>   1. Some ports do not have bus_space_alloc, because they do
>      not know which memory area is usable.
>
>what's the deal here?  these ports (??? which are they???) should be fixed!

At least PowerBook 2400c.  It has two cbbs, and the Open Firmware assigns
separate address ranges to them respectively.

So, bus_space_alloc (-like function) needs to know which cbb is the caller,
but bus_space_alloc can't.