usb: dwc2: host: implement test mode

Add support for SetPortFeature(PORT_TEST) for root port.
Acked-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Jingwu Lin <jingwu.lin@intel.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/dwc2/hcd.c

@@ -1779,6 +1779,15 @@ static int dwc2_hcd_hub_control(struct dwc2_hsotg *hsotg, u16 typereq,
 			/* Not supported */
 			break;
 
+		case USB_PORT_FEAT_TEST:
+			hprt0 = dwc2_read_hprt0(hsotg);
+			dev_dbg(hsotg->dev,
+				"SetPortFeature - USB_PORT_FEAT_TEST\n");
+			hprt0 &= ~HPRT0_TSTCTL_MASK;
+			hprt0 |= (windex >> 8) << HPRT0_TSTCTL_SHIFT;
+			writel(hprt0, hsotg->regs + HPRT0);
+			break;
+
 		default:
 			retval = -EINVAL;
 			dev_err(hsotg->dev,