Re: qemu/powernv: coreboot support?

[David Gibson <david@gibson.dropbear.id.au>]

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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.

Ah!  Now I understand.  I hadn't looked at that branch, so I had no
idea what all this pnor stuff was about.  In mainline we just load
skiboot as a normal firmware file and jump into it.

> However, you can bypass all this internal boot process by simply passing
> a -bios option and not passing a MTD device.

Right.

> 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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