static void mhi_pm_sys_error_transition()

in mhi/core/pm.c [554:695]

• 106 lines of code
• 13 McCabe index (conditional complexity)

static void mhi_pm_sys_error_transition(struct mhi_controller *mhi_cntrl)
{
	enum mhi_pm_state cur_state, prev_state;
	enum dev_st_transition next_state;
	struct mhi_event *mhi_event;
	struct mhi_cmd_ctxt *cmd_ctxt;
	struct mhi_cmd *mhi_cmd;
	struct mhi_event_ctxt *er_ctxt;
	struct device *dev = &mhi_cntrl->mhi_dev->dev;
	int ret, i;

	dev_dbg(dev, "Transitioning from PM state: %s to: %s\n",
		to_mhi_pm_state_str(mhi_cntrl->pm_state),
		to_mhi_pm_state_str(MHI_PM_SYS_ERR_PROCESS));

	/* We must notify MHI control driver so it can clean up first */
	mhi_cntrl->status_cb(mhi_cntrl, MHI_CB_SYS_ERROR);

	mutex_lock(&mhi_cntrl->pm_mutex);
	write_lock_irq(&mhi_cntrl->pm_lock);
	prev_state = mhi_cntrl->pm_state;
	cur_state = mhi_tryset_pm_state(mhi_cntrl, MHI_PM_SYS_ERR_PROCESS);
	write_unlock_irq(&mhi_cntrl->pm_lock);

	if (cur_state != MHI_PM_SYS_ERR_PROCESS) {
		dev_err(dev, "Failed to transition from PM state: %s to: %s\n",
			to_mhi_pm_state_str(cur_state),
			to_mhi_pm_state_str(MHI_PM_SYS_ERR_PROCESS));
		goto exit_sys_error_transition;
	}

	mhi_cntrl->ee = MHI_EE_DISABLE_TRANSITION;
	mhi_cntrl->dev_state = MHI_STATE_RESET;

	/* Wake up threads waiting for state transition */
	wake_up_all(&mhi_cntrl->state_event);

	/* Trigger MHI RESET so that the device will not access host memory */
	if (MHI_REG_ACCESS_VALID(prev_state)) {
		u32 in_reset = -1;
		unsigned long timeout = msecs_to_jiffies(mhi_cntrl->timeout_ms);

		dev_dbg(dev, "Triggering MHI Reset in device\n");
		mhi_set_mhi_state(mhi_cntrl, MHI_STATE_RESET);

		/* Wait for the reset bit to be cleared by the device */
		ret = wait_event_timeout(mhi_cntrl->state_event,
					 mhi_read_reg_field(mhi_cntrl,
							    mhi_cntrl->regs,
							    MHICTRL,
							    MHICTRL_RESET_MASK,
							    MHICTRL_RESET_SHIFT,
							    &in_reset) ||
					!in_reset, timeout);
		if (!ret || in_reset) {
			dev_err(dev, "Device failed to exit MHI Reset state\n");
			goto exit_sys_error_transition;
		}

		/*
		 * Device will clear BHI_INTVEC as a part of RESET processing,
		 * hence re-program it
		 */
		mhi_write_reg(mhi_cntrl, mhi_cntrl->bhi, BHI_INTVEC, 0);
	}

	dev_dbg(dev,
		"Waiting for all pending event ring processing to complete\n");
	mhi_event = mhi_cntrl->mhi_event;
	for (i = 0; i < mhi_cntrl->total_ev_rings; i++, mhi_event++) {
		if (mhi_event->offload_ev)
			continue;
		tasklet_kill(&mhi_event->task);
	}

	/* Release lock and wait for all pending threads to complete */
	mutex_unlock(&mhi_cntrl->pm_mutex);
	dev_dbg(dev, "Waiting for all pending threads to complete\n");
	wake_up_all(&mhi_cntrl->state_event);

	dev_dbg(dev, "Reset all active channels and remove MHI devices\n");
	device_for_each_child(&mhi_cntrl->mhi_dev->dev, NULL, mhi_destroy_device);

	mutex_lock(&mhi_cntrl->pm_mutex);

	WARN_ON(atomic_read(&mhi_cntrl->dev_wake));
	WARN_ON(atomic_read(&mhi_cntrl->pending_pkts));

	/* Reset the ev rings and cmd rings */
	dev_dbg(dev, "Resetting EV CTXT and CMD CTXT\n");
	mhi_cmd = mhi_cntrl->mhi_cmd;
	cmd_ctxt = mhi_cntrl->mhi_ctxt->cmd_ctxt;
	for (i = 0; i < NR_OF_CMD_RINGS; i++, mhi_cmd++, cmd_ctxt++) {
		struct mhi_ring *ring = &mhi_cmd->ring;

		ring->rp = ring->base;
		ring->wp = ring->base;
		cmd_ctxt->rp = cmd_ctxt->rbase;
		cmd_ctxt->wp = cmd_ctxt->rbase;
	}

	mhi_event = mhi_cntrl->mhi_event;
	er_ctxt = mhi_cntrl->mhi_ctxt->er_ctxt;
	for (i = 0; i < mhi_cntrl->total_ev_rings; i++, er_ctxt++,
	     mhi_event++) {
		struct mhi_ring *ring = &mhi_event->ring;

		/* Skip offload events */
		if (mhi_event->offload_ev)
			continue;

		ring->rp = ring->base;
		ring->wp = ring->base;
		er_ctxt->rp = er_ctxt->rbase;
		er_ctxt->wp = er_ctxt->rbase;
	}

	/* Transition to next state */
	if (MHI_IN_PBL(mhi_get_exec_env(mhi_cntrl))) {
		write_lock_irq(&mhi_cntrl->pm_lock);
		cur_state = mhi_tryset_pm_state(mhi_cntrl, MHI_PM_POR);
		write_unlock_irq(&mhi_cntrl->pm_lock);
		if (cur_state != MHI_PM_POR) {
			dev_err(dev, "Error moving to state %s from %s\n",
				to_mhi_pm_state_str(MHI_PM_POR),
				to_mhi_pm_state_str(cur_state));
			goto exit_sys_error_transition;
		}
		next_state = DEV_ST_TRANSITION_PBL;
	} else {
		next_state = DEV_ST_TRANSITION_READY;
	}

	mhi_queue_state_transition(mhi_cntrl, next_state);

exit_sys_error_transition:
	dev_dbg(dev, "Exiting with PM state: %s, MHI state: %s\n",
		to_mhi_pm_state_str(mhi_cntrl->pm_state),
		TO_MHI_STATE_STR(mhi_cntrl->dev_state));

	mutex_unlock(&mhi_cntrl->pm_mutex);
}