[U-Boot] Segmented RAM, big userspace.

[Sergey Lapin <slapin@ossfans.org>]

Hi, all!

We have a board, based on s3c2416, with 128MB of RAM
and 1GB of NAND flash.
RAM is organized as 2 memory banks with far placed bases:

TOP

UNUSED 64MB

64MB SDRAM

--- 128MB segment base 1 -----

UNUSED 64MB

64MB SDRAM

-- 128MB segment base 0 ------

BOTTOM

So we could have only 64MB as one piece; Due to u-boot reloaction code we
need to have u-boot in first 64MB also. And now we have root filesystem
which we need to flash using u-boot, which is a little over this 64MB limit.

Is there some way to use second memory bank from u-boot?
Is it possible to tftp file in parts and flash it on NAND in parts?
(This requires handling of bad blocks too)

We need to flash using u-boot, that's requirement for speedy production.

It is possible to flash filesystems in parts, but for this to work
these are needed to be properly split. This raises a problem of
bad blocks - writing previous piece might end not where you expect it to
end, but a few blocks later. Hand-handling this case is too error-prone.

Thanks a lot,
S.