[SPARC64]: Fix domain-services port probing.

We should only use ports underneath "domain-services", other DS ports
in the MDESC aren't for us to use.
Signed-off-by: David S. Miller <davem@davemloft.net>

arch/sparc64/kernel/vio.c

@@ -342,8 +342,33 @@ static struct mdesc_notifier_client vio_device_notifier = {
 	.node_name	= "virtual-device-port",
 };
 
+/* We are only interested in domain service ports under the
+ * "domain-services" node.  On control nodes there is another port
+ * under "openboot" that we should not mess with as aparently that is
+ * reserved exclusively for OBP use.
+ */
+static void vio_add_ds(struct mdesc_handle *hp, u64 node)
+{
+	int found;
+	u64 a;
+
+	found = 0;
+	mdesc_for_each_arc(a, hp, node, MDESC_ARC_TYPE_BACK) {
+		u64 target = mdesc_arc_target(hp, a);
+		const char *name = mdesc_node_name(hp, target);
+
+		if (!strcmp(name, "domain-services")) {
+			found = 1;
+			break;
+		}
+	}
+
+	if (found)
+		(void) vio_create_one(hp, node, &root_vdev->dev);
+}
+
 static struct mdesc_notifier_client vio_ds_notifier = {
-	.add		= vio_add,
+	.add		= vio_add_ds,
 	.remove		= vio_remove,
 	.node_name	= "domain-services-port",
 };