Re: [PATCH 05/16] arm: qemu: Add a devicetree file for qemu_arm64

[Simon Glass]

Hi all,

On Wed, 27 Oct 2021 at 08:56, Tom Rini <trini@konsulko.com> wrote:
>
> On Wed, Oct 27, 2021 at 03:44:08PM +0100, Alex Bennée wrote:
> >
> > François Ozog <francois.ozog@linaro.org> writes:
> >
> > > Hi Simon
> > >
> > > The only place I could agree with this file presence is in the 
> > > documentation directory, not in dts. It creates a mental picture  for the 
> > > reader
> > > an entirely bad mind scheme around Qemu and DT.
> > >
> > > And even in a documentation directory I would place a bug warning: don’t 
> > > use this with any kernel , Qemu generates a DT dynamically
> > > based on cpu, memory and devices specified at the command line.
> >
> > Certainly for the arm, aarch64 and riscv "virt" machines you should
> > always use the QEMU generated DTB. I'm not entirely clear what a
> > qemu_arm and qemu_arm64 def targets are meant to be in this context.
>
> Agreed.  We cannot include random device trees in U-Boot for devices
> that generate their own at run time or otherwise have the source of
> truth elsewhere.

Until we have a way of bringing in the u-boot.dtsi that people in QEMU
can agree on, I don't see an alternative. I will send a series for the
bloblist handoff next week and I think you will all see what I mean.

Perhaps all this will be easier a year or so, if we continue to make
progress on the devicetree validation/sharing stuff, but for now, this
seems like the only viable approach to me.

Regards,
Simon