Romulus to use Virtual PNOR

[Andrew Jeffery]

On Thu, 7 Feb 2019, at 01:31, Alexander Amelkin wrote:
> 
> 06.02.2019 3:39, Stewart Smith wrote:
> > Alexander Amelkin <a.amelkin at yadro.com> writes:
> >> 25.01.2019 10:40, Lei YU wrote:
> >>> This email is to notify that Romulus is going to use VirtualPNOR feature, if
> >>> no objections are received.
> >>>
> >>> ...
> >>>
> >>> Any objections?
> >> Well, the main concern is how it will affect vesnin, which is P8-based (like palmetto).
> >>
> >> All this virtual PNOR functionality is based on mbox/hiomap, which is
> >> not supported for P8 in openpower firmware.
> > For various reasons, this is now changing, so you'll be able to do hiomap
> > on P8.
> 
> Could you please elaborate on this? Some GitHub issues or discussion 
> threads anywhere?
> 
> The problem as we see it is that P8 must be supported everywhere 
> throughout op-build components.
> Even if there was no support in hostboot for hiomap being added, we 
> could be able to add it ourselves. But that still wouldn't work with 
> SBE, as while the SBE sources for P8 are public, they nonetheless 
> require a proprietary toolchain to build that, I quote the README.md, 
> "cannot be open-sourced". The op-build framework takes pre-built SBE 
> binaries for P8.
> 
> Anyway, if hiomap support is indeed being added for P8, we'd love to 
> know more about it.

Hostboot support for hiomap on P8 has landed as of[1] (on the master-p8
branch). This should with the latest skiboot stable releases once I've fixed up
the P8 fallback support in skiboot master[2]. From there we need to get the
BMC-side fixed up (add the hiomap daemon) and we should be good to go.

[1] https://github.com/open-power/hostboot/commit/adb33e73b32c133dc9c6d23b695884d0d8c0ec9e
[2] https://github.com/open-power/skiboot/issues/217

> 
> >
> >> As a result, we suspect that palmetto and (what concerns us most)
> >> vesnin will lose firmware update support completely.
> > I think this is a valid concern, and I'd be concerned if there's tight
> > coupling between VPNOR and the firmware update APIs.
> 
> So far it looks to me like there is such tight coupling.

Yes, this is something I've been concerned about since its introduction.
The coupling is unfortunate and should be unravelled IMO, but that's
work that someone needs to take on.

Andrew