Re: [PATCH v4 1/3] mtd: cfi_cmdset_0002: Move and rename chip_check/chip_ready/chip_good_for_write

[Miquel Raynal <miquel.raynal@bootlin.com>]

Hi Tokunori,

ikegami.t@gmail.com wrote on Thu, 17 Mar 2022 00:54:53 +0900:

> This is a preparation patch for the functional change in preparation to a change
> expected to fix the buffered writes on S29GL064N.

This is a preparation patch for the S29GL064N buffer writes fix. There
is no functional change.

> 
> Fixes: dfeae1073583("mtd: cfi_cmdset_0002: Change write buffer to check correct value")
> Signed-off-by: Tokunori Ikegami <ikegami.t@gmail.com>
> Cc: stable@vger.kernel.org
> ---
>  drivers/mtd/chips/cfi_cmdset_0002.c | 77 ++++++++++++-----------------
>  1 file changed, 32 insertions(+), 45 deletions(-)
> 
> diff --git a/drivers/mtd/chips/cfi_cmdset_0002.c b/drivers/mtd/chips/cfi_cmdset_0002.c
> index a761134fd3be..e68ddf0f7fc0 100644
> --- a/drivers/mtd/chips/cfi_cmdset_0002.c
> +++ b/drivers/mtd/chips/cfi_cmdset_0002.c
> @@ -801,22 +801,12 @@ static struct mtd_info *cfi_amdstd_setup(struct mtd_info *mtd)
>  	return NULL;
>  }
>  
> -/*
> - * Return true if the chip is ready.
> - *
> - * Ready is one of: read mode, query mode, erase-suspend-read mode (in any
> - * non-suspended sector) and is indicated by no toggle bits toggling.
> - *
> - * Note that anything more complicated than checking if no bits are toggling
> - * (including checking DQ5 for an error status) is tricky to get working
> - * correctly and is therefore not done	(particularly with interleaved chips
> - * as each chip must be checked independently of the others).
> - */
> -static int __xipram chip_ready(struct map_info *map, struct flchip *chip,
> -			       unsigned long addr)
> +static int __xipram chip_check(struct map_info *map, struct flchip *chip,
> +			       unsigned long addr, map_word *expected)
>  {
>  	struct cfi_private *cfi = map->fldrv_priv;
> -	map_word d, t;
> +	map_word oldd, curd;
> +	int ret;
>  
>  	if (cfi_use_status_reg(cfi)) {
>  		map_word ready = CMD(CFI_SR_DRB);
> @@ -826,17 +816,35 @@ static int __xipram chip_ready(struct map_info *map, struct flchip *chip,
>  		 */
>  		cfi_send_gen_cmd(0x70, cfi->addr_unlock1, chip->start, map, cfi,
>  				 cfi->device_type, NULL);
> -		d = map_read(map, addr);
> +		curd = map_read(map, addr);
>  
> -		return map_word_andequal(map, d, ready, ready);
> +		return map_word_andequal(map, curd, ready, ready);

A lot of the diff is just a rename. I am not against a rename if you
feel it's better, but in this order:
1: prepare the fix
2: fix
3: rename/define id's, whatever

>  	}
>  
> -	d = map_read(map, addr);
> -	t = map_read(map, addr);
> +	oldd = map_read(map, addr);
> +	curd = map_read(map, addr);
> +
> +	ret = map_word_equal(map, oldd, curd);
>  
> -	return map_word_equal(map, d, t);
> +	if (!ret || !expected)
> +		return ret;
> +
> +	return map_word_equal(map, curd, *expected);
>  }
>  
> +/*
> + * Return true if the chip is ready.
> + *
> + * Ready is one of: read mode, query mode, erase-suspend-read mode (in any
> + * non-suspended sector) and is indicated by no toggle bits toggling.
> + *
> + * Note that anything more complicated than checking if no bits are toggling
> + * (including checking DQ5 for an error status) is tricky to get working
> + * correctly and is therefore not done	(particularly with interleaved chips
> + * as each chip must be checked independently of the others).
> + */
> +#define chip_ready(map, chip, addr) chip_check(map, chip, addr, NULL)

I don't see the point of such a define. Just get rid of it.

> +
>  /*
>   * Return true if the chip is ready and has the correct value.
>   *
> @@ -852,32 +860,11 @@ static int __xipram chip_ready(struct map_info *map, struct flchip *chip,
>   * as each chip must be checked independently of the others).
>   *
>   */
> -static int __xipram chip_good(struct map_info *map, struct flchip *chip,
> -			      unsigned long addr, map_word expected)
> -{
> -	struct cfi_private *cfi = map->fldrv_priv;
> -	map_word oldd, curd;
> -
> -	if (cfi_use_status_reg(cfi)) {
> -		map_word ready = CMD(CFI_SR_DRB);
> -
> -		/*
> -		 * For chips that support status register, check device
> -		 * ready bit
> -		 */
> -		cfi_send_gen_cmd(0x70, cfi->addr_unlock1, chip->start, map, cfi,
> -				 cfi->device_type, NULL);
> -		curd = map_read(map, addr);
> -
> -		return map_word_andequal(map, curd, ready, ready);
> -	}
> -
> -	oldd = map_read(map, addr);
> -	curd = map_read(map, addr);
> -
> -	return	map_word_equal(map, oldd, curd) &&
> -		map_word_equal(map, curd, expected);
> -}
> +#define chip_good(map, chip, addr, expected) \
> +	({ \
> +		map_word datum = expected; \
> +		chip_check(map, chip, addr, &datum); \
> +	})

What is this for? Same here, I don't see the point. Please get rid of
all these unnecessary helpers which do nothing, besides complicating
user's life.

>  static int get_chip(struct map_info *map, struct flchip *chip, unsigned long adr, int mode)
>  {


Thanks,
Miquèl

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