slimbus: messaging: fix typos in comments

Spelling mistakes (triple letters) in comments.
Detected with the help of Coccinelle.

Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20220706101131.6934-3-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

slimbus: messaging: check for valid transaction id

In some usecases transaction ids are dynamically allocated inside
the controller driver after sending the messages which have generic
acknowledge responses. So check for this before refcounting pm_runtime.

Without this we would end up imbalancing runtime pm count by
doing pm_runtime_put() in both slim_do_transfer() and slim_msg_response()
for a single pm_runtime_get() in slim_do_transfer()

Fixes: d3062a210930 ("slimbus: messaging: add slim_alloc/free_txn_tid()")
Cc: <stable@vger.kernel.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20210809082428.11236-3-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

slimbus: messaging: start transaction ids from 1 instead of zero

As tid is unsigned its hard to figure out if the tid is valid or
invalid. So Start the transaction ids from 1 instead of zero
so that we could differentiate between a valid tid and invalid tids

This is useful in cases where controller would add a tid for controller
specific transfers.

Fixes: d3062a210930 ("slimbus: messaging: add slim_alloc/free_txn_tid()")
Cc: <stable@vger.kernel.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20210809082428.11236-2-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

slimbus: messaging: Fix fall-through warnings for Clang

In preparation to enable -Wimplicit-fallthrough for Clang, fix a warning
by explicitly adding a break statement instead of letting the code fall
through to the next case.

Link: https://github.com/KSPP/linux/issues/115
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20201127102451.17114-5-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

slimbus: messaging: add slim_alloc/free_txn_tid()

This patch adds slim_alloc_txn_tid() and slim_free_txn_tid() api
to allow controllers like ngd to allocate tids for user specific
commands. This also cleans up the existing code to use single place
for tid allocations and free.

This patch also make the tid allocation cyclic one, its very useful
to track the transactions back during debug.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

slimbus: messaging: initialize completion correctly

slim_val_inf can contain random value from stack, make sure the completion
is initialized to NULL while filling the msg.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

slimbus: messaging: remove multiple calls to pm_runtime_mark_last_busy

There seems to be a multiple calls to pm_runtime_mark_last_busy(),
which looks like a typo.
Fix this by properly adding pm_runtime_put_autosuspend to put controller
in auto suspend state.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

slimbus: messaging: pass correct wbuf

There seems to be a typo while filling msg for slim_write, wbuf is
set to NULL instead of rbuf.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

slimbus: Fix out-of-bounds access in slim_slicesize()

With gcc-4.1.2:

slimbus/messaging.c: In function ‘slim_slicesize’:
slimbus/messaging.c:186: warning: statement with no effect

Indeed, clamp() is a macro not operating in-place, but returning the
clamped value. Hence the value is not clamped at all, which may lead to
an out-of-bounds access.

Fix this by assigning the clamped value.

Fixes: afbdcc7c384b0d44 ("slimbus: Add messaging APIs to slimbus framework")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

slimbus: Fix missing unlock on error in slim_msg_response()

Add the missing unlock before return from function slim_msg_response()
in the error handling case.

Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

slimbus: Use GFP_ATOMIC under spin lock

A spin lock is taken here so we should use GFP_ATOMIC.

Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

slimbus: avoid null pointer dereference on msg

The pointer msg is checked to see if it is null at the start of
the function and jumps to the error exit label reterr that then
dereferences msg when it prints a dev_err error message. Avoid
this potential null pointer dereference by only printing the
error message if msg is not null.

Detected by CoverityScan, CID#1463141 ("Dereference after null check")

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

slimbus: Add support for 'clock-pause' feature

Per SLIMbus specification, a reconfiguration sequence known as
'clock pause' needs to be broadcast over the bus while entering low-
power mode. Clock-pause is initiated by the controller driver.
To exit clock-pause, controller typically wakes up the framer device.
Since wakeup precedure is controller-specific, framework calls it via
controller's function pointer to invoke it.

Signed-off-by: Sagar Dharia <sdharia@codeaurora.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Reviwed-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

slimbus: Add messaging APIs to slimbus framework

SLIMbus devices use value-element, and information elements to
control device parameters (e.g. value element is used to represent
gain for codec, information element is used to represent interrupt
status for codec when codec interrupt fires).
Messaging APIs are used to set/get these value and information
elements. SLIMbus specification uses 8-bit "transaction IDs" for
messages where a read-value is anticipated. Framework uses a table
of pointers to store those TIDs and responds back to the caller in
O(1).
Caller can do synchronous and asynchronous reads/writes.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Reviwed-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>