usb: dwc3: core: Print warning on unsupported speed

The user may have more information to override the HW parameter to
specify the maximum_speed. However, if the user specifies a
maximum_speed that the controller doesn't support, print out a warning.

Signed-off-by: Thinh Nguyen <thinhn@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

drivers/usb/dwc3/core.c

@@ -1399,8 +1399,17 @@ static void dwc3_check_params(struct dwc3 *dwc)
 	case USB_SPEED_LOW:
 	case USB_SPEED_FULL:
 	case USB_SPEED_HIGH:
+		break;
 	case USB_SPEED_SUPER:
+		if (hwparam_gen == DWC3_GHWPARAMS3_SSPHY_IFC_DIS)
+			dev_warn(dev, "UDC doesn't support Gen 1\n");
+		break;
 	case USB_SPEED_SUPER_PLUS:
+		if ((DWC3_IP_IS(DWC32) &&
+		     hwparam_gen == DWC3_GHWPARAMS3_SSPHY_IFC_DIS) ||
+		    (!DWC3_IP_IS(DWC32) &&
+		     hwparam_gen != DWC3_GHWPARAMS3_SSPHY_IFC_GEN2))
+			dev_warn(dev, "UDC doesn't support SSP\n");
 		break;
 	default:
 		dev_err(dev, "invalid maximum_speed parameter %d\n",