linux-kernel - Re: [PATCH] spi: sn-f-ospi: Fix division by zero

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Message-ID: <e606acef-adff-4e19-beb0-b587f8c269c6@socionext.com>
Date: Thu, 6 Feb 2025 17:36:07 +0900
From: Kunihiko Hayashi <hayashi.kunihiko@...ionext.com>
To: Mark Brown <broonie@...nel.org>
Cc: linux-spi@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] spi: sn-f-ospi: Fix division by zero

On 2025/02/06 17:27, Kunihiko Hayashi wrote:
> When there is no dummy cycle in the spi-nor commands, both dummy bus cycle
> bytes and width are zero. Because of the cpu's warning when divided by
> zero, the warning should be avoided. Return just zero to avoid such
> calculations.
> 
> Fixes: 1b74dd64c861 ("spi: Add Socionext F_OSPI SPI flash controller
> driver")
> Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@...ionext.com>
> ---
>   drivers/spi/spi-sn-f-ospi.c | 3 +++
>   1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/spi/spi-sn-f-ospi.c b/drivers/spi/spi-sn-f-ospi.c
> index adac645732fe..56ef114effc9 100644
> --- a/drivers/spi/spi-sn-f-ospi.c
> +++ b/drivers/spi/spi-sn-f-ospi.c
> @@ -116,6 +116,9 @@ struct f_ospi {
>   
>   static u32 f_ospi_get_dummy_cycle(const struct spi_mem_op *op)
>   {
> +	if (!op->dummy.nbytes)
> +		return 0;
> +
>   	return (op->dummy.nbytes * 8) / op->dummy.buswidth;
>   }
>   

Sorry, I missed a tag. I'll resend the patch.

Thank you,

---
Best Regards
Kunihiko Hayashi