ns: acknowledge the received creation message

the two phase handsake make the client could initiate the transfer
immediately without the server side send any dummy message first.

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

Author: xiaoxiang781216

lib/include/openamp/rpmsg.h

@@ -155,6 +155,7 @@ struct rpmsg_device {
 
 	/** Create/destroy namespace message */
 	bool support_ns;
+	bool support_ack;
 };
 
 /**

lib/include/openamp/rpmsg_virtio.h

@@ -29,6 +29,7 @@ extern "C" {
 
 /* The feature bitmap for virtio rpmsg */
 #define VIRTIO_RPMSG_F_NS	0 /* RP supports name service notifications */
+#define VIRTIO_RPMSG_F_ACK	1 /* RP supports name service acknowledge */
 
 #ifdef VIRTIO_CACHED_BUFFERS
 #warning "VIRTIO_CACHED_BUFFERS is deprecated, please use VIRTIO_USE_DCACHE"

lib/rpmsg/rpmsg.c

@@ -357,10 +357,13 @@ int rpmsg_create_ept(struct rpmsg_endpoint *ept, struct rpmsg_device *rdev,
 	rpmsg_register_endpoint(rdev, ept, name, addr, dest, cb, unbind_cb, NULL);
 	metal_mutex_release(&rdev->lock);
 
-	/* Send NS announcement to remote processor */
+	/* Send NS announcement/acknowledge to remote processor */
 	if (ept->name[0] && rdev->support_ns &&
 	    ept->dest_addr == RPMSG_ADDR_ANY)
 		status = rpmsg_send_ns_message(ept, RPMSG_NS_CREATE);
+	else if (ept->name[0] && rdev->support_ack &&
+		 ept->dest_addr != RPMSG_ADDR_ANY)
+		status = rpmsg_send_ns_message(ept, RPMSG_NS_CREATE_ACK);
 
 	if (status)
 		rpmsg_unregister_endpoint(ept);

lib/rpmsg/rpmsg_internal.h

@@ -44,6 +44,8 @@ enum rpmsg_ns_flags {
 	RPMSG_NS_CREATE = 0,
 	/** A known remote service was just destroyed */
 	RPMSG_NS_DESTROY = 1,
+	/** Acknowledge the previous creation message */
+	RPMSG_NS_CREATE_ACK = 2,
 };
 
 /**

lib/rpmsg/rpmsg_virtio.c

@@ -656,7 +656,7 @@ static int rpmsg_virtio_ns_callback(struct rpmsg_endpoint *ept, void *data,
 	 */
 	ept_to_release = _ept && _ept->release_cb;
 
-	if (ns_msg->flags & RPMSG_NS_DESTROY) {
+	if (ns_msg->flags == RPMSG_NS_DESTROY) {
 		if (_ept)
 			_ept->dest_addr = RPMSG_ADDR_ANY;
 		if (ept_to_release)
@@ -671,7 +671,7 @@ static int rpmsg_virtio_ns_callback(struct rpmsg_endpoint *ept, void *data,
 			rpmsg_ept_decref(_ept);
 			metal_mutex_release(&rdev->lock);
 		}
-	} else {
+	} else if (ns_msg->flags == RPMSG_NS_CREATE) {
 		if (!_ept) {
 			/*
 			 * send callback to application, that can
@@ -685,7 +685,15 @@ static int rpmsg_virtio_ns_callback(struct rpmsg_endpoint *ept, void *data,
 		} else {
 			_ept->dest_addr = dest;
 			metal_mutex_release(&rdev->lock);
+			if (_ept->name[0] && rdev->support_ack)
+				rpmsg_send_ns_message(_ept,
+						      RPMSG_NS_CREATE_ACK);
 		}
+	} else { /* RPMSG_NS_CREATE_ACK */
+		/* save the received destination address */
+		if (_ept)
+			_ept->dest_addr = dest;
+		metal_mutex_release(&rdev->lock);
 	}
 
 	return RPMSG_SUCCESS;
@@ -827,7 +835,9 @@ int rpmsg_init_vdev_with_config(struct rpmsg_virtio_device *rvdev,
 	status = virtio_get_features(rvdev->vdev, &features);
 	if (status)
 		return status;
+
 	rdev->support_ns = !!(features & (1 << VIRTIO_RPMSG_F_NS));
+	rdev->support_ack = !!(features & (1 << VIRTIO_RPMSG_F_ACK));
 
 	if (VIRTIO_ROLE_IS_DRIVER(rvdev->vdev)) {
 		/*
@@ -926,7 +936,7 @@ int rpmsg_init_vdev_with_config(struct rpmsg_virtio_device *rvdev,
 	 * Create name service announcement endpoint if device supports name
 	 * service announcement feature.
 	 */
-	if (rdev->support_ns) {
+	if (rdev->support_ns || rdev->support_ack) {
 		rpmsg_register_endpoint(rdev, &rdev->ns_ept, "NS",
 				     RPMSG_NS_EPT_ADDR, RPMSG_NS_EPT_ADDR,
 				     rpmsg_virtio_ns_callback, NULL, rvdev);