1 files changed, 82 insertions, 0 deletions

diff --git a/drivers/bus/mhi/ep/main.c b/drivers/bus/mhi/ep/main.c
index e2ed10b4a9d2..660d1e9791d3 100644
--- a/drivers/bus/mhi/ep/main.c
+++ b/drivers/bus/mhi/ep/main.c
@@ -434,6 +434,88 @@ static int mhi_ep_process_ch_ring(struct mhi_ep_ring *ring, struct mhi_ring_elem
 	return 0;
 }
 
+/* TODO: Handle partially formed TDs */
+int mhi_ep_queue_skb(struct mhi_ep_device *mhi_dev, struct sk_buff *skb)
+{
+	struct mhi_ep_cntrl *mhi_cntrl = mhi_dev->mhi_cntrl;
+	struct mhi_ep_chan *mhi_chan = mhi_dev->dl_chan;
+	struct device *dev = &mhi_chan->mhi_dev->dev;
+	struct mhi_ring_element *el;
+	u32 buf_left, read_offset;
+	struct mhi_ep_ring *ring;
+	enum mhi_ev_ccs code;
+	void *read_addr;
+	u64 write_addr;
+	size_t tr_len;
+	u32 tre_len;
+	int ret;
+
+	buf_left = skb->len;
+	ring = &mhi_cntrl->mhi_chan[mhi_chan->chan].ring;
+
+	mutex_lock(&mhi_chan->lock);
+
+	do {
+		/* Don't process the transfer ring if the channel is not in RUNNING state */
+		if (mhi_chan->state != MHI_CH_STATE_RUNNING) {
+			dev_err(dev, "Channel not available\n");
+			ret = -ENODEV;
+			goto err_exit;
+		}
+
+		if (mhi_ep_queue_is_empty(mhi_dev, DMA_FROM_DEVICE)) {
+			dev_err(dev, "TRE not available!\n");
+			ret = -ENOSPC;
+			goto err_exit;
+		}
+
+		el = &ring->ring_cache[ring->rd_offset];
+		tre_len = MHI_TRE_DATA_GET_LEN(el);
+
+		tr_len = min(buf_left, tre_len);
+		read_offset = skb->len - buf_left;
+		read_addr = skb->data + read_offset;
+		write_addr = MHI_TRE_DATA_GET_PTR(el);
+
+		dev_dbg(dev, "Writing %zd bytes to channel (%u)\n", tr_len, ring->ch_id);
+		ret = mhi_cntrl->write_to_host(mhi_cntrl, read_addr, write_addr, tr_len);
+		if (ret < 0) {
+			dev_err(dev, "Error writing to the channel\n");
+			goto err_exit;
+		}
+
+		buf_left -= tr_len;
+		/*
+		 * For all TREs queued by the host for DL channel, only the EOT flag will be set.
+		 * If the packet doesn't fit into a single TRE, send the OVERFLOW event to
+		 * the host so that the host can adjust the packet boundary to next TREs. Else send
+		 * the EOT event to the host indicating the packet boundary.
+		 */
+		if (buf_left)
+			code = MHI_EV_CC_OVERFLOW;
+		else
+			code = MHI_EV_CC_EOT;
+
+		ret = mhi_ep_send_completion_event(mhi_cntrl, ring, el, tr_len, code);
+		if (ret) {
+			dev_err(dev, "Error sending transfer completion event\n");
+			goto err_exit;
+		}
+
+		mhi_ep_ring_inc_index(ring);
+	} while (buf_left);
+
+	mutex_unlock(&mhi_chan->lock);
+
+	return 0;
+
+err_exit:
+	mutex_unlock(&mhi_chan->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(mhi_ep_queue_skb);
+
 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;