* Track which process (XXX really, vmspace) owns the mapping. When
we sync the map, if the mapping doesn't belong to the kernel or to
the current process (XXX really, vmspace), then no cache fobbing
is necessary, since the cache is Wb-Inv'd on context switch (XXX need
to revisit this when we support FCSE).
* Be smarter about which cache operation we do when sync'ing the map:
- PREREAD -- Invalidate D$ (XXX right now, we actually do Wb-Inv)
- PREWRITE -- Write-back D$ (note, we do NOT invalidate here)
- PREREAD|PREWRITE -- Wb-Inv D$
More work is needed here. In particular, a version for CPUs
with write-through caches should be provided, to eliminate
the write-back steps (which are noops on such CPUs, but skipping
two branches would be nice).
DMA via the Secondary Inbound window, for now. Will probably
need to revisit this at some point.
Require that the board-specific i80312 front-end slice off a
subregion for the memory controller before calling i80312_attach(),
and fix a bug in the IQ80310 front-end that caused the Secondary
Inbound window to be configured incorrectly.
thorpej