It's OK to keep the pending pin events when disabling or
enabling the 'adapter'. Zeroing this can cause a race condition
if this happens when the pin kthread is handling a pin event
and calls atomic_dec later, causing work_pin_num_events to become
negative.
Just leave pending events in the queue, they'll be read eventually.
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
When the adap_enable callback is called the adap->lock is held.
When disabling the adapter it attempts to stop the kthread that
deals with receiving and transmitting messages. However, kthread_stop
waits for the thread to stop, so all that time adap->lock is held.
Unfortunately, the kernel thread itself can call functions that take
that same lock, so a deadlock can occur.
Change the logic to keep the kernel thread running and instead when
disabling the adapter, just set the pin to high, go to idle and then
to state OFF and disable the interrupt. Only stop the kernel thread
when the adapter is deleted.
This way disabling the adapter will not wait for anything and the
deadlock is avoided.
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Use call_(void_)op consistently in the CEC core framework. Ditto
for the cec pin ops. And check if !adap->devnode.unregistered before
calling each op. This avoids calls to ops when the device has been
unregistered and the underlying hardware may be gone.
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
The en/disable_irq() functions keep track of the 'depth': i.e. if
interrupts are disabled twice, then it needs to enable_irq() calls to
enable them again. The cec-pin framework didn't take this into accound
and could disable irqs multiple times, and it expected that a single
enable_irq() would enable them again.
Move all calls to en/disable_irq() to the kthread where it is easy
to keep track of the current irq state and ensure that multiple
en/disable_irq calls never happen.
If interrupts where disabled twice, then they would never turn on
again, leaving the CEC adapter in a dead state.
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Fixes: 865463fc03 (media: cec-pin: add error injection support)
Cc: <stable@vger.kernel.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
This field is only set, but never used. Drop it.
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
The CEC pin framework has to wait for the CEC bus to be idle for the
requested Signal Free Time before it can start a transmit.
However, the check for that was off by one, so transmits would start one
bit period (2.4ms) too late.
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
The cec pin timer overruns are measured in microseconds, but the variable
names include the millisecond symbol "ms". To avoid confusion, replace
"ms" with "us" in the variable names and printed status message.
Signed-off-by: Deborah Brouwer <deborahbrouwer3563@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.
[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
In preparation for moving CEC drivers to the CEC directory,
move the core to a separate place.
Acked-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
