[PATCH 2.6.15-rc4] ppc32: Fixes for non-zero PPC_MEMSTART on PPC440

Josh Boyer jwboyer at jdub.homelinux.org
Sat Dec 3 08:14:37 EST 2005


On Fri, 2005-12-02 at 01:07 -0700, Jason Gunthorpe wrote:
> I have a custom embedded system with a 440GP derived CPU that places the
> memory starting at 0xc0000000 which requires a non-zero PPC_MEMSTART. There
> are a couple of places that assume PPC_MEMSTART is 0. This results in
> various tricky crashing during booting. Most of the problems are
> not accounting for PPC_MEMSTART during va/pa translations. My fixes
> convert these places to use pre-existing macros instead of duplicating
> the calculation.
> 
> The two items in head_4xx.S are critical, but I can't see a good way
> to link them in without an #ifdef, or maybe a CONFIG_* symbol. The
> alternate version of the tlb index picker will work for any platform,
> but is based on 'random' selection of the tlb index using the timebase
> rather than linear increment. I don't know if this is better, but it
> is an easy way to skip the problematic memory reference.

Shouldn't your board be using head_44x.S?

/me is confused...

josh





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