KEXEC on the Freescale MX31

[Dave Kroetsch <dave@xxxxxxxxxx>]

Hi All,

Wondering if anyone has had any experience running kexec on the arm cpu in the 
Freescale MX31?   My setup is:

	Kernel: 2.6.22
	Board:  LogicPD MX31 Litekit

First kernel boots and runs great.  I'm using the kexec-tools 1.101 to load 
the kernel.  To start I'm using the kernel that booted successfully the first 
time round and trying to kexec it.

I've done a fair amount of debugging and I have isolated the problem.
	- kexec relocation code works fine
	- the cpu resets to that address and begins running the new zImage
		- the zImage is loaded to 0x8100000
	- the zImage decompression code seems to work without a problem
		- decompresses the kernel to 0x80008000
		- this is the same location that the first kernel uses
	- the decompressed image beings running the kernel startup code:
		linux/arch/arm/kernel/head.S
		- using some GPIO LED debugging I can see that it gets
		  all the way through to __turn_mmu_on and then jumps
		  correctly to __switch_data
	- code in __switch_data (linux/arch/arm/kernel/head-common.S) starts
	  running, but something in here goes wrong, because the code
	  never gets to start_kernel( ) (from linux/init/main.c)

The spot in which it dies is only like 10 lines of assembler.  It looks like 
it's as simple as copying the data segment and zeroing some static variables 
and then branching to the start_kernel( ) function.

My fear is that something is going wacky with the mmu and so things are 
hanging.  Does any one have any ideas on how I can try to track down this 
problem further?  I can't upgrade to the latest version of the kernel, but 
I've looked at the kexec code in the latest kernel tree, and there are no 
changes.  Any ideas on what in the mmu might look different from the first 
time booting that's causing this problem?

Any help/suggestions would be appreciated.

Thanks,
	Dave

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