Re: [PATCH v7 4/5] usb: dwc3: dwc3-qcom: Enable tx-fifo-resize property by default

[Jack Pham <jackp@codeaurora.org>]

Hi Wesley,

On Thu, Jan 28, 2021 at 08:46:43PM -0800, Wesley Cheng wrote:
> In order to take advantage of the TX fifo resizing logic, manually add
> these properties to the DWC3 child node by default.  This will allow
> the DWC3 gadget to resize the TX fifos for the IN endpoints, which
> help with performance.
> 
> Signed-off-by: Wesley Cheng <wcheng@codeaurora.org>
> ---
>  drivers/usb/dwc3/dwc3-qcom.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/drivers/usb/dwc3/dwc3-qcom.c b/drivers/usb/dwc3/dwc3-qcom.c
> index d803ee9..4ea6be3 100644
> --- a/drivers/usb/dwc3/dwc3-qcom.c
> +++ b/drivers/usb/dwc3/dwc3-qcom.c
> @@ -564,6 +564,7 @@ static int dwc3_qcom_clk_init(struct dwc3_qcom *qcom, int count)
>  
>  static const struct property_entry dwc3_qcom_acpi_properties[] = {
>  	PROPERTY_ENTRY_STRING("dr_mode", "host"),
> +	PROPERTY_ENTRY_BOOL("tx-fifo-resize"),
>  	{}
>  };
>  
> @@ -634,6 +635,7 @@ static int dwc3_qcom_of_register_core(struct platform_device *pdev)
>  	struct dwc3_qcom	*qcom = platform_get_drvdata(pdev);
>  	struct device_node	*np = pdev->dev.of_node, *dwc3_np;
>  	struct device		*dev = &pdev->dev;
> +	struct property		*prop;
>  	int			ret;
>  
>  	dwc3_np = of_get_child_by_name(np, "dwc3");
> @@ -642,6 +644,14 @@ static int dwc3_qcom_of_register_core(struct platform_device *pdev)
>  		return -ENODEV;
>  	}
>  
> +	prop = kzalloc(sizeof(*prop), GFP_KERNEL);
> +	if (prop) {
> +		prop->name = "tx-fifo-resize";
> +		ret = of_add_property(dwc3_np, prop);
> +		if (ret < 0)
> +			dev_info(dev, "unable to add tx-fifo-resize prop\n");

You'll need to kfree(prop) both in case of error here as well as in the
driver's .remove() callback. Maybe easier to devm_kzalloc()?

Jack