int mhi_process_ctrl_ev_ring()

in mhi/core/main.c [792:960]

• 140 lines of code
• 24 McCabe index (conditional complexity)

int mhi_process_ctrl_ev_ring(struct mhi_controller *mhi_cntrl,
			     struct mhi_event *mhi_event,
			     u32 event_quota)
{
	struct mhi_tre *dev_rp, *local_rp;
	struct mhi_ring *ev_ring = &mhi_event->ring;
	struct mhi_event_ctxt *er_ctxt =
		&mhi_cntrl->mhi_ctxt->er_ctxt[mhi_event->er_index];
	struct mhi_chan *mhi_chan;
	struct device *dev = &mhi_cntrl->mhi_dev->dev;
	u32 chan;
	int count = 0;
	dma_addr_t ptr = er_ctxt->rp;

	/*
	 * This is a quick check to avoid unnecessary event processing
	 * in case MHI is already in error state, but it's still possible
	 * to transition to error state while processing events
	 */
	if (unlikely(MHI_EVENT_ACCESS_INVALID(mhi_cntrl->pm_state)))
		return -EIO;

	if (!is_valid_ring_ptr(ev_ring, ptr)) {
		dev_err(&mhi_cntrl->mhi_dev->dev,
			"Event ring rp points outside of the event ring\n");
		return -EIO;
	}

	dev_rp = mhi_to_virtual(ev_ring, ptr);
	local_rp = ev_ring->rp;

	while (dev_rp != local_rp) {
		enum mhi_pkt_type type = MHI_TRE_GET_EV_TYPE(local_rp);

		switch (type) {
		case MHI_PKT_TYPE_BW_REQ_EVENT:
		{
			struct mhi_link_info *link_info;

			link_info = &mhi_cntrl->mhi_link_info;
			write_lock_irq(&mhi_cntrl->pm_lock);
			link_info->target_link_speed =
				MHI_TRE_GET_EV_LINKSPEED(local_rp);
			link_info->target_link_width =
				MHI_TRE_GET_EV_LINKWIDTH(local_rp);
			write_unlock_irq(&mhi_cntrl->pm_lock);
			dev_dbg(dev, "Received BW_REQ event\n");
			mhi_cntrl->status_cb(mhi_cntrl, MHI_CB_BW_REQ);
			break;
		}
		case MHI_PKT_TYPE_STATE_CHANGE_EVENT:
		{
			enum mhi_state new_state;

			new_state = MHI_TRE_GET_EV_STATE(local_rp);

			dev_dbg(dev, "State change event to state: %s\n",
				TO_MHI_STATE_STR(new_state));

			switch (new_state) {
			case MHI_STATE_M0:
				mhi_pm_m0_transition(mhi_cntrl);
				break;
			case MHI_STATE_M1:
				mhi_pm_m1_transition(mhi_cntrl);
				break;
			case MHI_STATE_M3:
				mhi_pm_m3_transition(mhi_cntrl);
				break;
			case MHI_STATE_SYS_ERR:
			{
				enum mhi_pm_state pm_state;

				dev_dbg(dev, "System error detected\n");
				write_lock_irq(&mhi_cntrl->pm_lock);
				pm_state = mhi_tryset_pm_state(mhi_cntrl,
							MHI_PM_SYS_ERR_DETECT);
				write_unlock_irq(&mhi_cntrl->pm_lock);
				if (pm_state == MHI_PM_SYS_ERR_DETECT)
					mhi_pm_sys_err_handler(mhi_cntrl);
				break;
			}
			default:
				dev_err(dev, "Invalid state: %s\n",
					TO_MHI_STATE_STR(new_state));
			}

			break;
		}
		case MHI_PKT_TYPE_CMD_COMPLETION_EVENT:
			mhi_process_cmd_completion(mhi_cntrl, local_rp);
			break;
		case MHI_PKT_TYPE_EE_EVENT:
		{
			enum dev_st_transition st = DEV_ST_TRANSITION_MAX;
			enum mhi_ee_type event = MHI_TRE_GET_EV_EXECENV(local_rp);

			dev_dbg(dev, "Received EE event: %s\n",
				TO_MHI_EXEC_STR(event));
			switch (event) {
			case MHI_EE_SBL:
				st = DEV_ST_TRANSITION_SBL;
				break;
			case MHI_EE_WFW:
			case MHI_EE_AMSS:
				st = DEV_ST_TRANSITION_MISSION_MODE;
				break;
			case MHI_EE_FP:
				st = DEV_ST_TRANSITION_FP;
				break;
			case MHI_EE_RDDM:
				mhi_cntrl->status_cb(mhi_cntrl, MHI_CB_EE_RDDM);
				write_lock_irq(&mhi_cntrl->pm_lock);
				mhi_cntrl->ee = event;
				write_unlock_irq(&mhi_cntrl->pm_lock);
				wake_up_all(&mhi_cntrl->state_event);
				break;
			default:
				dev_err(dev,
					"Unhandled EE event: 0x%x\n", type);
			}
			if (st != DEV_ST_TRANSITION_MAX)
				mhi_queue_state_transition(mhi_cntrl, st);

			break;
		}
		case MHI_PKT_TYPE_TX_EVENT:
			chan = MHI_TRE_GET_EV_CHID(local_rp);

			WARN_ON(chan >= mhi_cntrl->max_chan);

			/*
			 * Only process the event ring elements whose channel
			 * ID is within the maximum supported range.
			 */
			if (chan < mhi_cntrl->max_chan) {
				mhi_chan = &mhi_cntrl->mhi_chan[chan];
				if (!mhi_chan->configured)
					break;
				parse_xfer_event(mhi_cntrl, local_rp, mhi_chan);
				event_quota--;
			}
			break;
		default:
			dev_err(dev, "Unhandled event type: %d\n", type);
			break;
		}

		mhi_recycle_ev_ring_element(mhi_cntrl, ev_ring);
		local_rp = ev_ring->rp;

		ptr = er_ctxt->rp;
		if (!is_valid_ring_ptr(ev_ring, ptr)) {
			dev_err(&mhi_cntrl->mhi_dev->dev,
				"Event ring rp points outside of the event ring\n");
			return -EIO;
		}

		dev_rp = mhi_to_virtual(ev_ring, ptr);
		count++;
	}

	read_lock_bh(&mhi_cntrl->pm_lock);
	if (likely(MHI_DB_ACCESS_VALID(mhi_cntrl)))
		mhi_ring_er_db(mhi_event);
	read_unlock_bh(&mhi_cntrl->pm_lock);

	return count;
}