I forgot to say one thing...

I wrote:
> I tried to keep Tyne suppport from OpenBSD on NetBSD/arc.
> So, it should not be too hard.
> But, since I don't have access to actuall hardware, probably
> I made some mistakes...

sys/arch/arc/conf/ARCTIC is the configuration file for DESKstation Tyne
and rPC44.
And currently ISA bus master DMA devices like AHA-1542 will not work 
on Tyne, although Buslogic scsi may work (not NetBSD standard one, but
"btl0 at isa?" in sys/arch/arc/dti/btl.c)
--
soda