usb: wusbcore: implement hwahc_op_get_frame_number

This patch adds an implementation for hwahc_op_get_frame_number.  The
request is fulfulled by forwarding it to the lower hcd.  This was done
because the GET_TIME request on the HWA requires sending an URB to the
HWA and waiting for the results which cannot be done in atomic context.

Signed-off-by: Thomas Pugliese <thomas.pugliese@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/hwa-hc.c

@@ -199,10 +199,14 @@ static int hwahc_op_get_frame_number(struct usb_hcd *usb_hcd)
 {
 	struct wusbhc *wusbhc = usb_hcd_to_wusbhc(usb_hcd);
 	struct hwahc *hwahc = container_of(wusbhc, struct hwahc, wusbhc);
+	struct wahc *wa = &hwahc->wa;
 
-	dev_err(wusbhc->dev, "%s (%p [%p]) UNIMPLEMENTED\n", __func__,
-		usb_hcd, hwahc);
-	return -ENOSYS;
+	/*
+	 * We cannot query the HWA for the WUSB time since that requires sending
+	 * a synchronous URB and this function can be called in_interrupt.
+	 * Instead, query the USB frame number for our parent and use that.
+	 */
+	return usb_get_current_frame_number(wa->usb_dev);
 }
 
 static int hwahc_op_urb_enqueue(struct usb_hcd *usb_hcd, struct urb *urb,