flush_cache when trying to compile agp support on linux ppc

Hi!
I hope you have not heard this before (but i am sure you have). I am trying to compile linux kernel 2.4.18 for suse linux ppc 7.1 and when i get to "agpgart_be.c" i get the message "#error "Please define flush_cache.". Does anyone know how to solve this? I have tried searching the internet and of course your mailing lists but came up with nothing.

Please help me out with this one

Peter