From 3aa07f72894d209fcf922ad686cbb28cf005aaad Mon Sep 17 00:00:00 2001
From: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Date: Wed, 9 Nov 2022 17:58:50 -0800
Subject: [PATCH] usb: dwc3: gadget: Disable GUSB2PHYCFG.SUSPHY for End Transfer
Git-commit: 3aa07f72894d209fcf922ad686cbb28cf005aaad
Patch-mainline: v6.1-rc7
References: git-fixes

If there's a disconnection while operating in eSS, there may be a delay
in VBUS drop response from the connector. In that case, the internal
link state may drop to operate in usb2 speed while the controller thinks
the VBUS is still high. The driver must make sure to disable
GUSB2PHYCFG.SUSPHY when sending endpoint command while in usb2 speed.
The End Transfer command may be called, and only that command needs to
go through at this point. Let's keep it simple and unconditionally
disable GUSB2PHYCFG.SUSPHY whenever we issue the command.

This scenario is not seen in real hardware. In a rare case, our
prototype type-c controller/interface may have a slow response
triggerring this issue.

Signed-off-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://lore.kernel.org/r/5651117207803c26e2f22ddf4e5ce9e865dcf7c7.1668045468.git.Thinh.Nguyen@synopsys.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/usb/dwc3/gadget.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 026d4029bda6..8b4cfa07539d 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -291,7 +291,8 @@ int dwc3_send_gadget_ep_cmd(struct dwc3_ep *dep, unsigned int cmd,
 	 *
 	 * DWC_usb3 3.30a and DWC_usb31 1.90a programming guide section 3.2.2
 	 */
-	if (dwc->gadget->speed <= USB_SPEED_HIGH) {
+	if (dwc->gadget->speed <= USB_SPEED_HIGH ||
+	    DWC3_DEPCMD_CMD(cmd) == DWC3_DEPCMD_ENDTRANSFER) {
 		reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYCFG(0));
 		if (unlikely(reg & DWC3_GUSB2PHYCFG_SUSPHY)) {
 			saved_config |= DWC3_GUSB2PHYCFG_SUSPHY;
-- 
2.35.3