[U-Boot] Chain loading an u-boot from an u-boot

[Helmut Raiger <helmut.raiger@hale.at>]

On 02/12/2014 10:59 PM, Scott Wood wrote:
>>
>> Most operations are read (we use a separate YAFFS partition for time
>> predictable writes),
>> so UBI will relocate read-only blocks anyway (due to read disturbances),
>> I think the
>> effect wont be too dramatic, but don't make me proof that ;-)
> This sounds like a very bad idea.
Agreed.

>> SPL on i.MX31 is limited to 2kB so we can't use BCH 4 here, just as you
>> guessed.
> You could use TPL (three stage extension of SPL).  2K SPL loads 126K
> TPL, which has BCH code and can load the real U-Boot.
>
> See doc/README.TPL, and include/configs/p1_p2_rdb_pc.h for an example.
Yes I read that, but it's not done for i.mx31 and I thought it might
be harder to do, than just a second u-boot. This might proof wrong.

>> jumping to it.
>> If I set a breakpoint in the do_go_exec() I can step right into the
>> second u-boot.
> Make sure you're cleaning the cache for that second load, if required.

Currently I turned off cashes in the first u-boot and hoped that would
do.

Helmut


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