[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.

OK, we seem to be peeling back the layers of the onion now.

I patched readenv to use the same nand_read_skip_bad function used in
the command line "nand read" tool.  I no longer get the -EUCLEAN errors
when reading the environment after using fw_setenv to write from linux.
Now I get:

*** Warning - bad CRC, using default environment

Checking the data with the "nand read" command line shows that the
changes I made in linux are indeed there, so I suspect that there is
also some mismatch in the CRC computation between the fw tools and the
u-boot code (i.e. I'm pretty sure this error does *not* refer to the
nand CRC)

Steve