From dc5a4fb32fdb922844c8f1382dc09a9817d52273 Mon Sep 17 00:00:00 2001
From: Chris Lew <clew@codeaurora.org>
Date: Mon, 20 Aug 2018 11:58:49 -0700
Subject: [PATCH] rpmsg: glink: Try to send rx done in irq

Some remote processors and usecases such as audio playback are
sensitive to the response time of rx done. Try to send the rx done cmd
from irq context. If trysend fails, defer the rx done work like before.

Change-Id: I862349b20f4ade11fa62f91c9c409f9b1b79d478
Signed-off-by: Chris Lew <clew@codeaurora.org>
---
 drivers/rpmsg/qcom_glink_native.c | 63 ++++++++++++++++++++-----------
 1 file changed, 41 insertions(+), 22 deletions(-)

diff --git a/drivers/rpmsg/qcom_glink_native.c b/drivers/rpmsg/qcom_glink_native.c
index 07586514991f..297959329633 100644
--- a/drivers/rpmsg/qcom_glink_native.c
+++ b/drivers/rpmsg/qcom_glink_native.c
@@ -497,39 +497,52 @@ static void qcom_glink_send_close_ack(struct qcom_glink *glink,
 	qcom_glink_tx(glink, &req, sizeof(req), NULL, 0, true);
 }
 
+static int __qcom_glink_rx_done(struct qcom_glink *glink,
+				struct glink_channel *channel,
+				struct glink_core_rx_intent *intent,
+				bool wait)
+{
+	struct {
+		u16 id;
+		u16 lcid;
+		u32 liid;
+	} __packed cmd;
+	unsigned int cid = channel->lcid;
+	unsigned int iid = intent->id;
+	bool reuse = intent->reuse;
+	int ret;
+
+	cmd.id = reuse ? RPM_CMD_RX_DONE_W_REUSE : RPM_CMD_RX_DONE;
+	cmd.lcid = cid;
+	cmd.liid = iid;
+
+	ret = qcom_glink_tx(glink, &cmd, sizeof(cmd), NULL, 0, wait);
+	if (ret)
+		return ret;
+
+	if (!reuse) {
+		kfree(intent->data);
+		kfree(intent);
+	}
+
+	return 0;
+}
+
 static void qcom_glink_rx_done_work(struct work_struct *work)
 {
 	struct glink_channel *channel = container_of(work, struct glink_channel,
 						     intent_work);
 	struct qcom_glink *glink = channel->glink;
 	struct glink_core_rx_intent *intent, *tmp;
-	struct {
-		u16 id;
-		u16 lcid;
-		u32 liid;
-	} __packed cmd;
-
-	unsigned int cid = channel->lcid;
-	unsigned int iid;
-	bool reuse;
 	unsigned long flags;
 
 	spin_lock_irqsave(&channel->intent_lock, flags);
 	list_for_each_entry_safe(intent, tmp, &channel->done_intents, node) {
 		list_del(&intent->node);
 		spin_unlock_irqrestore(&channel->intent_lock, flags);
-		iid = intent->id;
-		reuse = intent->reuse;
 
-		cmd.id = reuse ? RPM_CMD_RX_DONE_W_REUSE : RPM_CMD_RX_DONE;
-		cmd.lcid = cid;
-		cmd.liid = iid;
+		__qcom_glink_rx_done(glink, channel, intent, true);
 
-		qcom_glink_tx(glink, &cmd, sizeof(cmd), NULL, 0, true);
-		if (!reuse) {
-			kfree(intent->data);
-			kfree(intent);
-		}
 		spin_lock_irqsave(&channel->intent_lock, flags);
 	}
 	spin_unlock_irqrestore(&channel->intent_lock, flags);
@@ -539,6 +552,8 @@ static void qcom_glink_rx_done(struct qcom_glink *glink,
 			       struct glink_channel *channel,
 			       struct glink_core_rx_intent *intent)
 {
+	int ret = -EAGAIN;
+
 	/* We don't send RX_DONE to intentless systems */
 	if (glink->intentless) {
 		kfree(intent->data);
@@ -555,10 +570,14 @@ static void qcom_glink_rx_done(struct qcom_glink *glink,
 
 	/* Schedule the sending of a rx_done indication */
 	spin_lock(&channel->intent_lock);
-	list_add_tail(&intent->node, &channel->done_intents);
-	spin_unlock(&channel->intent_lock);
+	if (list_empty(&channel->done_intents))
+		ret = __qcom_glink_rx_done(glink, channel, intent, false);
 
-	schedule_work(&channel->intent_work);
+	if (ret) {
+		list_add_tail(&intent->node, &channel->done_intents);
+		schedule_work(&channel->intent_work);
+	}
+	spin_unlock(&channel->intent_lock);
 }
 
 /**