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

From: Wesley Cheng <wcheng@codeaurora.org>
To: Jack Pham <jackp@codeaurora.org>
Cc: agross@kernel.org, bjorn.andersson@linaro.org, balbi@kernel.org,
	gregkh@linuxfoundation.org, robh+dt@kernel.org,
	linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
	linux-arm-msm@vger.kernel.org, linux-usb@vger.kernel.org
Subject: Re: [PATCH v7 4/5] usb: dwc3: dwc3-qcom: Enable tx-fifo-resize property by default
Date: Fri, 29 Jan 2021 12:30:09 -0800	[thread overview]
Message-ID: <b9143845-0c40-392f-8c36-a11c0074f52e@codeaurora.org> (raw)
In-Reply-To: <20210129092418.GA1879@jackp-linux.qualcomm.com>

On 1/29/2021 1:24 AM, Jack Pham wrote:
> 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()?

Hi Jack,

Thanks for the catch, will fix this with the devm variant.

Hi Bjorn,

Just wanted to see what you thought about this approach?  This way we
can just keep the dt binding w/o having to re-add it in the future, as
well as not needing to enable this property on every qcom platform with
dwc3.

Tested on my set up, and removed the change which added the property
from the DTSI node.

Thanks
Wesley Cheng

> 
> Jack
> 

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