usb: dwc3: gadget: set PCM1 field of isochronous-first TRBs

commit 6b9018d4 upstream.

In case of High-Speed, High-Bandwidth endpoints, we
need to tell DWC3 that we have more than one packet
per interval. We do that by setting PCM1 field of
Isochronous-First TRB.
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

drivers/usb/dwc3/gadget.c

@@ -863,6 +863,8 @@ static void dwc3_prepare_one_trb(struct dwc3_ep *dep,
 {
 	struct dwc3		*dwc = dep->dwc;
 	struct dwc3_trb		*trb;
+	struct usb_gadget	*gadget = &dwc->gadget;
+	enum usb_device_speed	speed = gadget->speed;
 
 	dev_vdbg(dwc->dev, "%s: req %p dma %08llx length %d%s%s\n",
 			dep->name, req, (unsigned long long) dma,
@@ -895,10 +897,16 @@ static void dwc3_prepare_one_trb(struct dwc3_ep *dep,
 		break;
 
 	case USB_ENDPOINT_XFER_ISOC:
-		if (!node)
+		if (!node) {
 			trb->ctrl = DWC3_TRBCTL_ISOCHRONOUS_FIRST;
-		else
+
+			if (speed == USB_SPEED_HIGH) {
+				struct usb_ep *ep = &dep->endpoint;
+				trb->size |= DWC3_TRB_SIZE_PCM1(ep->mult - 1);
+			}
+		} else {
 			trb->ctrl = DWC3_TRBCTL_ISOCHRONOUS;
+		}
 		break;
 
 	case USB_ENDPOINT_XFER_BULK: