the `get window' method ends up with the wrong physical address to pass onto userspace (which wants to mmap the space). Compensate by adding a CHIP_PHYSADDR() macro which un-hacks the address suitably for mapping with other-than-KSEG.
EV56 for the assembler to emit BWX opcodes, so set the arch to "ev6".
This covers most or all of the presently-available 21264 systems.