rpmsg: glink: Use the local intents when receiving data

So previously on request from remote side, we allocated local intent
buffers and passed the ids to the remote. Now when we receive data
buffers from remote directed to that intent id, copy the data to the
corresponding preallocated intent buffer.

Acked-by: Arun Kumar Neelakantam <aneela@codeaurora.org>
Signed-off-by: Sricharan R <sricharan@codeaurora.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

Author: Sricharan R

drivers/rpmsg/qcom_glink_native.c

@@ -162,7 +162,7 @@ struct glink_channel {
 	spinlock_t intent_lock;
 	struct idr liids;
 
-	void *buf;
+	struct glink_core_rx_intent *buf;
 	int buf_offset;
 	int buf_size;
 
@@ -614,6 +614,7 @@ static int qcom_glink_rx_defer(struct qcom_glink *glink, size_t extra)
 
 static int qcom_glink_rx_data(struct qcom_glink *glink, size_t avail)
 {
+	struct glink_core_rx_intent *intent;
 	struct glink_channel *channel;
 	struct {
 		struct glink_msg msg;
@@ -623,6 +624,8 @@ static int qcom_glink_rx_data(struct qcom_glink *glink, size_t avail)
 	unsigned int chunk_size;
 	unsigned int left_size;
 	unsigned int rcid;
+	unsigned int liid;
+	int ret = 0;
 	unsigned long flags;
 
 	if (avail < sizeof(hdr)) {
@@ -650,56 +653,78 @@ static int qcom_glink_rx_data(struct qcom_glink *glink, size_t avail)
 		dev_dbg(glink->dev, "Data on non-existing channel\n");
 
 		/* Drop the message */
-		qcom_glink_rx_advance(glink,
-				      ALIGN(sizeof(hdr) + chunk_size, 8));
-		return 0;
+		goto advance_rx;
 	}
 
-	/* Might have an ongoing, fragmented, message to append */
-	if (!channel->buf) {
-		channel->buf = kmalloc(chunk_size + left_size, GFP_ATOMIC);
-		if (!channel->buf)
-			return -ENOMEM;
+	if (glink->intentless) {
+		/* Might have an ongoing, fragmented, message to append */
+		if (!channel->buf) {
+			intent = kzalloc(sizeof(*intent), GFP_ATOMIC);
+			if (!intent)
+				return -ENOMEM;
+
+			intent->data = kmalloc(chunk_size + left_size,
+					       GFP_ATOMIC);
+			if (!intent->data) {
+				kfree(intent);
+				return -ENOMEM;
+			}
+
+			intent->id = 0xbabababa;
+			intent->size = chunk_size + left_size;
+			intent->offset = 0;
+
+			channel->buf = intent;
+		} else {
+			intent = channel->buf;
+		}
+	} else {
+		liid = le32_to_cpu(hdr.msg.param2);
 
-		channel->buf_size = chunk_size + left_size;
-		channel->buf_offset = 0;
-	}
+		spin_lock_irqsave(&channel->intent_lock, flags);
+		intent = idr_find(&channel->liids, liid);
+		spin_unlock_irqrestore(&channel->intent_lock, flags);
 
-	qcom_glink_rx_advance(glink, sizeof(hdr));
+		if (!intent) {
+			dev_err(glink->dev,
+				"no intent found for channel %s intent %d",
+				channel->name, liid);
+			goto advance_rx;
+		}
+	}
 
-	if (channel->buf_size - channel->buf_offset < chunk_size) {
-		dev_err(glink->dev, "Insufficient space in input buffer\n");
+	if (intent->size - intent->offset < chunk_size) {
+		dev_err(glink->dev, "Insufficient space in intent\n");
 
 		/* The packet header lied, drop payload */
-		qcom_glink_rx_advance(glink, chunk_size);
-		return -ENOMEM;
+		goto advance_rx;
 	}
 
-	qcom_glink_rx_peak(glink, channel->buf + channel->buf_offset,
+	qcom_glink_rx_advance(glink, ALIGN(sizeof(hdr), 8));
+	qcom_glink_rx_peak(glink, intent->data + intent->offset,
 			   chunk_size);
-	channel->buf_offset += chunk_size;
+	intent->offset += chunk_size;
 
 	/* Handle message when no fragments remain to be received */
 	if (!left_size) {
 		spin_lock(&channel->recv_lock);
 		if (channel->ept.cb) {
 			channel->ept.cb(channel->ept.rpdev,
-					channel->buf,
-					channel->buf_offset,
+					intent->data,
+					intent->offset,
 					channel->ept.priv,
 					RPMSG_ADDR_ANY);
 		}
 		spin_unlock(&channel->recv_lock);
 
-		kfree(channel->buf);
+		intent->offset = 0;
 		channel->buf = NULL;
-		channel->buf_size = 0;
 	}
 
-	/* Each message starts at 8 byte aligned address */
+advance_rx:
 	qcom_glink_rx_advance(glink, ALIGN(chunk_size, 8));
 
-	return 0;
+	return ret;
 }
 
 static int qcom_glink_rx_open_ack(struct qcom_glink *glink, unsigned int lcid)