[PATCH] imx8m*_venice: move venice to OF_UPSTREAM

[Sumit Garg]

+ Tom

Hi Tim,

On Wed, 13 Mar 2024 at 22:01, Tim Harvey <tharvey at gateworks.com> wrote:
>
> On Wed, Mar 13, 2024 at 6:20 AM Sumit Garg <sumit.garg at linaro.org> wrote:
> >
> > On Wed, 13 Mar 2024 at 06:46, Fabio Estevam <festevam at gmail.com> wrote:
> > >
> > > Hi Tim,
> > >
> > > On Tue, Mar 12, 2024 at 4:05 PM Tim Harvey <tharvey at gateworks.com> wrote:
> > > >
> > > > Move to imx8m{m,n,p}-venice to OF_UPSTREAM:
> > > >  - replace the non-upstream generic imx8m{m,n,p}-venice dt with one of the
> > > >    dt's from the OF_LIST
> > > >  - handle the fact that dtbs now have a 'freescale/' prefix
> > > >  - imply OF_UPSTREAM
> > > >  - remove rudundant files from arch/arm/dts leaving only the
> > > >    *-u-boot.dtsi files
> > > >
> > > > Signed-off-by: Tim Harvey <tharvey at gateworks.com>
> > > ...
> > > >  33 files changed, 13 insertions(+), 10658 deletions(-)
> > >
> > > This diff looks great :-)
> >
> > +1
> >
> > Reviewed-by: Sumit Garg <sumit.garg at linaro.org>
> >
>
> Hi Sumit,
>
> Thanks for your work on this - I imagine over time this will
> de-duplicate a lot of work!
>
> I have a couple of questions about OF_UPSTREAM I haven't found the
> answer to yet:
> 1. how do you determine what the last sync point was in dts/upstream?
> (ie what kernel version is it currently sync'd with)

You can get that information from merge commits that happen over
dts/upstream sub-directory. It was somewhat raw information for the
first time we added dts/upstream as (commit aaba2d45dc2a pointing to
v6.7-dts [1]):

commit 53633a893a06bd5a0c807287d9cc29337806eaf7
Author: Tom Rini <trini at konsulko.com>
Date:   Thu Feb 29 12:33:36 2024 -0500

    Squashed 'dts/upstream/' content from commit aaba2d45dc2a

    git-subtree-dir: dts/upstream
    git-subtree-split: aaba2d45dc2a1b3bbb710f2a3808ee1c9f340abe

[1] https://git.kernel.org/pub/scm/linux/kernel/git/devicetree/devicetree-rebasing.git/tag/?h=v6.7-dts

However, further syncs would be more clear from merge commit
description, try following:

$ ./dts/update-dts-subtree.sh pull v6.8-dts

You will see merge commit saying:

commit 57508745cd2b07e55b5c414c6d646de4865418d2 (HEAD -> dt_uprev)
Merge: 3987e15e88a 14c9e8c0856
Author: Sumit Garg <sumit.garg at linaro.org>
Date:   Thu Mar 14 12:20:27 2024 +0530

    Subtree merge tag 'v6.8-dts' of devicetree-rebasing repo [1] into
dts/upstream

    [1] https://git.kernel.org/pub/scm/linux/kernel/git/devicetree/devicetree-rebasing.git/

> 2. how often will dts/upstream get re-synced (not the
> devicetree-rebasing.git but u-boot dts/upstream),

You can see the re-syncing details here (section: "Resyncing with
devicetree-rebasing",
https://source.denx.de/u-boot/u-boot/-/blob/next/doc/develop/devicetree/control.rst?ref_type=heads).

> who do you suspect
> will do be doing it?

Tom will be doing that. I suppose we are just in time for a resync
since the Linux kernel v6.8 was released.

Tom,

Do you think we can make v6.8-dts sync for the U-Boot next?

> 3. how would one go about adding a new feature via dt to uboot when
> the same feature has not yet landed in dts upstream? perhaps the
> answer is it must land upstream first or do you suspect it would be ok
> to put something in a u-boot.dtsi that can later get removed as
> redundant?

>From an upstream perspective, we should aim for minimal contents in
*-u-boot.dtsi, ideally it would be better to get rid of them. For eg.
all bootph_* properties should all be pushed upstream.

However, from the new features perspective we can consider using
*-u-boot.dtsi if the changes are minimal like enabling some DT nodes.
But if the changes are significant then that board can just opt out of
OF_USTREAM but still reusing all the DT includes. The reasoning behind
this is to minimize any chances of breakage if DT features in
*-u-boot.dtsi diverge from DT upstream.

> I ask mainly for being able to add things quickly to a
> downstream U-Boot repo that lags behind upstream U-Boot
>

Working downstream can always be fun, allowing additional options (can
be useful for advance testing too):

1. You can play around with $ ./dts/update-dts-subtree.sh pull <tag>
2. You can manually sync the vendor directories
(dts/upstream/src/<arch>/<vendor>/).
3. You can manually sync/update the individual DTS files too.

-Sumit

> Best Regards,
>
> Tim