Re: [PATCH] hw/arm: add versioning to sbsa-ref machine DT

[Leif Lindholm]

On Fri, Apr 29, 2022 at 09:17:09 +0200, Cédric Le Goater wrote:
> > Signed-off-by: Leif Lindholm <quic_llindhol@quicinc.com>
> > Cc: Peter Maydell <peter.maydell@linaro.org>
> > Cc: Radoslaw Biernacki <rad@semihalf.com>
> > Cc: Cédric Le Goater <clg@kaod.org>
> > ---
> >   hw/arm/sbsa-ref.c | 3 +++
> >   1 file changed, 3 insertions(+)
> > 
> > diff --git a/hw/arm/sbsa-ref.c b/hw/arm/sbsa-ref.c
> > index 2387401963..e05f6056c7 100644
> > --- a/hw/arm/sbsa-ref.c
> > +++ b/hw/arm/sbsa-ref.c
> > @@ -190,6 +190,9 @@ static void create_fdt(SBSAMachineState *sms)
> >       qemu_fdt_setprop_cell(fdt, "/", "#address-cells", 0x2);
> >       qemu_fdt_setprop_cell(fdt, "/", "#size-cells", 0x2);
> > +    qemu_fdt_setprop_cell(fdt, "/", "machine-version-major", 0);
> > +    qemu_fdt_setprop_cell(fdt, "/", "machine-version-minor", 0);
> 
> 
> Thanks for your reply in the other email. From what I captured, the
> DT aspect is not that important, but still, we could may be use some
> specific 'sbsa' property names :
> 
>     qemu_fdt_setprop_cell(fdt, "/", "sbsa,version-major", 0);
>     qemu_fdt_setprop_cell(fdt, "/", "sbsa,version-minor", 0);

I'm not wedded to the names, but given that SBSA is the (now defunct)
name of a (very much not defunct) versioned specification, I think it
would add to rather than remove from the confusion if we changed to
this; it makes it look like it's declaring compliance with a version
of the spec.

Fundamentally, these properties have no meaning to anything other than
the piece of firmware that knows that it is executing on top of the
qemu sbsa-ref machine. On one level, making it look *less* like a
well-designed device tree-binding is beneficial.

Best Regards,

Leif