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

[Joakim Tjernlund <Joakim.Tjernlund@infinera.com>]

On Thu, 2018-03-22 at 15:14 +0100, Richard Weinberger wrote:
> 
> On Thu, Mar 1, 2018 at 2:39 PM, Joakim Tjernlund
> <joakim.tjernlund@infinera.com> wrote:
> > From: Joakim Tjernlund <joakim.tjernlund@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@infinera.com>
> > Cc: <stable@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?

To be consistent, in_progress_block_addr is the block in progress. adr will work too
but it looks odd to mix adr and in_progress_block_addr so change it for clarity.

> 
> >                 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
> > 
> > 
> > ______________________________________________________
> > Linux MTD discussion mailing list
> > http://lists.infradead.org/mailman/listinfo/linux-mtd/
> 
> 
> 
> --
> Thanks,
> //richard