linux-kernel - Re: [PATCH 2/3] i2c: stm32f7: unmap DMA mapped buffer

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Message-ID: <20250626090301.GC348766@gnbcxd0016.gnb.st.com>
Date: Thu, 26 Jun 2025 11:03:01 +0200
From: Alain Volmat <alain.volmat@...s.st.com>
To: Clément Le Goffic <clement.legoffic@...s.st.com>
CC: Pierre-Yves MORDRET <pierre-yves.mordret@...s.st.com>,
        Andi Shyti
	<andi.shyti@...nel.org>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre Torgue <alexandre.torgue@...s.st.com>,
        Sumit Semwal
	<sumit.semwal@...aro.org>,
        Christian König
	<christian.koenig@....com>,
        M'boumba Cedric Madianga
	<cedric.madianga@...il.com>,
        Wolfram Sang <wsa@...nel.org>,
        "Pierre-Yves
 MORDRET" <pierre-yves.mordret@...com>,
        <linux-i2c@...r.kernel.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        <linux-arm-kernel@...ts.infradead.org>, <linux-kernel@...r.kernel.org>,
        <linux-media@...r.kernel.org>, <dri-devel@...ts.freedesktop.org>,
        <linaro-mm-sig@...ts.linaro.org>
Subject: Re: [PATCH 2/3] i2c: stm32f7: unmap DMA mapped buffer

Hi Clément,

thanks for the patch.

On Mon, Jun 16, 2025 at 10:53:55AM +0200, Clément Le Goffic wrote:
> Fix an issue where the mapped DMA buffer was not unmapped.
> 
> Fixes: 7ecc8cfde553 ("i2c: i2c-stm32f7: Add DMA support")
> Signed-off-by: Clément Le Goffic <clement.legoffic@...s.st.com>
> ---
>  drivers/i2c/busses/i2c-stm32f7.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/i2c/busses/i2c-stm32f7.c b/drivers/i2c/busses/i2c-stm32f7.c
> index 973a3a8c6d4a..a05cac5ee9db 100644
> --- a/drivers/i2c/busses/i2c-stm32f7.c
> +++ b/drivers/i2c/busses/i2c-stm32f7.c
> @@ -1622,6 +1622,8 @@ static irqreturn_t stm32f7_i2c_isr_event_thread(int irq, void *data)
>  		if (i2c_dev->use_dma) {
>  			stm32f7_i2c_disable_dma_req(i2c_dev);
>  			dmaengine_terminate_async(dma->chan_using);
> +			dma_unmap_single(i2c_dev->dev, dma->dma_buf, dma->dma_len,
> +					 dma->dma_data_dir);
>  		}
>  		f7_msg->result = -ENXIO;
>  	}
> @@ -1642,6 +1644,8 @@ static irqreturn_t stm32f7_i2c_isr_event_thread(int irq, void *data)
>  				dev_dbg(i2c_dev->dev, "<%s>: Timed out\n", __func__);
>  				stm32f7_i2c_disable_dma_req(i2c_dev);
>  				dmaengine_terminate_async(dma->chan_using);
> +				dma_unmap_single(i2c_dev->dev, dma->dma_buf, dma->dma_len,
> +						 dma->dma_data_dir);
>  				f7_msg->result = -ETIMEDOUT;
>  			}
>  		}
> 

Sounds good to me, however there might be an additional place to fix
within the function stm32f7_i2c_handle_isr_errs:
Could you also take care of the unmap in the error ITs handling ?

Regards,
Alain

> -- 
> 2.43.0
>