usb: dwc3: core: Check maximum_speed SSP genXxY

The DWC_usb32 controller supports dual-lane SuperSpeed Plus. Check the
maximum_speed property for any limitation in the HW to initialize and
validate the maximum number of lanes and speed the device will operate.

Currently the controller has no visibility into the HW parameter to
determine the maximum number of lanes the HW supports. If the number of
lanes is not specified for SSP, then set the default rate to gen2x2 for
DWC_usb32 and gen2x1 for DWC_usb31.

Signed-off-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://lore.kernel.org/r/08d43f2a99198bed84895c272340449a6d03710e.1611106162.git.Thinh.Nguyen@synopsys.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/dwc3/core.c

@@ -1252,6 +1252,7 @@ static void dwc3_get_properties(struct dwc3 *dwc)
 	hird_threshold = 12;
 
 	dwc->maximum_speed = usb_get_maximum_speed(dev);
+	dwc->max_ssp_rate = usb_get_maximum_ssp_rate(dev);
 	dwc->dr_mode = usb_get_dr_mode(dev);
 	dwc->hsphy_mode = of_usb_get_phy_mode(dev->of_node);
 
@@ -1423,6 +1424,42 @@ static void dwc3_check_params(struct dwc3 *dwc)
 		}
 		break;
 	}
+
+	/*
+	 * Currently the controller does not have visibility into the HW
+	 * parameter to determine the maximum number of lanes the HW supports.
+	 * If the number of lanes is not specified in the device property, then
+	 * set the default to support dual-lane for DWC_usb32 and single-lane
+	 * for DWC_usb31 for super-speed-plus.
+	 */
+	if (dwc->maximum_speed == USB_SPEED_SUPER_PLUS) {
+		switch (dwc->max_ssp_rate) {
+		case USB_SSP_GEN_2x1:
+			if (hwparam_gen == DWC3_GHWPARAMS3_SSPHY_IFC_GEN1)
+				dev_warn(dev, "UDC only supports Gen 1\n");
+			break;
+		case USB_SSP_GEN_1x2:
+		case USB_SSP_GEN_2x2:
+			if (DWC3_IP_IS(DWC31))
+				dev_warn(dev, "UDC only supports single lane\n");
+			break;
+		case USB_SSP_GEN_UNKNOWN:
+		default:
+			switch (hwparam_gen) {
+			case DWC3_GHWPARAMS3_SSPHY_IFC_GEN2:
+				if (DWC3_IP_IS(DWC32))
+					dwc->max_ssp_rate = USB_SSP_GEN_2x2;
+				else
+					dwc->max_ssp_rate = USB_SSP_GEN_2x1;
+				break;
+			case DWC3_GHWPARAMS3_SSPHY_IFC_GEN1:
+				if (DWC3_IP_IS(DWC32))
+					dwc->max_ssp_rate = USB_SSP_GEN_1x2;
+				break;
+			}
+			break;
+		}
+	}
 }
 
 static int dwc3_probe(struct platform_device *pdev)

drivers/usb/dwc3/core.h

@@ -964,6 +964,7 @@ struct dwc3_scratchpad_array {
  * @nr_scratch: number of scratch buffers
  * @u1u2: only used on revisions <1.83a for workaround
  * @maximum_speed: maximum speed requested (mainly for testing purposes)
+ * @max_ssp_rate: SuperSpeed Plus maximum signaling rate and lane count
  * @gadget_max_speed: maximum gadget speed requested
  * @ip: controller's ID
  * @revision: controller's version of an IP
@@ -1128,6 +1129,7 @@ struct dwc3 {
 	u32			u1u2;
 	u32			maximum_speed;
 	u32			gadget_max_speed;
+	enum usb_ssp_rate	max_ssp_rate;
 
 	u32			ip;
 

drivers/usb/dwc3/gadget.c

@@ -3888,6 +3888,7 @@ int dwc3_gadget_init(struct dwc3 *dwc)
 				dwc->revision);
 
 	dwc->gadget->max_speed		= dwc->maximum_speed;
+	dwc->gadget->max_ssp_rate	= dwc->max_ssp_rate;
 
 	/*
 	 * REVISIT: Here we should clear all pending IRQs to be