[PATCH 7/9] rpmsg: ns: add name service announcement service

[Arnaud Pouliquen <arnaud.pouliquen@xxxxxx>]

As the RPMsg driver is in charge of the name service announcement,
create an API to send channel creation and destruction to the remote
processor.
Notice that the source address of the message sent is now RPMSG_NS_ADDR.
Legacy implementation was to send the message with source address
corresponding to the ept created.
RPMSG_NS_ADDR as source address make sense as we want to send a message
belonging to the NS announcement service and the created ept address is
already in the message payload.

Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@xxxxxx>
---
 drivers/rpmsg/rpmsg_internal.h |  3 +++
 drivers/rpmsg/rpmsg_ns.c       | 39 ++++++++++++++++++++++++++++++++++
 2 files changed, 42 insertions(+)

diff --git a/drivers/rpmsg/rpmsg_internal.h b/drivers/rpmsg/rpmsg_internal.h
index 641b48f6bf2a..d1549e5cb607 100644
--- a/drivers/rpmsg/rpmsg_internal.h
+++ b/drivers/rpmsg/rpmsg_internal.h
@@ -119,4 +119,7 @@ static inline int rpmsg_ns_register_device(struct rpmsg_device *rpdev)
 	return rpmsg_register_device(rpdev);
 }
 
+int rpmsg_ns_announce_create(struct rpmsg_device *rpdev);
+int rpmsg_ns_announce_destroy(struct rpmsg_device *rpdev);
+
 #endif
diff --git a/drivers/rpmsg/rpmsg_ns.c b/drivers/rpmsg/rpmsg_ns.c
index fe7713e737c2..cc2bd47c415a 100644
--- a/drivers/rpmsg/rpmsg_ns.c
+++ b/drivers/rpmsg/rpmsg_ns.c
@@ -37,6 +37,45 @@ struct rpmsg_ns_msg {
 	u32 flags;
 } __packed;
 
+/**
+ * rpmsg_ns_announce_create() -announce to the remote processor
+ * the service creation or destruction
+ * @rpdev: the rpmsg channel
+ * @ns_flag: related to the @rpmsg_ns_flags enum
+ *
+ * This function can be called on a channel creation or destruction to inform
+ * the remote processor, using the reserved name service anouncement channel.
+ */
+static int rpmsg_ns_channel_announce(struct rpmsg_device *rpdev, int ns_flag)
+{
+	struct rpmsg_ns_msg nsm;
+
+	if (!rpdev->announce || !rpdev->ept)
+		return 0;
+
+	if (ns_flag != RPMSG_NS_CREATE && ns_flag != RPMSG_NS_DESTROY)
+		return -EINVAL;
+
+	strncpy(nsm.name, rpdev->id.name, RPMSG_NAME_SIZE);
+	nsm.addr = rpdev->ept->addr;
+	nsm.flags = ns_flag;
+
+	return rpmsg_send_offchannel(rpdev->ept, RPMSG_NS_ADDR, RPMSG_NS_ADDR,
+				     &nsm, sizeof(nsm));
+}
+
+int rpmsg_ns_announce_create(struct rpmsg_device *rpdev)
+{
+	return rpmsg_ns_channel_announce(rpdev, RPMSG_NS_CREATE);
+}
+EXPORT_SYMBOL(rpmsg_ns_announce_create);
+
+int rpmsg_ns_announce_destroy(struct rpmsg_device *rpdev)
+{
+	return rpmsg_ns_channel_announce(rpdev, RPMSG_NS_DESTROY);
+}
+EXPORT_SYMBOL(rpmsg_ns_announce_destroy);
+
 /* invoked when a name service announcement arrives */
 static int rpmsg_ns_cb(struct rpmsg_device *rpdev, void *data, int len,
 		       void *priv, u32 src)
-- 
2.17.1