[PATCH v2 1/3] usb: dwc3: xilinx: fix system suspend and resume PHY handling

[Radhey Shyam Pandey]

System suspend and resume error paths do not handle PHY and clock
resources correctly. Suspend calls phy_exit() without first powering
off the PHY and ignores failures, while resume can leave clocks
enabled if PHY reinitialization fails.

Propagate errors to the PM core and unwind resources to ensure a
consistent state on suspend and resume failures.

Fixes: d6edcdc1ef06 ("usb: dwc3: xilinx: fix usb3 non-wakeup source resume failure")
Cc: stable at vger.kernel.org
Assisted-by: Claude:claude-opus-5
Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey at amd.com>
---
Changes in v2:
- Split out of the combined five patch series so the fixes can be sent
  and backported on their own, per review feedback.
- Reordered ahead of the platform-data cleanups.
- Log a failure of the phy_power_on() rollback.  phy_exit() leaves
  init_count untouched when it fails, so if the rollback also fails the
  PHY is left with power_count and init_count out of step; that is now
  at least visible in the log.
- Added Cc: stable.

 drivers/usb/dwc3/dwc3-xilinx.c | 24 +++++++++++++++++++++---
 1 file changed, 21 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/dwc3/dwc3-xilinx.c b/drivers/usb/dwc3/dwc3-xilinx.c
index b832505e1b04..8c63e02575f1 100644
--- a/drivers/usb/dwc3/dwc3-xilinx.c
+++ b/drivers/usb/dwc3/dwc3-xilinx.c
@@ -383,13 +383,26 @@ static int __maybe_unused dwc3_xlnx_runtime_idle(struct device *dev)
 static int __maybe_unused dwc3_xlnx_suspend(struct device *dev)
 {
 	struct dwc3_xlnx *priv_data = dev_get_drvdata(dev);
+	int ret;
 
-	phy_exit(priv_data->usb3_phy);
+	ret = phy_power_off(priv_data->usb3_phy);
+	if (ret < 0)
+		return ret;
+
+	ret = phy_exit(priv_data->usb3_phy);
+	if (ret < 0)
+		goto err_phy_power_on;
 
 	/* Disable the clocks */
 	clk_bulk_disable(priv_data->num_clocks, priv_data->clks);
 
 	return 0;
+
+err_phy_power_on:
+	if (phy_power_on(priv_data->usb3_phy))
+		dev_err(dev, "failed to restore PHY power after suspend error\n");
+
+	return ret;
 }
 
 static int __maybe_unused dwc3_xlnx_resume(struct device *dev)
@@ -403,15 +416,20 @@ static int __maybe_unused dwc3_xlnx_resume(struct device *dev)
 
 	ret = phy_init(priv_data->usb3_phy);
 	if (ret < 0)
-		return ret;
+		goto err_clk_disable;
 
 	ret = phy_power_on(priv_data->usb3_phy);
 	if (ret < 0) {
 		phy_exit(priv_data->usb3_phy);
-		return ret;
+		goto err_clk_disable;
 	}
 
 	return 0;
+
+err_clk_disable:
+	clk_bulk_disable(priv_data->num_clocks, priv_data->clks);
+
+	return ret;
 }
 
 static const struct dev_pm_ops dwc3_xlnx_dev_pm_ops = {
-- 
2.43.0