linux-kernel - Re: [PATCH] mtd: spi-nor: add support to non-uniform SFDP SPI NOR flash memories

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Date:   Sun, 24 Jun 2018 22:00:03 +0200
From:   Boris Brezillon <boris.brezillon@...tlin.com>
To:     Tudor Ambarus <tudor.ambarus@...rochip.com>
Cc:     <marek.vasut@...il.com>, <cyrille.pitchen@...rochip.com>,
        <dwmw2@...radead.org>, <computersforpeace@...il.com>,
        <richard@....at>, linux-mtd@...ts.infradead.org,
        linux-kernel@...r.kernel.org, Cristian.Birsan@...rochip.com,
        nicolas.ferre@...rochip.com
Subject: Re: [PATCH] mtd: spi-nor: add support to non-uniform SFDP SPI NOR
 flash memories

Hi Tudor,

Just one minor comment, I'll let Marek review the patch in more details.

On Fri, 8 Jun 2018 16:48:18 +0300
Tudor Ambarus <tudor.ambarus@...rochip.com> wrote:

>  /*
>   * Erase an address range on the nor chip.  The address range may extend
>   * one or more erase sectors.  Return an error is there is a problem erasing.
> @@ -511,9 +721,11 @@ static int spi_nor_erase(struct mtd_info *mtd, struct erase_info *instr)
>  	dev_dbg(nor->dev, "at 0x%llx, len %lld\n", (long long)instr->addr,
>  			(long long)instr->len);
>  
> -	div_u64_rem(instr->len, mtd->erasesize, &rem);
> -	if (rem)
> -		return -EINVAL;
> +	if (likely(spi_nor_has_uniform_erase(nor))) {

To be honest, I don't think the likely() makes any difference here,
given the time it takes to actually erase the block. Can we just drop
it?

> +		div_u64_rem(instr->len, mtd->erasesize, &rem);
> +		if (rem)
> +			return -EINVAL;
> +	}

Regards,

Boris