rpmsg: notify the user when the remote address is received

without this notificaiton, user has to call is_rpmsg_ept_ready in a busy loop

Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>

Author: xiaoxiang781216

doc/rpmsg-design.md

@@ -152,6 +152,13 @@ running on two processors.
   void (*rpmsg_ns_unbind_cb)(struct rpmsg_device *rdev,
 			   const char *name, uint32_t dest)
   ```
+* RPMsg endpoint name service binding callback. If user defines such callback,
+  when there is a name service announcement arrives, if there is a registered
+  endpoint found to bind to this name service, it will call this callback to
+  notify the user application about the remote has created the service.:
+  ```
+  void (*rpmsg_ns_bind_cb)(struct rpmsg_endpoint *ept)
+  ```
 * RPMsg endpoint name service unbind callback. If user defines such callback,
   when there is name service destroy arrives, it will call this callback to
   notify the user application about the remote has destroyed the service.:

lib/include/openamp/rpmsg.h

@@ -87,6 +87,9 @@ struct rpmsg_endpoint {
 	 */
 	rpmsg_ept_cb cb;
 
+	/** Endpoint service bind callback, called when remote ept is created */
+	rpmsg_ns_unbind_cb ns_bind_cb;
+
 	/** Endpoint service unbind callback, called when remote ept is destroyed */
 	rpmsg_ns_unbind_cb ns_unbind_cb;
 

lib/rpmsg/rpmsg_virtio.c

@@ -698,6 +698,9 @@ static int rpmsg_virtio_ns_callback(struct rpmsg_endpoint *ept, void *data,
 		} else {
 			_ept->dest_addr = dest;
 			metal_mutex_release(&rdev->lock);
+			/* notify application the endpoint has been bound */
+			if (_ept->ns_bind_cb)
+				_ept->ns_bind_cb(_ept);
 		}
 	}