Linux/VAX boot protocol

[Will Deacon]

On Mon, Nov 26, 2012 at 06:28:34AM +0000, Pekka Enberg wrote:
> On Sat, Nov 24, 2012 at 10:26 PM, Maciej W. Rozycki
> <macro at linux-mips.org> wrote:
> >  The all-zeroes image parameters are probably accepted by client's
> > bootstrap firmware for backwards compatibility only and I have used the
> > daemon and the protocol with non-VAX devices (e.g. a terminal server or a
> > DECstation workstation) in a more sophisticated manner, where actual load
> > addresses (that need not be contiguous, BTW, as all Memory Load MOP data
> > transfer packets have an individual load address included in the packet
> > header) and entry point had meaningful values.
> >
> >  Beyond the note quoted I don't know if there has been any proper
> > documentation written up for these internals, perhaps someone else could
> > speak up.  I hope this helps regardless -- what do you need this
> > information for anyway?  Perhaps I could look into further details.
> >
> >  In the past I did some work on our `mopd' implementation (added ELF file
> > format support among others -- to support plain "vmlinux" images on the
> > DECstation), so perhaps I could dust off some old knowledge in that area
> > if that helped you.  OTOH I have never had a real need to look into our
> > early bootstrap code outlined in the note above, so unless someone else
> > steps in we'd have to explore that area from scratch.
> 
> I'm trying to understand the boot process so that I can emulate the
> relevant parts in QEMU.

FWIW: I've got a working mop setup for my vaxstation, with a TI pandaboard
acting as the server, so if you need anything testing I'm happy to give it a
go!

Will