linux-kernel - Re: [PATCH] dmaengine: timb_dma: Use proper enum in td_prep_slave

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Date:   Tue, 11 Sep 2018 16:44:08 -0700
From:   Nick Desaulniers <ndesaulniers@...gle.com>
To:     Nathan Chancellor <natechancellor@...il.com>
Cc:     dan.j.williams@...el.com, vkoul@...nel.org,
        dmaengine@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] dmaengine: timb_dma: Use proper enum in td_prep_slave_sg

On Tue, Sep 11, 2018 at 4:20 PM Nathan Chancellor
<natechancellor@...il.com> wrote:
>
> Clang warns when implicitly converting from one enumerated type to
> another. Avoid this by using the equivalent value from the expected
> type.
>
> drivers/dma/timb_dma.c:548:27: warning: implicit conversion from
> enumeration type 'enum dma_transfer_direction' to different enumeration
> type 'enum dma_data_direction' [-Wenum-conversion]
>                 td_desc->desc_list_len, DMA_MEM_TO_DEV);
>                                         ^~~~~~~~~~~~~~
> 1 warning generated.
>
> Reported-by: Nick Desaulniers <ndesaulniers@...gle.com>
> Signed-off-by: Nathan Chancellor <natechancellor@...il.com>
> ---
>  drivers/dma/timb_dma.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/dma/timb_dma.c b/drivers/dma/timb_dma.c
> index 395c698edb4d..fc0f9c8766a8 100644
> --- a/drivers/dma/timb_dma.c
> +++ b/drivers/dma/timb_dma.c
> @@ -545,7 +545,7 @@ static struct dma_async_tx_descriptor *td_prep_slave_sg(struct dma_chan *chan,
>         }
>
>         dma_sync_single_for_device(chan2dmadev(chan), td_desc->txd.phys,
> -               td_desc->desc_list_len, DMA_MEM_TO_DEV);
> +               td_desc->desc_list_len, DMA_TO_DEVICE);

Looks like DMA_MEM_TO_DEV and DMA_TO_DEVICE happen to have the same
value (today) so no functional change.
And dma_sync_single_for_device is defined to take the `enum
dma_data_direction` which `DMA_TO_DEVICE` is an enumeration of.

Thanks for the patch Nathan.
Reviewed-by: Nick Desaulniers <ndesaulniers@...gle.com>

>
>         return &td_desc->txd;
>  }
> --
> 2.18.0
>


-- 
Thanks,
~Nick Desaulniers