[U-Boot] [PATCH v2 3/5] sunxi: DT: A64: update device tree file for Allwinner A64 SoC

[Vasily Khoruzhick]

On Wed, Oct 17, 2018 at 9:54 AM Andre Przywara <andre.przywara at arm.com> wrote:
>
> On Wed, 17 Oct 2018 17:29:58 +0200
> Maxime Ripard <maxime.ripard at bootlin.com> wrote:
>
> Hi,
>
> > On Wed, Oct 17, 2018 at 04:18:41PM +0100, Andre Przywara wrote:
> > > On Tue, 16 Oct 2018 22:09:30 -0700
> > > Vasily Khoruzhick <anarsoul at gmail.com> wrote:
> > >
> > > Hi,
> > >
> > > > Updates the device tree file from the the Linux tree as of
> > > > v4.19-rc4, exactly Linux commit:
> > >
> > > Does this work easily without syncing the .dts files as well?
> > >
> > > > commit 7876320f8880 (tag: v4.19-rc4)
> > > > Author: Linus Torvalds <torvalds at linux-foundation.org>
> > > > Date:   Sun Sep 16 11:52:37 2018 -0700
> > > >
> > > >     Linux 4.19-rc4
> > >
> > > So this sounds like the right thing to do, but in this particular
> > > case breaks Ethernet with UEFI booting in all distribution
> > > installers or kernels out there (except >= Linux 4.19-rc1).
> > > I consider this a major use case of U-Boot's DTB, so what do we do
> > > about this?
> > > The reason is that we dropped the "syscon" compatible string at the
> > > end of the system-controller node, which older kernels rely on to
> > > find the syscon node.
> > > I suggested to re-add this[1], but didn't have much success,
> > > unfortunately.
> > > The easiest would be to re-add (or not remove) "syscon" for U-Boot's
> > > copy, but this would mean a deviation from the Linux DT's. I am fine
> > > with this, but would like to hear more opinions.
> >
> > tl; dr: You want to build something robust on top of assumptions that
> > have never been guaranteed.
>
> I just find it sad that "we do not guarantee" translates into "we
> actually don't even try". My understanding of your concern is that you
> can't rule this breakage out forever, which I can understand.
> But if it is possible to avoid breaking compatibility, I believe we
> should try this, on a case-by-case base.
> We have been pretty good so far (leaving alone the MMC regulator
> breakage in v4.15, but A64 support was quite basic before that anyway).
>
> > I'm fine with having it as a U-Boot
> > addition, if it's what it takes.
>
> Sounds good to me! Thanks!
>
> I will check what's the easiest path to get the 4.20 DTs into U-Boot,
> considering a stopover at the Pinebook DTs, and send patches ASAP.

So do you want me to wait for you to submit a patch that syncs sun50i-a64.dtsi?

>
> Cheers,
> Andre.