FAILED: patch "[PATCH] usb: dwc3: Fix timeout issue during controller enter/exit" failed to apply to 5.4-stable tree

FAILED: patch "[PATCH] usb: dwc3: Fix timeout issue during controller enter/exit" failed to apply to 5.4-stable tree

[gregkh]

The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y
git checkout FETCH_HEAD
git cherry-pick -x d3a8c28426fc1fb3252753a9f1db0d691ffc21b0
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025021803-magnesium-breeze-0a67@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From d3a8c28426fc1fb3252753a9f1db0d691ffc21b0 Mon Sep 17 00:00:00 2001
From: Selvarasu Ganesan <selvarasu.g@samsung.com>
Date: Sat, 1 Feb 2025 22:09:02 +0530
Subject: [PATCH] usb: dwc3: Fix timeout issue during controller enter/exit
 from halt state
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

There is a frequent timeout during controller enter/exit from halt state
after toggling the run_stop bit by SW. This timeout occurs when
performing frequent role switches between host and device, causing
device enumeration issues due to the timeout. This issue was not present
when USB2 suspend PHY was disabled by passing the SNPS quirks
(snps,dis_u2_susphy_quirk and snps,dis_enblslpm_quirk) from the DTS.
However, there is a requirement to enable USB2 suspend PHY by setting of
GUSB2PHYCFG.ENBLSLPM and GUSB2PHYCFG.SUSPHY bits when controller starts
in gadget or host mode results in the timeout issue.

This commit addresses this timeout issue by ensuring that the bits
GUSB2PHYCFG.ENBLSLPM and GUSB2PHYCFG.SUSPHY are cleared before starting
the dwc3_gadget_run_stop sequence and restoring them after the
dwc3_gadget_run_stop sequence is completed.

Fixes: 72246da40f37 ("usb: Introduce DesignWare USB3 DRD Driver")
Cc: stable <stable@kernel.org>
Signed-off-by: Selvarasu Ganesan <selvarasu.g@samsung.com>
Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://lore.kernel.org/r/20250201163903.459-1-selvarasu.g@samsung.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index d27af65eb08a..ddd6b2ce5710 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -2629,10 +2629,38 @@ static int dwc3_gadget_run_stop(struct dwc3 *dwc, int is_on)
 {
 	u32			reg;
 	u32			timeout = 2000;
+	u32			saved_config = 0;
 
 	if (pm_runtime_suspended(dwc->dev))
 		return 0;
 
+	/*
+	 * When operating in USB 2.0 speeds (HS/FS), ensure that
+	 * GUSB2PHYCFG.ENBLSLPM and GUSB2PHYCFG.SUSPHY are cleared before starting
+	 * or stopping the controller. This resolves timeout issues that occur
+	 * during frequent role switches between host and device modes.
+	 *
+	 * Save and clear these settings, then restore them after completing the
+	 * controller start or stop sequence.
+	 *
+	 * This solution was discovered through experimentation as it is not
+	 * mentioned in the dwc3 programming guide. It has been tested on an
+	 * Exynos platforms.
+	 */
+	reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYCFG(0));
+	if (reg & DWC3_GUSB2PHYCFG_SUSPHY) {
+		saved_config |= DWC3_GUSB2PHYCFG_SUSPHY;
+		reg &= ~DWC3_GUSB2PHYCFG_SUSPHY;
+	}
+
+	if (reg & DWC3_GUSB2PHYCFG_ENBLSLPM) {
+		saved_config |= DWC3_GUSB2PHYCFG_ENBLSLPM;
+		reg &= ~DWC3_GUSB2PHYCFG_ENBLSLPM;
+	}
+
+	if (saved_config)
+		dwc3_writel(dwc->regs, DWC3_GUSB2PHYCFG(0), reg);
+
 	reg = dwc3_readl(dwc->regs, DWC3_DCTL);
 	if (is_on) {
 		if (DWC3_VER_IS_WITHIN(DWC3, ANY, 187A)) {
@@ -2660,6 +2688,12 @@ static int dwc3_gadget_run_stop(struct dwc3 *dwc, int is_on)
 		reg &= DWC3_DSTS_DEVCTRLHLT;
 	} while (--timeout && !(!is_on ^ !reg));
 
+	if (saved_config) {
+		reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYCFG(0));
+		reg |= saved_config;
+		dwc3_writel(dwc->regs, DWC3_GUSB2PHYCFG(0), reg);
+	}
+
 	if (!timeout)
 		return -ETIMEDOUT;