K0: Original Montavista kernel
K1: Kernel without D-cache Adapted for 4x60(SDH 2/6
ch)
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
(~/kernel2.4.17/arch/ppc/8260_io/comproc.c)
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
faster
3. Tried to load K2 to target without Abatron result:
Failed
Conclusions & comments:
There are significant differences between fw4x60.cfg &
fw8270.cfg.
These differences need to be incorporated in the new
Kernel (OR I am not sure about it but may be into the
Boot-loader).
Core Initialization file in kernel:
~/kernel2.4.17/arch/ppc/kernel/head.S
Speculated changes:
~/kernel2.4.17/arch/ppc/8260_io/comproc.c
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:
~/u-boot/cpu/mpc8260
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.
Sincerely,
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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