[PATCH 1/3] cfi_cmdset_0001: Do not allow read/write to suspend erase block.

[Richard Weinberger]

On Thu, Mar 1, 2018 at 2:39 PM, Joakim Tjernlund
<joakim.tjernlund at infinera.com> wrote:
> From: Joakim Tjernlund <joakim.tjernlund at transmode.se>
>
> Currently it is possible to read and/or write to suspend EB's.
> Writing /dev/mtdX or /dev/mtdblockX from several processes may
> break the flash state machine.
>
> Signed-off-by: Joakim Tjernlund <joakim.tjernlund at infinera.com>
> Cc: <stable at vger.kernel.org>
> ---
>  drivers/mtd/chips/cfi_cmdset_0001.c | 16 +++++++++++-----
>  include/linux/mtd/flashchip.h       |  1 +
>  2 files changed, 12 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/mtd/chips/cfi_cmdset_0001.c b/drivers/mtd/chips/cfi_cmdset_0001.c
> index 60d5d19e347f..b59872304ae7 100644
> --- a/drivers/mtd/chips/cfi_cmdset_0001.c
> +++ b/drivers/mtd/chips/cfi_cmdset_0001.c
> @@ -849,21 +849,25 @@ static int chip_ready (struct map_info *map, struct flchip *chip, unsigned long
>                      (mode == FL_WRITING && (cfip->SuspendCmdSupport & 1))))
>                         goto sleep;
>
> +               /* Do not allow suspend iff read/write to EB address */
> +               if ((adr & chip->in_progress_block_mask) ==
> +                   chip->in_progress_block_addr)
> +                       goto sleep;
>
>                 /* Erase suspend */
> -               map_write(map, CMD(0xB0), adr);
> +               map_write(map, CMD(0xB0), chip->in_progress_block_addr);
>
>                 /* If the flash has finished erasing, then 'erase suspend'
>                  * appears to make some (28F320) flash devices switch to
>                  * 'read' mode.  Make sure that we switch to 'read status'
>                  * mode so we get the right data. --rmk
>                  */
> -               map_write(map, CMD(0x70), adr);
> +               map_write(map, CMD(0x70), chip->in_progress_block_addr);

Why do you change to chip->in_progress_block_addr here?

>                 chip->oldstate = FL_ERASING;
>                 chip->state = FL_ERASE_SUSPENDING;
>                 chip->erase_suspended = 1;
>                 for (;;) {
> -                       status = map_read(map, adr);
> +                       status = map_read(map, chip->in_progress_block_addr);
>                         if (map_word_andequal(map, status, status_OK, status_OK))
>                                 break;
>
> @@ -1059,8 +1063,8 @@ static void put_chip(struct map_info *map, struct flchip *chip, unsigned long ad
>                    sending the 0x70 (Read Status) command to an erasing
>                    chip and expecting it to be ignored, that's what we
>                    do. */
> -               map_write(map, CMD(0xd0), adr);
> -               map_write(map, CMD(0x70), adr);
> +               map_write(map, CMD(0xd0), chip->in_progress_block_addr);
> +               map_write(map, CMD(0x70), chip->in_progress_block_addr);
>                 chip->oldstate = FL_READY;
>                 chip->state = FL_ERASING;
>                 break;
> @@ -1951,6 +1955,8 @@ static int __xipram do_erase_oneblock(struct map_info *map, struct flchip *chip,
>         map_write(map, CMD(0xD0), adr);
>         chip->state = FL_ERASING;
>         chip->erase_suspended = 0;
> +       chip->in_progress_block_addr = adr;
> +       chip->in_progress_block_mask = ~(len - 1);
>
>         ret = INVAL_CACHE_AND_WAIT(map, chip, adr,
>                                    adr, len,
> diff --git a/include/linux/mtd/flashchip.h b/include/linux/mtd/flashchip.h
> index b63fa457febd..3529683f691e 100644
> --- a/include/linux/mtd/flashchip.h
> +++ b/include/linux/mtd/flashchip.h
> @@ -85,6 +85,7 @@ struct flchip {
>         unsigned int write_suspended:1;
>         unsigned int erase_suspended:1;
>         unsigned long in_progress_block_addr;
> +       unsigned long in_progress_block_mask;
>
>         struct mutex mutex;
>         wait_queue_head_t wq; /* Wait on here when we're waiting for the chip
> --
> 2.13.6
>
>
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> http://lists.infradead.org/mailman/listinfo/linux-mtd/



-- 
Thanks,
//richard