Re: [PATCH v3 6/8] dm: treewide: Complete migration to new driver model schema

[Simon Glass <sjg@chromium.org>]

Hi Tom,

On Tue, 7 Feb 2023 at 14:06, Tom Rini <trini@konsulko.com> wrote:
>
> On Mon, Feb 06, 2023 at 10:12:27AM -0700, Simon Glass wrote:
> [snip]
> > On Mon, 6 Feb 2023 at 07:56, Michal Simek <michal.simek@amd.com> wrote:
> > >
> > >
> > >
> > > On 2/6/23 15:44, Tom Rini wrote:
> > > > On Mon, Feb 06, 2023 at 01:22:48PM +0100, Michal Simek wrote:
> > > >> Hi Simon,
> > > >>
> > > >> On 2/1/23 23:54, Simon Glass wrote:
> > > >>> Update various build and test components to use the new schema.
> > > >>>
> > > >>> Signed-off-by: Simon Glass <sjg@chromium.org>
> > > >>> ---
> > > >>>
> > > >>> (no changes since v1)
> > > >>>
> > > >>>    drivers/core/ofnode.c            | 10 +++++-----
> > > >>>    drivers/video/video-uclass.c     |  4 ++--
> > > >>>    dts/Kconfig                      |  2 +-
> > > >>>    include/dm/device.h              |  2 +-
> > > >>>    include/dm/ofnode.h              | 10 +++++-----
> > > >>>    scripts/Makefile.lib             | 12 ++++++------
> > > >>>    test/dm/test-fdt.c               |  2 +-
> > > >>>    test/py/tests/test_ofplatdata.py |  8 ++++----
> > > >>>    tools/binman/binman.rst          |  3 +--
> > > >>>    tools/dtoc/test_fdt.py           |  8 ++++----
> > > >>>    10 files changed, 30 insertions(+), 31 deletions(-)
> > > >>>
> > > >>> diff --git a/drivers/core/ofnode.c b/drivers/core/ofnode.c
> > > >>> index 4d56b1a7675..5249a60639b 100644
> > > >>> --- a/drivers/core/ofnode.c
> > > >>> +++ b/drivers/core/ofnode.c
> > > >>> @@ -1265,22 +1265,22 @@ bool ofnode_pre_reloc(ofnode node)
> > > >>>    {
> > > >>>    #if defined(CONFIG_SPL_BUILD) || defined(CONFIG_TPL_BUILD)
> > > >>>     /* for SPL and TPL the remaining nodes after the fdtgrep 1st pass
> > > >>> -    * had property dm-pre-reloc or u-boot,dm-spl/tpl.
> > > >>> +    * had property bootph-all or bootph-pre-sram/bootph-pre-ram.
> > > >>>      * They are removed in final dtb (fdtgrep 2nd pass)
> > > >>>      */
> > > >>>     return true;
> > > >>>    #else
> > > >>> -   if (ofnode_read_bool(node, "u-boot,dm-pre-reloc"))
> > > >>> +   if (ofnode_read_bool(node, "bootph-all"))
> > > >>>             return true;
> > > >>> -   if (ofnode_read_bool(node, "u-boot,dm-pre-proper"))
> > > >>> +   if (ofnode_read_bool(node, "bootph-some-ram"))
> > > >>>             return true;
> > > >>>     /*
> > > >>>      * In regular builds individual spl and tpl handling both
> > > >>>      * count as handled pre-relocation for later second init.
> > > >>>      */
> > > >>> -   if (ofnode_read_bool(node, "u-boot,dm-spl") ||
> > > >>> -       ofnode_read_bool(node, "u-boot,dm-tpl"))
> > > >>> +   if (ofnode_read_bool(node, "bootph-pre-ram") ||
> > > >>> +       ofnode_read_bool(node, "bootph-pre-sram"))
> > > >>>             return true;
> > > >>
> > > >> Please correct me if I am wrong but this change will likely break all boards
> > > >> which didn't migrate to this at this stage. And because targeting early
> > > >> stages people will be without console.
> > > >> I think we should have transition period for 1-2 releases to give people
> > > >> enough time to migrate. It means print big warning that they have to migrate
> > > >> their DTS.
> > > >
> > > > What's the migration case here we're missing? Is it platforms that
> > > > maintain a dts externally, via tooling / etc, that populate those nodes?
> > >
> > > Yes and I expect there will be a lot of DTs around with some changes for
> > > specific products.
> > >
> > > Also for example QEMU is also generating DT based on it's configuration and
> > > provide it to U-Boot.
> > > https://gitlab.com/qemu-project/qemu/-/blob/master/hw/arm/xlnx-versal-virt.c#L91
> > > When this patch is applied CI loop should fail for Versal.
> >
> > I am not sure how it helps us to drag this out. It is a breaking
> > change, but a drawn-out process is just going to create a lot of
> > confusion. People should be free to use the schema in Linux .dts files
> > from now on, but if it is not immediately supported in U-Boot then
> > they cannot. This is the most important point, after all.
>
> Now that we've had some of the external migration issues laid out, what
> would it look like to have some sort of backwards compatible hook here
> to fixup an older tree we've been passed?

We can't do it for SPL, since the processing happens at built time,
but for U-Boot proper we can do something like what Michal suggests,
although perhaps with a warning rather than an error. Likely the
warning would have to be displayed later (if/when U-Boot starts up)
since the console may be one of the problem nodes.

Regards,
Simon