state_lock, the spinlock type is meant to protect race against concurrent
MHI state transitions. In mhi_ep_set_m0_state(), while the state_lock is
being held, the channels are resumed in mhi_ep_resume_channels() if the
previous state was M3. This causes sleeping in atomic bug, since
mhi_ep_resume_channels() use mutex internally.
Since the state_lock is supposed to be held throughout the state change,
it is not ideal to drop the lock before calling mhi_ep_resume_channels().
So to fix this issue, let's change the type of state_lock to mutex. This
would also allow holding the lock throughout all state transitions thereby
avoiding any potential race.
Cc: <stable@vger.kernel.org> # 5.19
Fixes: e4b7b5f0f3 ("bus: mhi: ep: Add support for suspending and resuming channels")
Reported-by: Dan Carpenter <error27@gmail.com>
Reviewed-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Add support for suspending and resuming the channels in MHI endpoint stack.
The channels will be moved to the suspended state during M3 state
transition and will be resumed during M0 transition.
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20220405135754.6622-18-manivannan.sadhasivam@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add support for handling SYS_ERR (System Error) condition in the MHI
endpoint stack. The SYS_ERR flag will be asserted by the endpoint device
when it detects an internal error. The host will then issue reset and
reinitializes MHI to recover from the error state.
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20220405135754.6622-13-manivannan.sadhasivam@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add support for managing the MHI state machine by controlling the state
transitions. Only the following MHI state transitions are supported:
1. Ready state
2. M0 state
3. M3 state
4. SYS_ERR state
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20220405135754.6622-8-manivannan.sadhasivam@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
