usb: core: enable remote wakeup function for usb controller

The remote wake up function is a regular function on usb device and
I think keeping it enabled by default will make the usb application
more convenient and usb device remote wake up function keep enabled
that ask usb controller remote wake up was enabled at first.

This patch only enable wake up on usb root hub device, among which,
usb3.0 root hub doesn't be set wakeup node property but use command
USB_INTRF_FUNC_SUSPEND to enable remote wake up function.

Signed-off-by: Yinbo Zhu <zhuyinbo@loongson.cn>

drivers/usb/core/hub.c

@@ -2509,6 +2509,8 @@ static void set_usb_port_removable(struct usb_device *udev)
  */
 int usb_new_device(struct usb_device *udev)
 {
+	struct usb_host_config *config;
+	int ncfg;
 	int err;
 
 	if (udev->parent) {
@@ -2540,6 +2542,18 @@ int usb_new_device(struct usb_device *udev)
 	udev->dev.devt = MKDEV(USB_DEVICE_MAJOR,
 			(((udev->bus->busnum-1) * 128) + (udev->devnum-1)));
 
+	for (ncfg = 0; ncfg < udev->descriptor.bNumConfigurations; ncfg++) {
+		config = &udev->config[ncfg];
+		if ((config->desc.bmAttributes & (1 << 5)) == 0)
+			break;
+		if (ncfg + 1 == udev->descriptor.bNumConfigurations) {
+			err = usb_enable_remote_wakeup(udev);
+			if (err)
+				dev_dbg(&udev->dev,
+				      "won't remote wakeup, err %d\n", err);
+		}
+	}
+
 	/* Tell the world! */
 	announce_device(udev);
 
@@ -3234,7 +3248,7 @@ EXPORT_SYMBOL_GPL(usb_enable_ltm);
  * enable remote wake for the first interface.  FIXME if the interface
  * association descriptor shows there's more than one function.
  */
-static int usb_enable_remote_wakeup(struct usb_device *udev)
+int usb_enable_remote_wakeup(struct usb_device *udev)
 {
 	if (udev->speed < USB_SPEED_SUPER)
 		return usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
@@ -3249,6 +3263,7 @@ static int usb_enable_remote_wakeup(struct usb_device *udev)
 					USB_INTRF_FUNC_SUSPEND_LP,
 				NULL, 0, USB_CTRL_SET_TIMEOUT);
 }
+EXPORT_SYMBOL_GPL(usb_enable_remote_wakeup);
 
 /*
  * usb_disable_remote_wakeup - disable remote wakeup for a device
@@ -3260,7 +3275,7 @@ static int usb_enable_remote_wakeup(struct usb_device *udev)
  * disable remote wake for the first interface.  FIXME if the interface
  * association descriptor shows there's more than one function.
  */
-static int usb_disable_remote_wakeup(struct usb_device *udev)
+int usb_disable_remote_wakeup(struct usb_device *udev)
 {
 	if (udev->speed < USB_SPEED_SUPER)
 		return usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
@@ -3273,6 +3288,7 @@ static int usb_disable_remote_wakeup(struct usb_device *udev)
 				USB_INTRF_FUNC_SUSPEND,	0, NULL, 0,
 				USB_CTRL_SET_TIMEOUT);
 }
+EXPORT_SYMBOL_GPL(usb_disable_remote_wakeup);
 
 /* Count of wakeup-enabled devices at or below udev */
 unsigned usb_wakeup_enabled_descendants(struct usb_device *udev)

include/linux/usb.h

@@ -754,8 +754,10 @@ static inline bool usb_acpi_power_manageable(struct usb_device *hdev, int index)
 	{ return true; }
 #endif
 
-/* USB autosuspend and autoresume */
 #ifdef CONFIG_PM
+extern int usb_enable_remote_wakeup(struct usb_device *udev);
+extern int usb_disable_remote_wakeup(struct usb_device *udev);
+
 extern void usb_enable_autosuspend(struct usb_device *udev);
 extern void usb_disable_autosuspend(struct usb_device *udev);