[PATCH 1/1] mtd:nor:timeout:fix do_write_buffer() timeout error

[Christian Riesch]

Hi,
When you send an updated version of a patch, please put version
numbers into the subject, e.g. [PATCH v2], [PATCH v3]..., and include
a changelog. And I think you shouldn't send the new versions as a
reply to an earlier mail, send them as a new post instead.

On Mon, May 26, 2014 at 3:01 AM, Bean Huo 霍斌斌 (beanhuo)
<beanhuo at micron.com> wrote:
> The size of the buffer program has been increased from 256 to 512 , 2ms maximum timeout can not adapt to all the different vendor's norflash, There maximum timeout information in the CFI area,so the best way is to choose the result calculated according to timeout field of struct cfi_ident that probed from norflash's CFI aera.This is also a standard defined by CFI.
>
> Without this change, if the size of buffer program is 512 or bigger than 256, due to timeout is the shorter than that the chip required,do_write_buffer sometimes fails.
>
> Tested with Micron JS28F512M29EWx and Micron MT28EW512ABA flash devices.

What kind of device is the MT28EW512ABA? Aren't MT28 devices
StrataFlashes that use the cfi_cmdset_0001.c driver?

>
> Signed-off-by: bean huo <beanhuo at micron.com>
> ---
>  drivers/mtd/chips/cfi_cmdset_0002.c |   49 ++++++++++++++++++++++++++++++++---
>  1 file changed, 45 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/mtd/chips/cfi_cmdset_0002.c b/drivers/mtd/chips/cfi_cmdset_0002.c
> index e21fde9..87d446a 100644
> --- a/drivers/mtd/chips/cfi_cmdset_0002.c
> +++ b/drivers/mtd/chips/cfi_cmdset_0002.c
> @@ -628,10 +628,42 @@ struct mtd_info *cfi_cmdset_0002(struct map_info *map, int primary)
>                 cfi->chips[i].word_write_time = 1<<cfi->cfiq->WordWriteTimeoutTyp;
>                 cfi->chips[i].buffer_write_time = 1<<cfi->cfiq->BufWriteTimeoutTyp;
>                 cfi->chips[i].erase_time = 1<<cfi->cfiq->BlockEraseTimeoutTyp;
> +               /*
> +                * We first calculate the timeout max according to timeout
> +                * field of struct cfi_ident that probed from chip's CFI
> +                * aera,If haven't probed this information,we will specify
> +                * a default value,and the time unit is us.
> +                */
> +               if (cfi->cfiq->WordWriteTimeoutTyp &&
> +                       cfi->cfiq->WordWriteTimeoutMax){
> +                       cfi->chips[i].word_write_time_max =
> +                               1<<(cfi->cfiq->WordWriteTimeoutTyp +
> +                                       cfi->cfiq->WordWriteTimeoutMax);
> +                       } else {
> +               /* specify maximum timeout for byte/word program 2000us */
> +                               cfi->chips[i].word_write_time_max = 2000;
> +                               }
> +               if (cfi->cfiq->BufWriteTimeoutTyp &&
> +                       cfi->cfiq->BufWriteTimeoutMax){
> +                       cfi->chips[i].buffer_write_time_max =
> +                               1<<(cfi->cfiq->BufWriteTimeoutTyp +
> +                                       cfi->cfiq->BufWriteTimeoutMax);
> +                       } else {
> +               /* specify maximum timeout for buffer program 2000us */
> +                               cfi->chips[i].buffer_write_time_max = 2000;
> +                               }
> +               if (cfi->cfiq->BlockEraseTimeoutTyp &&
> +                       cfi->cfiq->BlockEraseTimeoutMax){
> +                       cfi->chips[i].erase_time_max =
> +                               1<<(cfi->cfiq->BlockEraseTimeoutTyp +
> +                                       cfi->cfiq->BlockEraseTimeoutMax);
> +                       } else {
> +       /* specify maximum timeout per individual block erase 3000000us */
> +                               cfi->chips[i].erase_time_max = 3000000;
> +                               }

You are setting several parameters here, but you only use
buffer_write_time_max. Why?

>                 cfi->chips[i].ref_point_counter = 0;
>                 init_waitqueue_head(&(cfi->chips[i].wq));
>         }
> -
>         map->fldrv = &cfi_amdstd_chipdrv;
>
>         return cfi_amdstd_setup(mtd);
> @@ -1462,8 +1494,16 @@ static int __xipram do_write_buffer(struct map_info *map, struct flchip *chip,  {
>         struct cfi_private *cfi = map->fldrv_priv;
>         unsigned long timeo = jiffies + HZ;
> -       /* see comments in do_write_oneword() regarding uWriteTimeo. */
> -       unsigned long uWriteTimeout = ( HZ / 1000 ) + 1;
> +       /* The size of the buffer program has been increased from 256 to 512,
> +        * 2ms maximum timeout can not adapt to all the different vendor's
> +        * norflash.There maximum timeout information in the CFI area,so the
> +        * best way is to choose the result calculated according to timeout
> +        * field of struct cfi_ident that probed from norflash's CFI aera,see
> +        * comments in cfi_cmdset_0002().The time unit of uWriteTimeout is ms.
> +        */
> +       unsigned long uWriteTimeout = (chip->buffer_write_time_max % 1000) ?
> +                       (chip->buffer_write_time_max / 1000 + 1) :
> +                       (chip->buffer_write_time_max / 1000);

How about using usecs_to_jiffies below? Then you wouldn't need this
conversion, right?

>         int ret = -EIO;
>         unsigned long cmd_adr;
>         int z, words;
> @@ -1520,7 +1560,8 @@ static int __xipram do_write_buffer(struct map_info *map, struct flchip *chip,
>                                 adr, map_bankwidth(map),
>                                 chip->word_write_time);
>
> -       timeo = jiffies + uWriteTimeout;
> +       /*Maximum timeout must be converted into jiffies */
> +       timeo = jiffies + msecs_to_jiffies(uWriteTimeout);
>

A few lines below in the loop timeo is modified again, timeo = jiffies
+ (HZ / 2); This line has a big /* FIXME */ comment. Any ideas what
should be fixed here?

Best regards,
Christian

>         for (;;) {
>                 if (chip->state != FL_WRITING) {
> --
> 1.7.9.5
>
>
>