From 0ce6bd546d8ee462d5a77e88a07dfffbc635500c Mon Sep 17 00:00:00 2001
From: ligd <liguiding1@xiaomi.com>
Date: Sat, 30 Apr 2022 12:46:27 +0800
Subject: [PATCH] rptun: use local rx virtqueue idx to resolve remote low power

Store the rx virtqueue idx to the local headrx index, and only
process the data when the rx virtqueue has data to avoid access
the ram in low power mode.

Signed-off-by: ligd <liguiding1@xiaomi.com>
---
 drivers/rptun/rptun.c | 46 ++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 41 insertions(+), 5 deletions(-)

diff --git a/drivers/rptun/rptun.c b/drivers/rptun/rptun.c
index f80af913965..5f835160238 100644
--- a/drivers/rptun/rptun.c
+++ b/drivers/rptun/rptun.c
@@ -70,6 +70,7 @@ struct rptun_priv_s
   pid_t                        tid;
 #ifdef CONFIG_RPTUN_PM
   bool                         stay;
+  uint16_t                     headrx;
 #endif
 };
 
@@ -222,8 +223,40 @@ static inline void rptun_pm_action(FAR struct rptun_priv_s *priv,
   leave_critical_section(flags);
 }
 
+static inline void rptun_update_rx(FAR struct rptun_priv_s *priv)
+{
+  FAR struct rpmsg_virtio_device *rvdev = &priv->rvdev;
+  FAR struct virtqueue *rvq = rvdev->rvq;
+
+  if (rpmsg_virtio_get_role(rvdev) == RPMSG_HOST)
+    {
+      priv->headrx = rvq->vq_ring.used->idx;
+    }
+  else
+    {
+      priv->headrx = rvq->vq_ring.avail->idx;
+    }
+}
+
+static inline bool rptun_available_rx(FAR struct rptun_priv_s *priv)
+{
+  FAR struct rpmsg_virtio_device *rvdev = &priv->rvdev;
+  FAR struct virtqueue *rvq = rvdev->rvq;
+
+  if (rpmsg_virtio_get_role(rvdev) == RPMSG_HOST)
+    {
+      return priv->headrx != rvq->vq_used_cons_idx;
+    }
+  else
+    {
+      return priv->headrx != rvq->vq_available_idx;
+    }
+}
+
 #else
 #  define rptun_pm_action(priv, stay)
+#  define rptun_update_rx(priv)
+#  define rptun_available_rx(priv) true
 #endif
 
 static void rptun_start_worker(FAR void *arg)
@@ -240,7 +273,10 @@ static void rptun_worker(FAR void *arg)
 {
   FAR struct rptun_priv_s *priv = arg;
 
-  remoteproc_get_notification(&priv->rproc, RPTUN_NOTIFY_ALL);
+  if (rptun_available_rx(priv))
+    {
+      remoteproc_get_notification(&priv->rproc, RPTUN_NOTIFY_ALL);
+    }
 }
 
 static int rptun_thread(int argc, FAR char *argv[])
@@ -291,10 +327,8 @@ static int rptun_callback(FAR void *arg, uint32_t vqid)
   if (vqid == RPTUN_NOTIFY_ALL ||
       vqid == vdev->vrings_info[rvq->vq_queue_index].notifyid)
     {
-      if (rptun_buffer_nused(&priv->rvdev, true))
-        {
-          rptun_wakeup_rx(priv);
-        }
+      rptun_update_rx(priv);
+      rptun_wakeup_rx(priv);
     }
 
   if (vqid == RPTUN_NOTIFY_ALL ||
@@ -811,6 +845,8 @@ static int rptun_dev_start(FAR struct remoteproc *rproc)
   /* Register callback to mbox for receiving remote message */
 
   RPTUN_REGISTER_CALLBACK(priv->dev, rptun_callback, priv);
+
+  rptun_update_rx(priv);
   rptun_wakeup_rx(priv);
 
   /* Broadcast device_created to all registers */