[RFC/PATCH] powerpc: Rewrite IO allocation & mapping on powerpc64

[Segher Boessenkool]

>  - Cleanup and separate tracking of the ISA space in the reserved
>    low 64K of IO space. No ISA -> Nothing mapped there.

> I now always reserve the first 64K of IO space for the bridge with
> the ISA bus on it.

This is wrong -- there are systems with ISA that
also have PCI devices that require 16-bit legacy
I/O windows (e.g., systems with the AMD8111 chip,
like Maple).

Or do you mean you reserve the low 64k for the PHB?
That would work in this case, but still not in
general.  Not sure if we care though.


Segher