On Sat, 20 May 2000, Greg wrote:

> I know that this subject has been discussed briefly (maybe at length) and
> this is probably off-topic for both lists, however I would like to inquire
> anyway...
> 
> Is anyone working on a version of NetBSD for the NuBus based PowerMacs?  I
> know that MkLinux exists but it _just wasn't the same_ if you know what I
> mean.

*coughs*  I'll try not to feel hurt.  ;-)


> I have been thinking about this a lot lately and if I had the skills to port
> _anything_ I would be more than happy to work on it myself, sadly, I don't
> 
> I know from what I have briefly read on the mailing lists reads something
> like:
> 
> "create a new port which uses the port-mac68k device drivers, boot code,
> and utilities and uses the port-macppc stuff for everything else".

Most device drivers would most certainly be port-macppc in every way
except the need to hard-code addresses and interrupt numbers into the
drivers (since there's no open firmware from which to get them).  About
the only substantial (>2 lines of code) things needed are:


* non-contiguous memory support (ma68k probably does this already, so
  this should be a snap -- use the ludovic-patched BootX to get the
  memory regions and stuff from the MacOS nanokernel.  Neat trick.  ;-)
* booter (mac68k, modified, or use BootX -- highly recommended)
* 601 support
* AMIC DMA supoprt (if you want to do DMA for floppy, serial, ethernet,
  and/or SCSI)
* interrupt handler changes


> "FWIW, I've got a start at 601 support... My girlfriend has a 601 PCI
> Macintosh that she'd like to run NetBSD on :-)"
> 
> and there was at one point a brief discussion of DMA, AMIC and something
> called BART (maybe someone made that up for the discussion) that died off as
> well..

BART is the nubus controller.  If you want to support nubus cards, you'd
need to support that.  I have a driver for it that should do the basic
stuff (there's not much to it).  Beyond that, mac68k drivers would come in
here, albeit a big-endian version of them.  However, actually supporting
nubus cards isn't necessary immediately.  That's about the very last thing
you'd want to support, behind _everything_ else.  ;-)


> Granted, I don't know what goes into porting NetBSD to another architecture,
> nor do I know if I _really_ want to (I bet it is very difficult), but I for
> one, would love to be able to run NetBSD on some of the newer but before PCI
> PowerPC based Macs....

Well, if you decide to give it a go, and if you run into any problems
along the way, give me a shout.  I'm pretty familiar with the PDM
architecture, and I'd do this myself if I weren't swamped with classes and
work.  I'm thinking about tackling Darwin/OS X on the PDMs this summer,
though, time permitting.  :-)

I'm not sure what sorts of machines you have, so I don't know if you have
a machine that runs NetBSD-macppc already.  If not, your first step would
be to set up a cross-compiler.  That'll be good for a week or two.  :-)


David

---------------------------------------------------------------------
A brief Haiku:

Microsoft is bad.
It seems secure at first glance.
Then you read your mail.