xen: xenbus PM events support

Make xenbus frontend device subscribe to PM events
to receive suspend/resume/freeze/thaw/restore
notifications.

Signed-off-by: Kenji Wakamiya <[e-mail]>
Signed-off-by: Kazuhiro Suzuki <[e-mail]>
Signed-off-by: Shriram Rajagopalan <[e-mail]>
Acked-by: Ian Campbell <[e-mail]>
[shriram--minor mods and improved commit message]
Signed-off-by: Konrad Rzeszutek Wilk <[e-mail]>

drivers/xen/xenbus/xenbus_probe.c

···
 }
 EXPORT_SYMBOL_GPL(xenbus_dev_changed);
 
-int xenbus_dev_suspend(struct device *dev, pm_message_t state)
+int xenbus_dev_suspend(struct device *dev)
 {
 	int err = 0;
 	struct xenbus_driver *drv;
···
 		return 0;
 	drv = to_xenbus_driver(dev->driver);
 	if (drv->suspend)
-		err = drv->suspend(xdev, state);
+		err = drv->suspend(xdev);
 	if (err)
 		printk(KERN_WARNING
 		       "xenbus: suspend %s failed: %i\n", dev_name(dev), err);
···
 	return 0;
 }
 EXPORT_SYMBOL_GPL(xenbus_dev_resume);
+
+int xenbus_dev_cancel(struct device *dev)
+{
+	/* Do nothing */
+	DPRINTK("cancel");
+	return 0;
+}
+EXPORT_SYMBOL_GPL(xenbus_dev_cancel);
 
 /* A flag to determine if xenstored is 'ready' (i.e. has started) */
 int xenstored_ready = 0;

drivers/xen/xenbus/xenbus_probe.h

···
 
 extern void xenbus_dev_shutdown(struct device *_dev);
 
-extern int xenbus_dev_suspend(struct device *dev, pm_message_t state);
+extern int xenbus_dev_suspend(struct device *dev);
 extern int xenbus_dev_resume(struct device *dev);
+extern int xenbus_dev_cancel(struct device *dev);
 
 extern void xenbus_otherend_changed(struct xenbus_watch *watch,
 				    const char **vec, unsigned int len,

drivers/xen/xenbus/xenbus_probe_frontend.c

···
 	__ATTR_NULL
 };
 
+static const struct dev_pm_ops xenbus_pm_ops = {
+	.suspend = xenbus_dev_suspend,
+	.resume  = xenbus_dev_resume,
+	.thaw  = xenbus_dev_cancel,
+};
+
 static struct xen_bus_type xenbus_frontend = {
 	.root = "device",
 	.levels = 2,		/* device/type/<id> */
···
 		.shutdown	= xenbus_dev_shutdown,
 		.dev_attrs	= xenbus_frontend_dev_attrs,
 
-		.suspend	= xenbus_dev_suspend,
-		.resume		= xenbus_dev_resume,
+		.pm		= &xenbus_pm_ops,
 	},
 };
 

include/xen/xenbus.h

···
 	void (*otherend_changed)(struct xenbus_device *dev,
 				 enum xenbus_state backend_state);
 	int (*remove)(struct xenbus_device *dev);
-	int (*suspend)(struct xenbus_device *dev, pm_message_t state);
+	int (*suspend)(struct xenbus_device *dev);
 	int (*resume)(struct xenbus_device *dev);
 	int (*uevent)(struct xenbus_device *, struct kobj_uevent_env *);
 	struct device_driver driver;