[U-Boot-Users] board initialization problem

Om Vadlapatla pdfdoc15 at yahoo.com
Wed Jun 14 18:40:23 CEST 2006

K0: Original Montavista kernel
K1: Kernel without D-cache Adapted for 4x60(SDH 2/6
K2: Kernel with D-cache enabled for 4160 (SDH 6 ch)

Difference between K1 & K2: 
1. D-cache (~/kernel2.4.17/arch/ppc/kernel/head.S)
here only one line difference.

2. Page table & cache buffer allocation
I can send the difference only 4 lines only setting
the  buffer arrays.

Target: 4160 (compat SDH unit)
Abatron: Jtag Debugger 

fw4x60.cfg: old config file for Abatron
fw8270.cfg: new config file for Abatron

The tests tried using U-BOOT:

1. Loaded K1 onto target independent of Abatron

2. Loaded K2 onto target with Abatron fw8270.cfg 
     ran busy looptest for K1 & K2 result: K2 40 times

3. Tried to load K2 to target without Abatron result:

Conclusions & comments:

There are significant differences between fw4x60.cfg &
These differences need to be incorporated in the new
Kernel (OR I am not sure about it but may be into the

Core Initialization file in kernel: 

Speculated changes:
It was speculated that the cached buffers triggered
the exception. And commproc.c was modified to make
those buffers uncacheable. But that made things worse:
invalidate_dcache_range() and flush_tlb_page() cause
another exception to occur (not identified).

U-boot initialization files:
start.S, cpu_init.c

Both these files in u-boot are  meant to initialize
the core & MMU.

If the config changes need to go into the kernel I am
not sure if it is the head.S file.

If the config changes need to go into the boot loader
I am not sure while the kernel opperates if there will
be any unpredictable behaviour.

Irrespective of where the changes go, the main task is
to analize each difference between fw4x60.cfg &
fw8270.cfg and develope the initialization code. 

If any one has another plan of action please let me
know, I appreciate guidance. 

Attached are the two config files.

Om Vadlapatla

PS:- All I need is to load the new kernel with out a
glitch coz I can do it with the Abatron pluged in.

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