[U-Boot] fw_setenv broken?

[Steve Sakoman <steve@sakoman.com>]

On Wed, 2010-11-17 at 16:08 -0600, Scott Wood wrote:
> On Wed, 17 Nov 2010 22:40:49 +0100
> Wolfgang Denk <wd@denx.de> wrote:
> 
> > Dear Steve Sakoman,
> > 
> > In message <AANLkTimrfQ5+AWfdFy_fueTMH=x=xrkaZGNtK8fiSD48@mail.gmail.com> you wrote:
> > >
> > > readenv: offset = 240000
> > > readenv: nand_read failure = -117
> > > *** Warning - readenv() failed, using default environment
> > > 
> > > I then immediately tried to use the nand read command to read the same
> > > block, and it was successful!
> > 
> > Hm... any chance that - for example - your timers are not working
> > correctly before relocation (maybe because they try to write to the
> > not yet available data segment) ? This could cause timeouts or delays
> > to be too short, so the NAND driver is misbehaving?
> 
> The NAND driver only works after relocation.
> 
> It looks like the problem is that -EUCLEAN is a non-fatal error
> (indicates a correctable ECC error).  The code invoked by the "nand
> read" command succeeds if nand_read() returns either 0 or -EUCLEAN, but
> readenv() is missing this check.

Changing readenv to use nand_read_skip_bad eliminated the -117 (EUCLEAN) failures.

Now I am getting just the -74 (EBADMSG) errors for fw_setenv written environments.

It seems that fw_printenv can always read u-boot written environments, but 99.9%
of the time I get a -74 (EBADMSG) error in u-boot for environments written by fw_setenv:

NAND read from offset 240000 failed -74
*** Warning - readenv() failed, using default environment

If I try to read the environment using the nand read tool I get the same error.

Using fw_printenv always seems to work -- whether u-boot or fw_setenv was the writer.

The code generating both errors is in the nand_do_read_ops function in nand_base.c:

       if (mtd->ecc_stats.failed - stats.failed)
               return -EBADMSG;

       return  mtd->ecc_stats.corrected - stats.corrected ? -EUCLEAN : 0;
}

I understand that the -EUCLEAN error indicates a correctable ECC error.  What does the -EBADMSG error indicate?

This condition doesn't seem to bother the linux driver, but u-boot doesn't like it at all!

Steve