At 2:09 AM -0500 2/5/00, Dave Huang wrote:
>On Sat, 5 Feb 2000, David Johnston wrote:
>> Who would be the relevant experts on the 840av/660av DMA code and the sparc
>> esp DMA SCSI driver? I'm going to have questions...
>
>Well, I wouldn't consider myself an expert on the subject, but I did
>write the mc ethernet driver... I basically figured out what I needed to
>know by disassembling the MacOS driver; perhaps a (partial) disassembly
>of SCSI Manager 4.3 or whatever would be a start. With only one driver
>in NetBSD that uses the AV Mac's DMA, it's sorta hard to tell what's
>Ethernet-specific and what's applicable to DMA in general... anyways,
>feel free to ask me questions :) Hopefully I'll have some useful answers
>:)

The linux-m68k port has some additional info in their comments about the
DMA channels on the PSC including guesses about SCSI and sound. I would
imagine the DMA for SCSI probably isn't too much different from the DMA for
the ethernet. It's just a matter of getting the right channel and addresses.

I think I remember one unusal thing about the DMA engine is that it doesn't
have a request FIFO. It just has two registers and you have to sort of flop
back and forth between them. I could be thinking of something else, though.

Good luck!

____________________________________________________________________
 Michael Zucca - mrz5149@acm.org - http://www.mdc.net/~mrz5149/
 "I will choose a path that's clear. I will choose Freewill. "
  --Rush, Freewill
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