linux-kernel - Re: [RESEND PATCH v5 4/5] mtd: nand: implement 'max_bad

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Date:   Tue, 22 Nov 2016 10:55:16 -0800
From:   Brian Norris <computersforpeace@...il.com>
To:     Zach Brown <zach.brown@...com>
Cc:     dwmw2@...radead.org, boris.brezillon@...e-electrons.com,
        richard@....at, dedekind1@...il.com, linux-mtd@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: Re: [RESEND PATCH v5 4/5] mtd: nand: implement 'max_bad_blocks' mtd
 function

On Mon, Nov 21, 2016 at 01:51:38PM -0600, Zach Brown wrote:
> Implement the new mtd function 'max_bad_blocks'. Using the chip's
> max_bb_per_die and blocks_per_die fields to determine the maximum bad
> blocks to reserve for an MTD.
> 
> Signed-off-by: Jeff Westfahl <jeff.westfahl@...com>
> Signed-off-by: Zach Brown <zach.brown@...com>
> Acked-by: Boris Brezillon <boris.brezillon@...e-electron.com>
> ---
>  drivers/mtd/nand/nand_base.c | 35 +++++++++++++++++++++++++++++++++++
>  1 file changed, 35 insertions(+)
> 
> diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
> index 3bde96a..193a6b7 100644
> --- a/drivers/mtd/nand/nand_base.c
> +++ b/drivers/mtd/nand/nand_base.c
> @@ -3236,6 +3236,40 @@ static int nand_block_markbad(struct mtd_info *mtd, loff_t ofs)
>  }
>  
>  /**
> + * nand_max_bad_blocks - [MTD Interface] Max number of bad blocks for an mtd
> + * @mtd: MTD device structure
> + * @ofs: offset relative to mtd start
> + * @len: length of mtd
> + */
> +static int nand_max_bad_blocks(struct mtd_info *mtd, loff_t ofs, size_t len)
> +{
> +	struct nand_chip *chip = mtd_to_nand(mtd);
> +	uint32_t part_start_block;
> +	uint32_t part_end_block;
> +	uint32_t part_start_lun;
> +	uint32_t part_end_lun;
> +
> +	/* max_bb_per_lun and blocks_per_lun used to determine
> +	 * the maximum bad block count.
> +	 */

This is not the right multi-line comment style.

/*
 * Use something more like this, where the first line has only the
 * comment opening.
 */

> +	if (!chip->max_bb_per_die || !chip->blocks_per_die)
> +		return -ENOTSUPP;
> +
> +	/* Get the start and end of the partition in erase blocks. */
> +	part_start_block = mtd_div_by_eb(ofs, mtd);
> +	part_end_block = mtd_div_by_eb(len, mtd) + part_start_block - 1;
> +
> +	/* Get the start and end LUNs of the partition. */
> +	part_start_lun = part_start_block / chip->blocks_per_die;
> +	part_end_lun = part_end_block / chip->blocks_per_die;
> +
> +	/* Look up the bad blocks per unit and multiply by the number of units
> +	 * that the partition spans.
> +	 */

Same.

Brian

> +	return chip->max_bb_per_die * (part_end_lun - part_start_lun + 1);
> +}
> +
> +/**
>   * nand_onfi_set_features- [REPLACEABLE] set features for ONFI nand
>   * @mtd: MTD device structure
>   * @chip: nand chip info structure
> @@ -4767,6 +4801,7 @@ int nand_scan_tail(struct mtd_info *mtd)
>  	mtd->_block_isreserved = nand_block_isreserved;
>  	mtd->_block_isbad = nand_block_isbad;
>  	mtd->_block_markbad = nand_block_markbad;
> +	mtd->_max_bad_blocks = nand_max_bad_blocks;
>  	mtd->writebufsize = mtd->writesize;
>  
>  	/*
> -- 
> 2.7.4
>