linux-kernel - Re: [RESEND PATCH v2] mtd: spi-nor: Fix address width on flash chips

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Date:   Tue, 6 Oct 2020 20:48:07 +0530
From:   Pratyush Yadav <p.yadav@...com>
To:     Bert Vermeulen <bert@...t.com>
CC:     <tudor.ambarus@...rochip.com>, <miquel.raynal@...tlin.com>,
        <richard@....at>, <vigneshr@...com>,
        <linux-mtd@...ts.infradead.org>, <linux-kernel@...r.kernel.org>,
        <stable@...r.kernel.org>
Subject: Re: [RESEND PATCH v2] mtd: spi-nor: Fix address width on flash chips
 > 16MB

On 06/10/20 03:23PM, Bert Vermeulen wrote:
> If a flash chip has more than 16MB capacity but its BFPT reports
> BFPT_DWORD1_ADDRESS_BYTES_3_OR_4, the spi-nor framework defaults to 3.
> 
> The check in spi_nor_set_addr_width() doesn't catch it because addr_width
> did get set. This fixes that check.
> 
> Fixes: f9acd7fa80be ("mtd: spi-nor: sfdp: default to addr_width of 3 for configurable widths")
> Signed-off-by: Bert Vermeulen <bert@...t.com>
> Reviewed-by: Tudor Ambarus <tudor.ambarus@...rochip.com>
> ---
>  drivers/mtd/spi-nor/core.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
> index 0369d98b2d12..a2c35ad9645c 100644
> --- a/drivers/mtd/spi-nor/core.c
> +++ b/drivers/mtd/spi-nor/core.c
> @@ -3009,13 +3009,15 @@ static int spi_nor_set_addr_width(struct spi_nor *nor)
>  		/* already configured from SFDP */
>  	} else if (nor->info->addr_width) {
>  		nor->addr_width = nor->info->addr_width;
> -	} else if (nor->mtd.size > 0x1000000) {
> -		/* enable 4-byte addressing if the device exceeds 16MiB */
> -		nor->addr_width = 4;
>  	} else {
>  		nor->addr_width = 3;
>  	}
>  
> +	if (nor->addr_width == 3 && nor->mtd.size > 0x1000000) {
Nitpick:    ^^^^^^^^^^^^^^^^^^^^^^^^ you can drop this part. But its 
fine either way.

Reviewed-by: Pratyush Yadav <p.yadav@...com>

> +		/* enable 4-byte addressing if the device exceeds 16MiB */
> +		nor->addr_width = 4;
> +	}
> +
>  	if (nor->addr_width > SPI_NOR_MAX_ADDR_WIDTH) {
>  		dev_dbg(nor->dev, "address width is too large: %u\n",
>  			nor->addr_width);

-- 
Regards,
Pratyush Yadav
Texas Instruments India