Re[2]: NOR memory driver fail with MMU enabled

[Alexander Shiyan]

Hello.

> > I have a problem with NOR flash when enabling MMU.
> > Probably this happen due NOR start address is 0x0.
> > Should we a remap memory addresses same as we do it for kernel? 
> > Or can someone tell what could be the problem?
> 
> This is because the zero page is set to faulting so that you can
> catch NULL pointer exceptions. You could disable this (see
> vectors_init), but then you can't catch NULL pointer exceptions
> anymore. So the best you can do is use map_io_sections and map
> your flash to some free region, maybe like this:
> 
> map_io_sections(0x0, (void *)SZ_1M, SZ_32M);
> 
> Then register your flash flash with address 1M instead of 0x0.

So, this problem is gone. I found a next one MMU-related problem.
When I turn on option MMU_EARLY, barebox is entered to an endless
loop or die, I am not sure. Probably problem is in "create_sections"
procedure from mmu.c, since I tried to add some debug before this
procedure and we reach this mark, after this procedure we dead.
Can you get me a point for find a solution?
Below is a debug output with CONFIG_MMU_EARLY turned on.

barebox 2013.02.0-00235-g2de8827-dirty #25 Thu Feb 7 12:54:06 MSK 2013


Board: Cirrus Logic CLEP7212
initcall-> 0xc0788518
register_device: platform
initcall-> 0xc079c988
register_device: fs
initcall-> 0xc079e04c
initcall-> 0xc0794264
initcall-> 0xc079c958
xmalloc c0380008 (size 1024)
initcall-> 0xc079e170
initcall-> 0xc07886fc
register_driver: clps711x_serial
initcall-> 0xc079e004
xmalloc c0380410 (size 136)
register_device: clps711x_serial0
xmalloc c03804a0 (size 192)
register_device: cs0
xmalloc c0380568 (size 28)
xmalloc c03805a8 (size 28)
initcall-> 0xc078709c
register_device: global
initcall-> 0xc079dec4
xmalloc c03805e8 (size 24)
request_region ok: 0xc0000000:0xc1ffffff
xmalloc c0380608 (size 36)
xmalloc c0380640 (size 36)
xmalloc c0380678 (size 136)
register_device: mem0
initcall-> 0xc079fd24
request_region ok: 0xc07f4003:0xc07f8002
xmalloc c0380708 (size 36)
mmu: ttb: 0xc07f4003

(nothing more)

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