Re: [PATCH v2 3/3] usb: dwc3: xilinx: unwind ZynqMP platform init on probe failure and remove

[Thinh Nguyen <Thinh.Nguyen@synopsys.com>]

On Tue, Sep 22, 2026, Radhey Shyam Pandey wrote:
> dwc3_xlnx_init_zynqmp() deasserts resets and initialises the USB3 PHY,
> but nothing undoes that if a later probe step fails, and nothing undoes
> it on remove either. The resets stay deasserted and the PHY stays
> initialised while the clocks are disabled underneath them.
> 
> Add dwc3_xlnx_exit_zynqmp() and register it as the platform exit handler
> once ZynqMP init has completed. Call it from the probe error path for
> failures after init succeeded, and from remove(), which also serves as
> the shutdown callback.
> 
> Fixes: 84770f028fab ("usb: dwc3: Add driver for Xilinx platforms")
> Cc: stable@vger.kernel.org
> Assisted-by: Claude:claude-opus-5
> Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@amd.com>
> ---
> Changes in v2:
> - Reworked so the fix no longer depends on the platform-data cleanup.
>   v1 registered the teardown as plat->exit in struct dwc3_xlnx_platdata,
>   which is introduced by one of the cleanup patches; that made the fix
>   unbackportable.  It now uses a pltfm_exit pointer alongside the
>   existing pltfm_init in struct dwc3_xlnx, assigned by
>   dwc3_xlnx_init_zynqmp() once init has succeeded.  The follow-up
>   cleanup series folds both pointers into the platform data struct.
> - Made dwc3_xlnx_exit_zynqmp() idempotent by returning early when
>   usb_resets_released is clear, rather than guarding only the reset
>   assertions.  phy_power_off() and phy_exit() decrement their counts
>   unconditionally, so an unbalanced second call would underflow them.
> - Rewrote the commit message to describe the bug rather than the
>   implementation, since the callback it referred to no longer exists at
>   this point in the series.
> - Added Cc: stable.
> 
>  drivers/usb/dwc3/dwc3-xilinx.c | 28 ++++++++++++++++++++++++++--
>  1 file changed, 26 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/usb/dwc3/dwc3-xilinx.c b/drivers/usb/dwc3/dwc3-xilinx.c
> index d18d3e364381..31ac75b79709 100644
> --- a/drivers/usb/dwc3/dwc3-xilinx.c
> +++ b/drivers/usb/dwc3/dwc3-xilinx.c
> @@ -47,6 +47,7 @@ struct dwc3_xlnx {
>  	struct device			*dev;
>  	void __iomem			*regs;
>  	int				(*pltfm_init)(struct dwc3_xlnx *data);
> +	void				(*pltfm_exit)(struct dwc3_xlnx *data);
>  	struct phy			*usb3_phy;
>  	struct reset_control		*usb_crst;
>  	struct reset_control		*usb_hibrst;
> @@ -113,6 +114,21 @@ static int dwc3_xlnx_init_versal(struct dwc3_xlnx *priv_data)
>  	return 0;
>  }
>  
> +static void dwc3_xlnx_exit_zynqmp(struct dwc3_xlnx *priv_data)
> +{
> +	if (!priv_data->usb_resets_released)
> +		return;
> +
> +	phy_power_off(priv_data->usb3_phy);
> +
> +	reset_control_assert(priv_data->usb_hibrst);
> +	reset_control_assert(priv_data->usb_crst);
> +	reset_control_assert(priv_data->usb_apbrst);
> +	priv_data->usb_resets_released = false;
> +
> +	phy_exit(priv_data->usb3_phy);
> +}
> +
>  static int dwc3_xlnx_init_zynqmp(struct dwc3_xlnx *priv_data)
>  {
>  	struct device		*dev = priv_data->dev;
> @@ -230,6 +246,7 @@ static int dwc3_xlnx_init_zynqmp(struct dwc3_xlnx *priv_data)
>  	dwc3_xlnx_set_coherency(priv_data, XLNX_USB_TRAFFIC_ROUTE_CONFIG);
>  
>  	priv_data->usb_resets_released = true;
> +	priv_data->pltfm_exit = dwc3_xlnx_exit_zynqmp;
>  
>  	return 0;
>  
> @@ -326,11 +343,11 @@ static int dwc3_xlnx_probe(struct platform_device *pdev)
>  
>  	ret = dwc3_set_swnode(dev);
>  	if (ret)
> -		goto err_clk_put;
> +		goto err_pltfm_exit;
>  
>  	ret = of_platform_populate(np, NULL, NULL, dev);
>  	if (ret)
> -		goto err_clk_put;
> +		goto err_pltfm_exit;
>  
>  	pm_runtime_set_active(dev);
>  	ret = devm_pm_runtime_enable(dev);
> @@ -348,6 +365,10 @@ static int dwc3_xlnx_probe(struct platform_device *pdev)
>  	of_platform_depopulate(dev);
>  	pm_runtime_set_suspended(dev);
>  
> +err_pltfm_exit:
> +	if (priv_data->pltfm_exit)
> +		priv_data->pltfm_exit(priv_data);
> +
>  err_clk_put:
>  	clk_bulk_disable_unprepare(priv_data->num_clocks, priv_data->clks);
>  
> @@ -361,6 +382,9 @@ static void dwc3_xlnx_remove(struct platform_device *pdev)
>  
>  	of_platform_depopulate(dev);
>  
> +	if (priv_data->pltfm_exit)
> +		priv_data->pltfm_exit(priv_data);
> +
>  	clk_bulk_disable_unprepare(priv_data->num_clocks, priv_data->clks);
>  	priv_data->num_clocks = 0;
>  
> -- 
> 2.43.0
> 

Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>

Thanks,
Thinh