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

Cam camilo at mesias.co.uk
Sat Jan 28 13:14:58 CET 2006


We have used u-boot-1.0 on our 8260 based boards with great success.

We are trying to bring up a new mpc8555 based board with u-boot-1.1.4 
but have run into some problems.

We have a BDI probe which is used for programming flash and exercising 
hardware using JTAG.

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 
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.

The u-boot code is modified from the mpc8560ads code, the main 
difference being the boot flash is 32Mb and we have no localbus SDRAM.

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

Any suggestions how to proceed would be appreciated, does the alignment 
exception after allocating RAM suggest anything to anyone?




camilo at mesias.co.uk

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