Subject: Re: [0/16] Preliminary Ebony (440GP) support for arch/powerpc

From: David Gibson <[email-masked]>
Date: Fri, 16 Feb 2007 13:53:02 +1100

On Thu, Feb 15, 2007 at 08:19:56PM -0600, Josh Boyer wrote:
> On Thu, Feb 15, 2007 at 10:12:04AM +1100, David Gibson wrote:
> > > I still have this issue, just haven't had a chance to figure out why
> > > yet.  Likely because the openbios code is leaving garbage somewhere.
> > 
> > More likely simply because openbios just puts different things in the
> > registers on entry, and we're assuming it uses the same method OF
> > does.  Need to fix the entry path, and get rid of the hardcoded a1 and
> > a2 junk.
> 
> I looked a the openbios code this morning.  For all intents and purposes
> the values it pases in r3 and r4 to the zImage wrapper really are
> garbage.  However, you're right in that we need to fix the boot wrapper
> to not assume all firmwares will follow similar conventions for the entry
> path.

Yes.

> Is there a compat property or something similar that could be defined in
> the DTS that the wrapper could look at to determine what to expect?

I think that's getting way too keen on generality.  I'm almost ready
to send out a patch which alters the entry path to the zImage code to
let the platform code handle the entry parameters.  Then we can just
make the Ebony platform_init() ignore the r3 and r4 values.

Err... except, are they really both junk?  I thought at least one gave
an address for the openbios callback to grab the board info structure.

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson