How to make part of kseg0 uncached

["Jimmy Zhang" <jzhang@elmic.com>]

It is pretty simple to make the WHOLE kseg0 cached or uncached. However,
I only want part of kseg0 uncached. 

I must uncache that region because it gives me too much trouble with DMA
data, however, I don't want to uncache the whole kseg0 segment in order
to get better performance.  Kseg0 is not mapped through TLB, so it seems
I can't achieve my goal through TLB. 

Cite from the book See Mips Run, "if you feel that your system needs to
make uncached references to cacheable memory, then I strongly recommand
that you divide memory into regions that are always accessed uncached
and regions that are always accessed through the cache - and don't let
them overlap. " But how ?

Thanks,

Jimmy