diag regsiter to work out why the (non-existant) strbufs don't work.
- check for malloc failure in _all_ places.
- setup the PCI control register as recommended in the IIi users manual.
(`SUNW,sabre') for now, and it doesn't really quite work there yet anyway.
the bus space/dma code is cloned from the sbus driver. the IOMMU code also
is cloned from the sbus code, but separated out into iommu.c so that we can
share it with the sbus driver. hopefully, much of the bus space/dma code
can also be re-shared with the sbus driver and the ebus driver but for now
these copies will do.
support for the real UltraSPARC PCI (`SUNW,psycho') is unwritten, though
most of this code is shared with it.
we can probe PCI config space and try to configue devices, but interrupts
don't work yet...
eeh