Re: NAND Configuration

[Alice Hennessy <ahennessy@mvista.com>]

Thomas Gleixner wrote:

> On Wed, 2002-08-07 at 12:19, Steve Tsai wrote:
> > > > JFFS2 on NOR type flash does not use buffering, OOB check and bad
> > > > block management, but it can be used now. I meant that
> > > > CONFIG_JFFS2_FS_NAND is not defined, maybe the driver still
> > > can work,
> > > > but it is not good as the original one.
> > >
> > > JFFS2 cannot work on NAND flash without the extra code enabled by
> > > CONFIG_JFFS2_FS_NAND. You need to batch writes into
> > > page-sized chunks and
> > > use ECC. It looks like you have enabled CONFIG_JFFS2_FS_NAND
> > > in the log you
> > > show -- is that correct?
> > >
> >
> > Yes, I enable CONFIG_JFFS2_FS_NAND. I follow
> > http://www.linux-mtd.infradead.org/tech/nand.html to config the
> > settings. Can I do not care ECC on NAND flash?
> >
> ECC _HAS_ to be enabled !
>
> Have you ever erased your flash with erase /dev/mtdX ?
> This may have caused the problem, because erase is not aware of bad
> block handling and may have erased a block, which was marked as bad
> already and erased the bad block marker too. So if you write to this
> block, you get a write failure and therefor a read failure afterwards.
> I will change nand.c, so that bad blocks cannot be erased anymore.
>

>From looking at nand_erase(), it appears that the attempted erase of a bad
block would
result in not performing the erase and exiting with -EIO, correct?

What is the preferred method to erase nand?

Alice

>
> Another problem could be your command delay time. You have set it to
> 15µsec. Is that correct for your chip ? Which chip are you using ?
> Have you tried to set it to a higher value ?
>
> --
> Thomas
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