> AFAIK, we don't have doc for the bpp driver, but if someone here can coorect
> me, PLEASE DO.

There is some documentation. The device is part of the `slavio' chip
found in many sparcstations which also houses the ethernet & scsi
chip clones + DMA glue.  I entered some code into `-current' -- which 
you can find in `sys/dev/ic/lsi64854.c' and `sys/dev/sbus/bpp.c' --
while I did the MI Sbus reshuffle.

This code has not been tested in any way..

-pk