How to the the physical addresses under linux (au1500)

[Sergio Ruiz <quekio@gmail.com>]

I am trying to program  the DMA (with the ac97) in assembler using a
linux kernel module for mips teaching purposes.
The problem is that I need to get the physical address of the pointer
to the buffer to transfer to the AC97.
Looking at the kernel source code, I found that I can get the physical
address subtracting 0x8000000, but It doesnt seem to work.

Any idea?

Thanks,

Sergio