqres;
+	struct resource *mmres;
 	int ret;
+	int irq;
 
 	mmres = platform_get_resource(dev, IORESOURCE_MEM, 0);
-	irqres = platform_get_resource(dev, IORESOURCE_IRQ, 0);
+	if (!mmres)
-	if (!mmres || !irqres)
 		return -ENODEV;
 
+	irq = platform_get_irq(dev, 0);
+	if (irq < 0)
+		return irq;
+
 	sport = kzalloc(sizeof(struct uart_pxa_port), GFP_KERNEL);
 	if (!sport)
 		return -ENOMEM;
@@ -869,7 +873,7 @@ static int serial_pxa_probe(struct platform_device *dev)
 	sport->port.type = PORT_PXA;
 	sport->port.iotype = UPIO_MEM;
 	sport->port.mapbase = mmres->start;
-	sport->port.irq = irqres->start;
+	sport->port.irq = irq;
 	sport->port.fifosize = 64;
 	sport->port.ops = &serial_pxa_pops;
 	sport->port.dev = &dev->dev;

drivers/tty/serial/samsung_tty.c

@@ -65,7 +65,6 @@ enum s3c24xx_port_type {
 struct s3c24xx_uart_info {
 	char			*name;
 	enum s3c24xx_port_type	type;
-	bool			has_usi;
 	unsigned int		port_type;
 	unsigned int		fifosize;
 	unsigned long		rx_fifomask;
@@ -1357,28 +1356,6 @@ static int apple_s5l_serial_startup(struct uart_port *port)
 	return ret;
 }
 
-static void exynos_usi_init(struct uart_port *port)
-{
-	struct s3c24xx_uart_port *ourport = to_ourport(port);
-	struct s3c24xx_uart_info *info = ourport->info;
-	unsigned int val;
-
-	if (!info->has_usi)
-		return;
-
-	/* Clear the software reset of USI block (it's set at startup) */
-	val = rd_regl(port, USI_CON);
-	val &= ~USI_CON_RESET_MASK;
-	wr_regl(port, USI_CON, val);
-	udelay(1);
-
-	/* Continuously provide the clock to USI IP w/o gating (for Rx mode) */
-	val = rd_regl(port, USI_OPTION);
-	val &= ~USI_OPTION_HWACG_MASK;
-	val |= USI_OPTION_HWACG_CLKREQ_ON;
-	wr_regl(port, USI_OPTION, val);
-}
-
 /* power power management control */
 
 static void s3c24xx_serial_pm(struct uart_port *port, unsigned int level,
@@ -1405,8 +1382,6 @@ static void s3c24xx_serial_pm(struct uart_port *port, unsigned int level,
 
 		if (!IS_ERR(ourport->baudclk))
 			clk_prepare_enable(ourport->baudclk);
-
-		exynos_usi_init(port);
 		break;
 	default:
 		dev_err(port->dev, "s3c24xx_serial: unknown pm %d\n", level);
@@ -1740,15 +1715,21 @@ s3c24xx_serial_verify_port(struct uart_port *port, struct serial_struct *ser)
 
 static struct console s3c24xx_serial_console;
 
-static int __init s3c24xx_serial_console_init(void)
+static void __init s3c24xx_serial_register_console(void)
 {
 	register_console(&s3c24xx_serial_console);
-	return 0;
 }
-console_initcall(s3c24xx_serial_console_init);
+
+static void s3c24xx_serial_unregister_console(void)
+{
+	if (s3c24xx_serial_console.flags & CON_ENABLED)
+		unregister_console(&s3c24xx_serial_console);
+}
 
 #define S3C24XX_SERIAL_CONSOLE &s3c24xx_serial_console
 #else
+static inline void s3c24xx_serial_register_console(void) { }
+static inline void s3c24xx_serial_unregister_console(void) { }
 #define S3C24XX_SERIAL_CONSOLE NULL
 #endif
 
@@ -2130,8 +2111,6 @@ static int s3c24xx_serial_init_port(struct s3c24xx_uart_port *ourport,
 	if (ret)
 		pr_warn("uart: failed to enable baudclk\n");
 
-	exynos_usi_init(port);
-
 	/* Keep all interrupts masked and cleared */
 	switch (ourport->info->type) {
 	case TYPE_S3C6400:
@@ -2521,7 +2500,8 @@ s3c24xx_serial_console_write(struct console *co, const char *s,
 	uart_console_write(cons_uart, s, count, s3c24xx_serial_console_putchar);
 }
 
-static void __init
+/* Shouldn't be __init, as it can be instantiated from other module */
+static void
 s3c24xx_serial_get_options(struct uart_port *port, int *baud,
 			   int *parity, int *bits)
 {
@@ -2584,7 +2564,8 @@ s3c24xx_serial_get_options(struct uart_port *port, int *baud,
 	}
 }
 
-static int __init
+/* Shouldn't be __init, as it can be instantiated from other module */
+static int
 s3c24xx_serial_console_setup(struct console *co, char *options)
 {
 	struct uart_port *port;
@@ -2780,11 +2761,10 @@ static struct s3c24xx_serial_drv_data s5pv210_serial_drv_data = {
 #endif
 
 #if defined(CONFIG_ARCH_EXYNOS)
-#define EXYNOS_COMMON_SERIAL_DRV_DATA(_has_usi)			\
+#define EXYNOS_COMMON_SERIAL_DRV_DATA()				\
 	.info = &(struct s3c24xx_uart_info) {			\
 		.name		= "Samsung Exynos UART",	\
 		.type		= TYPE_S3C6400,			\
-		.has_usi	= _has_usi,			\
 		.port_type	= PORT_S3C6400,			\
 		.has_divslot	= 1,				\
 		.rx_fifomask	= S5PV210_UFSTAT_RXMASK,	\
@@ -2805,17 +2785,17 @@ static struct s3c24xx_serial_drv_data s5pv210_serial_drv_data = {
 	}							\
 
 static struct s3c24xx_serial_drv_data exynos4210_serial_drv_data = {
-	EXYNOS_COMMON_SERIAL_DRV_DATA(false),
+	EXYNOS_COMMON_SERIAL_DRV_DATA(),
 	.fifosize = { 256, 64, 16, 16 },
 };
 
 static struct s3c24xx_serial_drv_data exynos5433_serial_drv_data = {
-	EXYNOS_COMMON_SERIAL_DRV_DATA(false),
+	EXYNOS_COMMON_SERIAL_DRV_DATA(),
 	.fifosize = { 64, 256, 16, 256 },
 };
 
 static struct s3c24xx_serial_drv_data exynos850_serial_drv_data = {
-	EXYNOS_COMMON_SERIAL_DRV_DATA(true),
+	EXYNOS_COMMON_SERIAL_DRV_DATA(),
 	.fifosize = { 256, 64, 64, 64 },
 };
 
@@ -2926,7 +2906,29 @@ static struct platform_driver samsung_serial_driver = {
 	},
 };
 
-module_platform_driver(samsung_serial_driver);
+static int __init samsung_serial_init(void)
+{
+	int ret;
+
+	s3c24xx_serial_register_console();
+
+	ret = platform_driver_register(&samsung_serial_driver);
+	if (ret) {
+		s3c24xx_serial_unregister_console();
+		return ret;
+	}
+
+	return 0;
+}
+
+static void __exit samsung_serial_exit(void)
+{
+	platform_driver_unregister(&samsung_serial_driver);
+	s3c24xx_serial_unregister_console();
+}
+
+module_init(samsung_serial_init);
+module_exit(samsung_serial_exit);
 
 #ifdef CONFIG_SERIAL_SAMSUNG_CONSOLE
 /*

drivers/tty/serial/serial_core.c

@@ -162,7 +162,7 @@ static void uart_port_dtr_rts(struct uart_port *uport, int raise)
 	int RTS_after_send = !!(uport->rs485.flags & SER_RS485_RTS_AFTER_SEND);
 
 	if (raise) {
-		if (rs485_on && !RTS_after_send) {
+		if (rs485_on && RTS_after_send) {
 			uart_set_mctrl(uport, TIOCM_DTR);
 			uart_clear_mctrl(uport, TIOCM_RTS);
 		} else {
@@ -171,7 +171,7 @@ static void uart_port_dtr_rts(struct uart_port *uport, int raise)
 	} else {
 		unsigned int clear = TIOCM_DTR;
 
-		clear |= (!rs485_on || !RTS_after_send) ? TIOCM_RTS : 0;
+		clear |= (!rs485_on || RTS_after_send) ? TIOCM_RTS : 0;
 		uart_clear_mctrl(uport, clear);
 	}
 }
@@ -1701,17 +1701,13 @@ static void uart_port_shutdown(struct tty_port *port)
 	 */
 	wake_up_interruptible(&port->delta_msr_wait);
 
-	/*
+	if (uport) {
-	 * Free the IRQ and disable the port.
+		/* Free the IRQ and disable the port. */
-	 */
-	if (uport)
 		uport->ops->shutdown(uport);
 
-	/*
+		/* Ensure that the IRQ handler isn't running on another CPU. */
-	 * Ensure that the IRQ handler isn't running on another CPU.
-	 */
-	if (uport)
 		synchronize_irq(uport->irq);
+	}
 }
 
 static int uart_carrier_raised(struct tty_port *port)
@@ -2393,7 +2389,8 @@ uart_configure_port(struct uart_driver *drv, struct uart_state *state,
 		 * We probably don't need a spinlock around this, but
 		 */
 		spin_lock_irqsave(&port->lock, flags);
-		port->ops->set_mctrl(port, port->mctrl & TIOCM_DTR);
+		port->mctrl &= TIOCM_DTR;
+		port->ops->set_mctrl(port, port->mctrl);
 		spin_unlock_irqrestore(&port->lock, flags);
 
 		/*

drivers/tty/serial/sh-sci.c

@@ -37,6 +37,7 @@
 #include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
+#include <linux/reset.h>
 #include <linux/scatterlist.h>
 #include <linux/serial.h>
 #include <linux/serial_sci.h>
@@ -895,11 +896,9 @@ static void sci_receive_chars(struct uart_port *port)
 				if (status & SCxSR_FER(port)) {
 					flag = TTY_FRAME;
 					port->icount.frame++;
-					dev_notice(port->dev, "frame error\n");
 				} else if (status & SCxSR_PER(port)) {
 					flag = TTY_PARITY;
 					port->icount.parity++;
-					dev_notice(port->dev, "parity error\n");
 				} else
 					flag = TTY_NORMAL;
 
@@ -939,8 +938,6 @@ static int sci_handle_errors(struct uart_port *port)
 		/* overrun error */
 		if (tty_insert_flip_char(tport, 0, TTY_OVERRUN))
 			copied++;
-
-		dev_notice(port->dev, "overrun error\n");
 	}
 
 	if (status & SCxSR_FER(port)) {
@@ -949,8 +946,6 @@ static int sci_handle_errors(struct uart_port *port)
 
 		if (tty_insert_flip_char(tport, 0, TTY_FRAME))
 			copied++;
-
-		dev_notice(port->dev, "frame error\n");
 	}
 
 	if (status & SCxSR_PER(port)) {
@@ -959,8 +954,6 @@ static int sci_handle_errors(struct uart_port *port)
 
 		if (tty_insert_flip_char(tport, 0, TTY_PARITY))
 			copied++;
-
-		dev_notice(port->dev, "parity error\n");
 	}
 
 	if (copied)
@@ -990,8 +983,6 @@ static int sci_handle_fifo_overrun(struct uart_port *port)
 
 		tty_insert_flip_char(tport, 0, TTY_OVERRUN);
 		tty_flip_buffer_push(tport);
-
-		dev_dbg(port->dev, "overrun error\n");
 		copied++;
 	}
 
@@ -1013,8 +1004,6 @@ static int sci_handle_breaks(struct uart_port *port)
 		/* Notify of BREAK */
 		if (tty_insert_flip_char(tport, 0, TTY_BREAK))
 			copied++;
-
-		dev_dbg(port->dev, "BREAK detected\n");
 	}
 
 	if (copied)
@@ -2778,44 +2767,29 @@ static int sci_init_clocks(struct sci_port *sci_port, struct device *dev)
 		clk_names[SCI_SCK] = "hsck";
 
 	for (i = 0; i < SCI_NUM_CLKS; i++) {
-		clk = devm_clk_get(dev, clk_names[i]);
+		clk = devm_clk_get_optional(dev, clk_names[i]);
-		if (PTR_ERR(clk) == -EPROBE_DEFER)
+		if (IS_ERR(clk))
-			return -EPROBE_DEFER;
+			return PTR_ERR(clk);
-
-		if (IS_ERR(clk) && i == SCI_FCK) {
-			/*
-			 * "fck" used to be called "sci_ick", and we need to
-			 * maintain DT backward compatibility.
-			 */
-			clk = devm_clk_get(dev, "sci_ick");
-			if (PTR_ERR(clk) == -EPROBE_DEFER)
-				return -EPROBE_DEFER;
-
-			if (!IS_ERR(clk))
-				goto found;
 
+		if (!clk && i == SCI_FCK) {
 			/*
 			 * Not all SH platforms declare a clock lookup entry
 			 * for SCI devices, in which case we need to get the
 			 * global "peripheral_clk" clock.
 			 */
 			clk = devm_clk_get(dev, "peripheral_clk");
-			if (!IS_ERR(clk))
+			if (IS_ERR(clk))
-				goto found;
+				return dev_err_probe(dev, PTR_ERR(clk),
-
+						     "failed to get %s\n",
-			dev_err(dev, "failed to get %s (%ld)\n", clk_names[i],
+						     clk_names[i]);
-				PTR_ERR(clk));
-			return PTR_ERR(clk);
 		}
 
-found:
+		if (!clk)
-		if (IS_ERR(clk))
+			dev_dbg(dev, "failed to get %s\n", clk_names[i]);
-			dev_dbg(dev, "failed to get %s (%ld)\n", clk_names[i],
-				PTR_ERR(clk));
 		else
 			dev_dbg(dev, "clk %s is %pC rate %lu\n", clk_names[i],
 				clk, clk_get_rate(clk));
-		sci_port->clks[i] = IS_ERR(clk) ? NULL : clk;
+		sci_port->clks[i] = clk;
 	}
 	return 0;
 }
@@ -3180,6 +3154,9 @@ static const struct of_device_id of_sci_match[] = {
 	}, {
 		.compatible = "renesas,rcar-gen3-scif",
 		.data = SCI_OF_DATA(PORT_SCIF, SCIx_SH4_SCIF_BRG_REGTYPE),
+	}, {
+		.compatible = "renesas,rcar-gen4-scif",
+		.data = SCI_OF_DATA(PORT_SCIF, SCIx_SH4_SCIF_BRG_REGTYPE),
 	},
 	/* Generic types */
 	{
@@ -3203,23 +3180,47 @@ static const struct of_device_id of_sci_match[] = {
 };
 MODULE_DEVICE_TABLE(of, of_sci_match);
 
+static void sci_reset_control_assert(void *data)
+{
+	reset_control_assert(data);
+}
+
 static struct plat_sci_port *sci_parse_dt(struct platform_device *pdev,
 					  unsigned int *dev_id)
 {
 	struct device_node *np = pdev->dev.of_node;
+	struct reset_control *rstc;
 	struct plat_sci_port *p;
 	struct sci_port *sp;
 	const void *data;
-	int id;
+	int id, ret;
 
 	if (!IS_ENABLED(CONFIG_OF) || !np)
-		return NULL;
+		return ERR_PTR(-EINVAL);
 
 	data = of_device_get_match_data(&pdev->dev);
 
+	rstc = devm_reset_control_get_optional_exclusive(&pdev->dev, NULL);
+	if (IS_ERR(rstc))
+		return ERR_PTR(dev_err_probe(&pdev->dev, PTR_ERR(rstc),
+					     "failed to get reset ctrl\n"));
+
+	ret = reset_control_deassert(rstc);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to deassert reset %d\n", ret);
+		return ERR_PTR(ret);
+	}
+
+	ret = devm_add_action_or_reset(&pdev->dev, sci_reset_control_assert, rstc);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to register assert devm action, %d\n",
+			ret);
+		return ERR_PTR(ret);
+	}
+
 	p = devm_kzalloc(&pdev->dev, sizeof(struct plat_sci_port), GFP_KERNEL);
 	if (!p)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 
 	/* Get the line number from the aliases node. */
 	id = of_alias_get_id(np, "serial");
@@ -3227,11 +3228,11 @@ static struct plat_sci_port *sci_parse_dt(struct platform_device *pdev,
 		id = ffz(sci_ports_in_use);
 	if (id < 0) {
 		dev_err(&pdev->dev, "failed to get alias id (%d)\n", id);
-		return NULL;
+		return ERR_PTR(-EINVAL);
 	}
 	if (id >= ARRAY_SIZE(sci_ports)) {
 		dev_err(&pdev->dev, "serial%d out of range\n", id);
-		return NULL;
+		return ERR_PTR(-EINVAL);
 	}
 
 	sp = &sci_ports[id];
@@ -3318,8 +3319,8 @@ static int sci_probe(struct platform_device *dev)
 
 	if (dev->dev.of_node) {
 		p = sci_parse_dt(dev, &dev_id);
-		if (p == NULL)
+		if (IS_ERR(p))
-			return -EINVAL;
+			return PTR_ERR(p);
 	} else {
 		p = dev->dev.platform_data;
 		if (p == NULL) {

drivers/tty/serial/stm32-usart.c

@@ -365,6 +365,31 @@ static unsigned int stm32_usart_receive_chars(struct uart_port *port, bool force
 	return size;
 }
 
+static void stm32_usart_tx_dma_terminate(struct stm32_port *stm32_port)
+{
+	dmaengine_terminate_async(stm32_port->tx_ch);
+	stm32_port->tx_dma_busy = false;
+}
+
+static bool stm32_usart_tx_dma_started(struct stm32_port *stm32_port)
+{
+	/*
+	 * We cannot use the function "dmaengine_tx_status" to know the
+	 * status of DMA. This function does not show if the "dma complete"
+	 * callback of the DMA transaction has been called. So we prefer
+	 * to use "tx_dma_busy" flag to prevent dual DMA transaction at the
+	 * same time.
+	 */
+	return stm32_port->tx_dma_busy;
+}
+
+static bool stm32_usart_tx_dma_enabled(struct stm32_port *stm32_port)
+{
+	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
+
+	return !!(readl_relaxed(stm32_port->port.membase + ofs->cr3) & USART_CR3_DMAT);
+}
+
 static void stm32_usart_tx_dma_complete(void *arg)
 {
 	struct uart_port *port = arg;
@@ -372,9 +397,8 @@ static void stm32_usart_tx_dma_complete(void *arg)
 	const struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
 	unsigned long flags;
 
-	dmaengine_terminate_async(stm32port->tx_ch);
 	stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
-	stm32port->tx_dma_busy = false;
+	stm32_usart_tx_dma_terminate(stm32port);
 
 	/* Let's see if we have pending data to send */
 	spin_lock_irqsave(&port->lock, flags);
@@ -428,10 +452,8 @@ static void stm32_usart_transmit_chars_pio(struct uart_port *port)
 	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 	struct circ_buf *xmit = &port->state->xmit;
 
-	if (stm32_port->tx_dma_busy) {
+	if (stm32_usart_tx_dma_enabled(stm32_port))
 		stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
-		stm32_port->tx_dma_busy = false;
-	}
 
 	while (!uart_circ_empty(xmit)) {
 		/* Check that TDR is empty before filling FIFO */
@@ -455,12 +477,13 @@ static void stm32_usart_transmit_chars_dma(struct uart_port *port)
 	const struct stm32_usart_offsets *ofs = &stm32port->info->ofs;
 	struct circ_buf *xmit = &port->state->xmit;
 	struct dma_async_tx_descriptor *desc = NULL;
-	unsigned int count, i;
+	unsigned int count;
 
-	if (stm32port->tx_dma_busy)
+	if (stm32_usart_tx_dma_started(stm32port)) {
+		if (!stm32_usart_tx_dma_enabled(stm32port))
+			stm32_usart_set_bits(port, ofs->cr3, USART_CR3_DMAT);
 		return;
-
+	}
-	stm32port->tx_dma_busy = true;
 
 	count = uart_circ_chars_pending(xmit);
 
@@ -491,13 +514,21 @@ static void stm32_usart_transmit_chars_dma(struct uart_port *port)
 	if (!desc)
 		goto fallback_err;
 
+	/*
+	 * Set "tx_dma_busy" flag. This flag will be released when
+	 * dmaengine_terminate_async will be called. This flag helps
+	 * transmit_chars_dma not to start another DMA transaction
+	 * if the callback of the previous is not yet called.
+	 */
+	stm32port->tx_dma_busy = true;
+
 	desc->callback = stm32_usart_tx_dma_complete;
 	desc->callback_param = port;
 
 	/* Push current DMA TX transaction in the pending queue */
 	if (dma_submit_error(dmaengine_submit(desc))) {
 		/* dma no yet started, safe to free resources */
-		dmaengine_terminate_async(stm32port->tx_ch);
+		stm32_usart_tx_dma_terminate(stm32port);
 		goto fallback_err;
 	}
 
@@ -511,7 +542,6 @@ static void stm32_usart_transmit_chars_dma(struct uart_port *port)
 	return;
 
 fallback_err:
-	for (i = count; i > 0; i--)
 	stm32_usart_transmit_chars_pio(port);
 }
 
@@ -522,12 +552,13 @@ static void stm32_usart_transmit_chars(struct uart_port *port)
 	struct circ_buf *xmit = &port->state->xmit;
 
 	if (port->x_char) {
-		if (stm32_port->tx_dma_busy)
+		if (stm32_usart_tx_dma_started(stm32_port) &&
+		    stm32_usart_tx_dma_enabled(stm32_port))
 			stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
 		writel_relaxed(port->x_char, port->membase + ofs->tdr);
 		port->x_char = 0;
 		port->icount.tx++;
-		if (stm32_port->tx_dma_busy)
+		if (stm32_usart_tx_dma_started(stm32_port))
 			stm32_usart_set_bits(port, ofs->cr3, USART_CR3_DMAT);
 		return;
 	}
@@ -675,8 +706,11 @@ static void stm32_usart_stop_tx(struct uart_port *port)
 {
 	struct stm32_port *stm32_port = to_stm32_port(port);
 	struct serial_rs485 *rs485conf = &port->rs485;
+	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 
 	stm32_usart_tx_interrupt_disable(port);
+	if (stm32_usart_tx_dma_started(stm32_port) && stm32_usart_tx_dma_enabled(stm32_port))
+		stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
 
 	if (rs485conf->flags & SER_RS485_ENABLED) {
 		if (rs485conf->flags & SER_RS485_RTS_ON_SEND) {
@@ -719,9 +753,8 @@ static void stm32_usart_flush_buffer(struct uart_port *port)
 	const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
 
 	if (stm32_port->tx_ch) {
-		dmaengine_terminate_async(stm32_port->tx_ch);
+		stm32_usart_tx_dma_terminate(stm32_port);
 		stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
-		stm32_port->tx_dma_busy = false;
 	}
 }
 
@@ -883,6 +916,12 @@ static void stm32_usart_shutdown(struct uart_port *port)
 	u32 val, isr;
 	int ret;
 
+	if (stm32_usart_tx_dma_enabled(stm32_port))
+		stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
+
+	if (stm32_usart_tx_dma_started(stm32_port))
+		stm32_usart_tx_dma_terminate(stm32_port);
+
 	/* Disable modem control interrupts */
 	stm32_usart_disable_ms(port);
 
@@ -1419,8 +1458,6 @@ static int stm32_usart_of_dma_tx_probe(struct stm32_port *stm32port,
 	struct dma_slave_config config;
 	int ret;
 
-	stm32port->tx_dma_busy = false;
-
 	stm32port->tx_buf = dma_alloc_coherent(dev, TX_BUF_L,
 					       &stm32port->tx_dma_buf,
 					       GFP_KERNEL);
@@ -1570,7 +1607,6 @@ static int stm32_usart_serial_remove(struct platform_device *pdev)
 	writel_relaxed(cr3, port->membase + ofs->cr3);
 
 	if (stm32_port->tx_ch) {
-		dmaengine_terminate_async(stm32_port->tx_ch);
 		stm32_usart_of_dma_tx_remove(stm32_port, pdev);
 		dma_release_channel(stm32_port->tx_ch);
 	}

drivers/tty/serial/stm32-usart.h

@@ -264,7 +264,7 @@ struct stm32_port {
 	u32 cr1_irq;		 /* USART_CR1_RXNEIE or RTOIE */
 	u32 cr3_irq;		 /* USART_CR3_RXFTIE */
 	int last_res;
-	bool tx_dma_busy;	 /* dma tx busy               */
+	bool tx_dma_busy;	 /* dma tx transaction in progress */
 	bool throttled;		 /* port throttled            */
 	bool hw_flow_control;
 	bool swap;		 /* swap RX & TX pins */

drivers/tty/serial/sunsu.c

@@ -127,7 +127,8 @@ static void serial_out(struct uart_sunsu_port *up, int offset, int value)
 	 * gate outputs a logical one. Since we use level triggered interrupts
 	 * we have lockup and watchdog reset. We cannot mask IRQ because
 	 * keyboard shares IRQ with us (Word has it as Bob Smelik's design).
-	 * This problem is similar to what Alpha people suffer, see serial.c.
+	 * This problem is similar to what Alpha people suffer, see
+	 * 8250_alpha.c.
 	 */
 	if (offset == UART_MCR)
 		value |= UART_MCR_OUT2;

drivers/tty/serial/uartlite.c

@@ -626,7 +626,7 @@ static struct uart_driver ulite_uart_driver = {
  *
  * Returns: 0 on success, <0 otherwise
  */
-static int ulite_assign(struct device *dev, int id, u32 base, int irq,
+static int ulite_assign(struct device *dev, int id, phys_addr_t base, int irq,
 			struct uartlite_data *pdata)
 {
 	struct uart_port *port;

drivers/tty/serial/vt8500_serial.c

@@ -621,21 +621,25 @@ static const struct of_device_id wmt_dt_ids[] = {
 static int vt8500_serial_probe(struct platform_device *pdev)
 {
 	struct vt8500_port *vt8500_port;
-	struct resource *mmres, *irqres;
+	struct resource *mmres;
 	struct device_node *np = pdev->dev.of_node;
 	const unsigned int *flags;
 	int ret;
 	int port;
+	int irq;
 
 	flags = of_device_get_match_data(&pdev->dev);
 	if (!flags)
 		return -EINVAL;
 
 	mmres = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	irqres = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
+	if (!mmres)
-	if (!mmres || !irqres)
 		return -ENODEV;
 
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
 	if (np) {
 		port = of_alias_get_id(np, "serial");
 		if (port >= VT8500_MAX_PORTS)
@@ -688,7 +692,7 @@ static int vt8500_serial_probe(struct platform_device *pdev)
 	vt8500_port->uart.type = PORT_VT8500;
 	vt8500_port->uart.iotype = UPIO_MEM;
 	vt8500_port->uart.mapbase = mmres->start;
-	vt8500_port->uart.irq = irqres->start;
+	vt8500_port->uart.irq = irq;
 	vt8500_port->uart.fifosize = 16;
 	vt8500_port->uart.ops = &vt8500_uart_pops;
 	vt8500_port->uart.line = port;

drivers/tty/tty_buffer.c

@@ -40,19 +40,14 @@
 
 /**
  * tty_buffer_lock_exclusive	-	gain exclusive access to buffer
- *	tty_buffer_unlock_exclusive	-	release exclusive access
- *
  * @port: tty port owning the flip buffer
  *
- *	Guarantees safe use of the line discipline's receive_buf() method by
+ * Guarantees safe use of the &tty_ldisc_ops.receive_buf() method by excluding
- *	excluding the buffer work and any pending flush from using the flip
+ * the buffer work and any pending flush from using the flip buffer. Data can
- *	buffer. Data can continue to be added concurrently to the flip buffer
+ * continue to be added concurrently to the flip buffer from the driver side.
- *	from the driver side.
  *
- *	On release, the buffer work is restarted if there is data in the
+ * See also tty_buffer_unlock_exclusive().
- *	flip buffer
  */
-
 void tty_buffer_lock_exclusive(struct tty_port *port)
 {
 	struct tty_bufhead *buf = &port->buf;
@@ -62,6 +57,14 @@ void tty_buffer_lock_exclusive(struct tty_port *port)
 }
 EXPORT_SYMBOL_GPL(tty_buffer_lock_exclusive);
 
+/**
+ * tty_buffer_unlock_exclusive	-	release exclusive access
+ * @port: tty port owning the flip buffer
+ *
+ * The buffer work is restarted if there is data in the flip buffer.
+ *
+ * See also tty_buffer_lock_exclusive().
+ */
 void tty_buffer_unlock_exclusive(struct tty_port *port)
 {
 	struct tty_bufhead *buf = &port->buf;
@@ -80,14 +83,13 @@ EXPORT_SYMBOL_GPL(tty_buffer_unlock_exclusive);
  * tty_buffer_space_avail	-	return unused buffer space
  * @port: tty port owning the flip buffer
  *
- *	Returns the # of bytes which can be written by the driver without
+ * Returns: the # of bytes which can be written by the driver without reaching
- *	reaching the buffer limit.
+ * the buffer limit.
  *
- *	Note: this does not guarantee that memory is available to write
+ * Note: this does not guarantee that memory is available to write the returned
- *	the returned # of bytes (use tty_prepare_flip_string_xxx() to
+ * # of bytes (use tty_prepare_flip_string() to pre-allocate if memory
- *	pre-allocate if memory guarantee is required).
+ * guarantee is required).
  */
-
 unsigned int tty_buffer_space_avail(struct tty_port *port)
 {
 	int space = port->buf.mem_limit - atomic_read(&port->buf.mem_used);
@@ -110,10 +112,9 @@ static void tty_buffer_reset(struct tty_buffer *p, size_t size)
  * tty_buffer_free_all		-	free buffers used by a tty
  * @port: tty port to free from
  *
- *	Remove all the buffers pending on a tty whether queued with data
+ * Remove all the buffers pending on a tty whether queued with data or in the
- *	or in the free ring. Must be called when the tty is no longer in use
+ * free ring. Must be called when the tty is no longer in use.
  */
-
 void tty_buffer_free_all(struct tty_port *port)
 {
 	struct tty_bufhead *buf = &port->buf;
@@ -146,13 +147,13 @@ void tty_buffer_free_all(struct tty_port *port)
  * @port: tty port
  * @size: desired size (characters)
  *
- *	Allocate a new tty buffer to hold the desired number of characters.
+ * Allocate a new tty buffer to hold the desired number of characters. We
- *	We round our buffers off in 256 character chunks to get better
+ * round our buffers off in 256 character chunks to get better allocation
- *	allocation behaviour.
+ * behaviour.
- *	Return NULL if out of memory or the allocation would exceed the
+ *
- *	per device queue
+ * Returns: %NULL if out of memory or the allocation would exceed the per
+ * device queue.
  */
-
 static struct tty_buffer *tty_buffer_alloc(struct tty_port *port, size_t size)
 {
 	struct llist_node *free;
@@ -189,10 +190,9 @@ found:
  * @port: tty port owning the buffer
  * @b: the buffer to free
  *
- *	Free a tty buffer, or add it to the free list according to our
+ * Free a tty buffer, or add it to the free list according to our internal
- *	internal strategy
+ * strategy.
  */
-
 static void tty_buffer_free(struct tty_port *port, struct tty_buffer *b)
 {
 	struct tty_bufhead *buf = &port->buf;
@@ -211,13 +211,11 @@ static void tty_buffer_free(struct tty_port *port, struct tty_buffer *b)
  * @tty: tty to flush
  * @ld: optional ldisc ptr (must be referenced)
  *
- *	flush all the buffers containing receive data. If ld != NULL,
+ * Flush all the buffers containing receive data. If @ld != %NULL, flush the
- *	flush the ldisc input buffer.
+ * ldisc input buffer.
  *
- *	Locking: takes buffer lock to ensure single-threaded flip buffer
+ * Locking: takes buffer lock to ensure single-threaded flip buffer 'consumer'.
- *		 'consumer'
  */
-
 void tty_buffer_flush(struct tty_struct *tty, struct tty_ldisc *ld)
 {
 	struct tty_port *port = tty->port;
@@ -249,12 +247,13 @@ void tty_buffer_flush(struct tty_struct *tty, struct tty_ldisc *ld)
  * @size: size desired
  * @flags: buffer flags if new buffer allocated (default = 0)
  *
- *	Make at least size bytes of linear space available for the tty
+ * Make at least @size bytes of linear space available for the tty buffer.
- *	buffer. If we fail return the size we managed to find.
  *
  * Will change over to a new buffer if the current buffer is encoded as
- *	TTY_NORMAL (so has no flags buffer) and the new buffer requires
+ * %TTY_NORMAL (so has no flags buffer) and the new buffer requires a flags
- *	a flags buffer.
+ * buffer.
+ *
+ * Returns: the size we managed to find.
  */
 static int __tty_buffer_request_room(struct tty_port *port, size_t size,
 				     int flags)
@@ -300,16 +299,17 @@ int tty_buffer_request_room(struct tty_port *port, size_t size)
 EXPORT_SYMBOL_GPL(tty_buffer_request_room);
 
 /**
- *	tty_insert_flip_string_fixed_flag - Add characters to the tty buffer
+ * tty_insert_flip_string_fixed_flag - add characters to the tty buffer
  * @port: tty port
  * @chars: characters
  * @flag: flag value for each character
  * @size: size
  *
- *	Queue a series of bytes to the tty buffering. All the characters
+ * Queue a series of bytes to the tty buffering. All the characters passed are
- *	passed are marked with the supplied flag. Returns the number added.
+ * marked with the supplied flag.
+ *
+ * Returns: the number added.
  */
-
 int tty_insert_flip_string_fixed_flag(struct tty_port *port,
 		const unsigned char *chars, char flag, size_t size)
 {
@@ -338,17 +338,17 @@ int tty_insert_flip_string_fixed_flag(struct tty_port *port,
 EXPORT_SYMBOL(tty_insert_flip_string_fixed_flag);
 
 /**
- *	tty_insert_flip_string_flags	-	Add characters to the tty buffer
+ * tty_insert_flip_string_flags	-	add characters to the tty buffer
  * @port: tty port
  * @chars: characters
  * @flags: flag bytes
  * @size: size
  *
- *	Queue a series of bytes to the tty buffering. For each character
+ * Queue a series of bytes to the tty buffering. For each character the flags
- *	the flags array indicates the status of the character. Returns the
+ * array indicates the status of the character.
- *	number added.
+ *
+ * Returns: the number added.
  */
-
 int tty_insert_flip_string_flags(struct tty_port *port,
 		const unsigned char *chars, const char *flags, size_t size)
 {
@@ -376,13 +376,13 @@ int tty_insert_flip_string_flags(struct tty_port *port,
 EXPORT_SYMBOL(tty_insert_flip_string_flags);
 
 /**
- *	__tty_insert_flip_char   -	Add one character to the tty buffer
+ * __tty_insert_flip_char   -	add one character to the tty buffer
  * @port: tty port
  * @ch: character
  * @flag: flag byte
  *
- *	Queue a single byte to the tty buffering, with an optional flag.
+ * Queue a single byte @ch to the tty buffering, with an optional flag. This is
- *	This is the slow path of tty_insert_flip_char.
+ * the slow path of tty_insert_flip_char().
  */
 int __tty_insert_flip_char(struct tty_port *port, unsigned char ch, char flag)
 {
@@ -401,40 +401,20 @@ int __tty_insert_flip_char(struct tty_port *port, unsigned char ch, char flag)
 }
 EXPORT_SYMBOL(__tty_insert_flip_char);
 
-/**
- *	tty_schedule_flip	-	push characters to ldisc
- *	@port: tty port to push from
- *
- *	Takes any pending buffers and transfers their ownership to the
- *	ldisc side of the queue. It then schedules those characters for
- *	processing by the line discipline.
- */
-
-void tty_schedule_flip(struct tty_port *port)
-{
-	struct tty_bufhead *buf = &port->buf;
-
-	/* paired w/ acquire in flush_to_ldisc(); ensures
-	 * flush_to_ldisc() sees buffer data.
-	 */
-	smp_store_release(&buf->tail->commit, buf->tail->used);
-	queue_work(system_unbound_wq, &buf->work);
-}
-EXPORT_SYMBOL(tty_schedule_flip);
-
 /**
  * tty_prepare_flip_string	-	make room for characters
  * @port: tty port
  * @chars: return pointer for character write area
  * @size: desired size
  *
- *	Prepare a block of space in the buffer for data. Returns the length
+ * Prepare a block of space in the buffer for data.
- *	available and buffer pointer to the space which is now allocated and
+ *
- *	accounted for as ready for normal characters. This is used for drivers
+ * This is used for drivers that need their own block copy routines into the
- *	that need their own block copy routines into the buffer. There is no
+ * buffer. There is no guarantee the buffer is a DMA target!
- *	guarantee the buffer is a DMA target!
+ *
+ * Returns: the length available and buffer pointer (@chars) to the space which
+ * is now allocated and accounted for as ready for normal characters.
  */
-
 int tty_prepare_flip_string(struct tty_port *port, unsigned char **chars,
 		size_t size)
 {
@@ -456,13 +436,13 @@ EXPORT_SYMBOL_GPL(tty_prepare_flip_string);
  * tty_ldisc_receive_buf	-	forward data to line discipline
  * @ld: line discipline to process input
  * @p: char buffer
- *	@f:	TTY_* flags buffer
+ * @f: %TTY_NORMAL, %TTY_BREAK, etc. flags buffer
  * @count: number of bytes to process
  *
- *	Callers other than flush_to_ldisc() need to exclude the kworker
+ * Callers other than flush_to_ldisc() need to exclude the kworker from
- *	from concurrent use of the line discipline, see paste_selection().
+ * concurrent use of the line discipline, see paste_selection().
  *
- *	Returns the number of bytes processed
+ * Returns: the number of bytes processed.
  */
 int tty_ldisc_receive_buf(struct tty_ldisc *ld, const unsigned char *p,
 			  const char *f, int count)
@@ -495,18 +475,16 @@ receive_buf(struct tty_port *port, struct tty_buffer *head, int count)
 }
 
 /**
- *	flush_to_ldisc
+ * flush_to_ldisc		-	flush data from buffer to ldisc
  * @work: tty structure passed from work queue.
  *
- *	This routine is called out of the software interrupt to flush data
+ * This routine is called out of the software interrupt to flush data from the
- *	from the buffer chain to the line discipline.
+ * buffer chain to the line discipline.
  *
- *	The receive_buf method is single threaded for each tty instance.
+ * The receive_buf() method is single threaded for each tty instance.
  *
- *	Locking: takes buffer lock to ensure single-threaded flip buffer
+ * Locking: takes buffer lock to ensure single-threaded flip buffer 'consumer'.
- *		 'consumer'
  */
-
 static void flush_to_ldisc(struct work_struct *work)
 {
 	struct tty_port *port = container_of(work, struct tty_port, buf.work);
@@ -554,19 +532,25 @@ static void flush_to_ldisc(struct work_struct *work)
 }
 
 /**
- *	tty_flip_buffer_push	-	terminal
+ * tty_flip_buffer_push		-	push terminal buffers
  * @port: tty port to push
  *
- *	Queue a push of the terminal flip buffers to the line discipline.
+ * Queue a push of the terminal flip buffers to the line discipline. Can be
- *	Can be called from IRQ/atomic context.
+ * called from IRQ/atomic context.
  *
- *	In the event of the queue being busy for flipping the work will be
+ * In the event of the queue being busy for flipping the work will be held off
- *	held off and retried later.
+ * and retried later.
  */
-
 void tty_flip_buffer_push(struct tty_port *port)
 {
-	tty_schedule_flip(port);
+	struct tty_bufhead *buf = &port->buf;
+
+	/*
+	 * Paired w/ acquire in flush_to_ldisc(); ensures flush_to_ldisc() sees
+	 * buffer data.
+	 */
+	smp_store_release(&buf->tail->commit, buf->tail->used);
+	queue_work(system_unbound_wq, &buf->work);
 }
 EXPORT_SYMBOL(tty_flip_buffer_push);
 
@@ -574,10 +558,9 @@ EXPORT_SYMBOL(tty_flip_buffer_push);
  * tty_buffer_init		-	prepare a tty buffer structure
  * @port: tty port to initialise
  *
- *	Set up the initial state of the buffer management for a tty device.
+ * Set up the initial state of the buffer management for a tty device. Must be
- *	Must be called before the other tty buffer functions are used.
+ * called before the other tty buffer functions are used.
  */
-
 void tty_buffer_init(struct tty_port *port)
 {
 	struct tty_bufhead *buf = &port->buf;
@@ -599,9 +582,9 @@ void tty_buffer_init(struct tty_port *port)
  * @limit: memory limit to set
  *
  * Change the tty buffer memory limit.
+ *
  * Must be called before the other tty buffer functions are used.
  */
-
 int tty_buffer_set_limit(struct tty_port *port, int limit)
 {
 	if (limit < MIN_TTYB_SIZE)

drivers/tty/tty_ldisc.c

@@ -50,14 +50,11 @@ static struct tty_ldisc_ops *tty_ldiscs[NR_LDISCS];
  * tty_register_ldisc	-	install a line discipline
  * @new_ldisc: pointer to the ldisc object
  *
- *	Installs a new line discipline into the kernel. The discipline
+ * Installs a new line discipline into the kernel. The discipline is set up as
- *	is set up as unreferenced and then made available to the kernel
+ * unreferenced and then made available to the kernel from this point onwards.
- *	from this point onwards.
  *
- *	Locking:
+ * Locking: takes %tty_ldiscs_lock to guard against ldisc races
- *		takes tty_ldiscs_lock to guard against ldisc races
  */
-
 int tty_register_ldisc(struct tty_ldisc_ops *new_ldisc)
 {
 	unsigned long flags;
@@ -78,11 +75,10 @@ EXPORT_SYMBOL(tty_register_ldisc);
  * tty_unregister_ldisc	-	unload a line discipline
  * @ldisc: ldisc number
  *
- *	Remove a line discipline from the kernel providing it is not
+ * Remove a line discipline from the kernel providing it is not currently in
- *	currently in use.
+ * use.
  *
- *	Locking:
+ * Locking: takes %tty_ldiscs_lock to guard against ldisc races
- *		takes tty_ldiscs_lock to guard against ldisc races
  */
 
 void tty_unregister_ldisc(struct tty_ldisc_ops *ldisc)
@@ -122,27 +118,25 @@ static void put_ldops(struct tty_ldisc_ops *ldops)
 }
 
 static int tty_ldisc_autoload = IS_BUILTIN(CONFIG_LDISC_AUTOLOAD);
+
 /**
  * tty_ldisc_get	-	take a reference to an ldisc
  * @tty: tty device
  * @disc: ldisc number
  *
- *	Takes a reference to a line discipline. Deals with refcounts and
+ * Takes a reference to a line discipline. Deals with refcounts and module
- *	module locking counts.
+ * locking counts. If the discipline is not available, its module loaded, if
+ * possible.
  *
- *	Returns: -EINVAL if the discipline index is not [N_TTY..NR_LDISCS] or
+ * Returns:
- *			 if the discipline is not registered
+ * * -%EINVAL if the discipline index is not [%N_TTY .. %NR_LDISCS] or if the
- *		 -EAGAIN if request_module() failed to load or register the
+ *   discipline is not registered
- *			 discipline
+ * * -%EAGAIN if request_module() failed to load or register the discipline
- *		 -ENOMEM if allocation failure
+ * * -%ENOMEM if allocation failure
+ * * Otherwise, returns a pointer to the discipline and bumps the ref count
  *
- *		 Otherwise, returns a pointer to the discipline and bumps the
+ * Locking: takes %tty_ldiscs_lock to guard against ldisc races
- *		 ref count
- *
- *	Locking:
- *		takes tty_ldiscs_lock to guard against ldisc races
  */
-
 static struct tty_ldisc *tty_ldisc_get(struct tty_struct *tty, int disc)
 {
 	struct tty_ldisc *ld;
@@ -176,8 +170,9 @@ static struct tty_ldisc *tty_ldisc_get(struct tty_struct *tty, int disc)
 	return ld;
 }
 
-/*
+/**
  * tty_ldisc_put	-	release the ldisc
+ * @ld: lisdsc to release
  *
  * Complement of tty_ldisc_get().
  */
@@ -229,22 +224,19 @@ const struct seq_operations tty_ldiscs_seq_ops = {
  * tty_ldisc_ref_wait	-	wait for the tty ldisc
  * @tty: tty device
  *
- *	Dereference the line discipline for the terminal and take a
+ * Dereference the line discipline for the terminal and take a reference to it.
- *	reference to it. If the line discipline is in flux then
+ * If the line discipline is in flux then wait patiently until it changes.
- *	wait patiently until it changes.
  *
- *	Returns: NULL if the tty has been hungup and not re-opened with
+ * Returns: %NULL if the tty has been hungup and not re-opened with a new file
- *		 a new file descriptor, otherwise valid ldisc reference
+ * descriptor, otherwise valid ldisc reference
  *
- *	Note 1: Must not be called from an IRQ/timer context. The caller
+ * Note 1: Must not be called from an IRQ/timer context. The caller must also
- *	must also be careful not to hold other locks that will deadlock
+ * be careful not to hold other locks that will deadlock against a discipline
- *	against a discipline change, such as an existing ldisc reference
+ * change, such as an existing ldisc reference (which we check for).
- *	(which we check for)
  *
- *	Note 2: a file_operations routine (read/poll/write) should use this
+ * Note 2: a file_operations routine (read/poll/write) should use this function
- *	function to wait for any ldisc lifetime events to finish.
+ * to wait for any ldisc lifetime events to finish.
  */
-
 struct tty_ldisc *tty_ldisc_ref_wait(struct tty_struct *tty)
 {
 	struct tty_ldisc *ld;
@@ -261,11 +253,10 @@ EXPORT_SYMBOL_GPL(tty_ldisc_ref_wait);
  * tty_ldisc_ref	-	get the tty ldisc
  * @tty: tty device
  *
- *	Dereference the line discipline for the terminal and take a
+ * Dereference the line discipline for the terminal and take a reference to it.
- *	reference to it. If the line discipline is in flux then
+ * If the line discipline is in flux then return %NULL. Can be called from IRQ
- *	return NULL. Can be called from IRQ and timer functions.
+ * and timer functions.
  */
-
 struct tty_ldisc *tty_ldisc_ref(struct tty_struct *tty)
 {
 	struct tty_ldisc *ld = NULL;
@@ -283,10 +274,9 @@ EXPORT_SYMBOL_GPL(tty_ldisc_ref);
  * tty_ldisc_deref	-	free a tty ldisc reference
  * @ld: reference to free up
  *
- *	Undoes the effect of tty_ldisc_ref or tty_ldisc_ref_wait. May
+ * Undoes the effect of tty_ldisc_ref() or tty_ldisc_ref_wait(). May be called
- *	be called in IRQ context.
+ * in IRQ context.
  */
-
 void tty_ldisc_deref(struct tty_ldisc *ld)
 {
 	ldsem_up_read(&ld->tty->ldisc_sem);
@@ -387,12 +377,11 @@ static void tty_ldisc_unlock_pair(struct tty_struct *tty,
 
 /**
  * tty_ldisc_flush		-	flush line discipline queue
- *	@tty: tty
+ * @tty: tty to flush ldisc for
  *
- *	Flush the line discipline queue (if any) and the tty flip buffers
+ * Flush the line discipline queue (if any) and the tty flip buffers for this
- *	for this tty.
+ * @tty.
  */
-
 void tty_ldisc_flush(struct tty_struct *tty)
 {
 	struct tty_ldisc *ld = tty_ldisc_ref(tty);
@@ -408,17 +397,14 @@ EXPORT_SYMBOL_GPL(tty_ldisc_flush);
  * @tty: tty structure
  * @disc: line discipline number
  *
- *	This is probably overkill for real world processors but
+ * This is probably overkill for real world processors but they are not on hot
- *	they are not on hot paths so a little discipline won't do
+ * paths so a little discipline won't do any harm.
- *	any harm.
  *
- *	The line discipline-related tty_struct fields are reset to
+ * The line discipline-related tty_struct fields are reset to prevent the ldisc
- *	prevent the ldisc driver from re-using stale information for
+ * driver from re-using stale information for the new ldisc instance.
- *	the new ldisc instance.
  *
  * Locking: takes termios_rwsem
  */
-
 static void tty_set_termios_ldisc(struct tty_struct *tty, int disc)
 {
 	down_write(&tty->termios_rwsem);
@@ -434,12 +420,10 @@ static void tty_set_termios_ldisc(struct tty_struct *tty, int disc)
  * @tty: tty we are opening the ldisc on
  * @ld: discipline to open
  *
- *	A helper opening method. Also a convenient debugging and check
+ * A helper opening method. Also a convenient debugging and check point.
- *	point.
  *
  * Locking: always called with BTM already held.
  */
-
 static int tty_ldisc_open(struct tty_struct *tty, struct tty_ldisc *ld)
 {
 	WARN_ON(test_and_set_bit(TTY_LDISC_OPEN, &tty->flags));
@@ -461,10 +445,8 @@ static int tty_ldisc_open(struct tty_struct *tty, struct tty_ldisc *ld)
  * @tty: tty we are opening the ldisc on
  * @ld: discipline to close
  *
- *	A helper close method. Also a convenient debugging and check
+ * A helper close method. Also a convenient debugging and check point.
- *	point.
  */
-
 static void tty_ldisc_close(struct tty_struct *tty, struct tty_ldisc *ld)
 {
 	lockdep_assert_held_write(&tty->ldisc_sem);
@@ -480,10 +462,9 @@ static void tty_ldisc_close(struct tty_struct *tty, struct tty_ldisc *ld)
  * @tty: tty to open the ldisc on
  * @ld: ldisc we are trying to fail back to
  *
- *	Helper to try and recover a tty when switching back to the old
+ * Helper to try and recover a tty when switching back to the old ldisc fails
- *	ldisc fails and we need something attached.
+ * and we need something attached.
  */
-
 static int tty_ldisc_failto(struct tty_struct *tty, int ld)
 {
 	struct tty_ldisc *disc = tty_ldisc_get(tty, ld);
@@ -505,10 +486,9 @@ static int tty_ldisc_failto(struct tty_struct *tty, int ld)
  * @tty: tty to recover
  * @old: previous ldisc
  *
- *	Restore the previous line discipline or N_TTY when a line discipline
+ * Restore the previous line discipline or %N_TTY when a line discipline change
- *	change fails due to an open error
+ * fails due to an open error
  */
-
 static void tty_ldisc_restore(struct tty_struct *tty, struct tty_ldisc *old)
 {
 	/* There is an outstanding reference here so this is safe */
@@ -532,12 +512,11 @@ static void tty_ldisc_restore(struct tty_struct *tty, struct tty_ldisc *old)
  * @tty: the terminal to set
  * @disc: the line discipline number
  *
- *	Set the discipline of a tty line. Must be called from a process
+ * Set the discipline of a tty line. Must be called from a process context. The
- *	context. The ldisc change logic has to protect itself against any
+ * ldisc change logic has to protect itself against any overlapping ldisc
- *	overlapping ldisc change (including on the other end of pty pairs),
+ * change (including on the other end of pty pairs), the close of one side of a
- *	the close of one side of a tty/pty pair, and eventually hangup.
+ * tty/pty pair, and eventually hangup.
  */
-
 int tty_set_ldisc(struct tty_struct *tty, int disc)
 {
 	int retval;
@@ -616,7 +595,7 @@ EXPORT_SYMBOL_GPL(tty_set_ldisc);
  * tty_ldisc_kill	-	teardown ldisc
  * @tty: tty being released
  *
- *	Perform final close of the ldisc and reset tty->ldisc
+ * Perform final close of the ldisc and reset @tty->ldisc
  */
 static void tty_ldisc_kill(struct tty_struct *tty)
 {
@@ -638,7 +617,6 @@ static void tty_ldisc_kill(struct tty_struct *tty)
  *
  * Restore a terminal to the driver default state.
  */
-
 static void tty_reset_termios(struct tty_struct *tty)
 {
 	down_write(&tty->termios_rwsem);
@@ -654,15 +632,13 @@ static void tty_reset_termios(struct tty_struct *tty)
  * @tty: tty to reinit
  * @disc: line discipline to reinitialize
  *
- *	Completely reinitialize the line discipline state, by closing the
+ * Completely reinitialize the line discipline state, by closing the current
- *	current instance, if there is one, and opening a new instance. If
+ * instance, if there is one, and opening a new instance. If an error occurs
- *	an error occurs opening the new non-N_TTY instance, the instance
+ * opening the new non-%N_TTY instance, the instance is dropped and @tty->ldisc
- *	is dropped and tty->ldisc reset to NULL. The caller can then retry
+ * reset to %NULL. The caller can then retry with %N_TTY instead.
- *	with N_TTY instead.
  *
- *	Returns 0 if successful, otherwise error code < 0
+ * Returns: 0 if successful, otherwise error code < 0
  */
-
 int tty_ldisc_reinit(struct tty_struct *tty, int disc)
 {
 	struct tty_ldisc *ld;
@@ -696,17 +672,16 @@ int tty_ldisc_reinit(struct tty_struct *tty, int disc)
  * @tty: tty being hung up
  * @reinit: whether to re-initialise the tty
  *
- *	Some tty devices reset their termios when they receive a hangup
+ * Some tty devices reset their termios when they receive a hangup event. In
- *	event. In that situation we must also switch back to N_TTY properly
+ * that situation we must also switch back to %N_TTY properly before we reset
- *	before we reset the termios data.
+ * the termios data.
  *
- *	Locking: We can take the ldisc mutex as the rest of the code is
+ * Locking: We can take the ldisc mutex as the rest of the code is careful to
- *	careful to allow for this.
+ * allow for this.
  *
- *	In the pty pair case this occurs in the close() path of the
+ * In the pty pair case this occurs in the close() path of the tty itself so we
- *	tty itself so we must be careful about locking rules.
+ * must be careful about locking rules.
  */
-
 void tty_ldisc_hangup(struct tty_struct *tty, bool reinit)
 {
 	struct tty_ldisc *ld;
@@ -756,11 +731,10 @@ void tty_ldisc_hangup(struct tty_struct *tty, bool reinit)
  * @tty: tty being shut down
  * @o_tty: pair tty for pty/tty pairs
  *
- *	Called during the initial open of a tty/pty pair in order to set up the
+ * Called during the initial open of a tty/pty pair in order to set up the line
- *	line disciplines and bind them to the tty. This has no locking issues
+ * disciplines and bind them to the @tty. This has no locking issues as the
- *	as the device isn't yet active.
+ * device isn't yet active.
  */
-
 int tty_ldisc_setup(struct tty_struct *tty, struct tty_struct *o_tty)
 {
 	int retval = tty_ldisc_open(tty, tty->ldisc);
@@ -786,10 +760,9 @@ int tty_ldisc_setup(struct tty_struct *tty, struct tty_struct *o_tty)
  * tty_ldisc_release	-	release line discipline
  * @tty: tty being shut down (or one end of pty pair)
  *
- *	Called during the final close of a tty or a pty pair in order to shut
+ * Called during the final close of a tty or a pty pair in order to shut down
- *	down the line discpline layer. On exit, each tty's ldisc is NULL.
+ * the line discpline layer. On exit, each tty's ldisc is %NULL.
  */
-
 void tty_ldisc_release(struct tty_struct *tty)
 {
 	struct tty_struct *o_tty = tty->link;
@@ -817,10 +790,9 @@ void tty_ldisc_release(struct tty_struct *tty)
  * tty_ldisc_init	-	ldisc setup for new tty
  * @tty: tty being allocated
  *
- *	Set up the line discipline objects for a newly allocated tty. Note that
+ * Set up the line discipline objects for a newly allocated tty. Note that the
- *	the tty structure is not completely set up when this call is made.
+ * tty structure is not completely set up when this call is made.
  */
-
 int tty_ldisc_init(struct tty_struct *tty)
 {
 	struct tty_ldisc *ld = tty_ldisc_get(tty, N_TTY);
@@ -835,7 +807,7 @@ int tty_ldisc_init(struct tty_struct *tty)
  * tty_ldisc_deinit	-	ldisc cleanup for new tty
  * @tty: tty that was allocated recently
  *
- *	The tty structure must not becompletely set up (tty_ldisc_setup) when
+ * The tty structure must not be completely set up (tty_ldisc_setup()) when
  * this call is made.
  */
 void tty_ldisc_deinit(struct tty_struct *tty)

drivers/tty/tty_ldsem.c

@@ -163,7 +163,7 @@ down_read_failed(struct ld_semaphore *sem, long count, long timeout)
 
 	/*
 	 * Try to reverse the lock attempt but if the count has changed
-	 * so that reversing fails, check if there are are no waiters,
+	 * so that reversing fails, check if there are no waiters,
 	 * and early-out if not
 	 */
 	do {

drivers/tty/tty_port.c

@@ -59,6 +59,15 @@ const struct tty_port_client_operations tty_port_default_client_ops = {
 };
 EXPORT_SYMBOL_GPL(tty_port_default_client_ops);
 
+/**
+ * tty_port_init -- initialize tty_port
+ * @port: tty_port to initialize
+ *
+ * Initializes the state of struct tty_port. When a port was initialized using
+ * this function, one has to destroy the port by tty_port_destroy(). Either
+ * indirectly by using &tty_port refcounting (tty_port_put()) or directly if
+ * refcounting is not used.
+ */
 void tty_port_init(struct tty_port *port)
 {
 	memset(port, 0, sizeof(*port));
@@ -82,9 +91,9 @@ EXPORT_SYMBOL(tty_port_init);
  * @index: index of the tty
  *
  * Provide the tty layer with a link from a tty (specified by @index) to a
- * tty_port (@port). Use this only if neither tty_port_register_device nor
+ * tty_port (@port). Use this only if neither tty_port_register_device() nor
- * tty_port_install is used in the driver. If used, this has to be called before
+ * tty_port_install() is used in the driver. If used, this has to be called
- * tty_register_driver.
+ * before tty_register_driver().
  */
 void tty_port_link_device(struct tty_port *port,
 		struct tty_driver *driver, unsigned index)
@@ -102,9 +111,9 @@ EXPORT_SYMBOL_GPL(tty_port_link_device);
  * @index: index of the tty
  * @device: parent if exists, otherwise NULL
  *
- * It is the same as tty_register_device except the provided @port is linked to
+ * It is the same as tty_register_device() except the provided @port is linked
- * a concrete tty specified by @index. Use this or tty_port_install (or both).
+ * to a concrete tty specified by @index. Use this or tty_port_install() (or
- * Call tty_port_link_device as a last resort.
+ * both). Call tty_port_link_device() as a last resort.
  */
 struct device *tty_port_register_device(struct tty_port *port,
 		struct tty_driver *driver, unsigned index,
@@ -123,9 +132,9 @@ EXPORT_SYMBOL_GPL(tty_port_register_device);
  * @drvdata: Driver data to be set to device.
  * @attr_grp: Attribute group to be set on device.
  *
- * It is the same as tty_register_device_attr except the provided @port is
+ * It is the same as tty_register_device_attr() except the provided @port is
- * linked to a concrete tty specified by @index. Use this or tty_port_install
+ * linked to a concrete tty specified by @index. Use this or tty_port_install()
- * (or both). Call tty_port_link_device as a last resort.
+ * (or both). Call tty_port_link_device() as a last resort.
  */
 struct device *tty_port_register_device_attr(struct tty_port *port,
 		struct tty_driver *driver, unsigned index,
@@ -240,9 +249,9 @@ EXPORT_SYMBOL(tty_port_free_xmit_buf);
  * tty_port_destroy -- destroy inited port
  * @port: tty port to be destroyed
  *
- * When a port was initialized using tty_port_init, one has to destroy the
+ * When a port was initialized using tty_port_init(), one has to destroy the
- * port by this function. Either indirectly by using tty_port refcounting
+ * port by this function. Either indirectly by using &tty_port refcounting
- * (tty_port_put) or directly if refcounting is not used.
+ * (tty_port_put()) or directly if refcounting is not used.
  */
 void tty_port_destroy(struct tty_port *port)
 {
@@ -267,6 +276,13 @@ static void tty_port_destructor(struct kref *kref)
 		kfree(port);
 }
 
+/**
+ * tty_port_put -- drop a reference to tty_port
+ * @port: port to drop a reference of (can be NULL)
+ *
+ * The final put will destroy and free up the @port using
+ * @port->ops->destruct() hook, or using kfree() if not provided.
+ */
 void tty_port_put(struct tty_port *port)
 {
 	if (port)
@@ -278,8 +294,8 @@ EXPORT_SYMBOL(tty_port_put);
  * tty_port_tty_get	-	get a tty reference
  * @port: tty port
  *
- *	Return a refcount protected tty instance or NULL if the port is not
+ * Return a refcount protected tty instance or %NULL if the port is not
- *	associated with a tty (eg due to close or hangup)
+ * associated with a tty (eg due to close or hangup).
  */
 struct tty_struct *tty_port_tty_get(struct tty_port *port)
 {
@@ -298,8 +314,8 @@ EXPORT_SYMBOL(tty_port_tty_get);
  * @port: tty port
  * @tty: the tty
  *
- *	Associate the port and tty pair. Manages any internal refcounts.
+ * Associate the port and tty pair. Manages any internal refcounts. Pass %NULL
- *	Pass NULL to deassociate a port
+ * to deassociate a port.
  */
 void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty)
 {
@@ -312,6 +328,16 @@ void tty_port_tty_set(struct tty_port *port, struct tty_struct *tty)
 }
 EXPORT_SYMBOL(tty_port_tty_set);
 
+/**
+ * tty_port_shutdown - internal helper to shutdown the device
+ * @port: tty port to be shut down
+ * @tty: the associated tty
+ *
+ * It is used by tty_port_hangup() and tty_port_close(). Its task is to
+ * shutdown the device if it was initialized (note consoles remain
+ * functioning). It lowers DTR/RTS (if @tty has HUPCL set) and invokes
+ * @port->ops->shutdown().
+ */
 static void tty_port_shutdown(struct tty_port *port, struct tty_struct *tty)
 {
 	mutex_lock(&port->mutex);
@@ -365,9 +391,8 @@ EXPORT_SYMBOL(tty_port_hangup);
 
 /**
  * tty_port_tty_hangup - helper to hang up a tty
- *
  * @port: tty port
- * @check_clocal: hang only ttys with CLOCAL unset?
+ * @check_clocal: hang only ttys with %CLOCAL unset?
  */
 void tty_port_tty_hangup(struct tty_port *port, bool check_clocal)
 {
@@ -381,7 +406,6 @@ EXPORT_SYMBOL_GPL(tty_port_tty_hangup);
 
 /**
  * tty_port_tty_wakeup - helper to wake up a tty
- *
  * @port: tty port
  */
 void tty_port_tty_wakeup(struct tty_port *port)
@@ -410,9 +434,9 @@ EXPORT_SYMBOL(tty_port_carrier_raised);
  * tty_port_raise_dtr_rts	-	Raise DTR/RTS
  * @port: tty port
  *
- *	Wrapper for the DTR/RTS raise logic. For the moment this is used
+ * Wrapper for the DTR/RTS raise logic. For the moment this is used to hide
- *	to hide some internal details. This will eventually become entirely
+ * some internal details. This will eventually become entirely internal to the
- *	internal to the tty port.
+ * tty port.
  */
 void tty_port_raise_dtr_rts(struct tty_port *port)
 {
@@ -425,9 +449,9 @@ EXPORT_SYMBOL(tty_port_raise_dtr_rts);
  * tty_port_lower_dtr_rts	-	Lower DTR/RTS
  * @port: tty port
  *
- *	Wrapper for the DTR/RTS raise logic. For the moment this is used
+ * Wrapper for the DTR/RTS raise logic. For the moment this is used to hide
- *	to hide some internal details. This will eventually become entirely
+ * some internal details. This will eventually become entirely internal to the
- *	internal to the tty port.
+ * tty port.
  */
 void tty_port_lower_dtr_rts(struct tty_port *port)
 {
@@ -440,25 +464,26 @@ EXPORT_SYMBOL(tty_port_lower_dtr_rts);
  * tty_port_block_til_ready	-	Waiting logic for tty open
  * @port: the tty port being opened
  * @tty: the tty device being bound
- *	@filp: the file pointer of the opener or NULL
+ * @filp: the file pointer of the opener or %NULL
  *
  * Implement the core POSIX/SuS tty behaviour when opening a tty device.
  * Handles:
+ *
  *	- hangup (both before and during)
  *	- non blocking open
  *	- rts/dtr/dcd
  *	- signals
  *	- port flags and counts
  *
- *	The passed tty_port must implement the carrier_raised method if it can
+ * The passed @port must implement the @port->ops->carrier_raised method if it
- *	do carrier detect and the dtr_rts method if it supports software
+ * can do carrier detect and the @port->ops->dtr_rts method if it supports
- *	management of these lines. Note that the dtr/rts raise is done each
+ * software management of these lines. Note that the dtr/rts raise is done each
  * iteration as a hangup may have previously dropped them while we wait.
  *
  * Caller holds tty lock.
  *
- *      NB: May drop and reacquire tty lock when blocking, so tty and tty_port
+ * Note: May drop and reacquire tty lock when blocking, so @tty and @port may
- *      may have changed state (eg., may have been hung up).
+ * have changed state (eg., may have been hung up).
  */
 int tty_port_block_til_ready(struct tty_port *port,
 				struct tty_struct *tty, struct file *filp)
@@ -560,7 +585,21 @@ static void tty_port_drain_delay(struct tty_port *port, struct tty_struct *tty)
 	schedule_timeout_interruptible(timeout);
 }
 
-/* Caller holds tty lock. */
+/**
+ * tty_port_close_start - helper for tty->ops->close, part 1/2
+ * @port: tty_port of the device
+ * @tty: tty being closed
+ * @filp: passed file pointer
+ *
+ * Decrements and checks open count. Flushes the port if this is the last
+ * close. That means, dropping the data from the outpu buffer on the device and
+ * waiting for sending logic to finish. The rest of close handling is performed
+ * in tty_port_close_end().
+ *
+ * Locking: Caller holds tty lock.
+ *
+ * Return: 1 if this is the last close, otherwise 0
+ */
 int tty_port_close_start(struct tty_port *port,
 				struct tty_struct *tty, struct file *filp)
 {
@@ -606,7 +645,17 @@ int tty_port_close_start(struct tty_port *port,
 }
 EXPORT_SYMBOL(tty_port_close_start);
 
-/* Caller holds tty lock */
+/**
+ * tty_port_close_end - helper for tty->ops->close, part 2/2
+ * @port: tty_port of the device
+ * @tty: tty being closed
+ *
+ * This is a continuation of the first part: tty_port_close_start(). This
+ * should be called after turning off the device. It flushes the data from the
+ * line discipline and delays the close by @port->close_delay.
+ *
+ * Locking: Caller holds tty lock.
+ */
 void tty_port_close_end(struct tty_port *port, struct tty_struct *tty)
 {
 	unsigned long flags;
@@ -628,10 +677,18 @@ void tty_port_close_end(struct tty_port *port, struct tty_struct *tty)
 }
 EXPORT_SYMBOL(tty_port_close_end);
 
-/*
+/**
- * tty_port_close
+ * tty_port_close - generic tty->ops->close handler
+ * @port: tty_port of the device
+ * @tty: tty being closed
+ * @filp: passed file pointer
  *
- * Caller holds tty lock
+ * It is a generic helper to be used in driver's @tty->ops->close. It wraps a
+ * sequence of tty_port_close_start(), tty_port_shutdown(), and
+ * tty_port_close_end(). The latter two are called only if this is the last
+ * close. See the respective functions for the details.
+ *
+ * Locking: Caller holds tty lock
  */
 void tty_port_close(struct tty_port *port, struct tty_struct *tty,
 							struct file *filp)
@@ -652,9 +709,9 @@ EXPORT_SYMBOL(tty_port_close);
  * @driver: tty_driver for this device
  * @tty: tty to be installed
  *
- * It is the same as tty_standard_install except the provided @port is linked
+ * It is the same as tty_standard_install() except the provided @port is linked
- * to a concrete tty specified by @tty. Use this or tty_port_register_device
+ * to a concrete tty specified by @tty. Use this or tty_port_register_device()
- * (or both). Call tty_port_link_device as a last resort.
+ * (or both). Call tty_port_link_device() as a last resort.
  */
 int tty_port_install(struct tty_port *port, struct tty_driver *driver,
 		struct tty_struct *tty)
@@ -664,13 +721,21 @@ int tty_port_install(struct tty_port *port, struct tty_driver *driver,
 }
 EXPORT_SYMBOL_GPL(tty_port_install);
 
-/*
+/**
- * tty_port_open
+ * tty_port_open - generic tty->ops->open handler
+ * @port: tty_port of the device
+ * @tty: tty to be opened
+ * @filp: passed file pointer
  *
- * Caller holds tty lock.
+ * It is a generic helper to be used in driver's @tty->ops->open. It activates
+ * the devices using @port->ops->activate if not active already. And waits for
+ * the device to be ready using tty_port_block_til_ready() (e.g.  raises
+ * DTR/CTS and waits for carrier).
  *
- * NB: may drop and reacquire tty lock (in tty_port_block_til_ready()) so
+ * Locking: Caller holds tty lock.
- * tty and tty_port may have changed state (eg., may be hung up now)
+ *
+ * Note: may drop and reacquire tty lock (in tty_port_block_til_ready()) so
+ * @tty and @port may have changed state (eg., may be hung up now).
  */
 int tty_port_open(struct tty_port *port, struct tty_struct *tty,
 							struct file *filp)

drivers/tty/vt/keyboard.c

@@ -153,6 +153,7 @@ static int shift_state = 0;
 
 static unsigned int ledstate = -1U;			/* undefined */
 static unsigned char ledioctl;
+static bool vt_switch;
 
 /*
  * Notifier list for console keyboard events
@@ -324,13 +325,13 @@ int kbd_rate(struct kbd_repeat *rpt)
 static void put_queue(struct vc_data *vc, int ch)
 {
 	tty_insert_flip_char(&vc->port, ch, 0);
-	tty_schedule_flip(&vc->port);
+	tty_flip_buffer_push(&vc->port);
 }
 
 static void puts_queue(struct vc_data *vc, const char *cp)
 {
 	tty_insert_flip_string(&vc->port, cp, strlen(cp));
-	tty_schedule_flip(&vc->port);
+	tty_flip_buffer_push(&vc->port);
 }
 
 static void applkey(struct vc_data *vc, int key, char mode)
@@ -414,6 +415,12 @@ void vt_set_leds_compute_shiftstate(void)
 {
 	unsigned long flags;
 
+	/*
+	 * When VT is switched, the keyboard led needs to be set once.
+	 * Ensure that after the switch is completed, the state of the
+	 * keyboard LED is consistent with the state of the keyboard lock.
+	 */
+	vt_switch = true;
 	set_leds();
 
 	spin_lock_irqsave(&kbd_event_lock, flags);
@@ -584,7 +591,7 @@ static void fn_inc_console(struct vc_data *vc)
 static void fn_send_intr(struct vc_data *vc)
 {
 	tty_insert_flip_char(&vc->port, 0, TTY_BREAK);
-	tty_schedule_flip(&vc->port);
+	tty_flip_buffer_push(&vc->port);
 }
 
 static void fn_scroll_forw(struct vc_data *vc)
@@ -1255,6 +1262,11 @@ static void kbd_bh(struct tasklet_struct *unused)
 	leds |= (unsigned int)kbd->lockstate << 8;
 	spin_unlock_irqrestore(&led_lock, flags);
 
+	if (vt_switch) {
+		ledstate = ~leds;
+		vt_switch = false;
+	}
+
 	if (leds != ledstate) {
 		kbd_propagate_led_state(ledstate, leds);
 		ledstate = leds;

drivers/tty/vt/vt.c

@@ -1833,7 +1833,7 @@ static void csi_m(struct vc_data *vc)
 static void respond_string(const char *p, size_t len, struct tty_port *port)
 {
 	tty_insert_flip_string(port, p, len);
-	tty_schedule_flip(port);
+	tty_flip_buffer_push(port);
 }
 
 static void cursor_report(struct vc_data *vc, struct tty_struct *tty)

drivers/usb/class/cdc-acm.c

@@ -685,10 +685,6 @@ static int acm_port_activate(struct tty_port *port, struct tty_struct *tty)
 	if (retval)
 		goto error_get_interface;
 
-	/*
-	 * FIXME: Why do we need this? Allocating 64K of physically contiguous
-	 * memory is really nasty...
-	 */
 	set_bit(TTY_NO_WRITE_SPLIT, &tty->flags);
 	acm->control->needs_remote_wakeup = 1;
 

include/linux/amba/bus.h

@@ -90,14 +90,8 @@ enum amba_vendor {
 	AMBA_VENDOR_ST = 0x80,
 	AMBA_VENDOR_QCOM = 0x51,
 	AMBA_VENDOR_LSI = 0xb6,
-	AMBA_VENDOR_LINUX = 0xfe,	/* This value is not official */
 };
 
-/* This is used to generate pseudo-ID for AMBA device */
-#define AMBA_LINUX_ID(conf, rev, part) \
-	(((conf) & 0xff) << 24 | ((rev) & 0xf) << 20 | \
-	AMBA_VENDOR_LINUX << 12 | ((part) & 0xfff))
-
 extern struct bus_type amba_bustype;
 
 #define to_amba_device(d)	container_of(d, struct amba_device, dev)

include/linux/pci_ids.h

@@ -1965,24 +1965,6 @@
 #define PCI_DEVICE_ID_APPLICOM_PCI2000PFB 0x0003
 
 #define PCI_VENDOR_ID_MOXA		0x1393
-#define PCI_DEVICE_ID_MOXA_RC7000	0x0001
-#define PCI_DEVICE_ID_MOXA_CP102	0x1020
-#define PCI_DEVICE_ID_MOXA_CP102UL	0x1021
-#define PCI_DEVICE_ID_MOXA_CP102U	0x1022
-#define PCI_DEVICE_ID_MOXA_C104		0x1040
-#define PCI_DEVICE_ID_MOXA_CP104U	0x1041
-#define PCI_DEVICE_ID_MOXA_CP104JU	0x1042
-#define PCI_DEVICE_ID_MOXA_CP104EL	0x1043
-#define PCI_DEVICE_ID_MOXA_CT114	0x1140
-#define PCI_DEVICE_ID_MOXA_CP114	0x1141
-#define PCI_DEVICE_ID_MOXA_CP118U	0x1180
-#define PCI_DEVICE_ID_MOXA_CP118EL	0x1181
-#define PCI_DEVICE_ID_MOXA_CP132	0x1320
-#define PCI_DEVICE_ID_MOXA_CP132U	0x1321
-#define PCI_DEVICE_ID_MOXA_CP134U	0x1340
-#define PCI_DEVICE_ID_MOXA_C168		0x1680
-#define PCI_DEVICE_ID_MOXA_CP168U	0x1681
-#define PCI_DEVICE_ID_MOXA_CP168EL	0x1682
 #define PCI_DEVICE_ID_MOXA_CP204J	0x2040
 #define PCI_DEVICE_ID_MOXA_C218		0x2180
 #define PCI_DEVICE_ID_MOXA_C320		0x3200

include/linux/serial_8250.h

@@ -104,8 +104,6 @@ struct uart_8250_port {
 	unsigned char		ier;
 	unsigned char		lcr;
 	unsigned char		mcr;
-	unsigned char		mcr_mask;	/* mask of user bits */
-	unsigned char		mcr_force;	/* mask of forced bits */
 	unsigned char		cur_iotype;	/* Running I/O type */
 	unsigned int		rpm_tx_active;
 	unsigned char		canary;		/* non-zero during system sleep

include/linux/serial_s3c.h

@@ -27,15 +27,6 @@
 #define S3C2410_UERSTAT	  (0x14)
 #define S3C2410_UFSTAT	  (0x18)
 #define S3C2410_UMSTAT	  (0x1C)
-#define USI_CON		  (0xC4)
-#define USI_OPTION	  (0xC8)
-
-#define USI_CON_RESET			(1<<0)
-#define USI_CON_RESET_MASK		(1<<0)
-
-#define USI_OPTION_HWACG_CLKREQ_ON	(1<<1)
-#define USI_OPTION_HWACG_CLKSTOP_ON	(1<<2)
-#define USI_OPTION_HWACG_MASK		(3<<1)
 
 #define S3C2410_LCON_CFGMASK	  ((0xF<<3)|(0x3))
 

include/linux/tty.h

@@ -122,33 +122,84 @@ struct tty_operations;
 /**
  * struct tty_struct - state associated with a tty while open
  *
- * @flow.lock: lock for flow members
+ * @magic: magic value set early in @alloc_tty_struct to %TTY_MAGIC, for
- * @flow.stopped: tty stopped/started by tty_stop/tty_start
+ *	   debugging purposes
- * @flow.tco_stopped: tty stopped/started by TCOOFF/TCOON ioctls (it has
+ * @kref: reference counting by tty_kref_get() and tty_kref_put(), reaching zero
- *		      precedense over @flow.stopped)
+ *	  frees the structure
+ * @dev: class device or %NULL (e.g. ptys, serdev)
+ * @driver: &struct tty_driver operating this tty
+ * @ops: &struct tty_operations of @driver for this tty (open, close, etc.)
+ * @index: index of this tty (e.g. to construct @name like tty12)
+ * @ldisc_sem: protects line discipline changes (@ldisc) -- lock tty not pty
+ * @ldisc: the current line discipline for this tty (n_tty by default)
+ * @atomic_write_lock: protects against concurrent writers, i.e. locks
+ *		       @write_cnt, @write_buf and similar
+ * @legacy_mutex: leftover from history (BKL -> BTM -> @legacy_mutex),
+ *		  protecting several operations on this tty
+ * @throttle_mutex: protects against concurrent tty_throttle_safe() and
+ *		    tty_unthrottle_safe() (but not tty_unthrottle())
+ * @termios_rwsem: protects @termios and @termios_locked
+ * @winsize_mutex: protects @winsize
+ * @termios: termios for the current tty, copied from/to @driver.termios
+ * @termios_locked: locked termios (by %TIOCGLCKTRMIOS and %TIOCSLCKTRMIOS
+ *		    ioctls)
+ * @name: name of the tty constructed by tty_line_name() (e.g. ttyS3)
+ * @flags: bitwise OR of %TTY_THROTTLED, %TTY_IO_ERROR, ...
+ * @count: count of open processes, reaching zero cancels all the work for
+ *	   this tty and drops a @kref too (but does not free this tty)
+ * @winsize: size of the terminal "window" (cf. @winsize_mutex)
+ * @flow: flow settings grouped together, see also @flow.unused
+ * @flow.lock: lock for @flow members
+ * @flow.stopped: tty stopped/started by stop_tty()/start_tty()
+ * @flow.tco_stopped: tty stopped/started by %TCOOFF/%TCOON ioctls (it has
+ *		      precedence over @flow.stopped)
  * @flow.unused: alignment for Alpha, so that no members other than @flow.* are
  *		 modified by the same 64b word store. The @flow's __aligned is
  *		 there for the very same reason.
- * @ctrl.lock: lock for ctrl members
+ * @ctrl: control settings grouped together, see also @ctrl.unused
+ * @ctrl.lock: lock for @ctrl members
  * @ctrl.pgrp: process group of this tty (setpgrp(2))
  * @ctrl.session: session of this tty (setsid(2)). Writes are protected by both
- *		  @ctrl.lock and legacy mutex, readers must use at least one of
+ *		  @ctrl.lock and @legacy_mutex, readers must use at least one of
  *		  them.
- * @ctrl.pktstatus: packet mode status (bitwise OR of TIOCPKT_* constants)
+ * @ctrl.pktstatus: packet mode status (bitwise OR of %TIOCPKT_ constants)
  * @ctrl.packet: packet mode enabled
+ * @ctrl.unused: alignment for Alpha, see @flow.unused for explanation
+ * @hw_stopped: not controlled by the tty layer, under @driver's control for CTS
+ *		handling
+ * @receive_room: bytes permitted to feed to @ldisc without any being lost
+ * @flow_change: controls behavior of throttling, see tty_throttle_safe() and
+ *		 tty_unthrottle_safe()
+ * @link: link to another pty (master -> slave and vice versa)
+ * @fasync: state for %O_ASYNC (for %SIGIO); managed by fasync_helper()
+ * @write_wait: concurrent writers are waiting in this queue until they are
+ *		allowed to write
+ * @read_wait: readers wait for data in this queue
+ * @hangup_work: normally a work to perform a hangup (do_tty_hangup()); while
+ *		 freeing the tty, (re)used to release_one_tty()
+ * @disc_data: pointer to @ldisc's private data (e.g. to &struct n_tty_data)
+ * @driver_data: pointer to @driver's private data (e.g. &struct uart_state)
+ * @files_lock:	protects @tty_files list
+ * @tty_files: list of (re)openers of this tty (i.e. linked &struct
+ *	       tty_file_private)
+ * @closing: when set during close, n_tty processes only START & STOP chars
+ * @write_buf: temporary buffer used during tty_write() to copy user data to
+ * @write_cnt: count of bytes written in tty_write() to @write_buf
+ * @SAK_work: if the tty has a pending do_SAK, it is queued here
+ * @port: persistent storage for this device (i.e. &struct tty_port)
  *
  * All of the state associated with a tty while the tty is open. Persistent
- * storage for tty devices is referenced here as @port in struct tty_port.
+ * storage for tty devices is referenced here as @port and is documented in
+ * &struct tty_port.
  */
 struct tty_struct {
 	int	magic;
 	struct kref kref;
-	struct device *dev;	/* class device or NULL (e.g. ptys, serdev) */
+	struct device *dev;
 	struct tty_driver *driver;
 	const struct tty_operations *ops;
 	int index;
 
-	/* Protects ldisc changes: Lock tty not pty */
 	struct ld_semaphore ldisc_sem;
 	struct tty_ldisc *ldisc;
 
@@ -157,12 +208,11 @@ struct tty_struct {
 	struct mutex throttle_mutex;
 	struct rw_semaphore termios_rwsem;
 	struct mutex winsize_mutex;
-	/* Termios values are protected by the termios rwsem */
 	struct ktermios termios, termios_locked;
 	char name[64];
 	unsigned long flags;
 	int count;
-	struct winsize winsize;		/* winsize_mutex */
+	struct winsize winsize;
 
 	struct {
 		spinlock_t lock;
@@ -181,7 +231,7 @@ struct tty_struct {
 	} __aligned(sizeof(unsigned long)) ctrl;
 
 	int hw_stopped;
-	unsigned int receive_room;	/* Bytes free for queue */
+	unsigned int receive_room;
 	int flow_change;
 
 	struct tty_struct *link;
@@ -191,7 +241,7 @@ struct tty_struct {
 	struct work_struct hangup_work;
 	void *disc_data;
 	void *driver_data;
-	spinlock_t files_lock;		/* protects tty_files list */
+	spinlock_t files_lock;
 	struct list_head tty_files;
 
 #define N_TTY_BUF_SIZE 4096
@@ -199,7 +249,6 @@ struct tty_struct {
 	int closing;
 	unsigned char *write_buf;
 	int write_cnt;
-	/* If the tty has a pending do_SAK, queue it here - akpm */
 	struct work_struct SAK_work;
 	struct tty_port *port;
 } __randomize_layout;
@@ -214,26 +263,72 @@ struct tty_file_private {
 /* tty magic number */
 #define TTY_MAGIC		0x5401
 
-/*
+/**
- * These bits are used in the flags field of the tty structure.
+ * DOC: TTY Struct Flags
+ *
+ * These bits are used in the :c:member:`tty_struct.flags` field.
  *
  * So that interrupts won't be able to mess up the queues,
  * copy_to_cooked must be atomic with respect to itself, as must
  * tty->write.  Thus, you must use the inline functions set_bit() and
  * clear_bit() to make things atomic.
+ *
+ * TTY_THROTTLED
+ *	Driver input is throttled. The ldisc should call
+ *	:c:member:`tty_driver.unthrottle()` in order to resume reception when
+ *	it is ready to process more data (at threshold min).
+ *
+ * TTY_IO_ERROR
+ *	If set, causes all subsequent userspace read/write calls on the tty to
+ *	fail, returning -%EIO. (May be no ldisc too.)
+ *
+ * TTY_OTHER_CLOSED
+ *	Device is a pty and the other side has closed.
+ *
+ * TTY_EXCLUSIVE
+ *	Exclusive open mode (a single opener).
+ *
+ * TTY_DO_WRITE_WAKEUP
+ *	If set, causes the driver to call the
+ *	:c:member:`tty_ldisc_ops.write_wakeup()` method in order to resume
+ *	transmission when it can accept more data to transmit.
+ *
+ * TTY_LDISC_OPEN
+ *	Indicates that a line discipline is open. For debugging purposes only.
+ *
+ * TTY_PTY_LOCK
+ *	A flag private to pty code to implement %TIOCSPTLCK/%TIOCGPTLCK logic.
+ *
+ * TTY_NO_WRITE_SPLIT
+ *	Prevent driver from splitting up writes into smaller chunks (preserve
+ *	write boundaries to driver).
+ *
+ * TTY_HUPPED
+ *	The TTY was hung up. This is set post :c:member:`tty_driver.hangup()`.
+ *
+ * TTY_HUPPING
+ *	The TTY is in the process of hanging up to abort potential readers.
+ *
+ * TTY_LDISC_CHANGING
+ *	Line discipline for this TTY is being changed. I/O should not block
+ *	when this is set. Use tty_io_nonblock() to check.
+ *
+ * TTY_LDISC_HALTED
+ *	Line discipline for this TTY was stopped. No work should be queued to
+ *	this ldisc.
  */
-#define TTY_THROTTLED 		0	/* Call unthrottle() at threshold min */
+#define TTY_THROTTLED		0
-#define TTY_IO_ERROR 		1	/* Cause an I/O error (may be no ldisc too) */
+#define TTY_IO_ERROR		1
-#define TTY_OTHER_CLOSED 	2	/* Other side (if any) has closed */
+#define TTY_OTHER_CLOSED	2
-#define TTY_EXCLUSIVE 		3	/* Exclusive open mode */
+#define TTY_EXCLUSIVE		3
-#define TTY_DO_WRITE_WAKEUP 	5	/* Call write_wakeup after queuing new */
+#define TTY_DO_WRITE_WAKEUP	5
-#define TTY_LDISC_OPEN	 	11	/* Line discipline is open */
+#define TTY_LDISC_OPEN		11
-#define TTY_PTY_LOCK 		16	/* pty private */
+#define TTY_PTY_LOCK		16
-#define TTY_NO_WRITE_SPLIT 	17	/* Preserve write boundaries to driver */
+#define TTY_NO_WRITE_SPLIT	17
-#define TTY_HUPPED 		18	/* Post driver->hangup() */
+#define TTY_HUPPED		18
-#define TTY_HUPPING		19	/* Hangup in progress */
+#define TTY_HUPPING		19
-#define TTY_LDISC_CHANGING	20	/* Change pending - non-block IO */
+#define TTY_LDISC_CHANGING	20
-#define TTY_LDISC_HALTED	22	/* Line discipline is halted */
+#define TTY_LDISC_HALTED	22
 
 static inline bool tty_io_nonblock(struct tty_struct *tty, struct file *file)
 {

include/linux/tty_driver.h

@@ -2,235 +2,6 @@
 #ifndef _LINUX_TTY_DRIVER_H
 #define _LINUX_TTY_DRIVER_H
 
-/*
- * This structure defines the interface between the low-level tty
- * driver and the tty routines.  The following routines can be
- * defined; unless noted otherwise, they are optional, and can be
- * filled in with a null pointer.
- *
- * struct tty_struct * (*lookup)(struct tty_driver *self, struct file *, int idx)
- *
- *	Return the tty device corresponding to idx, NULL if there is not
- *	one currently in use and an ERR_PTR value on error. Called under
- *	tty_mutex (for now!)
- *
- *	Optional method. Default behaviour is to use the ttys array
- *
- * int (*install)(struct tty_driver *self, struct tty_struct *tty)
- *
- *	Install a new tty into the tty driver internal tables. Used in
- *	conjunction with lookup and remove methods.
- *
- *	Optional method. Default behaviour is to use the ttys array
- *
- * void (*remove)(struct tty_driver *self, struct tty_struct *tty)
- *
- *	Remove a closed tty from the tty driver internal tables. Used in
- *	conjunction with lookup and remove methods.
- *
- *	Optional method. Default behaviour is to use the ttys array
- *
- * int  (*open)(struct tty_struct * tty, struct file * filp);
- *
- * 	This routine is called when a particular tty device is opened.
- * 	This routine is mandatory; if this routine is not filled in,
- * 	the attempted open will fail with ENODEV.
- *
- *	Required method. Called with tty lock held.
- *
- * void (*close)(struct tty_struct * tty, struct file * filp);
- *
- * 	This routine is called when a particular tty device is closed.
- *	Note: called even if the corresponding open() failed.
- *
- *	Required method. Called with tty lock held.
- *
- * void (*shutdown)(struct tty_struct * tty);
- *
- * 	This routine is called under the tty lock when a particular tty device
- *	is closed for the last time. It executes before the tty resources
- *	are freed so may execute while another function holds a tty kref.
- *
- * void (*cleanup)(struct tty_struct * tty);
- *
- *	This routine is called asynchronously when a particular tty device
- *	is closed for the last time freeing up the resources. This is
- *	actually the second part of shutdown for routines that might sleep.
- *
- *
- * int (*write)(struct tty_struct * tty,
- * 		 const unsigned char *buf, int count);
- *
- * 	This routine is called by the kernel to write a series of
- * 	characters to the tty device.  The characters may come from
- * 	user space or kernel space.  This routine will return the
- *	number of characters actually accepted for writing.
- *
- *	Optional: Required for writable devices.
- *
- * int (*put_char)(struct tty_struct *tty, unsigned char ch);
- *
- * 	This routine is called by the kernel to write a single
- * 	character to the tty device.  If the kernel uses this routine,
- * 	it must call the flush_chars() routine (if defined) when it is
- * 	done stuffing characters into the driver.  If there is no room
- * 	in the queue, the character is ignored.
- *
- *	Optional: Kernel will use the write method if not provided.
- *
- *	Note: Do not call this function directly, call tty_put_char
- *
- * void (*flush_chars)(struct tty_struct *tty);
- *
- * 	This routine is called by the kernel after it has written a
- * 	series of characters to the tty device using put_char().  
- *
- *	Optional:
- *
- *	Note: Do not call this function directly, call tty_driver_flush_chars
- * 
- * unsigned int  (*write_room)(struct tty_struct *tty);
- *
- * 	This routine returns the numbers of characters the tty driver
- * 	will accept for queuing to be written.  This number is subject
- * 	to change as output buffers get emptied, or if the output flow
- *	control is acted.
- *
- *	Required if write method is provided else not needed.
- *
- *	Note: Do not call this function directly, call tty_write_room
- * 
- * int  (*ioctl)(struct tty_struct *tty, unsigned int cmd, unsigned long arg);
- *
- * 	This routine allows the tty driver to implement
- *	device-specific ioctls.  If the ioctl number passed in cmd
- * 	is not recognized by the driver, it should return ENOIOCTLCMD.
- *
- *	Optional
- *
- * long (*compat_ioctl)(struct tty_struct *tty,,
- * 	                unsigned int cmd, unsigned long arg);
- *
- * 	implement ioctl processing for 32 bit process on 64 bit system
- *
- *	Optional
- * 
- * void (*set_termios)(struct tty_struct *tty, struct ktermios * old);
- *
- * 	This routine allows the tty driver to be notified when
- * 	device's termios settings have changed.
- *
- *	Optional: Called under the termios lock
- *
- *
- * void (*set_ldisc)(struct tty_struct *tty);
- *
- * 	This routine allows the tty driver to be notified when the
- * 	device's termios settings have changed.
- *
- *	Optional: Called under BKL (currently)
- * 
- * void (*throttle)(struct tty_struct * tty);
- *
- * 	This routine notifies the tty driver that input buffers for
- * 	the line discipline are close to full, and it should somehow
- * 	signal that no more characters should be sent to the tty.
- *
- *	Optional: Always invoke via tty_throttle_safe(), called under the
- *	termios lock.
- * 
- * void (*unthrottle)(struct tty_struct * tty);
- *
- * 	This routine notifies the tty drivers that it should signals
- * 	that characters can now be sent to the tty without fear of
- * 	overrunning the input buffers of the line disciplines.
- * 
- *	Optional: Always invoke via tty_unthrottle(), called under the
- *	termios lock.
- *
- * void (*stop)(struct tty_struct *tty);
- *
- * 	This routine notifies the tty driver that it should stop
- * 	outputting characters to the tty device.  
- *
- *	Called with ->flow.lock held. Serialized with start() method.
- *
- *	Optional:
- *
- *	Note: Call stop_tty not this method.
- * 
- * void (*start)(struct tty_struct *tty);
- *
- * 	This routine notifies the tty driver that it resume sending
- *	characters to the tty device.
- *
- *	Called with ->flow.lock held. Serialized with stop() method.
- *
- *	Optional:
- *
- *	Note: Call start_tty not this method.
- * 
- * void (*hangup)(struct tty_struct *tty);
- *
- * 	This routine notifies the tty driver that it should hang up the
- * 	tty device.
- *
- *	Optional:
- *
- *	Called with tty lock held.
- *
- * int (*break_ctl)(struct tty_struct *tty, int state);
- *
- * 	This optional routine requests the tty driver to turn on or
- * 	off BREAK status on the RS-232 port.  If state is -1,
- * 	then the BREAK status should be turned on; if state is 0, then
- * 	BREAK should be turned off.
- *
- * 	If this routine is implemented, the high-level tty driver will
- * 	handle the following ioctls: TCSBRK, TCSBRKP, TIOCSBRK,
- * 	TIOCCBRK.
- *
- *	If the driver sets TTY_DRIVER_HARDWARE_BREAK then the interface
- *	will also be called with actual times and the hardware is expected
- *	to do the delay work itself. 0 and -1 are still used for on/off.
- *
- *	Optional: Required for TCSBRK/BRKP/etc handling.
- *
- * void (*wait_until_sent)(struct tty_struct *tty, int timeout);
- * 
- * 	This routine waits until the device has written out all of the
- * 	characters in its transmitter FIFO.
- *
- *	Optional: If not provided the device is assumed to have no FIFO
- *
- *	Note: Usually correct to call tty_wait_until_sent
- *
- * void (*send_xchar)(struct tty_struct *tty, char ch);
- *
- * 	This routine is used to send a high-priority XON/XOFF
- * 	character to the device.
- *
- *	Optional: If not provided then the write method is called under
- *	the atomic write lock to keep it serialized with the ldisc.
- *
- * int (*resize)(struct tty_struct *tty, struct winsize *ws)
- *
- *	Called when a termios request is issued which changes the
- *	requested terminal geometry.
- *
- *	Optional: the default action is to update the termios structure
- *	without error. This is usually the correct behaviour. Drivers should
- *	not force errors here if they are not resizable objects (eg a serial
- *	line). See tty_do_resize() if you need to wrap the standard method
- *	in your own logic - the usual case.
- *
- * int (*get_icount)(struct tty_struct *tty, struct serial_icounter *icount);
- *
- *	Called when the device receives a TIOCGICOUNT ioctl. Passed a kernel
- *	structure to complete. This method is optional and will only be called
- *	if provided (otherwise ENOTTY will be returned).
- */
-
 #include <linux/export.h>
 #include <linux/fs.h>
 #include <linux/kref.h>
@@ -244,6 +15,337 @@ struct tty_driver;
 struct serial_icounter_struct;
 struct serial_struct;
 
+/**
+ * struct tty_operations -- interface between driver and tty
+ *
+ * @lookup: ``struct tty_struct *()(struct tty_driver *self, struct file *,
+ *				    int idx)``
+ *
+ *	Return the tty device corresponding to @idx, %NULL if there is not
+ *	one currently in use and an %ERR_PTR value on error. Called under
+ *	%tty_mutex (for now!)
+ *
+ *	Optional method. Default behaviour is to use the @self->ttys array.
+ *
+ * @install: ``int ()(struct tty_driver *self, struct tty_struct *tty)``
+ *
+ *	Install a new @tty into the @self's internal tables. Used in
+ *	conjunction with @lookup and @remove methods.
+ *
+ *	Optional method. Default behaviour is to use the @self->ttys array.
+ *
+ * @remove: ``void ()(struct tty_driver *self, struct tty_struct *tty)``
+ *
+ *	Remove a closed @tty from the @self's internal tables. Used in
+ *	conjunction with @lookup and @remove methods.
+ *
+ *	Optional method. Default behaviour is to use the @self->ttys array.
+ *
+ * @open: ``int ()(struct tty_struct *tty, struct file *)``
+ *
+ *	This routine is called when a particular @tty device is opened. This
+ *	routine is mandatory; if this routine is not filled in, the attempted
+ *	open will fail with %ENODEV.
+ *
+ *	Required method. Called with tty lock held. May sleep.
+ *
+ * @close: ``void ()(struct tty_struct *tty, struct file *)``
+ *
+ *	This routine is called when a particular @tty device is closed. At the
+ *	point of return from this call the driver must make no further ldisc
+ *	calls of any kind.
+ *
+ *	Remark: called even if the corresponding @open() failed.
+ *
+ *	Required method. Called with tty lock held. May sleep.
+ *
+ * @shutdown: ``void ()(struct tty_struct *tty)``
+ *
+ *	This routine is called under the tty lock when a particular @tty device
+ *	is closed for the last time. It executes before the @tty resources
+ *	are freed so may execute while another function holds a @tty kref.
+ *
+ * @cleanup: ``void ()(struct tty_struct *tty)``
+ *
+ *	This routine is called asynchronously when a particular @tty device
+ *	is closed for the last time freeing up the resources. This is
+ *	actually the second part of shutdown for routines that might sleep.
+ *
+ * @write: ``int ()(struct tty_struct *tty, const unsigned char *buf,
+ *		    int count)``
+ *
+ *	This routine is called by the kernel to write a series (@count) of
+ *	characters (@buf) to the @tty device. The characters may come from
+ *	user space or kernel space.  This routine will return the
+ *	number of characters actually accepted for writing.
+ *
+ *	May occur in parallel in special cases. Because this includes panic
+ *	paths drivers generally shouldn't try and do clever locking here.
+ *
+ *	Optional: Required for writable devices. May not sleep.
+ *
+ * @put_char: ``int ()(struct tty_struct *tty, unsigned char ch)``
+ *
+ *	This routine is called by the kernel to write a single character @ch to
+ *	the @tty device. If the kernel uses this routine, it must call the
+ *	@flush_chars() routine (if defined) when it is done stuffing characters
+ *	into the driver. If there is no room in the queue, the character is
+ *	ignored.
+ *
+ *	Optional: Kernel will use the @write method if not provided. Do not
+ *	call this function directly, call tty_put_char().
+ *
+ * @flush_chars: ``void ()(struct tty_struct *tty)``
+ *
+ *	This routine is called by the kernel after it has written a
+ *	series of characters to the tty device using @put_char().
+ *
+ *	Optional. Do not call this function directly, call
+ *	tty_driver_flush_chars().
+ *
+ * @write_room: ``unsigned int ()(struct tty_struct *tty)``
+ *
+ *	This routine returns the numbers of characters the @tty driver
+ *	will accept for queuing to be written.  This number is subject
+ *	to change as output buffers get emptied, or if the output flow
+ *	control is acted.
+ *
+ *	The ldisc is responsible for being intelligent about multi-threading of
+ *	write_room/write calls
+ *
+ *	Required if @write method is provided else not needed. Do not call this
+ *	function directly, call tty_write_room()
+ *
+ * @chars_in_buffer: ``unsigned int ()(struct tty_struct *tty)``
+ *
+ *	This routine returns the number of characters in the device private
+ *	output queue. Used in tty_wait_until_sent() and for poll()
+ *	implementation.
+ *
+ *	Optional: if not provided, it is assumed there is no queue on the
+ *	device. Do not call this function directly, call tty_chars_in_buffer().
+ *
+ * @ioctl: ``int ()(struct tty_struct *tty, unsigned int cmd,
+ *		    unsigned long arg)``
+ *
+ *	This routine allows the @tty driver to implement device-specific
+ *	ioctls. If the ioctl number passed in @cmd is not recognized by the
+ *	driver, it should return %ENOIOCTLCMD.
+ *
+ *	Optional.
+ *
+ * @compat_ioctl: ``long ()(struct tty_struct *tty, unsigned int cmd,
+ *			  unsigned long arg)``
+ *
+ *	Implement ioctl processing for 32 bit process on 64 bit system.
+ *
+ *	Optional.
+ *
+ * @set_termios: ``void ()(struct tty_struct *tty, struct ktermios *old)``
+ *
+ *	This routine allows the @tty driver to be notified when device's
+ *	termios settings have changed. New settings are in @tty->termios.
+ *	Previous settings are passed in the @old argument.
+ *
+ *	The API is defined such that the driver should return the actual modes
+ *	selected. This means that the driver is responsible for modifying any
+ *	bits in @tty->termios it cannot fulfill to indicate the actual modes
+ *	being used.
+ *
+ *	Optional. Called under the @tty->termios_rwsem. May sleep.
+ *
+ * @set_ldisc: ``void ()(struct tty_struct *tty)``
+ *
+ *	This routine allows the @tty driver to be notified when the device's
+ *	line discipline is being changed. At the point this is done the
+ *	discipline is not yet usable.
+ *
+ *	Optional. Called under the @tty->ldisc_sem and @tty->termios_rwsem.
+ *
+ * @throttle: ``void ()(struct tty_struct *tty)``
+ *
+ *	This routine notifies the @tty driver that input buffers for the line
+ *	discipline are close to full, and it should somehow signal that no more
+ *	characters should be sent to the @tty.
+ *
+ *	Serialization including with @unthrottle() is the job of the ldisc
+ *	layer.
+ *
+ *	Optional: Always invoke via tty_throttle_safe(). Called under the
+ *	@tty->termios_rwsem.
+ *
+ * @unthrottle: ``void ()(struct tty_struct *tty)``
+ *
+ *	This routine notifies the @tty driver that it should signal that
+ *	characters can now be sent to the @tty without fear of overrunning the
+ *	input buffers of the line disciplines.
+ *
+ *	Optional. Always invoke via tty_unthrottle(). Called under the
+ *	@tty->termios_rwsem.
+ *
+ * @stop: ``void ()(struct tty_struct *tty)``
+ *
+ *	This routine notifies the @tty driver that it should stop outputting
+ *	characters to the tty device.
+ *
+ *	Called with @tty->flow.lock held. Serialized with @start() method.
+ *
+ *	Optional. Always invoke via stop_tty().
+ *
+ * @start: ``void ()(struct tty_struct *tty)``
+ *
+ *	This routine notifies the @tty driver that it resumed sending
+ *	characters to the @tty device.
+ *
+ *	Called with @tty->flow.lock held. Serialized with stop() method.
+ *
+ *	Optional. Always invoke via start_tty().
+ *
+ * @hangup: ``void ()(struct tty_struct *tty)``
+ *
+ *	This routine notifies the @tty driver that it should hang up the @tty
+ *	device.
+ *
+ *	Optional. Called with tty lock held.
+ *
+ * @break_ctl: ``int ()(struct tty_struct *tty, int state)``
+ *
+ *	This optional routine requests the @tty driver to turn on or off BREAK
+ *	status on the RS-232 port. If @state is -1, then the BREAK status
+ *	should be turned on; if @state is 0, then BREAK should be turned off.
+ *
+ *	If this routine is implemented, the high-level tty driver will handle
+ *	the following ioctls: %TCSBRK, %TCSBRKP, %TIOCSBRK, %TIOCCBRK.
+ *
+ *	If the driver sets %TTY_DRIVER_HARDWARE_BREAK in tty_alloc_driver(),
+ *	then the interface will also be called with actual times and the
+ *	hardware is expected to do the delay work itself. 0 and -1 are still
+ *	used for on/off.
+ *
+ *	Optional: Required for %TCSBRK/%BRKP/etc. handling. May sleep.
+ *
+ * @flush_buffer: ``void ()(struct tty_struct *tty)``
+ *
+ *	This routine discards device private output buffer. Invoked on close,
+ *	hangup, to implement %TCOFLUSH ioctl and similar.
+ *
+ *	Optional: if not provided, it is assumed there is no queue on the
+ *	device. Do not call this function directly, call
+ *	tty_driver_flush_buffer().
+ *
+ * @wait_until_sent: ``void ()(struct tty_struct *tty, int timeout)``
+ *
+ *	This routine waits until the device has written out all of the
+ *	characters in its transmitter FIFO. Or until @timeout (in jiffies) is
+ *	reached.
+ *
+ *	Optional: If not provided, the device is assumed to have no FIFO.
+ *	Usually correct to invoke via tty_wait_until_sent(). May sleep.
+ *
+ * @send_xchar: ``void ()(struct tty_struct *tty, char ch)``
+ *
+ *	This routine is used to send a high-priority XON/XOFF character (@ch)
+ *	to the @tty device.
+ *
+ *	Optional: If not provided, then the @write method is called under
+ *	the @tty->atomic_write_lock to keep it serialized with the ldisc.
+ *
+ * @tiocmget: ``int ()(struct tty_struct *tty)``
+ *
+ *	This routine is used to obtain the modem status bits from the @tty
+ *	driver.
+ *
+ *	Optional: If not provided, then %ENOTTY is returned from the %TIOCMGET
+ *	ioctl. Do not call this function directly, call tty_tiocmget().
+ *
+ * @tiocmset: ``int ()(struct tty_struct *tty,
+ *		       unsigned int set, unsigned int clear)``
+ *
+ *	This routine is used to set the modem status bits to the @tty driver.
+ *	First, @clear bits should be cleared, then @set bits set.
+ *
+ *	Optional: If not provided, then %ENOTTY is returned from the %TIOCMSET
+ *	ioctl. Do not call this function directly, call tty_tiocmset().
+ *
+ * @resize: ``int ()(struct tty_struct *tty, struct winsize *ws)``
+ *
+ *	Called when a termios request is issued which changes the requested
+ *	terminal geometry to @ws.
+ *
+ *	Optional: the default action is to update the termios structure
+ *	without error. This is usually the correct behaviour. Drivers should
+ *	not force errors here if they are not resizable objects (e.g. a serial
+ *	line). See tty_do_resize() if you need to wrap the standard method
+ *	in your own logic -- the usual case.
+ *
+ * @get_icount: ``int ()(struct tty_struct *tty,
+ *			 struct serial_icounter *icount)``
+ *
+ *	Called when the @tty device receives a %TIOCGICOUNT ioctl. Passed a
+ *	kernel structure @icount to complete.
+ *
+ *	Optional: called only if provided, otherwise %ENOTTY will be returned.
+ *
+ * @get_serial: ``int ()(struct tty_struct *tty, struct serial_struct *p)``
+ *
+ *	Called when the @tty device receives a %TIOCGSERIAL ioctl. Passed a
+ *	kernel structure @p (&struct serial_struct) to complete.
+ *
+ *	Optional: called only if provided, otherwise %ENOTTY will be returned.
+ *	Do not call this function directly, call tty_tiocgserial().
+ *
+ * @set_serial: ``int ()(struct tty_struct *tty, struct serial_struct *p)``
+ *
+ *	Called when the @tty device receives a %TIOCSSERIAL ioctl. Passed a
+ *	kernel structure @p (&struct serial_struct) to set the values from.
+ *
+ *	Optional: called only if provided, otherwise %ENOTTY will be returned.
+ *	Do not call this function directly, call tty_tiocsserial().
+ *
+ * @show_fdinfo: ``void ()(struct tty_struct *tty, struct seq_file *m)``
+ *
+ *	Called when the @tty device file descriptor receives a fdinfo request
+ *	from VFS (to show in /proc/<pid>/fdinfo/). @m should be filled with
+ *	information.
+ *
+ *	Optional: called only if provided, otherwise nothing is written to @m.
+ *	Do not call this function directly, call tty_show_fdinfo().
+ *
+ * @poll_init: ``int ()(struct tty_driver *driver, int line, char *options)``
+ *
+ *	kgdboc support (Documentation/dev-tools/kgdb.rst). This routine is
+ *	called to initialize the HW for later use by calling @poll_get_char or
+ *	@poll_put_char.
+ *
+ *	Optional: called only if provided, otherwise skipped as a non-polling
+ *	driver.
+ *
+ * @poll_get_char: ``int ()(struct tty_driver *driver, int line)``
+ *
+ *	kgdboc support (see @poll_init). @driver should read a character from a
+ *	tty identified by @line and return it.
+ *
+ *	Optional: called only if @poll_init provided.
+ *
+ * @poll_put_char: ``void ()(struct tty_driver *driver, int line, char ch)``
+ *
+ *	kgdboc support (see @poll_init). @driver should write character @ch to
+ *	a tty identified by @line.
+ *
+ *	Optional: called only if @poll_init provided.
+ *
+ * @proc_show: ``int ()(struct seq_file *m, void *driver)``
+ *
+ *	Driver @driver (cast to &struct tty_driver) can show additional info in
+ *	/proc/tty/driver/<driver_name>. It is enough to fill in the information
+ *	into @m.
+ *
+ *	Optional: called only if provided, otherwise no /proc entry created.
+ *
+ * This structure defines the interface between the low-level tty driver and
+ * the tty routines. These routines can be defined. Unless noted otherwise,
+ * they are optional, and can be filled in with a %NULL pointer.
+ */
 struct tty_operations {
 	struct tty_struct * (*lookup)(struct tty_driver *driver,
 			struct file *filp, int idx);
@@ -288,26 +390,64 @@ struct tty_operations {
 	int (*poll_get_char)(struct tty_driver *driver, int line);
 	void (*poll_put_char)(struct tty_driver *driver, int line, char ch);
 #endif
-	int (*proc_show)(struct seq_file *, void *);
+	int (*proc_show)(struct seq_file *m, void *driver);
 } __randomize_layout;
 
+/**
+ * struct tty_driver -- driver for TTY devices
+ *
+ * @magic: set to %TTY_DRIVER_MAGIC in __tty_alloc_driver()
+ * @kref: reference counting. Reaching zero frees all the internals and the
+ *	  driver.
+ * @cdevs: allocated/registered character /dev devices
+ * @owner: modules owning this driver. Used drivers cannot be rmmod'ed.
+ *	   Automatically set by tty_alloc_driver().
+ * @driver_name: name of the driver used in /proc/tty
+ * @name: used for constructing /dev node name
+ * @name_base: used as a number base for constructing /dev node name
+ * @major: major /dev device number (zero for autoassignment)
+ * @minor_start: the first minor /dev device number
+ * @num: number of devices allocated
+ * @type: type of tty driver (%TTY_DRIVER_TYPE_)
+ * @subtype: subtype of tty driver (%SYSTEM_TYPE_, %PTY_TYPE_, %SERIAL_TYPE_)
+ * @init_termios: termios to set to each tty initially (e.g. %tty_std_termios)
+ * @flags: tty driver flags (%TTY_DRIVER_)
+ * @proc_entry: proc fs entry, used internally
+ * @other: driver of the linked tty; only used for the PTY driver
+ * @ttys: array of active &struct tty_struct, set by tty_standard_install()
+ * @ports: array of &struct tty_port; can be set during initialization by
+ *	   tty_port_link_device() and similar
+ * @termios: storage for termios at each TTY close for the next open
+ * @driver_state: pointer to driver's arbitrary data
+ * @ops: driver hooks for TTYs. Set them using tty_set_operations(). Use &struct
+ *	 tty_port helpers in them as much as possible.
+ * @tty_drivers: used internally to link tty_drivers together
+ *
+ * The usual handling of &struct tty_driver is to allocate it by
+ * tty_alloc_driver(), set up all the necessary members, and register it by
+ * tty_register_driver(). At last, the driver is torn down by calling
+ * tty_unregister_driver() followed by tty_driver_kref_put().
+ *
+ * The fields required to be set before calling tty_register_driver() include
+ * @driver_name, @name, @type, @subtype, @init_termios, and @ops.
+ */
 struct tty_driver {
-	int	magic;		/* magic number for this structure */
+	int	magic;
-	struct kref kref;	/* Reference management */
+	struct kref kref;
 	struct cdev **cdevs;
 	struct module	*owner;
 	const char	*driver_name;
 	const char	*name;
-	int	name_base;	/* offset of printed name */
+	int	name_base;
-	int	major;		/* major device number */
+	int	major;
-	int	minor_start;	/* start of minor device number */
+	int	minor_start;
-	unsigned int	num;	/* number of devices allocated */
+	unsigned int	num;
-	short	type;		/* type of tty driver */
+	short	type;
-	short	subtype;	/* subtype of tty driver */
+	short	subtype;
-	struct ktermios init_termios; /* Initial termios */
+	struct ktermios init_termios;
-	unsigned long	flags;		/* tty driver flags */
+	unsigned long	flags;
-	struct proc_dir_entry *proc_entry; /* /proc fs entry */
+	struct proc_dir_entry *proc_entry;
-	struct tty_driver *other; /* only used for the PTY driver */
+	struct tty_driver *other;
 
 	/*
 	 * Pointer to the tty data structures
@@ -352,49 +492,53 @@ static inline void tty_set_operations(struct tty_driver *driver,
 /* tty driver magic number */
 #define TTY_DRIVER_MAGIC		0x5402
 
-/*
+/**
- * tty driver flags
+ * DOC: TTY Driver Flags
  *
- * TTY_DRIVER_RESET_TERMIOS --- requests the tty layer to reset the
+ * TTY_DRIVER_RESET_TERMIOS
- * 	termios setting when the last process has closed the device.
+ *	Requests the tty layer to reset the termios setting when the last
- * 	Used for PTY's, in particular.
+ *	process has closed the device. Used for PTYs, in particular.
  *
- * TTY_DRIVER_REAL_RAW --- if set, indicates that the driver will
+ * TTY_DRIVER_REAL_RAW
- * 	guarantee never to set any special character handling
+ *	Indicates that the driver will guarantee not to set any special
- * 	flags if ((IGNBRK || (!BRKINT && !PARMRK)) && (IGNPAR ||
+ *	character handling flags if this is set for the tty:
- * 	!INPCK)).  That is, if there is no reason for the driver to
- * 	send notifications of parity and break characters up to the
- * 	line driver, it won't do so.  This allows the line driver to
- *	optimize for this case if this flag is set.  (Note that there
- * 	is also a promise, if the above case is true, not to signal
- * 	overruns, either.)
  *
- * TTY_DRIVER_DYNAMIC_DEV --- if set, the individual tty devices need
+ *	``(IGNBRK || (!BRKINT && !PARMRK)) && (IGNPAR || !INPCK)``
- *	to be registered with a call to tty_register_device() when the
- *	device is found in the system and unregistered with a call to
- *	tty_unregister_device() so the devices will be show up
- *	properly in sysfs.  If not set, driver->num entries will be
- *	created by the tty core in sysfs when tty_register_driver() is
- *	called.  This is to be used by drivers that have tty devices
- *	that can appear and disappear while the main tty driver is
- *	registered with the tty core.
  *
- * TTY_DRIVER_DEVPTS_MEM -- don't use the standard arrays, instead
+ *	That is, if there is no reason for the driver to
- *	use dynamic memory keyed through the devpts filesystem.  This
+ *	send notifications of parity and break characters up to the line
- *	is only applicable to the pty driver.
+ *	driver, it won't do so.  This allows the line driver to optimize for
+ *	this case if this flag is set.  (Note that there is also a promise, if
+ *	the above case is true, not to signal overruns, either.)
  *
- * TTY_DRIVER_HARDWARE_BREAK -- hardware handles break signals. Pass
+ * TTY_DRIVER_DYNAMIC_DEV
- *	the requested timeout to the caller instead of using a simple
+ *	The individual tty devices need to be registered with a call to
- *	on/off interface.
+ *	tty_register_device() when the device is found in the system and
+ *	unregistered with a call to tty_unregister_device() so the devices will
+ *	be show up properly in sysfs.  If not set, all &tty_driver.num entries
+ *	will be created by the tty core in sysfs when tty_register_driver() is
+ *	called.  This is to be used by drivers that have tty devices that can
+ *	appear and disappear while the main tty driver is registered with the
+ *	tty core.
  *
- * TTY_DRIVER_DYNAMIC_ALLOC -- do not allocate structures which are
+ * TTY_DRIVER_DEVPTS_MEM
- *	needed per line for this driver as it would waste memory.
+ *	Don't use the standard arrays (&tty_driver.ttys and
- *	The driver will take care.
+ *	&tty_driver.termios), instead use dynamic memory keyed through the
+ *	devpts filesystem. This is only applicable to the PTY driver.
  *
- * TTY_DRIVER_UNNUMBERED_NODE -- do not create numbered /dev nodes. In
+ * TTY_DRIVER_HARDWARE_BREAK
- *	other words create /dev/ttyprintk and not /dev/ttyprintk0.
+ *	Hardware handles break signals. Pass the requested timeout to the
- *	Applicable only when a driver for a single tty device is
+ *	&tty_operations.break_ctl instead of using a simple on/off interface.
- *	being allocated.
+ *
+ * TTY_DRIVER_DYNAMIC_ALLOC
+ *	Do not allocate structures which are needed per line for this driver
+ *	(&tty_driver.ports) as it would waste memory. The driver will take
+ *	care. This is only applicable to the PTY driver.
+ *
+ * TTY_DRIVER_UNNUMBERED_NODE
+ *	Do not create numbered ``/dev`` nodes. For example, create
+ *	``/dev/ttyprintk`` and not ``/dev/ttyprintk0``. Applicable only when a
+ *	driver for a single tty device is being allocated.
  */
 #define TTY_DRIVER_INSTALLED		0x0001
 #define TTY_DRIVER_RESET_TERMIOS	0x0002

include/linux/tty_flip.h

@@ -17,7 +17,6 @@ int tty_insert_flip_string_fixed_flag(struct tty_port *port,
 int tty_prepare_flip_string(struct tty_port *port, unsigned char **chars,
 		size_t size);
 void tty_flip_buffer_push(struct tty_port *port);
-void tty_schedule_flip(struct tty_port *port);
 int __tty_insert_flip_char(struct tty_port *port, unsigned char ch, char flag);
 
 static inline int tty_insert_flip_char(struct tty_port *port,

include/linux/tty_ldisc.h

@@ -4,127 +4,6 @@
 
 struct tty_struct;
 
-/*
- * This structure defines the interface between the tty line discipline
- * implementation and the tty routines.  The following routines can be
- * defined; unless noted otherwise, they are optional, and can be
- * filled in with a null pointer.
- *
- * int	(*open)(struct tty_struct *);
- *
- *	This function is called when the line discipline is associated
- *	with the tty.  The line discipline can use this as an
- *	opportunity to initialize any state needed by the ldisc routines.
- *
- * void	(*close)(struct tty_struct *);
- *
- *	This function is called when the line discipline is being
- *	shutdown, either because the tty is being closed or because
- *	the tty is being changed to use a new line discipline
- *
- * void	(*flush_buffer)(struct tty_struct *tty);
- *
- *	This function instructs the line discipline to clear its
- *	buffers of any input characters it may have queued to be
- *	delivered to the user mode process.
- *
- * ssize_t (*read)(struct tty_struct * tty, struct file * file,
- *		   unsigned char * buf, size_t nr);
- *
- *	This function is called when the user requests to read from
- *	the tty.  The line discipline will return whatever characters
- *	it has buffered up for the user.  If this function is not
- *	defined, the user will receive an EIO error.
- *
- * ssize_t (*write)(struct tty_struct * tty, struct file * file,
- *		    const unsigned char * buf, size_t nr);
- *
- *	This function is called when the user requests to write to the
- *	tty.  The line discipline will deliver the characters to the
- *	low-level tty device for transmission, optionally performing
- *	some processing on the characters first.  If this function is
- *	not defined, the user will receive an EIO error.
- *
- * int	(*ioctl)(struct tty_struct * tty, struct file * file,
- *		 unsigned int cmd, unsigned long arg);
- *
- *	This function is called when the user requests an ioctl which
- *	is not handled by the tty layer or the low-level tty driver.
- *	It is intended for ioctls which affect line discpline
- *	operation.  Note that the search order for ioctls is (1) tty
- *	layer, (2) tty low-level driver, (3) line discpline.  So a
- *	low-level driver can "grab" an ioctl request before the line
- *	discpline has a chance to see it.
- *
- * int	(*compat_ioctl)(struct tty_struct * tty, struct file * file,
- *		        unsigned int cmd, unsigned long arg);
- *
- *	Process ioctl calls from 32-bit process on 64-bit system
- *
- *	NOTE: only ioctls that are neither "pointer to compatible
- *	structure" nor tty-generic.  Something private that takes
- *	an integer or a pointer to wordsize-sensitive structure
- *	belongs here, but most of ldiscs will happily leave
- *	it NULL.
- *
- * void	(*set_termios)(struct tty_struct *tty, struct ktermios * old);
- *
- *	This function notifies the line discpline that a change has
- *	been made to the termios structure.
- *
- * int	(*poll)(struct tty_struct * tty, struct file * file,
- *		  poll_table *wait);
- *
- *	This function is called when a user attempts to select/poll on a
- *	tty device.  It is solely the responsibility of the line
- *	discipline to handle poll requests.
- *
- * void	(*receive_buf)(struct tty_struct *, const unsigned char *cp,
- *		       char *fp, int count);
- *
- *	This function is called by the low-level tty driver to send
- *	characters received by the hardware to the line discpline for
- *	processing.  <cp> is a pointer to the buffer of input
- *	character received by the device.  <fp> is a pointer to a
- *	pointer of flag bytes which indicate whether a character was
- *	received with a parity error, etc. <fp> may be NULL to indicate
- *	all data received is TTY_NORMAL.
- *
- * void	(*write_wakeup)(struct tty_struct *);
- *
- *	This function is called by the low-level tty driver to signal
- *	that line discpline should try to send more characters to the
- *	low-level driver for transmission.  If the line discpline does
- *	not have any more data to send, it can just return. If the line
- *	discipline does have some data to send, please arise a tasklet
- *	or workqueue to do the real data transfer. Do not send data in
- *	this hook, it may leads to a deadlock.
- *
- * int (*hangup)(struct tty_struct *)
- *
- *	Called on a hangup. Tells the discipline that it should
- *	cease I/O to the tty driver. Can sleep. The driver should
- *	seek to perform this action quickly but should wait until
- *	any pending driver I/O is completed.
- *
- * void (*dcd_change)(struct tty_struct *tty, unsigned int status)
- *
- *	Tells the discipline that the DCD pin has changed its status.
- *	Used exclusively by the N_PPS (Pulse-Per-Second) line discipline.
- *
- * int	(*receive_buf2)(struct tty_struct *, const unsigned char *cp,
- *			char *fp, int count);
- *
- *	This function is called by the low-level tty driver to send
- *	characters received by the hardware to the line discpline for
- *	processing.  <cp> is a pointer to the buffer of input
- *	character received by the device.  <fp> is a pointer to a
- *	pointer of flag bytes which indicate whether a character was
- *	received with a parity error, etc. <fp> may be NULL to indicate
- *	all data received is TTY_NORMAL.
- *	If assigned, prefer this function for automatic flow control.
- */
-
 #include <linux/fs.h>
 #include <linux/wait.h>
 #include <linux/atomic.h>
@@ -176,7 +55,147 @@ int ldsem_down_write_nested(struct ld_semaphore *sem, int subclass,
 		ldsem_down_write(sem, timeout)
 #endif
 
-
+/**
+ * struct tty_ldisc_ops - ldisc operations
+ *
+ * @name: name of this ldisc rendered in /proc/tty/ldiscs
+ * @num: ``N_*`` number (%N_TTY, %N_HDLC, ...) reserved to this ldisc
+ *
+ * @open: [TTY] ``int ()(struct tty_struct *tty)``
+ *
+ *	This function is called when the line discipline is associated with the
+ *	@tty. No other call into the line discipline for this tty will occur
+ *	until it completes successfully. It should initialize any state needed
+ *	by the ldisc, and set @tty->receive_room to the maximum amount of data
+ *	the line discipline is willing to accept from the driver with a single
+ *	call to @receive_buf(). Returning an error will prevent the ldisc from
+ *	being attached.
+ *
+ *	Can sleep.
+ *
+ * @close: [TTY] ``void ()(struct tty_struct *tty)``
+ *
+ *	This function is called when the line discipline is being shutdown,
+ *	either because the @tty is being closed or because the @tty is being
+ *	changed to use a new line discipline. At the point of execution no
+ *	further users will enter the ldisc code for this tty.
+ *
+ *	Can sleep.
+ *
+ * @flush_buffer: [TTY] ``void ()(struct tty_struct *tty)``
+ *
+ *	This function instructs the line discipline to clear its buffers of any
+ *	input characters it may have queued to be delivered to the user mode
+ *	process. It may be called at any point between open and close.
+ *
+ * @read: [TTY] ``ssize_t ()(struct tty_struct *tty, struct file *file,
+ *		unsigned char *buf, size_t nr)``
+ *
+ *	This function is called when the user requests to read from the @tty.
+ *	The line discipline will return whatever characters it has buffered up
+ *	for the user. If this function is not defined, the user will receive
+ *	an %EIO error. Multiple read calls may occur in parallel and the ldisc
+ *	must deal with serialization issues.
+ *
+ *	Can sleep.
+ *
+ * @write: [TTY] ``ssize_t ()(struct tty_struct *tty, struct file *file,
+ *		const unsigned char *buf, size_t nr)``
+ *
+ *	This function is called when the user requests to write to the @tty.
+ *	The line discipline will deliver the characters to the low-level tty
+ *	device for transmission, optionally performing some processing on the
+ *	characters first. If this function is not defined, the user will
+ *	receive an %EIO error.
+ *
+ *	Can sleep.
+ *
+ * @ioctl: [TTY] ``int ()(struct tty_struct *tty, unsigned int cmd,
+ *		unsigned long arg)``
+ *
+ *	This function is called when the user requests an ioctl which is not
+ *	handled by the tty layer or the low-level tty driver. It is intended
+ *	for ioctls which affect line discpline operation.  Note that the search
+ *	order for ioctls is (1) tty layer, (2) tty low-level driver, (3) line
+ *	discpline. So a low-level driver can "grab" an ioctl request before
+ *	the line discpline has a chance to see it.
+ *
+ * @compat_ioctl: [TTY] ``int ()(struct tty_struct *tty, unsigned int cmd,
+ *		unsigned long arg)``
+ *
+ *	Process ioctl calls from 32-bit process on 64-bit system.
+ *
+ *	Note that only ioctls that are neither "pointer to compatible
+ *	structure" nor tty-generic.  Something private that takes an integer or
+ *	a pointer to wordsize-sensitive structure belongs here, but most of
+ *	ldiscs will happily leave it %NULL.
+ *
+ * @set_termios: [TTY] ``void ()(struct tty_struct *tty, struct ktermios *old)``
+ *
+ *	This function notifies the line discpline that a change has been made
+ *	to the termios structure.
+ *
+ * @poll: [TTY] ``int ()(struct tty_struct *tty, struct file *file,
+ *		  struct poll_table_struct *wait)``
+ *
+ *	This function is called when a user attempts to select/poll on a @tty
+ *	device. It is solely the responsibility of the line discipline to
+ *	handle poll requests.
+ *
+ * @hangup: [TTY] ``void ()(struct tty_struct *tty)``
+ *
+ *	Called on a hangup. Tells the discipline that it should cease I/O to
+ *	the tty driver. The driver should seek to perform this action quickly
+ *	but should wait until any pending driver I/O is completed. No further
+ *	calls into the ldisc code will occur.
+ *
+ *	Can sleep.
+ *
+ * @receive_buf: [DRV] ``void ()(struct tty_struct *tty,
+ *		       const unsigned char *cp, const char *fp, int count)``
+ *
+ *	This function is called by the low-level tty driver to send characters
+ *	received by the hardware to the line discpline for processing. @cp is
+ *	a pointer to the buffer of input character received by the device. @fp
+ *	is a pointer to an array of flag bytes which indicate whether a
+ *	character was received with a parity error, etc. @fp may be %NULL to
+ *	indicate all data received is %TTY_NORMAL.
+ *
+ * @write_wakeup: [DRV] ``void ()(struct tty_struct *tty)``
+ *
+ *	This function is called by the low-level tty driver to signal that line
+ *	discpline should try to send more characters to the low-level driver
+ *	for transmission. If the line discpline does not have any more data to
+ *	send, it can just return. If the line discipline does have some data to
+ *	send, please arise a tasklet or workqueue to do the real data transfer.
+ *	Do not send data in this hook, it may lead to a deadlock.
+ *
+ * @dcd_change: [DRV] ``void ()(struct tty_struct *tty, unsigned int status)``
+ *
+ *	Tells the discipline that the DCD pin has changed its status. Used
+ *	exclusively by the %N_PPS (Pulse-Per-Second) line discipline.
+ *
+ * @receive_buf2: [DRV] ``int ()(struct tty_struct *tty,
+ *			const unsigned char *cp, const char *fp, int count)``
+ *
+ *	This function is called by the low-level tty driver to send characters
+ *	received by the hardware to the line discpline for processing. @cp is a
+ *	pointer to the buffer of input character received by the device.  @fp
+ *	is a pointer to an array of flag bytes which indicate whether a
+ *	character was received with a parity error, etc. @fp may be %NULL to
+ *	indicate all data received is %TTY_NORMAL. If assigned, prefer this
+ *	function for automatic flow control.
+ *
+ * @owner: module containting this ldisc (for reference counting)
+ *
+ * This structure defines the interface between the tty line discipline
+ * implementation and the tty routines. The above routines can be defined.
+ * Unless noted otherwise, they are optional, and can be filled in with a %NULL
+ * pointer.
+ *
+ * Hooks marked [TTY] are invoked from the TTY core, the [DRV] ones from the
+ * tty_driver side.
+ */
 struct tty_ldisc_ops {
 	char	*name;
 	int	num;
@@ -184,31 +203,31 @@ struct tty_ldisc_ops {
 	/*
 	 * The following routines are called from above.
 	 */
-	int	(*open)(struct tty_struct *);
+	int	(*open)(struct tty_struct *tty);
-	void	(*close)(struct tty_struct *);
+	void	(*close)(struct tty_struct *tty);
 	void	(*flush_buffer)(struct tty_struct *tty);
 	ssize_t	(*read)(struct tty_struct *tty, struct file *file,
 			unsigned char *buf, size_t nr,
 			void **cookie, unsigned long offset);
 	ssize_t	(*write)(struct tty_struct *tty, struct file *file,
 			 const unsigned char *buf, size_t nr);
-	int	(*ioctl)(struct tty_struct *tty, struct file *file,
+	int	(*ioctl)(struct tty_struct *tty, unsigned int cmd,
-			 unsigned int cmd, unsigned long arg);
+			unsigned long arg);
-	int	(*compat_ioctl)(struct tty_struct *tty, struct file *file,
+	int	(*compat_ioctl)(struct tty_struct *tty, unsigned int cmd,
-				unsigned int cmd, unsigned long arg);
+			unsigned long arg);
 	void	(*set_termios)(struct tty_struct *tty, struct ktermios *old);
-	__poll_t (*poll)(struct tty_struct *, struct file *,
+	__poll_t (*poll)(struct tty_struct *tty, struct file *file,
-			     struct poll_table_struct *);
+			     struct poll_table_struct *wait);
 	void	(*hangup)(struct tty_struct *tty);
 
 	/*
 	 * The following routines are called from below.
 	 */
-	void	(*receive_buf)(struct tty_struct *, const unsigned char *cp,
+	void	(*receive_buf)(struct tty_struct *tty, const unsigned char *cp,
 			       const char *fp, int count);
-	void	(*write_wakeup)(struct tty_struct *);
+	void	(*write_wakeup)(struct tty_struct *tty);
-	void	(*dcd_change)(struct tty_struct *, unsigned int);
+	void	(*dcd_change)(struct tty_struct *tty, unsigned int status);
-	int	(*receive_buf2)(struct tty_struct *, const unsigned char *cp,
+	int	(*receive_buf2)(struct tty_struct *tty, const unsigned char *cp,
 				const char *fp, int count);
 
 	struct  module *owner;

include/linux/tty_port.h

@@ -7,37 +7,33 @@
 #include <linux/tty_buffer.h>
 #include <linux/wait.h>
 
-/*
- * Port level information. Each device keeps its own port level information
- * so provide a common structure for those ports wanting to use common support
- * routines.
- *
- * The tty port has a different lifetime to the tty so must be kept apart.
- * In addition be careful as tty -> port mappings are valid for the life
- * of the tty object but in many cases port -> tty mappings are valid only
- * until a hangup so don't use the wrong path.
- */
-
 struct attribute_group;
 struct tty_driver;
 struct tty_port;
 struct tty_struct;
 
+/**
+ * struct tty_port_operations -- operations on tty_port
+ * @carrier_raised: return 1 if the carrier is raised on @port
+ * @dtr_rts: raise the DTR line if @raise is nonzero, otherwise lower DTR
+ * @shutdown: called when the last close completes or a hangup finishes IFF the
+ *	port was initialized. Do not use to free resources. Turn off the device
+ *	only. Called under the port mutex to serialize against @activate and
+ *	@shutdown.
+ * @activate: called under the port mutex from tty_port_open(), serialized using
+ *	the port mutex. Supposed to turn on the device.
+ *
+ *	FIXME: long term getting the tty argument *out* of this would be good
+ *	for consoles.
+ *
+ * @destruct: called on the final put of a port. Free resources, possibly incl.
+ *	the port itself.
+ */
 struct tty_port_operations {
-	/* Return 1 if the carrier is raised */
 	int (*carrier_raised)(struct tty_port *port);
-	/* Control the DTR line */
 	void (*dtr_rts)(struct tty_port *port, int raise);
-	/* Called when the last close completes or a hangup finishes
-	   IFF the port was initialized. Do not use to free resources. Called
-	   under the port mutex to serialize against activate/shutdowns */
 	void (*shutdown)(struct tty_port *port);
-	/* Called under the port mutex from tty_port_open, serialized using
-	   the port mutex */
-        /* FIXME: long term getting the tty argument *out* of this would be
-           good for consoles */
 	int (*activate)(struct tty_port *port, struct tty_struct *tty);
-	/* Called on the final put of a port */
 	void (*destruct)(struct tty_port *port);
 };
 
@@ -48,29 +44,76 @@ struct tty_port_client_operations {
 
 extern const struct tty_port_client_operations tty_port_default_client_ops;
 
+/**
+ * struct tty_port -- port level information
+ *
+ * @buf: buffer for this port, locked internally
+ * @tty: back pointer to &struct tty_struct, valid only if the tty is open. Use
+ *	 tty_port_tty_get() to obtain it (and tty_kref_put() to release).
+ * @itty: internal back pointer to &struct tty_struct. Avoid this. It should be
+ *	  eliminated in the long term.
+ * @ops: tty port operations (like activate, shutdown), see &struct
+ *	 tty_port_operations
+ * @client_ops: tty port client operations (like receive_buf, write_wakeup).
+ *		By default, tty_port_default_client_ops is used.
+ * @lock: lock protecting @tty
+ * @blocked_open: # of procs waiting for open in tty_port_block_til_ready()
+ * @count: usage count
+ * @open_wait: open waiters queue (waiting e.g. for a carrier)
+ * @delta_msr_wait: modem status change queue (waiting for MSR changes)
+ * @flags: user TTY flags (%ASYNC_)
+ * @iflags: internal flags (%TTY_PORT_)
+ * @console: when set, the port is a console
+ * @mutex: locking, for open, shutdown and other port operations
+ * @buf_mutex: @xmit_buf alloc lock
+ * @xmit_buf: optional xmit buffer used by some drivers
+ * @close_delay: delay in jiffies to wait when closing the port
+ * @closing_wait: delay in jiffies for output to be sent before closing
+ * @drain_delay: set to zero if no pure time based drain is needed else set to
+ *		 size of fifo
+ * @kref: references counter. Reaching zero calls @ops->destruct() if non-%NULL
+ *	  or frees the port otherwise.
+ * @client_data: pointer to private data, for @client_ops
+ *
+ * Each device keeps its own port level information. &struct tty_port was
+ * introduced as a common structure for such information. As every TTY device
+ * shall have a backing tty_port structure, every driver can use these members.
+ *
+ * The tty port has a different lifetime to the tty so must be kept apart.
+ * In addition be careful as tty -> port mappings are valid for the life
+ * of the tty object but in many cases port -> tty mappings are valid only
+ * until a hangup so don't use the wrong path.
+ *
+ * Tty port shall be initialized by tty_port_init() and shut down either by
+ * tty_port_destroy() (refcounting not used), or tty_port_put() (refcounting).
+ *
+ * There is a lot of helpers around &struct tty_port too. To name the most
+ * significant ones: tty_port_open(), tty_port_close() (or
+ * tty_port_close_start() and tty_port_close_end() separately if need be), and
+ * tty_port_hangup(). These call @ops->activate() and @ops->shutdown() as
+ * needed.
+ */
 struct tty_port {
-	struct tty_bufhead	buf;		/* Locked internally */
+	struct tty_bufhead	buf;
-	struct tty_struct	*tty;		/* Back pointer */
+	struct tty_struct	*tty;
-	struct tty_struct	*itty;		/* internal back ptr */
+	struct tty_struct	*itty;
-	const struct tty_port_operations *ops;	/* Port operations */
+	const struct tty_port_operations *ops;
-	const struct tty_port_client_operations *client_ops; /* Port client operations */
+	const struct tty_port_client_operations *client_ops;
-	spinlock_t		lock;		/* Lock protecting tty field */
+	spinlock_t		lock;
-	int			blocked_open;	/* Waiting to open */
+	int			blocked_open;
-	int			count;		/* Usage count */
+	int			count;
-	wait_queue_head_t	open_wait;	/* Open waiters */
+	wait_queue_head_t	open_wait;
-	wait_queue_head_t	delta_msr_wait;	/* Modem status change */
+	wait_queue_head_t	delta_msr_wait;
-	unsigned long		flags;		/* User TTY flags ASYNC_ */
+	unsigned long		flags;
-	unsigned long		iflags;		/* Internal flags TTY_PORT_ */
+	unsigned long		iflags;
-	unsigned char		console:1;	/* port is a console */
+	unsigned char		console:1;
-	struct mutex		mutex;		/* Locking */
+	struct mutex		mutex;
-	struct mutex		buf_mutex;	/* Buffer alloc lock */
+	struct mutex		buf_mutex;
-	unsigned char		*xmit_buf;	/* Optional buffer */
+	unsigned char		*xmit_buf;
-	unsigned int		close_delay;	/* Close port delay */
+	unsigned int		close_delay;
-	unsigned int		closing_wait;	/* Delay for output */
+	unsigned int		closing_wait;
-	int			drain_delay;	/* Set to zero if no pure time
+	int			drain_delay;
-						   based drain is needed else
+	struct kref		kref;
-						   set to size of fifo */
-	struct kref		kref;		/* Ref counter */
 	void			*client_data;
 };
 

net/nfc/nci/uart.c

@@ -317,14 +317,13 @@ static void nci_uart_tty_receive(struct tty_struct *tty, const u8 *data,
  * Arguments:
  *
  *    tty        pointer to tty instance data
- *    file       pointer to open file object for device
  *    cmd        IOCTL command code
  *    arg        argument for IOCTL call (cmd dependent)
  *
  * Return Value:    Command dependent
  */
-static int nci_uart_tty_ioctl(struct tty_struct *tty, struct file *file,
+static int nci_uart_tty_ioctl(struct tty_struct *tty, unsigned int cmd,
-			      unsigned int cmd, unsigned long arg)
+			      unsigned long arg)
 {
 	struct nci_uart *nu = (void *)tty->disc_data;
 	int err = 0;