It is possible for a GSI channel's state to be changed as a result
of an action by a different execution environment. Specifically,
the modem is able to issue a GSI generic command that causes a state
change on a GSI channel associated with the AP.
A channel's state only needs to be known when a channel is allocated
or deallocaed, started or stopped, or reset. So there is little
value in caching the state anyway.
Stop recording a copy of the channel's last known state, and instead
fetch the true state from hardware whenever it's needed. In such
cases, *do* record the state in a local variable, in case an error
message reports it (so the value reported is the value seen).
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pass a channel pointer rather than a GSI pointer and channel ID to
gsi_channel_state().
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Zero the result code stored in a field of the scratch 0 register
before issuing a generic EE command. This just guarantees that
the value we read later was actually written as a result of the
command.
Also add the definitions of two more possible result codes that can
be returned when issuing flow control enable or disable commands:
INCORRECT_CHANNEL_STATE: - channel must be in started state
INCORRECT_DIRECTION - flow control is only valid for TX channels
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
An error message about limiting the number of TREs used prints the
wrong value. Fix this bug.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch includes "gsi.c", which implements the generic software
interface (GSI) for IPA. The generic software interface abstracts
channels, which provide a means of transferring data either from the
AP to the IPA, or from the IPA to the AP. A ring buffer of "transfer
elements" (TREs) is used to describe data transfers to perform. The
AP writes a doorbell register associated with a channel to let it know
it has added new entries (for an AP->IPA channel) or has finished
processing entries (for an IPA->AP channel).
Each channel also has an event ring buffer, used by the IPA to
communicate information about events related to a channel (for
example, the completion of TREs). The IPA writes its own doorbell
register, which triggers an interrupt on the AP, to signal that
new event information has arrived.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
