> make it something like (note: the names are suggestions only):
> 
> mainbus_of* at root
> mainbus_nubus* at root
> 
> cpu* at mainbus_of?
> cpu* at mainbus_nubus?
> pci* at mainbus_of? bus ?
> nubus* at mainbus_nubus?
> 
> 
> obio_of0 at pci? dev ? function ?
> obio_old0 at mainbus_nubus?

Why two different obios? Wouldn't we want just one obio with two
different attachments, and let the attachment code do the necessary
frobbing?

As for mainbus, it would have to logically be two completely different
mainbusses, but I think you'd want to still call them both "mainbus".

-- Dan