I'm currently looking into recoding the asc driver...
Is it more proper to bus_space_map the R4030 DMA registers, and read/write
them with the bus_space functions, or make use of the pDmaReg struct from
dma.h to write to the DMA registers that way?  I would think the bus_space
functions are the way to go, but all the DMA register definitions in dma.h
would still be needed (the #defines), so I'm thinking of moving these into
pica.h so we can ultimately get rid of dma.[ch] completely.
What do you all think?

-Mark