[PATCH 3/4] rpmsg: glink: Try to send rx done in irq

[Chris Lew <quic_clew@quicinc.com>]

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.

Signed-off-by: Chris Lew <quic_clew@quicinc.com>
---
 drivers/rpmsg/qcom_glink_native.c | 60 ++++++++++++++++++++++++++-------------
 1 file changed, 40 insertions(+), 20 deletions(-)

diff --git a/drivers/rpmsg/qcom_glink_native.c b/drivers/rpmsg/qcom_glink_native.c
index 07586514991f..799e602113a1 100644
--- a/drivers/rpmsg/qcom_glink_native.c
+++ b/drivers/rpmsg/qcom_glink_native.c
@@ -497,12 +497,11 @@ static void qcom_glink_send_close_ack(struct qcom_glink *glink,
 	qcom_glink_tx(glink, &req, sizeof(req), NULL, 0, true);
 }
 
-static void qcom_glink_rx_done_work(struct work_struct *work)
+static int qcom_glink_send_rx_done(struct qcom_glink *glink,
+				struct glink_channel *channel,
+				struct glink_core_rx_intent *intent,
+				bool wait)
 {
-	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;
@@ -510,26 +509,41 @@ static void qcom_glink_rx_done_work(struct work_struct *work)
 	} __packed cmd;
 
 	unsigned int cid = channel->lcid;
-	unsigned int iid;
-	bool reuse;
+	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;
 	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_send_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 +553,8 @@ 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 +571,14 @@ 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_send_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);
 }
 
 /**
-- 
2.7.4