treated as just another available VMEbus slave image as far as
bus_dma(9) is concerned.
To preserve faster onboard memory, mvmebus_dmamem_alloc() will
allocate first from the offboard VMEbus RAM slave image if present,
and assuming its address modifier matches the caller's constraints.
This can be overidden by specifying the BUS_DMA_ONBOARD_RAM flag.
deal with dynamic address modifier generation based on the CPU's
function code pins.
Also implement VMEbus slave mode for mvme147. (Not yet 100% working.)
These changes add support for:
o The MI VMEbus framework on both MVME147 and MVME167.
o Enhancements to the existing MD bus_space(9) implementation.
o Most of the bus_dma(9) API.
scw