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

lib/include/openamp/rpmsg.h

@@ -61,6 +61,8 @@ typedef void (*rpmsg_ns_bind_cb)(struct rpmsg_device *rdev,
  * @dest_addr: address of the default remote endpoint binded.
  * @cb: user rx callback, return value of this callback is reserved
  *      for future use, for now, only allow RPMSG_SUCCESS as return value.
+ * @ns_bind_cb: end point service bind callback, called when remote
+ *                ept address is received.
  * @ns_unbind_cb: end point service unbind callback, called when remote
  *                ept is destroyed.
  * @node: end point node.
@@ -75,6 +77,7 @@ struct rpmsg_endpoint {
 	uint32_t addr;
 	uint32_t dest_addr;
 	rpmsg_ept_cb cb;
+	rpmsg_ns_unbind_cb ns_bind_cb;
 	rpmsg_ns_unbind_cb ns_unbind_cb;
 	struct metal_list node;
 	void *priv;

lib/rpmsg/rpmsg_virtio.c

@@ -599,6 +599,9 @@ 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);
 		}
 	}