Re: [Qemu-devel] Setting up PPC440 Virtex Image for Qemu

[Edgar E. Iglesias]

On Thu, Jun 30, 2011 at 06:30:04PM +0530, Suzuki Poulose wrote:
> On 06/30/11 18:02, Edgar E. Iglesias wrote:
> > On Thu, Jun 30, 2011 at 05:45:23PM +0530, Suzuki Poulose wrote:
> >> Hi,
> >>
> >> I am working on enabling the KEXEC on PPC440 chipsets. To debug my patches,
> >> I would like to use the Qemu. The only available PPC440 support in Qemu is
> >> for the ppc-virtex. (Thanks for adding the support).
> >>
> >> I was trying to use the default image provided at
> >>
> >> http://wiki.qemu.org/download/ppc-virtexml507-linux-2_6_34.tgz
> >>
> >> However I cannot get the network up for the board to use the nfs root file
> >> system.
> >
> > Hi,
> >
> > The problem is that there is no model of the LL-TEMAC in qemu, the one in
> > the refdesign beeing emulated. An easy way out is probably to connect
> > a xilinx,ethlite instead. You'll need to modify both QEMU and the dtb.
> >
> > IIRC, the dtb published with the image has the lltemac removed.
> >
> > I've got a working LL-temac model here, will try to post it this weekend.
> > Or if you're interested in hacking on it, I could probably code dump it as
> > is.
> 
> Edgar,
> 
> Thanks a lot for the quick reply.
> >>
> >> Is there something I can do to get the networking up ? I think this may 
> >> need to
> >> be fixed in the dtb.
> >>
> >>    Or is there any other mechanism to use a different file system ?
> >> ( I have the tool chain to build the kernel etc)
> >
> >
> > Another way is to create ramdisks with all the stuff you need and just
> > not use networking. Thats how the image from the wiki does it.
> 
> I think I can try this option. By the way, could you pass on the steps to
> attach the ramdisks to the image ?

Hi,

If I dont remember wrong, the image on the wiki contains a kernelconfig file.
The config file sets the CONFIG_INITRAMFS_SOURCE option to "./romfs".
In my case I created a romfs subdir right in my linux-2.6 kernel tree,
e.g linux-2.6/romfs/.

You'll then have to populate the romfs directory with all the things
you need. romfs/dev/xxx, romfs/lib/xxx etc etc.

Then, once you build the kernel, an image of the romfs/ will be baked
into the kernel image. You then need to choose your init cmd by
passing an rdinit option in ther kernel cmd line.

With qemu:
-append "rdinit=/bin/sh"

The qemu-run.sh script from the wiki does that aswell.

There are probably other better ways to do it that I am not aware
of at the moment. But I hope it helps as example.

Cheers