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: <20250912164942.p7w2p63wvracosra@pengutronix.de>
Date: Fri, 12 Sep 2025 18:49:42 +0200
From: Marco Felsch <m.felsch@...gutronix.de>
To: Frank Li <Frank.li@....com>
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 25-09-12, Frank Li wrote:
> On Fri, Sep 12, 2025 at 05:25:08PM +0200, Marco Felsch wrote:
> > On 25-09-12, Frank Li wrote:
> > > 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.
> >
> > You mean by setting irq_set_status_flags(irq, IRQ_DISABLE_UNLAZY)
> > infront? Not sure if this is required since this is just the cleanup
> > path.
> 
> It is not important for this patch.
> 
> >
> > > > +	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?
> >
> > Please see my last patch.
> 
> You can direct use dev_err_probe() here, instead replace all in last one.

I get your point and yes I could do this, but I have to do the last
patch anyway. Therefore I'm not sure what difference this makes for this
series.

> 
> Frank
> 
> >
> > Regards,
> >   Marco
> >
> > >
> > > > +
> > > >  	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
> > > >
> > >
>