Re: [Qemu-devel] [6064] Implement device tree support needed for Bamboo emulation

[Hollis Blanchard <hollisb@us.ibm.com>]

On Tue, 2008-12-16 at 12:30 +0000, Paul Brook wrote:
> > To implement the -kernel, -initrd, and -append options, 4xx board emulation
> > must load the guest kernel as if firmware had loaded it. Where u-boot would
> > be the firmware, we must load the flat device tree into memory and set key
> > fields such as /chosen/bootargs.
> 
> Then why is it optional?

As you mention below, libfdt isn't generally available yet, and since
it's possible to make a real firmware work in this environment (in which
case -kernel isn't needed), the code can still be useful.

If you'd prefer to make libfdt mandatory, I'm fine with that.

> > This patch introduces a dependency on libfdt for flat device tree support.
> 
> I don't like the way this is done.
> 
> AFAIK libfdt isn't present in any of the major distros. I thought the 
> conclusion was that we should import libfdt into qemu.

That was our conclusion, but Anthony never agreed.

FWIW, I have requested that Fedora and Debian package libfdt, and they
agreed in principle, but it's still missing in Fedora 10 for example.

Is the existence of distribution packages a requirement for use, or
should we say "install it by hand into /usr/local"? If it is a
requirement, which versions of which distributions?

> Certainly adding libfdt_env.h, which is never used, seems very wrong. I'm 
> pretty sure this won't build on win32 either.

Oops, that was a holdover from when we *were* importing libfdt source. I
can remove that, or if we want to import a copy of libfdt, I can leave
it.

I doubt anyone has tried to build libfdt on Windows...

-- 
Hollis Blanchard
IBM Linux Technology Center