Re: [PATCH v2 21/33] emulation: fdt: Relax condition for OF_HAS_PRIOR_STAGE

[Tom Rini <trini@konsulko.com>]

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On Thu, Jan 09, 2025 at 08:01:22AM -0700, Simon Glass wrote:
> Hi Tom,
> 
> On Mon, 6 Jan 2025 at 14:40, Tom Rini <trini@konsulko.com> wrote:
> >
> > On Mon, Jan 06, 2025 at 07:32:17AM -0700, Simon Glass wrote:
> > > QEMU always gets its devicetree from the OF_BOARD mechanism so we should
> > > not depend on !BLOBLIST here.
> > >
> > > The logic of PRIOR_STAGE is quite a mess, unfortuantely. We should rely
> > > only standard passage to receive things from the prior stage. QEMU
> > > should implement standard passage to provide its devicetree to U-Boot
> > > However Linaro has blocked my patch to provide devicetree additions[1],
> > > so little breath should be held in respect of either change.
> > >
> > > [1] https://lore.kernel.org/qemu-devel/20210926183410.256484-1-sjg@chromium.org/
> > >
> > > Signed-off-by: Simon Glass <sjg@chromium.org>
> > > Fixes: 2b71470628c dts: OF_HAS_PRIOR_STAGE should depend on !BLOBLIST
> > > ---
> > >
> > > (no changes since v1)
> > >
> > >  dts/Kconfig | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/dts/Kconfig b/dts/Kconfig
> > > index 41a758e83a6..fc25a854708 100644
> > > --- a/dts/Kconfig
> > > +++ b/dts/Kconfig
> > > @@ -191,7 +191,7 @@ config OF_BOARD
> > >
> > >  config OF_HAS_PRIOR_STAGE
> > >       bool
> > > -     depends on !BLOBLIST
> > > +     depends on !BLOBLIST || ARCH_QEMU
> > >       help
> > >         Indicates that a prior stage of the firmware (before U-Boot proper)
> > >         makes use of device tree and this board normally boots with that prior
> >
> > Since OF_HAS_PRIOR_STAGE has no prompt, it shouldn't have a depends line
> > either really. I believe 2b71470628c is part of an attempt to say that
> > if you have bloblist enabled then that's how the previous loader needs
> > to pass the device tree. But indeed that's not quite how to enforce that
> > kind of demand, so we should just drop the restriction here (and some
> > other time fix the "imply OF_HAS_PRIOR_STAGE" to be "select
> > OF_HAS_PRIOR_STAGE" because it's not prompted, imply is the wrong
> > keyword.
> 
> So, just drop the 'depends' line?

Correct.

> I don't understand all this prior-stage stuff and I believe it is the
> Wrong Direction. We should just say where the DT comes from.

Yes, but we're all keen to not rehash years worth of discussion here
either.

-- 
Tom

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