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Commit 4ab3f867 authored by Bhaumik Bhatt's avatar Bhaumik Bhatt Committed by Gerrit - the friendly Code Review server
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mhi: core: handle pm error state transition within fast suspend/resume 



During fast suspend/resume, the power management states in MHI
can change to any error state. Allow for it by re-checking and
handling it such that pm states are not lost or over-written in
the process.

Change-Id: I264ae096d20b9752837624dc3a4b3ea6131ad9a6
Signed-off-by: default avatarBhaumik Bhatt <bbhatt@codeaurora.org>
parent f8b00cea

drivers/bus/mhi/core/mhi_pm.c

+37 −4
Original line number Diff line number Diff line
@@ -1219,11 +1219,17 @@ int mhi_pm_fast_suspend(struct mhi_controller *mhi_cntrl, bool notify_client) 
	enum MHI_PM_STATE new_state;

	struct mhi_chan *itr, *tmp;



	if (mhi_cntrl->pm_state == MHI_PM_DISABLE)

	read_lock_bh(&mhi_cntrl->pm_lock);

	if (mhi_cntrl->pm_state == MHI_PM_DISABLE) {

		read_unlock_bh(&mhi_cntrl->pm_lock);

		return -EINVAL;

	}



	if (MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state))

	if (MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state)) {

		read_unlock_bh(&mhi_cntrl->pm_lock);

		return -EIO;

	}

	read_unlock_bh(&mhi_cntrl->pm_lock);



	/* do a quick check to see if any pending votes to keep us busy */

	if (atomic_read(&mhi_cntrl->pending_pkts)) {
@@ -1251,6 +1257,12 @@ int mhi_pm_fast_suspend(struct mhi_controller *mhi_cntrl, bool notify_client) 
		goto error_suspend;

	}



	/* check pm state before saving it */

	if (MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state)) {

		ret = -EIO;

		goto error_suspend;

	}



	/* anytime after this, we will resume thru runtime pm framework */

	MHI_LOG("Allowing Fast M3 transition\n");
@@ -1400,17 +1412,23 @@ int mhi_pm_fast_resume(struct mhi_controller *mhi_cntrl, bool notify_client) 
	struct mhi_event *mhi_event;

	int i;



	read_lock_bh(&mhi_cntrl->pm_lock);

	MHI_LOG("Entered with pm_state:%s dev_state:%s\n",

		to_mhi_pm_state_str(mhi_cntrl->pm_state),

		TO_MHI_STATE_STR(mhi_cntrl->dev_state));



	if (mhi_cntrl->pm_state == MHI_PM_DISABLE)

	if (mhi_cntrl->pm_state == MHI_PM_DISABLE) {

		read_unlock_bh(&mhi_cntrl->pm_lock);

		return 0;

	}



	if (MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state))

	if (MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state)) {

		read_unlock_bh(&mhi_cntrl->pm_lock);

		return -EIO;

	}



	MHI_ASSERT(mhi_cntrl->pm_state != MHI_PM_M3, "mhi_pm_state != M3");

	read_unlock_bh(&mhi_cntrl->pm_lock);



	/* notify any clients we're about to exit lpm */

	if (notify_client) {
@@ -1424,10 +1442,19 @@ int mhi_pm_fast_resume(struct mhi_controller *mhi_cntrl, bool notify_client) 
	/* do not process control events */

	tasklet_disable(&mhi_cntrl->mhi_event->task);



	/* check if we entered error state again before doing the restore */

	write_lock_irq(&mhi_cntrl->pm_lock);



	if (MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state)) {

		write_unlock_irq(&mhi_cntrl->pm_lock);

		tasklet_enable(&mhi_cntrl->mhi_event->task);

		return -EIO;

	}



	/* restore the states */

	mhi_cntrl->pm_state = mhi_cntrl->saved_pm_state;

	mhi_cntrl->dev_state = mhi_cntrl->saved_dev_state;



	write_unlock_irq(&mhi_cntrl->pm_lock);



	switch (mhi_cntrl->pm_state) {
@@ -1439,6 +1466,12 @@ int mhi_pm_fast_resume(struct mhi_controller *mhi_cntrl, bool notify_client) 
		mhi_cntrl->wake_get(mhi_cntrl, true);

		mhi_cntrl->wake_put(mhi_cntrl, true);

		read_unlock_bh(&mhi_cntrl->pm_lock);

		break;

	default:

		MHI_ERR("Unexpected PM state:%s after restore\n",

			to_mhi_pm_state_str(mhi_cntrl->pm_state));

		tasklet_enable(&mhi_cntrl->mhi_event->task);

		return -EIO;

	}



	/* now it's safe to process ctrl events */