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PCI/doc: cleanup references to the legacy PCI DMA API

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Mention the regular DMA API calls instead of the now removed PCI DMA API.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
This commit is contained in:
Christoph Hellwig 2022-03-30 07:24:21 +02:00
parent 7968778914
commit 05b0ebd06a
1 changed files with 7 additions and 7 deletions
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14
Documentation/PCI/pci.rst
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@ -278,20 +278,20 @@ appropriate parameters. In general this allows more efficient DMA
on systems where System RAM exists above 4G _physical_ address. on systems where System RAM exists above 4G _physical_ address.
Drivers for all PCI-X and PCIe compliant devices must call Drivers for all PCI-X and PCIe compliant devices must call
pci_set_dma_mask() as they are 64-bit DMA devices. set_dma_mask() as they are 64-bit DMA devices.
Similarly, drivers must also "register" this capability if the device Similarly, drivers must also "register" this capability if the device
can directly address "consistent memory" in System RAM above 4G physical can directly address "coherent memory" in System RAM above 4G physical
address by calling pci_set_consistent_dma_mask(). address by calling dma_set_coherent_mask().
Again, this includes drivers for all PCI-X and PCIe compliant devices. Again, this includes drivers for all PCI-X and PCIe compliant devices.
Many 64-bit "PCI" devices (before PCI-X) and some PCI-X devices are Many 64-bit "PCI" devices (before PCI-X) and some PCI-X devices are
64-bit DMA capable for payload ("streaming") data but not control 64-bit DMA capable for payload ("streaming") data but not control
("consistent") data. ("coherent") data.
Setup shared control data Setup shared control data
------------------------- -------------------------
Once the DMA masks are set, the driver can allocate "consistent" (a.k.a. shared) Once the DMA masks are set, the driver can allocate "coherent" (a.k.a. shared)
memory. See Documentation/core-api/dma-api.rst for a full description of memory. See Documentation/core-api/dma-api.rst for a full description of
the DMA APIs. This section is just a reminder that it needs to be done the DMA APIs. This section is just a reminder that it needs to be done
before enabling DMA on the device. before enabling DMA on the device.
@ -367,7 +367,7 @@ steps need to be performed:
- Disable the device from generating IRQs - Disable the device from generating IRQs
- Release the IRQ (free_irq()) - Release the IRQ (free_irq())
- Stop all DMA activity - Stop all DMA activity
- Release DMA buffers (both streaming and consistent) - Release DMA buffers (both streaming and coherent)
- Unregister from other subsystems (e.g. scsi or netdev) - Unregister from other subsystems (e.g. scsi or netdev)
- Disable device from responding to MMIO/IO Port addresses - Disable device from responding to MMIO/IO Port addresses
- Release MMIO/IO Port resource(s) - Release MMIO/IO Port resource(s)
@ -420,7 +420,7 @@ Once DMA is stopped, clean up streaming DMA first.
I.e. unmap data buffers and return buffers to "upstream" I.e. unmap data buffers and return buffers to "upstream"
owners if there is one. owners if there is one.
Then clean up "consistent" buffers which contain the control data. Then clean up "coherent" buffers which contain the control data.
See Documentation/core-api/dma-api.rst for details on unmapping interfaces. See Documentation/core-api/dma-api.rst for details on unmapping interfaces.