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Commit cfc9d198 authored by Bhaumik Bhatt's avatar Bhaumik Bhatt
Browse files

mhi: core: block low power modes only in mission mode 



While attempting to block low power modes before sending
commands to modify channel state, make sure that execution
environment is in mission mode as we may run into a race
condition where a forced suspend/resume cycle does not get
a chance to run.

Change-Id: Ibc7ca5a52036e18677bb597dc0cd95be96d6698a
Signed-off-by: default avatarBhaumik Bhatt <bbhatt@codeaurora.org>
parent b89739f1

drivers/bus/mhi/core/mhi_main.c

+27 −6
Original line number Diff line number Diff line
@@ -1852,6 +1852,7 @@ int mhi_prepare_channel(struct mhi_controller *mhi_cntrl, 
			struct mhi_chan *mhi_chan)

{

	int ret = 0;

	bool in_mission_mode = false;



	MHI_LOG("Entered: preparing channel:%d\n", mhi_chan->chan);
@@ -1890,7 +1891,12 @@ int mhi_prepare_channel(struct mhi_controller *mhi_cntrl, 
		goto error_pm_state;

	}



	/* block host low power modes */

	if (MHI_IN_MISSION_MODE(mhi_cntrl->ee)) {

		atomic_inc(&mhi_cntrl->pending_pkts);

		in_mission_mode = true;

	}



	mhi_cntrl->wake_toggle(mhi_cntrl);

	if (MHI_PM_IN_SUSPEND_STATE(mhi_cntrl->pm_state))

		mhi_trigger_resume(mhi_cntrl);
@@ -1911,6 +1917,7 @@ int mhi_prepare_channel(struct mhi_controller *mhi_cntrl, 
		goto error_dec_pendpkt;

	}



	if (in_mission_mode)

		atomic_dec(&mhi_cntrl->pending_pkts);



	write_lock_irq(&mhi_chan->lock);
@@ -2095,6 +2102,7 @@ static void __mhi_unprepare_channel(struct mhi_controller *mhi_cntrl, 
				    struct mhi_chan *mhi_chan)

{

	int ret;

	bool in_mission_mode = false;



	MHI_LOG("Entered: unprepare channel:%d\n", mhi_chan->chan);
@@ -2118,7 +2126,12 @@ static void __mhi_unprepare_channel(struct mhi_controller *mhi_cntrl, 
		goto error_invalid_state;

	}



	/* block host low power modes */

	if (MHI_IN_MISSION_MODE(mhi_cntrl->ee)) {

		atomic_inc(&mhi_cntrl->pending_pkts);

		in_mission_mode = true;

	}



	mhi_cntrl->wake_toggle(mhi_cntrl);

	if (MHI_PM_IN_SUSPEND_STATE(mhi_cntrl->pm_state))

		mhi_trigger_resume(mhi_cntrl);
@@ -2137,6 +2150,7 @@ static void __mhi_unprepare_channel(struct mhi_controller *mhi_cntrl, 
		MHI_ERR("Failed to receive cmd completion, still resetting\n");



error_dec_pendpkt:

	if (in_mission_mode)

		atomic_dec(&mhi_cntrl->pending_pkts);

error_invalid_state:

	if (!mhi_chan->offload_ch) {
@@ -2346,6 +2360,7 @@ static int mhi_update_channel_state(struct mhi_controller *mhi_cntrl, 
				    enum MHI_CMD cmd)

{

	int ret = -EIO;

	bool in_mission_mode = false;



	mutex_lock(&mhi_chan->mutex);
@@ -2368,7 +2383,12 @@ static int mhi_update_channel_state(struct mhi_controller *mhi_cntrl, 
		goto error_chan_state;

	}



	/* block host low power modes */

	if (MHI_IN_MISSION_MODE(mhi_cntrl->ee)) {

		atomic_inc(&mhi_cntrl->pending_pkts);

		in_mission_mode = true;

	}



	mhi_cntrl->wake_toggle(mhi_cntrl);

	if (MHI_PM_IN_SUSPEND_STATE(mhi_cntrl->pm_state))

		mhi_trigger_resume(mhi_cntrl);
@@ -2395,6 +2415,7 @@ static int mhi_update_channel_state(struct mhi_controller *mhi_cntrl, 
		 mhi_chan->chan, cmd == MHI_CMD_START_CHAN ? "START" : "STOP");



error_dec_pendpkt:

	if (in_mission_mode)

		atomic_dec(&mhi_cntrl->pending_pkts);

error_chan_state:

	mutex_unlock(&mhi_chan->mutex);