linux-kernel - Re: [PATCH] crypto: marvell/cesa

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Date:   Wed, 10 Jan 2018 16:25:22 +0100
From:   Boris Brezillon <boris.brezillon@...e-electrons.com>
To:     Robin Murphy <robin.murphy@....com>
Cc:     arno@...isbad.org, herbert@...dor.apana.org.au,
        davem@...emloft.net, hch@....de, linux-crypto@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] crypto: marvell/cesa - Fix DMA API misuse

On Wed, 10 Jan 2018 15:15:43 +0000
Robin Murphy <robin.murphy@....com> wrote:

> phys_to_dma() is an internal helper for certain DMA API implementations,
> and is not appropriate for drivers to use. It appears that what the CESA
> driver really wants to be using is dma_map_resource() - admittedly that
> didn't exist when the offending code was first merged, but it does now.
> 
> Signed-off-by: Robin Murphy <robin.murphy@....com>

Acked-by: Boris Brezillon <boris.brezillon@...e-electrons.com>

> ---
> 
> Found by inspection and compile-tested only
> 
>  drivers/crypto/marvell/cesa.c | 19 ++++++++++++-------
>  1 file changed, 12 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/crypto/marvell/cesa.c b/drivers/crypto/marvell/cesa.c
> index 293832488cc9..f81fa4a3e66b 100644
> --- a/drivers/crypto/marvell/cesa.c
> +++ b/drivers/crypto/marvell/cesa.c
> @@ -15,6 +15,7 @@
>   */
>  
>  #include <linux/delay.h>
> +#include <linux/dma-mapping.h>
>  #include <linux/genalloc.h>
>  #include <linux/interrupt.h>
>  #include <linux/io.h>
> @@ -409,8 +410,11 @@ static int mv_cesa_get_sram(struct platform_device *pdev, int idx)
>  	if (IS_ERR(engine->sram))
>  		return PTR_ERR(engine->sram);
>  
> -	engine->sram_dma = phys_to_dma(cesa->dev,
> -				       (phys_addr_t)res->start);
> +	engine->sram_dma = dma_map_resource(cesa->dev, res->start,
> +					    cesa->sram_size,
> +					    DMA_BIDIRECTIONAL, 0);
> +	if (dma_mapping_error(cesa->dev, engine->sram_dma))
> +		return -ENOMEM;
>  
>  	return 0;
>  }
> @@ -420,11 +424,12 @@ static void mv_cesa_put_sram(struct platform_device *pdev, int idx)
>  	struct mv_cesa_dev *cesa = platform_get_drvdata(pdev);
>  	struct mv_cesa_engine *engine = &cesa->engines[idx];
>  
> -	if (!engine->pool)
> -		return;
> -
> -	gen_pool_free(engine->pool, (unsigned long)engine->sram,
> -		      cesa->sram_size);
> +	if (engine->pool)
> +		gen_pool_free(engine->pool, (unsigned long)engine->sram,
> +			      cesa->sram_size);
> +	else
> +		dma_unmap_resource(cesa->dev, engine->sram_dma,
> +				   cesa->sram_size, DMA_BIDIRECTIONAL, 0);
>  }
>  
>  static int mv_cesa_probe(struct platform_device *pdev)