[U-Boot-Users] board bring up, mpc8555 custom board

Wolfgang Denk wd at denx.de
Sat Jan 28 14:37:54 CET 2006

In message <43DB6042.9050000 at mesias.co.uk> you wrote:
> Using the BDI probe and a fairly extensive config file (which sets up 
> TLBs and LAWBARs) we are able to step through the programmed u-boot 

I'd like to point out that this is NOT the recommended way of  debug-
ging  U-Boot. It is usually much more efficient to use only a MINIMAL
config file for the BDI2000.

> although it has an alignment exception whilst running 
> cpu/mpc85xx/start.S (at the part after the comment "Allocate Initial RAM 
> in data cache"). We think it's an alignment exception because it jumps 
> to the alignment exception handler address and continues briefly.

It can be anything - including a consequence  of  your  inappropriate
BDI config file.

> I have a suspicion that we shouldn't be trying to single step this 
> initialisation code after the BDI has set up the hardware somewhat. I 

You shouldn't make the BDI initialize the HW in the first place.

> have tried a reduced BDI config file and it still doesn't work, and it 
> no longer single steps.

You have to work on the BDI  init  file  until  you  can  single-step
U-Boot right from the reset entry point. As long as this doesn't work
you cannot continue.

Best regards,

Wolfgang Denk

Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
If all the Chinese simultaneously jumped into the Pacific  off  a  10
foot platform erected 10 feet off their coast, it would cause a tidal
wave that would destroy everything in this country west of Nebraska.

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