int mhi_pm_suspend()

in mhi/core/pm.c [796:881]
67 lines of code
16 McCabe index (conditional complexity)

int mhi_pm_suspend(struct mhi_controller *mhi_cntrl)
{
	struct mhi_chan *itr, *tmp;
	struct device *dev = &mhi_cntrl->mhi_dev->dev;
	enum mhi_pm_state new_state;
	int ret;

	if (mhi_cntrl->pm_state == MHI_PM_DISABLE)
		return -EINVAL;

	if (MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state))
		return -EIO;

	/* Return busy if there are any pending resources */
	if (atomic_read(&mhi_cntrl->dev_wake) ||
	    atomic_read(&mhi_cntrl->pending_pkts))
		return -EBUSY;

	/* Take MHI out of M2 state */
	read_lock_bh(&mhi_cntrl->pm_lock);
	mhi_cntrl->wake_get(mhi_cntrl, false);
	read_unlock_bh(&mhi_cntrl->pm_lock);

	ret = wait_event_timeout(mhi_cntrl->state_event,
				 mhi_cntrl->dev_state == MHI_STATE_M0 ||
				 mhi_cntrl->dev_state == MHI_STATE_M1 ||
				 MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state),
				 msecs_to_jiffies(mhi_cntrl->timeout_ms));

	read_lock_bh(&mhi_cntrl->pm_lock);
	mhi_cntrl->wake_put(mhi_cntrl, false);
	read_unlock_bh(&mhi_cntrl->pm_lock);

	if (!ret || MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state)) {
		dev_err(dev,
			"Could not enter M0/M1 state");
		return -EIO;
	}

	write_lock_irq(&mhi_cntrl->pm_lock);

	if (atomic_read(&mhi_cntrl->dev_wake) ||
	    atomic_read(&mhi_cntrl->pending_pkts)) {
		write_unlock_irq(&mhi_cntrl->pm_lock);
		return -EBUSY;
	}

	dev_dbg(dev, "Allowing M3 transition\n");
	new_state = mhi_tryset_pm_state(mhi_cntrl, MHI_PM_M3_ENTER);
	if (new_state != MHI_PM_M3_ENTER) {
		write_unlock_irq(&mhi_cntrl->pm_lock);
		dev_err(dev,
			"Error setting to PM state: %s from: %s\n",
			to_mhi_pm_state_str(MHI_PM_M3_ENTER),
			to_mhi_pm_state_str(mhi_cntrl->pm_state));
		return -EIO;
	}

	/* Set MHI to M3 and wait for completion */
	mhi_set_mhi_state(mhi_cntrl, MHI_STATE_M3);
	write_unlock_irq(&mhi_cntrl->pm_lock);
	dev_dbg(dev, "Waiting for M3 completion\n");

	ret = wait_event_timeout(mhi_cntrl->state_event,
				 mhi_cntrl->dev_state == MHI_STATE_M3 ||
				 MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state),
				 msecs_to_jiffies(mhi_cntrl->timeout_ms));

	if (!ret || MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state)) {
		dev_err(dev,
			"Did not enter M3 state, MHI state: %s, PM state: %s\n",
			TO_MHI_STATE_STR(mhi_cntrl->dev_state),
			to_mhi_pm_state_str(mhi_cntrl->pm_state));
		return -EIO;
	}

	/* Notify clients about entering LPM */
	list_for_each_entry_safe(itr, tmp, &mhi_cntrl->lpm_chans, node) {
		mutex_lock(&itr->mutex);
		if (itr->mhi_dev)
			mhi_notify(itr->mhi_dev, MHI_CB_LPM_ENTER);
		mutex_unlock(&itr->mutex);
	}

	return 0;
}