[Patch 1/1] don't suspend erase for erase in cfi_cmdset_0002

[Joakim Tjernlund]

Peter Wippich <pewi at gw-instruments.de> wrote on 03/08/2009 15:07:30:
>
>
> Hi Jocke,
>
> On Mon, 3 Aug 2009, Joakim Tjernlund wrote:
>
> > linux-mtd-bounces at lists.infradead.org wrote on 03/08/2009 12:50:44:
> >
> > >
> > >
> > > Hi,
> > >
> > > came around this problem while stress testing jffs2. From time to time the
> > > block erase failed and the file system overflows. I don't know if there
> > > are any Nor chips out there which allow a new erase to start when in erase
> > > suspend. However, the chips on my board dont't. And even when it doesn't
> > > make much sense to suspend an erase operation for another erase.
> > >
> > > Patch below fixes the problem for me.
> > >
> > > Have fun and take care,
> > >
> > > Peter
> > >
> > > Signed-off-by: Peter Wippich <pewi at gw-instruments.de>
> > > ---
> > > diff -Naur a/drivers/mtd/chips/cfi_cmdset_0002.c
> > > b/drivers/mtd/chips/cfi_cmdset_0002.c
> > > --- a/drivers/mtd/chips/cfi_cmdset_0002.c   2007-07-10 20:56:30.000000000 +0200
> > > +++ b/drivers/mtd/chips/cfi_cmdset_0002.c   2009-08-02 19:55:34.000000000 +0200
> > > @@ -521,6 +521,10 @@
> > >     case FL_ERASING:
> > >        if (mode == FL_WRITING) /* FIXME: Erase-suspend-program appears broken. */
> > >           goto sleep;
> > > +      if (mode == FL_ERASING) {
> > > +         printk(KERN_INFO "attempt erase suspend with mode FL_ERASING\n") ;
> > > +         goto sleep;
> > > +      }
> > >
> > >        if (!(   mode == FL_READY
> > >              || mode == FL_POINT
> > >
> >
> > This change looks bogus. You are not supposed to need the extra test.
> > I do think this test is faulty though:
> >
> >    if (!(   mode == FL_READY
> >             || mode == FL_POINT
> >             || !cfip
> >             || (mode == FL_WRITING && (cfip->EraseSuspend & 0x2))
> >             || (mode == FL_WRITING && (cfip->EraseSuspend & 0x1)
> >           )))
> >
> > What happens if cfip is NULL?
>
> Checked this one. Because the Chip is jedec probed (not cfi) and there is
> no fixup cfip should be NULL. Then the above will evaluate to :
>    mode == FL_READY = FALSE
>    mode == FL_POINT = FALSE
>    !cfip       = TRUE
>    (next two skipped, hopefully ...... ;-)
>
> End ! TRUE = FALSE -> we will not go to sleep ! Actually, it is not quite
> clear to me what the intention of this expression was. But if the original
> intention was to only allow erase suspend when requested mode is FL_READY
> or FL_POINT it is obviously wrong.....

Probably:
if (!cfip || !(cfip->EraseSuspend & (0x1|0x2)) ||
    !(mode == FL_READY || mode == FL_POINT ||
     (mode == FL_WRITING && (cfip->EraseSuspend & 0x2))))

Pehaps you can remove the
  if (mode == FL_WRITING) /* FIXME: Erase-suspend-program appears broken. */
	goto sleep;
too? ( in a separate patch though)

  Jocke