[U-Boot] Nand dump and nand bad block disagree

[Mike Frysinger <vapier@gentoo.org>]

On Wednesday 29 February 2012 14:09:44 Scott Wood wrote:
> On 02/29/2012 01:06 PM, Mike Frysinger wrote:
> > On Wednesday 29 February 2012 04:02:39 jean-philippe francois wrote:
> >> Le 29 f?vrier 2012 00:40, Scott Wood a ?crit :
> >>> Is this a 16-bit NAND?  If so, the first two bytes have to be 0xffff,
> >>> unless the controller driver defines the bad block pattern differently.
> >> 
> >> It is an 8 bit nand. The badblock patern can be redefined by the
> >> controller driver to be different from the one in nand_base.c ? Do you
> >> have an example of this ?
> > 
> > look at the Blackfin nand driver (in u-boot and linux).  we have to
> > override the badblock layout because our on-chip boot rom expects
> > something other than what linux uses.
> 
> But be careful when doing this -- it really should match what
> manufacturers will write.

yep

on the Blackfin side, nothing to be done now.  the rom team didn't consult with 
the linux team before implementing things, and these roms are fixed in the 
processor, and they can't change now without breaking backwards compat.

> If it's an 8-bit NAND, I don't see why it would be looking for anything
> but the first byte by default.  Overriding should not be necessary.

you can see the Blackfin OOB layout used here if you have a passing interest:
http://docs.blackfin.uclinux.org/doku.php?id=bootloaders:bootrom#nand_considerations
-mike
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