I have just got DVMA transfers working for the Sun 3/260 VME si
interface.

If you want to experiment with the code, then you need to get
http://www.achilles.net/~dej/dvma_diff.tar.gz and
http://www.achilles.net/~dej/5380.tar.gz

The first is a set of patches to fix the DVMA code for the sun3.
The second is a new SCSI driver that uses the DVMA stuff.

You will also need to add /sys/dev/ic/ncr5380.c to files.sun3.


The code as shipped is in "most stable, most hacky" mode.
It's fairly stable for me, but use at your own risk.
By tweaking flags in the code (such as ncr5380_permit_reselect
and si_pollcnt) you can experiment with reselection and
interrupts.  But be prepared to crash.

DVMA works, but interrupts don't.  Right now I am polling for
DVMA completion.  It's not as bad as it sounds, and transfers
are better than 1 MB/second.  If I enable interrupts, then I
get a combination of spurious and lost interrupts.

Oh yeah, one final thing: this is VME only.  It won't work
with OBIO at all.  If you're lucky it will drop back to
PIO mode for all transfers.