linux-kernel - Re: [PATCH v2 08/10] dmaengine: imx-sdma: make use of devm_add_action_or_reset to unregiser the dma

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Message-ID: <aMQy+Ocs+UWq7WoR@lizhi-Precision-Tower-5810>
Date: Fri, 12 Sep 2025 10:49:28 -0400
From: Frank Li <Frank.li@....com>
To: Marco Felsch <m.felsch@...gutronix.de>
Cc: Vinod Koul <vkoul@...nel.org>, Shawn Guo <shawnguo@...nel.org>,
	Sascha Hauer <s.hauer@...gutronix.de>,
	Pengutronix Kernel Team <kernel@...gutronix.de>,
	Fabio Estevam <festevam@...il.com>,
	Jiada Wang <jiada_wang@...tor.com>, dmaengine@...r.kernel.org,
	imx@...ts.linux.dev, linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 08/10] dmaengine: imx-sdma: make use of
 devm_add_action_or_reset to unregiser the dma_device

On Thu, Sep 11, 2025 at 11:56:49PM +0200, Marco Felsch wrote:
> Make use of the devm_add_action_or_reset() to register a custom devm_
> release hook. This is required to turn off the IRQs before calling
> dma_async_device_unregister().
>
> Furthermore it removes the last goto error handling within probe() and
> trims the remove().
>
> Make use of disable_irq() and let the devm-irq do the job to free the
> IRQ, because the only purpose of using devm_free_irq() was to disable
> the IRQ before calling dma_async_device_unregister().
>
> Signed-off-by: Marco Felsch <m.felsch@...gutronix.de>
> ---
>  drivers/dma/imx-sdma.c | 23 +++++++++++++++--------
>  1 file changed, 15 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c
> index d39589c20c4b2a26d0239feb86cce8d5a0f5acdd..d6d0d4300f540268a3ab4a6b14af685f7b93275a 100644
> --- a/drivers/dma/imx-sdma.c
> +++ b/drivers/dma/imx-sdma.c
> @@ -2264,6 +2264,14 @@ static struct dma_chan *sdma_xlate(struct of_phandle_args *dma_spec,
>  				     ofdma->of_node);
>  }
>
> +static void sdma_dma_device_unregister_action(void *data)
> +{
> +	struct sdma_engine *sdma = data;
> +
> +	disable_irq(sdma->irq);

May not related this cleanup patch, I am just curious why not mask sdma irq
request.

> +	dma_async_device_unregister(&sdma->dma_device);
> +}
> +
>  static int sdma_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
> @@ -2388,10 +2396,16 @@ static int sdma_probe(struct platform_device *pdev)
>  		return ret;
>  	}
>
> +	ret = devm_add_action_or_reset(dev, sdma_dma_device_unregister_action, sdma);
> +	if (ret) {
> +		dev_err(dev, "Unable to register release hook\n");
> +		return ret;
> +	}

why not use dev_err_probe() her?

> +
>  	ret = of_dma_controller_register(np, sdma_xlate, sdma);
>  	if (ret) {
>  		dev_err(dev, "failed to register controller\n");
> -		goto err_register;
> +		return ret;

the same here.

Frank
>  	}
>
>  	/*
> @@ -2410,11 +2424,6 @@ static int sdma_probe(struct platform_device *pdev)
>  	}
>
>  	return 0;
> -
> -err_register:
> -	dma_async_device_unregister(&sdma->dma_device);
> -
> -	return ret;
>  }
>
>  static void sdma_remove(struct platform_device *pdev)
> @@ -2423,8 +2432,6 @@ static void sdma_remove(struct platform_device *pdev)
>  	int i;
>
>  	of_dma_controller_free(sdma->dev->of_node);
> -	devm_free_irq(&pdev->dev, sdma->irq, sdma);
> -	dma_async_device_unregister(&sdma->dma_device);
>  	/* Kill the tasklet */
>  	for (i = 0; i < MAX_DMA_CHANNELS; i++) {
>  		struct sdma_channel *sdmac = &sdma->channel[i];
>
> --
> 2.47.3
>