USB: refactor code for enabling/disabling remote wakeup

The hub driver is inconsistent in its organization of code for
enabling and disabling remote wakeup.  There is a special routine to
disable wakeup for SuperSpeed devices but not for slower devices, and
there is no special routine to enable wakeup.

This patch refactors the code.  It renames and changes the existing
function to make it handle both SuperSpeed and non-SuperSpeed devices,
and it adds a corresponding routine to enable remote wakeup.  It also
changes the speed determination to look at the device's speed rather
than the speed of the parent hub -- this shouldn't make any difference
because a SuperSpeed device always has to be attached to a SuperSpeed
hub and conversely.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/core/hub.c

@@ -2838,18 +2838,50 @@ void usb_enable_ltm(struct usb_device *udev)
 EXPORT_SYMBOL_GPL(usb_enable_ltm);
 
 /*
- * usb_disable_function_remotewakeup - disable usb3.0
- * device's function remote wakeup
+ * usb_enable_remote_wakeup - enable remote wakeup for a device
  * @udev: target device
  *
- * Assume there's only one function on the USB 3.0
- * device and disable remote wake for the first
- * interface. FIXME if the interface association
- * descriptor shows there's more than one function.
+ * For USB-2 devices: Set the device's remote wakeup feature.
+ *
+ * For USB-3 devices: Assume there's only one function on the device and
+ * enable remote wake for the first interface.  FIXME if the interface
+ * association descriptor shows there's more than one function.
  */
-static int usb_disable_function_remotewakeup(struct usb_device *udev)
+static int usb_enable_remote_wakeup(struct usb_device *udev)
 {
-	return usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
+	if (udev->speed < USB_SPEED_SUPER)
+		return usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
+				USB_REQ_SET_FEATURE, USB_RECIP_DEVICE,
+				USB_DEVICE_REMOTE_WAKEUP, 0, NULL, 0,
+				USB_CTRL_SET_TIMEOUT);
+	else
+		return usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
+				USB_REQ_SET_FEATURE, USB_RECIP_INTERFACE,
+				USB_INTRF_FUNC_SUSPEND,
+				USB_INTRF_FUNC_SUSPEND_RW |
+					USB_INTRF_FUNC_SUSPEND_LP,
+				NULL, 0, USB_CTRL_SET_TIMEOUT);
+}
+
+/*
+ * usb_disable_remote_wakeup - disable remote wakeup for a device
+ * @udev: target device
+ *
+ * For USB-2 devices: Clear the device's remote wakeup feature.
+ *
+ * For USB-3 devices: Assume there's only one function on the device and
+ * 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)
+{
+	if (udev->speed < USB_SPEED_SUPER)
+		return usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
+				USB_REQ_CLEAR_FEATURE, USB_RECIP_DEVICE,
+				USB_DEVICE_REMOTE_WAKEUP, 0, NULL, 0,
+				USB_CTRL_SET_TIMEOUT);
+	else
+		return usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
 				USB_REQ_CLEAR_FEATURE, USB_RECIP_INTERFACE,
 				USB_INTRF_FUNC_SUSPEND,	0, NULL, 0,
 				USB_CTRL_SET_TIMEOUT);
@@ -2928,27 +2960,7 @@ int usb_port_suspend(struct usb_device *udev, pm_message_t msg)
 	 * we don't explicitly enable it here.
 	 */
 	if (udev->do_remote_wakeup) {
-		if (!hub_is_superspeed(hub->hdev)) {
-			status = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
-					USB_REQ_SET_FEATURE, USB_RECIP_DEVICE,
-					USB_DEVICE_REMOTE_WAKEUP, 0,
-					NULL, 0,
-					USB_CTRL_SET_TIMEOUT);
-		} else {
-			/* Assume there's only one function on the USB 3.0
-			 * device and enable remote wake for the first
-			 * interface. FIXME if the interface association
-			 * descriptor shows there's more than one function.
-			 */
-			status = usb_control_msg(udev, usb_sndctrlpipe(udev, 0),
-					USB_REQ_SET_FEATURE,
-					USB_RECIP_INTERFACE,
-					USB_INTRF_FUNC_SUSPEND,
-					USB_INTRF_FUNC_SUSPEND_RW |
-					USB_INTRF_FUNC_SUSPEND_LP,
-					NULL, 0,
-					USB_CTRL_SET_TIMEOUT);
-		}
+		status = usb_enable_remote_wakeup(udev);
 		if (status) {
 			dev_dbg(&udev->dev, "won't remote wakeup, status %d\n",
 					status);
@@ -2999,19 +3011,8 @@ int usb_port_suspend(struct usb_device *udev, pm_message_t msg)
 		dev_dbg(hub->intfdev, "can't suspend port %d, status %d\n",
 				port1, status);
 		/* paranoia:  "should not happen" */
-		if (udev->do_remote_wakeup) {
-			if (!hub_is_superspeed(hub->hdev)) {
-				(void) usb_control_msg(udev,
-						usb_sndctrlpipe(udev, 0),
-						USB_REQ_CLEAR_FEATURE,
-						USB_RECIP_DEVICE,
-						USB_DEVICE_REMOTE_WAKEUP, 0,
-						NULL, 0,
-						USB_CTRL_SET_TIMEOUT);
-			} else
-				(void) usb_disable_function_remotewakeup(udev);
-
-		}
+		if (udev->do_remote_wakeup)
+			(void) usb_disable_remote_wakeup(udev);
 
 		/* Try to enable USB2 hardware LPM again */
 		if (udev->usb2_hw_lpm_capable == 1)
@@ -3119,22 +3120,15 @@ static int finish_port_resume(struct usb_device *udev)
 	 * udev->reset_resume
 	 */
 	} else if (udev->actconfig && !udev->reset_resume) {
-		if (!hub_is_superspeed(udev->parent)) {
+		if (udev->speed < USB_SPEED_SUPER) {
 			if (devstatus & (1 << USB_DEVICE_REMOTE_WAKEUP))
-				status = usb_control_msg(udev,
-						usb_sndctrlpipe(udev, 0),
-						USB_REQ_CLEAR_FEATURE,
-						USB_RECIP_DEVICE,
-						USB_DEVICE_REMOTE_WAKEUP, 0,
-						NULL, 0,
-						USB_CTRL_SET_TIMEOUT);
+				status = usb_disable_remote_wakeup(udev);
 		} else {
 			status = usb_get_status(udev, USB_RECIP_INTERFACE, 0,
 					&devstatus);
 			if (!status && devstatus & (USB_INTRF_STAT_FUNC_RW_CAP
 					| USB_INTRF_STAT_FUNC_RW))
-				status =
-					usb_disable_function_remotewakeup(udev);
+				status = usb_disable_remote_wakeup(udev);
 		}
 
 		if (status)