Re: [U-Boot] U-Boot and UBI

[Enrico Scholz <enrico.scholz@sigma-chemnitz.de>]

Josh Boyer <jwboyer@linux.vnet.ibm.com> writes:

>> Yes, we should make a u-boot within one block size since flash
>> only guarantees the first one block as bad block free. e.g.,
>> exactly (128KiB - 2KiB) size if OneNAND case.
>> For this, we need to code or size optimization.  If this is
>> solved, we can use flash as bad block free device with UBI.
>
> An alternative to that is to have a very small IPL that loads
> U-Boot to DRAM as the SPL.

Yes; our implementation of such an IPL (for PXA320) can be found
at

   https://www.cvg.de/people/ensc/elito-mobm320-0.0.4.tar.bz2

This allows to jump into an image either located in a 'bootloader'
volume (which contains U-Boot) or in a 'kernel' image.

Latter is faster (by about 3-5 seconds plus the duplicate UBI
scan within U-Boot) which can make a difference as the IPL itself
needs 3.5 seconds to scan a 1GiB NAND :(


> That would require some relocatable support in U-Boot.

Depends on the system resp. how U-Boot was built (e.g. set its
TEXTADDR so that it does not conflict with the IPL).


Enrico