Re: qemu/powernv: coreboot support?

[David Gibson]

On Sat, Oct 19, 2019 at 10:31:09AM -0500, Marty E. Plummer wrote:
> On Sat, Oct 19, 2019 at 03:46:59PM +0200, Cédric Le Goater wrote:
> > On 18/10/2019 19:28, Marty E. Plummer wrote:
> > > Hello,
> > > 
> > > First off, thank you for the work you've done on the ppc64 support, it
> > > has been very useful. I'm currently working on a coreboot port for the
> > > talos ii line of systems (which means more ppc64 support, support
> > > specifically for the power9 sforza chip, and specific mainboard support.
> > > My plate is very full lol) and have been using qemu to debug the
> > > bootblock.
> > > 
> > > It has been very useful for that, but I'm now at the point where I need
> > > to jump to romstage, and that's where it gets tricky. qemu parses the rom
> > > image and looks for a ffs header, locates skiboot on it, and jumps 
> > > straight
> > > to that. Not exactly ideal for debugging something not produced from 
> > > op-build.
> > 
> > yes. I suppose you are using my branch powernv-4.2 which adds PNOR support
> > and a way to boot directly from PNOR. In that case, QEMU parses the PNOR
> > file to extract the PAYLOAD partition (skiboot). skiboot also detects the
> > flash and extract the kernel and initramfs from the PNOR.
> > 
> > However, you can bypass all this internal boot process by simply passing
> > a -bios option and not passing a MTD device.
> > 
> Doing so gives me the following error:
> qemu-system-ppc64: Could not load OPAL firmware 'build/coreboot.rom'
> (this is after I patched the 4mb size limit up)

Hm curious.  We'd have to delve into load_image_targphys() and see why
it's failing.  Have you checked for simple causes: incorrect path, or
bad permissions to your coreboot image.

> > I haven't published the PNOR support and the boot from PNOR yet. Lack
> > of time and because sPAPR is the priority.
> > 
> > > Do you think it would be within your wheelhouse to provide a generic, 
> > > non-ffs
> > > pnor interface for loading arbitary rom images? 
> > 
> > I should probably send the PNOR patchset now so that we can discuss on 
> > a better way to satisfy all needs.  
> > 
> > > It would be of great help if
> > > you could. (This would still hopefully have the bmc support code as
> > > well, as I'm still needing to support a system using one).
> > 
> > We have support for Aspeed machines AST2400, AST2500 and AST2600. It 
> > is possible to interconnect them through the BT device. Or you can use
> > the IPMI BT simulator of QEMU on the PowerNV machine
> > 
> > Thanks,
> > 
> > C. 
> > 
> 

-- 
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

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