Generic DISCONTIGMEM Support on 32bit MIPS

[Phil Thompson <phil@river-bank.demon.co.uk>]

I'm working on a port of 32bit MIPS to a board with several large holes
in the memory map. So I need to re-implement paging_init() and
mem_init().

The first question is: has anybody already done this? Particularly as,
once you've identified where the holes are, the code isn't board
specific.

If not then I'll try to work out what needed from the corresponding
mips64 and ip27 code, but I'd appreciate any pointers.

Thanks,
Phil