s3c244x hardware ecc

[Werner Almesberger]

Andy Green wrote:
> So U-boot used soft ECC and its data was incompatible with the hard ECC
> used in the kernel?

Yup.

> Presumably if we farm out ECC to the hardware it is
> going to be the same in U-Boot and kernel.

Yes.

> Trying to understand this so
> it doesn't trip us up in kboot world.

Yet another problem that simply can't happen since the same code
is used for all these operations :-)

However, I think we should do ECC error correction also in the
kboot loader, because NAND performance is only guaranteed for
correctable errors (i.e., single-bits), but not for the raw
memory. (I guess this makes you like NAND yet a little less ? ;-)

By the way, for "kboot" userspace, it's interesting to follow what
the PS3 Linux project is doing since they've been using kboot for
a while. It turns out that they've abandoned kboot and now have
something called petitboot:
http://ozlabs.org/~jk/projects/petitboot/

Petitboot makes the build process easier (kboot basically builds
its own little Linux distribution, with all the problems associated
with doing that) and it provides a neat little GUI.

Given that the shell features of kboot wouldn't be terribly useful
in everyday use on our devices anyway (Petitboot has a shell
escape, so no functinality is lost), I think we should try to make
Petitboot work as our main "kboot" interface. (That is, in
non-fastpath mode.)

- Werner