1 files changed, 108 insertions, 0 deletions

diff --git a/drivers/bus/mhi/ep/main.c b/drivers/bus/mhi/ep/main.c
index 1e24eae4b446..e2ed10b4a9d2 100644
--- a/drivers/bus/mhi/ep/main.c
+++ b/drivers/bus/mhi/ep/main.c
@@ -383,6 +383,57 @@ static int mhi_ep_read_channel(struct mhi_ep_cntrl *mhi_cntrl,
 	return 0;
 }
 
+static int mhi_ep_process_ch_ring(struct mhi_ep_ring *ring, struct mhi_ring_element *el)
+{
+	struct mhi_ep_cntrl *mhi_cntrl = ring->mhi_cntrl;
+	struct mhi_result result = {};
+	u32 len = MHI_EP_DEFAULT_MTU;
+	struct mhi_ep_chan *mhi_chan;
+	int ret;
+
+	mhi_chan = &mhi_cntrl->mhi_chan[ring->ch_id];
+
+	/*
+	 * Bail out if transfer callback is not registered for the channel.
+	 * This is most likely due to the client driver not loaded at this point.
+	 */
+	if (!mhi_chan->xfer_cb) {
+		dev_err(&mhi_chan->mhi_dev->dev, "Client driver not available\n");
+		return -ENODEV;
+	}
+
+	if (ring->ch_id % 2) {
+		/* DL channel */
+		result.dir = mhi_chan->dir;
+		mhi_chan->xfer_cb(mhi_chan->mhi_dev, &result);
+	} else {
+		/* UL channel */
+		result.buf_addr = kzalloc(len, GFP_KERNEL);
+		if (!result.buf_addr)
+			return -ENOMEM;
+
+		do {
+			ret = mhi_ep_read_channel(mhi_cntrl, ring, &result, len);
+			if (ret < 0) {
+				dev_err(&mhi_chan->mhi_dev->dev, "Failed to read channel\n");
+				kfree(result.buf_addr);
+				return ret;
+			}
+
+			result.dir = mhi_chan->dir;
+			mhi_chan->xfer_cb(mhi_chan->mhi_dev, &result);
+			result.bytes_xferd = 0;
+			memset(result.buf_addr, 0, len);
+
+			/* Read until the ring becomes empty */
+		} while (!mhi_ep_queue_is_empty(mhi_chan->mhi_dev, DMA_TO_DEVICE));
+
+		kfree(result.buf_addr);
+	}
+
+	return 0;
+}
+
 static int mhi_ep_cache_host_cfg(struct mhi_ep_cntrl *mhi_cntrl)
 {
 	size_t cmd_ctx_host_size, ch_ctx_host_size, ev_ctx_host_size;
@@ -565,6 +616,60 @@ static void mhi_ep_cmd_ring_worker(struct work_struct *work)
 	}
 }
 
+static void mhi_ep_ch_ring_worker(struct work_struct *work)
+{
+	struct mhi_ep_cntrl *mhi_cntrl = container_of(work, struct mhi_ep_cntrl, ch_ring_work);
+	struct device *dev = &mhi_cntrl->mhi_dev->dev;
+	struct mhi_ep_ring_item *itr, *tmp;
+	struct mhi_ring_element *el;
+	struct mhi_ep_ring *ring;
+	struct mhi_ep_chan *chan;
+	unsigned long flags;
+	LIST_HEAD(head);
+	int ret;
+
+	spin_lock_irqsave(&mhi_cntrl->list_lock, flags);
+	list_splice_tail_init(&mhi_cntrl->ch_db_list, &head);
+	spin_unlock_irqrestore(&mhi_cntrl->list_lock, flags);
+
+	/* Process each queued channel ring. In case of an error, just process next element. */
+	list_for_each_entry_safe(itr, tmp, &head, node) {
+		list_del(&itr->node);
+		ring = itr->ring;
+
+		/* Update the write offset for the ring */
+		ret = mhi_ep_update_wr_offset(ring);
+		if (ret) {
+			dev_err(dev, "Error updating write offset for ring\n");
+			kfree(itr);
+			continue;
+		}
+
+		/* Sanity check to make sure there are elements in the ring */
+		if (ring->rd_offset == ring->wr_offset) {
+			kfree(itr);
+			continue;
+		}
+
+		el = &ring->ring_cache[ring->rd_offset];
+		chan = &mhi_cntrl->mhi_chan[ring->ch_id];
+
+		mutex_lock(&chan->lock);
+		dev_dbg(dev, "Processing the ring for channel (%u)\n", ring->ch_id);
+		ret = mhi_ep_process_ch_ring(ring, el);
+		if (ret) {
+			dev_err(dev, "Error processing ring for channel (%u): %d\n",
+				ring->ch_id, ret);
+			mutex_unlock(&chan->lock);
+			kfree(itr);
+			continue;
+		}
+
+		mutex_unlock(&chan->lock);
+		kfree(itr);
+	}
+}
+
 static void mhi_ep_state_worker(struct work_struct *work)
 {
 	struct mhi_ep_cntrl *mhi_cntrl = container_of(work, struct mhi_ep_cntrl, state_work);
@@ -630,6 +735,8 @@ static void mhi_ep_queue_channel_db(struct mhi_ep_cntrl *mhi_cntrl, unsigned lon
 		spin_lock(&mhi_cntrl->list_lock);
 		list_splice_tail_init(&head, &mhi_cntrl->ch_db_list);
 		spin_unlock(&mhi_cntrl->list_lock);
+
+		queue_work(mhi_cntrl->wq, &mhi_cntrl->ch_ring_work);
 	}
 }
 
@@ -1120,6 +1227,7 @@ int mhi_ep_register_controller(struct mhi_ep_cntrl *mhi_cntrl,
 	INIT_WORK(&mhi_cntrl->state_work, mhi_ep_state_worker);
 	INIT_WORK(&mhi_cntrl->reset_work, mhi_ep_reset_worker);
 	INIT_WORK(&mhi_cntrl->cmd_ring_work, mhi_ep_cmd_ring_worker);
+	INIT_WORK(&mhi_cntrl->ch_ring_work, mhi_ep_ch_ring_worker);
 
 	mhi_cntrl->wq = alloc_workqueue("mhi_ep_wq", 0, 0);
 	if (!mhi_cntrl->wq) {