Subject: Re: SONIC driver?
To: Christopher R. Bowman <crb@glue.umd.edu>
From: Bill Studenmund <wrstuden@loki.stanford.edu>
List: port-mac68k
Date: 12/05/1996 14:22:01
> SONIC support will do you no good becuase the 660 and 840 use a chip called
> curio that is basically an AMD MACE + 53c94 + SCC on a single ASIC.  In
> addition it is probably hard to get a good implementation of ethernet on
> these machines because the MACE is really designed to be used with an
> external DMA controller and though docs are available onthe MACE and 53c94
> there is no publicly available information on the apple DMA controller.

Hmm. Apple hasn't (AFAIK) released the addresses for the DMA controller,
but I'd guess they are doing DBDMA (Descriptor Block DMA). Which is
documented in the Apple CHRP (PPcP?) documentation. And mkLinux.
Does anyone know if I'm full of it here?

Oh, DMA for serial'd be nice. Supporting 230k bps would be no problem.

> Having said all that; I have looked at the driver files for the MACE chip
> that are part of DR1 of mklinux, and the AMD docs on the MACE, and I think
> it should be possible to take the current ethernet driver code for 8390
> based boards and cobble up a programmed io style driver for the 660/840
> ethernet.

Sounds like a good start.

> After exams are over a week from saturday, and if I can get my IIci to stay
> up reliably, I plan to take a stab at this, unfortunately I have never
> hacked the kernel before, and I have little knowledge of the
> driver/ether/TCP workings, I just intend to take the functions in the
> current driver and replace them with code that does the same thing for the
> MACE.  I have little hope that I will get things working, but it'll be fun
> anyway.

That's how I got started hacking on the serial ports. Take working code
and beat on it until it behaves. :-)

Take care,

Bill