ppc85xx DMA

Dear sirs,

I am trying to add a DMA transfer component to my driver on linux 2.6 on a
ppc 8541.  Following the steps listed in the reference manual, I write the
SAR, SATR, DAR, DATR and BCR registers before cycling the bit in the MR
register to start the transfer.

The SR register though indicates a transfer error as soon as I write the
DAR register.  Clearly I've gotten the mapping wrong. I know what the
address I am trying to write to in kernel space is, what is unclear is
what address the DAR register is expecting.

Any help would be appreciated

-naru