mhi: core: Fix runtime_pm call

This change ensures that PM reference is always get during packet
queueing and released either after queuing completion (RX) or once
the buffer has been consumed (TX).

Signed-off-by: Loic Poulain <loic.poulain@linaro.org>

1 files changed, 16 insertions, 4 deletions

diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
index c780234c9ef0..16b9640465af 100644
--- a/drivers/bus/mhi/core/main.c
+++ b/drivers/bus/mhi/core/main.c
@@ -584,8 +584,11 @@ static int parse_xfer_event(struct mhi_controller *mhi_cntrl,
 			/* notify client */
 			mhi_chan->xfer_cb(mhi_chan->mhi_dev, &result);
 
-			if (mhi_chan->dir == DMA_TO_DEVICE)
+			if (mhi_chan->dir == DMA_TO_DEVICE) {
 				atomic_dec(&mhi_cntrl->pending_pkts);
+				/* Release the reference got from mhi_queue() */
+				mhi_cntrl->runtime_put(mhi_cntrl);
+			}
 
 			/*
 			 * Recycle the buffer if buffer is pre-allocated,
@@ -1021,9 +1024,11 @@ static int mhi_queue(struct mhi_device *mhi_dev, struct mhi_buf_info *buf_info,
 	if (unlikely(ret))
 		goto exit_unlock;
 
-	/* trigger M3 exit if necessary */
-	if (MHI_PM_IN_SUSPEND_STATE(mhi_cntrl->pm_state))
-		mhi_trigger_resume(mhi_cntrl);
+	/* Packet is queued, take a usage ref to exit M3 if necessary
+	 * for host->device buffer, balanced put is done on buffer completion
+	 * for device->host buffer, balanced put is after ringing the DB
+	 */
+	mhi_cntrl->runtime_get(mhi_cntrl);
 
 	/* Assert dev_wake (to exit/prevent M1/M2)*/
 	mhi_cntrl->wake_toggle(mhi_cntrl);
@@ -1034,6 +1039,9 @@ static int mhi_queue(struct mhi_device *mhi_dev, struct mhi_buf_info *buf_info,
 	if (likely(MHI_DB_ACCESS_VALID(mhi_cntrl)))
 		mhi_ring_chan_db(mhi_cntrl, mhi_chan);
 
+	if (dir == DMA_FROM_DEVICE)
+		mhi_cntrl->runtime_put(mhi_cntrl);
+
 exit_unlock:
 	read_unlock_irqrestore(&mhi_cntrl->pm_lock, flags);
 
@@ -1431,6 +1439,10 @@ static void mhi_reset_data_chan(struct mhi_controller *mhi_cntrl,
 			result.buf_addr = buf_info->cb_buf;
 			mhi_chan->xfer_cb(mhi_chan->mhi_dev, &result);
 		}
+
+		/* Release the reference got from mhi_queue() */
+		if (mhi_chan->dir == DMA_TO_DEVICE)
+			mhi_cntrl->runtime_put(mhi_cntrl);
 	}
 }