What are the units of "offset" parameter to bus_space_subregion?  The
arm32 "mainbus" (and the current arm26) space seems to make it the units
of the underlying CPU address space, which means that the offsets make
sense to someone looking at addresses in the manual, while the arm32
"podulebus" space makes it the same units as the "offset" parameter to the
bus_space_read_* and bus_space_write_* functions.

Thinking about it, I think the latter way is right, since otherwise MI
drivers can't sensibly use bus_space_subregion.  Anyone disagree?

-- 
Ben Harris
Unix Support, University of Cambridge Computing Service.