linux-kernel - Re: [PATCH v2 06/12] mtd: nand_bbt: use erase() and is_bad

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Date:	Wed, 6 Jan 2016 14:49:12 +0100
From:	Boris Brezillon <boris.brezillon@...e-electrons.com>
To:	Peter Pan <peterpansjtu@...il.com>
Cc:	computersforpeace@...il.com, dwmw2@...radead.org,
	fransklaver@...il.com, Peter Pan <peterpandong@...ron.com>,
	beanhuo@...ron.com, linux-mtd@...ts.infradead.org,
	linux-kernel@...r.kernel.org, karlzhang@...ron.com
Subject: Re: [PATCH v2 06/12] mtd: nand_bbt: use erase() and is_bad_bbm()
 hook in BBT

On Tue, 15 Dec 2015 05:59:32 +0000
Peter Pan <peterpansjtu@...il.com> wrote:

> From: Brian Norris <computersforpeace@...il.com>
> 
> Since NAND already create its nand_bbt struct, we can use erase()
> hook instead of call nand_erase_nand() directly. Also, we can use
> is_bad_bbm() to avoid passing badblock_pattern to BBT.
> 
> Signed-off-by: Brian Norris <computersforpeace@...il.com>
> [Peter: remove @buf in create_bbt()]
> Signed-off-by: Peter Pan <peterpandong@...ron.com>
> ---
>  drivers/mtd/nand/nand_bbt.c | 138 ++++----------------------------------------
>  1 file changed, 12 insertions(+), 126 deletions(-)
> 
> diff --git a/drivers/mtd/nand/nand_bbt.c b/drivers/mtd/nand/nand_bbt.c
> index f256be1..a5c8ab5 100644
> --- a/drivers/mtd/nand/nand_bbt.c
> +++ b/drivers/mtd/nand/nand_bbt.c
> @@ -122,23 +122,6 @@ static int check_pattern(uint8_t *buf, int len, int paglen, struct nand_bbt_desc
>  }

[...]

>  /**
>   * create_bbt - [GENERIC] Create a bad block table by scanning the device
>   * @mtd: MTD device structure
> - * @buf: temporary buffer
> - * @bd: descriptor for the good/bad block search pattern
>   * @chip: create the table for a specific chip, -1 read all chips; applies only
>   *        if NAND_BBT_PERCHIP option is set
>   *
>   * Create a bad block table by scanning the device for the given good/bad block
>   * identify pattern.
>   */
> -static int create_bbt(struct mtd_info *mtd, uint8_t *buf,
> -	struct nand_bbt_descr *bd, int chip)
> +static int create_bbt(struct mtd_info *mtd, int chip)
>  {
>  	struct nand_chip *this = mtd_to_nand(mtd);
> -	int i, numblocks, numpages;
> -	int startblock;
> +	int i, startblock, numblocks;
>  	loff_t from;
>  
>  	pr_info("Scanning device for bad blocks\n");
>  
> -	if (bd->options & NAND_BBT_SCAN2NDPAGE)
> -		numpages = 2;
> -	else
> -		numpages = 1;
> -
>  	if (chip == -1) {
>  		numblocks = mtd->size >> this->bbt_erase_shift;
>  		startblock = 0;
> @@ -482,15 +425,10 @@ static int create_bbt(struct mtd_info *mtd, uint8_t *buf,
>  		from = (loff_t)startblock << this->bbt_erase_shift;
>  	}
>  
> -	if (this->bbt_options & NAND_BBT_SCANLASTPAGE)
> -		from += mtd->erasesize - (mtd->writesize * numpages);
> -
>  	for (i = startblock; i < numblocks; i++) {
>  		int ret;
>  
> -		BUG_ON(bd->options & NAND_BBT_NO_OOB);
> -
> -		ret = scan_block_fast(mtd, bd, from, buf, numpages);
> +		ret = this->nand_bbt->is_bad_bbm(mtd, from);

Same comment as for the previous patch: I think it would be safer to
create a wrapper function to do that.

>  		if (ret < 0)
>  			return ret;
>  
> @@ -619,7 +557,6 @@ static int write_bbt(struct mtd_info *mtd, uint8_t *buf,
>  		     int chipsel)
>  {
>  	struct nand_chip *this = mtd_to_nand(mtd);
> -	struct erase_info einfo;
>  	int i, res, chip = 0;
>  	int bits, startblock, dir, page, offs, numblocks, sft, sftmsk;
>  	int nrchips, pageoffs, ooboffs;
> @@ -782,11 +719,7 @@ static int write_bbt(struct mtd_info *mtd, uint8_t *buf,
>  			buf[offs + (i >> sft)] &= ~(msk[dat] << sftcnt);
>  		}
>  
> -		memset(&einfo, 0, sizeof(einfo));
> -		einfo.mtd = mtd;
> -		einfo.addr = to;
> -		einfo.len = 1 << this->bbt_erase_shift;
> -		res = nand_erase_nand(mtd, &einfo, 1);
> +		res = this->nand_bbt->erase(mtd, to);

Ditto.





-- 
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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