physical and virtual memory questions

[David M. Siegel]

Two related questions:

We need to access the word registers of a home-brewed device on the
CMI (main memory) bus of a VAX/750. How does one do this from the
Kernel of 4.2 BSD Unix? 

Next, we want to map a large set of memory-like addresses that are
part of this device directly into some users virtual address space.
These addresses will respond exactly like VAX main memory, except that
they should not be used by the operating system as memory. We want to
allocate and deallocate them on command to different users. How does
one do this?

Ideally, we want a device driver that when opened will load some stuff
into the device's registers, map the memory-like portion of the device
to the user, and when closed, un-map the memory. I assume we must do
this by frobbing the pte in some way.

More specifically, the device registers are within the CMI IO space,
somewhere above 0xf00000. The memory like area is below that
address, but above the real memory arrays.

Thanks!
-Dave

-- 
					Arpa:	dms at mit-hermes.arpa
					Usenet:	mit-eddie!mit-hermes!dms