linux-kernel - RE: [PATCH v3 8/9] media: chips-media: wave6: Add Wave6 control driver

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Message-ID:
 <SL2P216MB1246A048955A09A5A4D15CA3FB07A@SL2P216MB1246.KORP216.PROD.OUTLOOK.COM>
Date: Mon, 1 Sep 2025 08:13:44 +0000
From: Nas Chung <nas.chung@...psnmedia.com>
To: Krzysztof Kozlowski <krzk@...nel.org>, "mchehab@...nel.org"
	<mchehab@...nel.org>, "hverkuil@...all.nl" <hverkuil@...all.nl>,
	"robh@...nel.org" <robh@...nel.org>, "krzk+dt@...nel.org"
	<krzk+dt@...nel.org>, "conor+dt@...nel.org" <conor+dt@...nel.org>,
	"shawnguo@...nel.org" <shawnguo@...nel.org>, "s.hauer@...gutronix.de"
	<s.hauer@...gutronix.de>
CC: "linux-media@...r.kernel.org" <linux-media@...r.kernel.org>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-imx@....com" <linux-imx@....com>,
	"linux-arm-kernel@...ts.infradead.org"
	<linux-arm-kernel@...ts.infradead.org>, jackson.lee
	<jackson.lee@...psnmedia.com>, lafley.kim <lafley.kim@...psnmedia.com>, Ming
 Qian <ming.qian@....nxp.com>
Subject: RE: [PATCH v3 8/9] media: chips-media: wave6: Add Wave6 control
 driver

Hi, Krzysztof.

Thanks for the feedback.

>-----Original Message-----
>From: Krzysztof Kozlowski <krzk@...nel.org>
>Sent: Friday, August 29, 2025 11:06 PM
>To: Nas Chung <nas.chung@...psnmedia.com>; mchehab@...nel.org;
>hverkuil@...all.nl; robh@...nel.org; krzk+dt@...nel.org;
>conor+dt@...nel.org; shawnguo@...nel.org; s.hauer@...gutronix.de
>Cc: linux-media@...r.kernel.org; devicetree@...r.kernel.org; linux-
>kernel@...r.kernel.org; linux-imx@....com; linux-arm-
>kernel@...ts.infradead.org; jackson.lee <jackson.lee@...psnmedia.com>;
>lafley.kim <lafley.kim@...psnmedia.com>; Ming Qian <ming.qian@....nxp.com>
>Subject: Re: [PATCH v3 8/9] media: chips-media: wave6: Add Wave6 control
>driver
>
>On 29/08/2025 10:46, Nas Chung wrote:
>> +
>> +static void wave6_vpu_load_firmware(const struct firmware *fw, void
>*context)
>> +{
>> +	struct wave6_vpu_device *vpu = context;
>> +
>> +	guard(mutex)(&vpu->lock);
>
>Why? How could this be called in parallel, before the probe?

This callback is called asynchronously via firmware_request_nowait_nowarn().
In practice, I observed a case where the callback was executing
while the device's release() function was being called.

>
>> +
>> +	if (!fw || !fw->data) {
>> +		dev_err(vpu->dev, "No firmware.\n");
>> +		return;
>> +	}
>> +
>> +	if (!vpu->fw_available)
>> +		goto exit;
>> +
>> +	if (fw->size + W6_EXTRA_CODE_BUF_SIZE >
>wave6_vpu_get_code_buf_size(vpu)) {
>> +		dev_err(vpu->dev, "firmware size (%ld > %zd) is too big\n",
>> +			fw->size, vpu->code_buf.size);
>> +		vpu->fw_available = false;
>> +		goto exit;
>> +	}
>> +
>> +	memcpy(vpu->code_buf.vaddr, fw->data, fw->size);
>> +
>> +	vpu->get_vpu = wave6_vpu_get;
>> +	vpu->put_vpu = wave6_vpu_put;
>> +	vpu->req_work_buffer = wave6_vpu_require_work_buffer;
>> +	of_platform_populate(vpu->dev->of_node, NULL, NULL, vpu->dev);
>> +
>> +exit:
>> +	release_firmware(fw);
>> +}
>> +
>> +static int wave6_vpu_probe(struct platform_device *pdev)
>> +{
>> +	struct device_node *np;
>> +	struct wave6_vpu_device *vpu;
>> +	const struct wave6_vpu_resource *res;
>> +	int ret;
>> +
>> +	ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
>> +	if (ret < 0) {
>> +		dev_err(&pdev->dev, "dma_set_mask_and_coherent failed: %d\n",
>ret);
>> +		return ret;
>> +	}
>> +
>> +	res = of_device_get_match_data(&pdev->dev);
>> +	if (!res)
>> +		return -ENODEV;
>> +
>> +	vpu = devm_kzalloc(&pdev->dev, sizeof(*vpu), GFP_KERNEL);
>> +	if (!vpu)
>> +		return -ENOMEM;
>> +
>> +	ret = devm_mutex_init(&pdev->dev, &vpu->lock);
>> +	if (ret)
>> +		return ret;
>> +
>> +	atomic_set(&vpu->core_count, 0);
>> +	INIT_LIST_HEAD(&vpu->work_buffers);
>> +	dev_set_drvdata(&pdev->dev, vpu);
>> +	vpu->dev = &pdev->dev;
>> +	vpu->res = res;
>> +	vpu->reg_base = devm_platform_ioremap_resource(pdev, 0);
>> +	if (IS_ERR(vpu->reg_base))
>> +		return PTR_ERR(vpu->reg_base);
>> +
>> +	ret = devm_clk_bulk_get_all(&pdev->dev, &vpu->clks);
>> +	if (ret < 0) {
>> +		dev_warn(&pdev->dev, "unable to get clocks: %d\n", ret);
>
>You need to handle deferred probe.

Got it, I will address this in v4 using dev_err_probe().

Thanks,
Nas.

>
>> +		ret = 0;
>> +	}
>> +	vpu->num_clks = ret;
>Best regards,
>Krzysztof