incompatible device trees between u-boot and linux

[Vladimir Oltean]

On Wed, Aug 25, 2021 at 04:09:50PM -0400, Tom Rini wrote:
> I'm saying that because it's what's been said for what feels like 10+
> years.  I don't want to think how many countless hours have been spent
> on that point at conferences over the years.  It's not even a Linux
> thing.  I would swear you can (or could, unless it got broken) take the
> same DTB for some platforms and boot Linux or FreeBSD or some other BSD
> or maybe even VxWorks and it works.

So I absolutely do not oppose the greater goal, and if you say that
other silicon vendors do it, then shame on us really, NXP should step up
their game and be way stricter during internal review and such for things
that matter.

I'm afraid it's something that must trickle down from the management and
maintainership level before it could be effective.

In any case, it doesn't sound absurd at all, with a bit of passion it
could be done on all Layerscapes. I would be absolutely glad to help on
the Ethernet / DSA side of things (which I believe is the reason why
Michael summoned me into this thread), but I don't believe that's where
the problem is right now. When I added the DM_DSA uclass to U-Boot I did
my best to pick a reasonable subset of Linux DSA, and with compatible
device tree bindings. Also maintaining the Linux side of things, I did
provide feedback to Tim Harvey for the Microchip KSZ switches as to
what is the subset supported by U-Boot that would also be DT-compatible
with Linux. If it turns out that I failed at that, I am willing to
rework what we have.

I have been known on a few occasions to say "U-Boot does not parse this
part of the device tree, you can just strip it away", but I will keep my
mouth shut from now on.