From b574ce3ee45937f4a01edc98c59213bfc7effe50 Mon Sep 17 00:00:00 2001
From: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Date: Fri, 24 Jul 2020 14:01:02 -0700
Subject: [PATCH] usb: dwc3: core: Properly default unspecified speed
Git-commit: b574ce3ee45937f4a01edc98c59213bfc7effe50
References: git-fixes
Patch-mainline: v5.10-rc1

If the maximum_speed is not specified, default the device speed base on
its HW capability. Don't prematurely check HW capability before
validating the maximum_speed device property. The device property takes
precedence in dwc->maximum_speed.

Fixes: 0e1e5c47f7a9 ("usb: dwc3: add support for USB 2.0-only core configuration")
Reported-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Signed-off-by: Thinh Nguyen <thinhn@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>
Signed-off-by: Oliver Neukum <oneukum@suse.com>
---
 drivers/usb/dwc3/core.c |   35 ++++++++++++++++++-----------------
 1 file changed, 18 insertions(+), 17 deletions(-)

--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -935,13 +935,6 @@ static int dwc3_core_init(struct dwc3 *d
 	 */
 	dwc3_writel(dwc->regs, DWC3_GUID, LINUX_VERSION_CODE);
 
-	/* Handle USB2.0-only core configuration */
-	if (DWC3_GHWPARAMS3_SSPHY_IFC(dwc->hwparams.hwparams3) ==
-			DWC3_GHWPARAMS3_SSPHY_IFC_DIS) {
-		if (dwc->maximum_speed == USB_SPEED_SUPER)
-			dwc->maximum_speed = USB_SPEED_HIGH;
-	}
-
 	ret = dwc3_phy_setup(dwc);
 	if (ret)
 		goto err0;
@@ -1388,6 +1381,8 @@ bool dwc3_has_imod(struct dwc3 *dwc)
 static void dwc3_check_params(struct dwc3 *dwc)
 {
 	struct device *dev = dwc->dev;
+	unsigned int hwparam_gen =
+		DWC3_GHWPARAMS3_SSPHY_IFC(dwc->hwparams.hwparams3);
 
 	/* Check for proper value of imod_interval */
 	if (dwc->imod_interval && !dwc3_has_imod(dwc)) {
@@ -1419,17 +1414,23 @@ static void dwc3_check_params(struct dwc
 			dwc->maximum_speed);
 		/* fall through */
 	case USB_SPEED_UNKNOWN:
-		/* default to superspeed */
-		dwc->maximum_speed = USB_SPEED_SUPER;
-
-		/*
-		 * default to superspeed plus if we are capable.
-		 */
-		if ((DWC3_IP_IS(DWC31) || DWC3_IP_IS(DWC32)) &&
-		    (DWC3_GHWPARAMS3_SSPHY_IFC(dwc->hwparams.hwparams3) ==
-		     DWC3_GHWPARAMS3_SSPHY_IFC_GEN2))
+		switch (hwparam_gen) {
+		case DWC3_GHWPARAMS3_SSPHY_IFC_GEN2:
 			dwc->maximum_speed = USB_SPEED_SUPER_PLUS;
-
+			break;
+		case DWC3_GHWPARAMS3_SSPHY_IFC_GEN1:
+			if (DWC3_IP_IS(DWC32))
+				dwc->maximum_speed = USB_SPEED_SUPER_PLUS;
+			else
+				dwc->maximum_speed = USB_SPEED_SUPER;
+			break;
+		case DWC3_GHWPARAMS3_SSPHY_IFC_DIS:
+			dwc->maximum_speed = USB_SPEED_HIGH;
+			break;
+		default:
+			dwc->maximum_speed = USB_SPEED_SUPER;
+			break;
+		}
 		break;
 	}
 }