greybus: interface: clean up control-connection handling

Clean up control-connection handling by managing it through the control
structure and a higher-level control interface. Also make both the
control structure and connection lifetimes coincide with that of the
interface.

The control connection is now only enabled and disabled when the
interface is initialised and removed.
Signed-off-by: Johan Hovold <johan@hovoldconsulting.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/control.c

@@ -59,31 +59,70 @@ int gb_control_disconnected_operation(struct gb_control *control, u16 cport_id)
 				 sizeof(request), NULL, 0);
 }
 
-static int gb_control_connection_init(struct gb_connection *connection)
+struct gb_control *gb_control_create(struct gb_interface *intf)
 {
 	struct gb_control *control;
 
 	control = kzalloc(sizeof(*control), GFP_KERNEL);
 	if (!control)
-		return -ENOMEM;
+		return NULL;
+
+	control->connection = gb_connection_create_dynamic(intf, NULL,
+						GB_CONTROL_CPORT_ID,
+						GREYBUS_PROTOCOL_CONTROL);
+	if (!control->connection) {
+		dev_err(&intf->dev, "failed to create control connection\n");
+		kfree(control);
+		return NULL;
+	}
 
-	control->connection = connection;
-	connection->private = control;
+	control->connection->private = control;
+
+	return control;
+}
+
+int gb_control_enable(struct gb_control *control)
+{
+	int ret;
 
-	/* Set interface's control connection */
-	connection->intf->control = control;
+	dev_dbg(&control->connection->intf->dev, "%s\n", __func__);
+
+	ret = gb_connection_init(control->connection);
+	if (ret) {
+		dev_err(&control->connection->intf->dev,
+				"failed to enable control connection: %d\n",
+				ret);
+		return ret;
+	}
 
 	return 0;
 }
 
-static void gb_control_connection_exit(struct gb_connection *connection)
+void gb_control_disable(struct gb_control *control)
 {
-	struct gb_control *control = connection->private;
+	dev_dbg(&control->connection->intf->dev, "%s\n", __func__);
 
-	connection->intf->control = NULL;
+	gb_connection_exit(control->connection);
+}
+
+void gb_control_destroy(struct gb_control *control)
+{
+	gb_connection_destroy(control->connection);
 	kfree(control);
 }
 
+static int gb_control_connection_init(struct gb_connection *connection)
+{
+	dev_dbg(&connection->intf->dev, "%s\n", __func__);
+
+	return 0;
+}
+
+static void gb_control_connection_exit(struct gb_connection *connection)
+{
+	dev_dbg(&connection->intf->dev, "%s\n", __func__);
+}
+
 static struct gb_protocol control_protocol = {
 	.name			= "control",
 	.id			= GREYBUS_PROTOCOL_CONTROL,

drivers/staging/greybus/control.h

@@ -14,6 +14,11 @@ struct gb_control {
 	struct gb_connection	*connection;
 };
 
+struct gb_control *gb_control_create(struct gb_interface *intf);
+int gb_control_enable(struct gb_control *control);
+void gb_control_disable(struct gb_control *control);
+void gb_control_destroy(struct gb_control *control);
+
 int gb_control_connected_operation(struct gb_control *control, u16 cport_id);
 int gb_control_disconnected_operation(struct gb_control *control, u16 cport_id);
 int gb_control_get_manifest_size_operation(struct gb_interface *intf);

drivers/staging/greybus/interface.c

@@ -61,6 +61,9 @@ static void gb_interface_release(struct device *dev)
 	kfree(intf->product_string);
 	kfree(intf->vendor_string);
 
+	if (intf->control)
+		gb_control_destroy(intf->control);
+
 	kfree(intf);
 }
 
@@ -106,6 +109,12 @@ struct gb_interface *gb_interface_create(struct gb_host_device *hd,
 	device_initialize(&intf->dev);
 	dev_set_name(&intf->dev, "%d-%d", hd->bus_id, interface_id);
 
+	intf->control = gb_control_create(intf);
+	if (!intf->control) {
+		put_device(&intf->dev);
+		return NULL;
+	}
+
 	spin_lock_irq(&gb_interfaces_lock);
 	list_add(&intf->links, &hd->interfaces);
 	spin_unlock_irq(&gb_interfaces_lock);
@@ -127,8 +136,7 @@ void gb_interface_remove(struct gb_interface *intf)
 	if (device_is_registered(&intf->dev))
 		device_del(&intf->dev);
 
-	if (intf->control)
-		gb_connection_destroy(intf->control->connection);
+	gb_control_disable(intf->control);
 
 	spin_lock_irq(&gb_interfaces_lock);
 	list_del(&intf->links);
@@ -161,20 +169,10 @@ int gb_interface_init(struct gb_interface *intf, u8 device_id)
 
 	intf->device_id = device_id;
 
-	/* Establish control CPort connection */
-	connection = gb_connection_create_dynamic(intf, NULL,
-						GB_CONTROL_CPORT_ID,
-						GREYBUS_PROTOCOL_CONTROL);
-	if (!connection) {
-		dev_err(&intf->dev, "failed to create control connection\n");
-		return -ENOMEM;
-	}
-
-	ret = gb_connection_init(connection);
-	if (ret) {
-		gb_connection_destroy(connection);
+	/* Establish control connection */
+	ret = gb_control_enable(intf->control);
+	if (ret)
 		return ret;
-	}
 
 	/* Get manifest size using control protocol on CPort */
 	size = gb_control_get_manifest_size_operation(intf);