Re: [PATCH v2 05/10] mtd: cfi_cmdset_0002: Split do_write_oneword() to reduce function size

[Chris Packham <Chris.Packham@xxxxxxxxxxxxxxxxxxx>]

Hi Ikegami-san,

On 20/10/18 5:55 AM, Tokunori Ikegami wrote:
> The function is longer so add do_write_oneword_once() to split.
> This is also for to reduce goto statement by additional patch.

I think the following would be easier to understand.

"Reduce the size of do_write_oneword() by extracting a helper function 
for the hardware access."

With that change

Reviewed-by: Chris Packham <chris.packham@xxxxxxxxxxxxxxxxxxx>

> 
> Signed-off-by: Tokunori Ikegami <ikegami@xxxxxxxxxxxxxxxxxxxx>
> Cc: Fabio Bettoni <fbettoni@xxxxxxxxx>
> Co: Hauke Mehrtens <hauke@xxxxxxxxxx>
> Co: Koen Vandeputte <koen.vandeputte@xxxxxxxxxxxx>
> Cc: Chris Packham <chris.packham@xxxxxxxxxxxxxxxxxxx>
> Cc: Joakim Tjernlund <Joakim.Tjernlund@xxxxxxxxxxxx>
> Cc: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxxxxxxx>
> Cc: linux-mtd@xxxxxxxxxxxxxxxxxxx
> ---
> Changes since v1:
> - Add the patch.
> 
>   drivers/mtd/chips/cfi_cmdset_0002.c | 89 ++++++++++++++++-------------
>   1 file changed, 50 insertions(+), 39 deletions(-)
> 
> diff --git a/drivers/mtd/chips/cfi_cmdset_0002.c b/drivers/mtd/chips/cfi_cmdset_0002.c
> index a3fa2d7b1ba0..ae2d8bd7154e 100644
> --- a/drivers/mtd/chips/cfi_cmdset_0002.c
> +++ b/drivers/mtd/chips/cfi_cmdset_0002.c
> @@ -1547,11 +1547,10 @@ static int cfi_amdstd_lock_user_prot_reg(struct mtd_info *mtd, loff_t from,
>   				   do_otp_lock, 1);
>   }
>   
> -static int __xipram do_write_oneword(struct map_info *map, struct flchip *chip,
> -				     unsigned long adr, map_word datum,
> -				     int mode)
> +static int __xipram do_write_oneword_once(struct map_info *map, struct flchip *chip,
> +					  unsigned long adr, map_word datum,
> +					  int mode, struct cfi_private *cfi)

No particular objections to the name (i.e. don't change it unless the 
maintainer insists) but often these kinds of helpers are just prefixed 
with '_' (e.g. _do_write_oneword).

>   {
> -	struct cfi_private *cfi = map->fldrv_priv;
>   	unsigned long timeo = jiffies + HZ;
>   	/*
>   	 * We use a 1ms + 1 jiffies generic timeout for writes (most devices
> @@ -1564,42 +1563,7 @@ static int __xipram do_write_oneword(struct map_info *map, struct flchip *chip,
>   	 */
>   	unsigned long uWriteTimeout = (HZ / 1000) + 1;
>   	int ret = 0;
> -	map_word oldd;
> -	int retry_cnt = 0;
> -
> -	adr += chip->start;
> -
> -	mutex_lock(&chip->mutex);
> -	ret = get_chip(map, chip, adr, mode);
> -	if (ret) {
> -		mutex_unlock(&chip->mutex);
> -		return ret;
> -	}
>   
> -	pr_debug("MTD %s(): WRITE 0x%.8lx(0x%.8lx)\n",
> -		 __func__, adr, datum.x[0]);
> -
> -	if (mode == FL_OTP_WRITE)
> -		otp_enter(map, chip, adr, map_bankwidth(map));
> -
> -	/*
> -	 * Check for a NOP for the case when the datum to write is already
> -	 * present - it saves time and works around buggy chips that corrupt
> -	 * data at other locations when 0xff is written to a location that
> -	 * already contains 0xff.
> -	 */
> -	oldd = map_read(map, adr);
> -	if (map_word_equal(map, oldd, datum)) {
> -		pr_debug("MTD %s(): NOP\n",
> -		       __func__);
> -		goto op_done;
> -	}
> -
> -	XIP_INVAL_CACHED_RANGE(map, adr, map_bankwidth(map));
> -	ENABLE_VPP(map);
> -	xip_disable(map, chip, adr);
> -
> - retry:
>   	cfi_send_gen_cmd(0xAA, cfi->addr_unlock1, chip->start, map, cfi, cfi->device_type, NULL);
>   	cfi_send_gen_cmd(0x55, cfi->addr_unlock2, chip->start, map, cfi, cfi->device_type, NULL);
>   	cfi_send_gen_cmd(0xA0, cfi->addr_unlock1, chip->start, map, cfi, cfi->device_type, NULL);
> @@ -1642,6 +1606,53 @@ static int __xipram do_write_oneword(struct map_info *map, struct flchip *chip,
>   		UDELAY(map, chip, adr, 1);
>   	}
>   
> +	return ret;
> +}
> +
> +static int __xipram do_write_oneword(struct map_info *map, struct flchip *chip,
> +				     unsigned long adr, map_word datum,
> +				     int mode)
> +{
> +	struct cfi_private *cfi = map->fldrv_priv;
> +	int ret = 0;
> +	map_word oldd;
> +	int retry_cnt = 0;
> +
> +	adr += chip->start;
> +
> +	mutex_lock(&chip->mutex);
> +	ret = get_chip(map, chip, adr, mode);
> +	if (ret) {
> +		mutex_unlock(&chip->mutex);
> +		return ret;
> +	}
> +
> +	pr_debug("MTD %s(): WRITE 0x%.8lx(0x%.8lx)\n",
> +		 __func__, adr, datum.x[0]);
> +
> +	if (mode == FL_OTP_WRITE)
> +		otp_enter(map, chip, adr, map_bankwidth(map));
> +
> +	/*
> +	 * Check for a NOP for the case when the datum to write is already
> +	 * present - it saves time and works around buggy chips that corrupt
> +	 * data at other locations when 0xff is written to a location that
> +	 * already contains 0xff.
> +	 */
> +	oldd = map_read(map, adr);
> +	if (map_word_equal(map, oldd, datum)) {
> +		pr_debug("MTD %s(): NOP\n",
> +		       __func__);
> +		goto op_done;
> +	}
> +
> +	XIP_INVAL_CACHED_RANGE(map, adr, map_bankwidth(map));
> +	ENABLE_VPP(map);
> +	xip_disable(map, chip, adr);
> +
> + retry:
> +	ret = do_write_oneword_once(map, chip, adr, datum, mode, cfi);
> +
>   	/* Did we succeed? */
>   	if (ret) {
>   		/* reset on all failures. */
> 


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