[U-Boot] relocation on freescale mx35 doesn't work after update to 2015.01

[Albert ARIBAUD]

Hello Sebastian,

Cc:ing Stefano since he's the i.MX custodian.

On Fri, 6 Feb 2015 09:38:17 +0000, Priebe, Sebastian
<Sebastian.Priebe at cadcon.de> wrote:
> Hello Albert,
> 
> thanks for your answer.
> I tried to look up some information in the iMX35 reference manual but couldn't find anything. It doesn't say anything about the exception vectors. Can you point me at any direction where to look for information?

I'll try and have a look, but basically, you should search for a
chapter describing the boot sequence or exception handling.

> What is the consequence of skipping the relocation?
> Until now we don't use interrupts in the U-Boot.

It's not only about interrupts... It's about exceptions, which include
data aborts, prefetch aborts, undefined instructions...

Catching such exceptions properly means you will get to *know*
something went wrong, and moreover you will get to know *what*
was going wrong exactly.

Without proper exception vectors... Maybe you'll get a board reset
when the exception occurs, and you strictly won't have any clue as to
what happened and why.

> I want to know if we could update to the new version using the workaround I used, or if we might facing problems with that.

Depends. Do you feel lucky? :)

If so, you can go on with not relocating vectors at all; but if I have
my say, that patch won't end up in the mainline, so you'll have to keep
it somewhere locally.

If you think you might encounter data or prefetch aborts for some
reason while working on U-Boot, and if you don't want to spend hours
just finding out that you hit an abort then trying to determine why
you did, then I'd say you should fix the vector relocation properly.

> Greetings,
> Sebastian Priebe
> Telefon: +49 (0)621 685996-26

Amicalement,
-- 
Albert.