[RFC PATCH 0/5] Allow for removal of DT nodes and properties

[Tom Rini]

On Mon, Aug 28, 2023 at 10:19:55AM -0600, Simon Glass wrote:
> Hi,
> 
> On Sat, 26 Aug 2023 at 03:07, Sughosh Ganu <sughosh.ganu at linaro.org> wrote:
> >
> >
> > Provide a way for removing certain devicetree nodes and/or properties
> > from the devicetree. This is needed to purge certain nodes and
> > properties which may be relevant only in U-Boot. Such nodes and
> > properties are then removed from the devicetree before it is passed to
> > the kernel. This ensures that the devicetree passed to the OS does not
> > contain any non-compliant nodes and properties.
> >
> > The removal of the nodes and properties is being done through an
> > EVT_FT_FIXUP handler. I am not sure if the removal code needs to be
> > behind any Kconfig symbol.
> >
> > I have only build tested this on sandbox, and tested on qemu arm64
> > virt platform. This being a RFC, I have not put this through a CI run.
> >
> > Sughosh Ganu (5):
> >   dt: Provide a way to remove non-compliant nodes and properties
> >   fwu: Add the fwu-mdata node for removal from devicetree
> >   capsule: Add the capsule-key property for removal from devicetree
> >   bootefi: Call the EVT_FT_FIXUP event handler
> >   doc: Add a document for non-compliant DT node/property removal
> >
> >  cmd/bootefi.c                                 | 18 +++++
> >  .../devicetree/dt_non_compliant_purge.rst     | 64 ++++++++++++++++
> >  drivers/fwu-mdata/fwu-mdata-uclass.c          |  5 ++
> >  include/dt-structs.h                          | 11 +++
> >  lib/Makefile                                  |  1 +
> >  lib/dt_purge.c                                | 73 +++++++++++++++++++
> >  lib/efi_loader/efi_capsule.c                  |  7 ++
> >  7 files changed, 179 insertions(+)
> >  create mode 100644 doc/develop/devicetree/dt_non_compliant_purge.rst
> >  create mode 100644 lib/dt_purge.c
> 
> What is the point of removing them? Instead, we should make sure that
> we upstream the bindings and encourage SoC vendors to sync them. If we
> remove them, no one will bother and U-Boot just becomes a dumping
> ground.

It's about having a defined process to remove them, rather than an
ad-hoc process like one can do today to remove them. And it's about
having control over the situation rather than dismissing it, as vendor
can already say they used $this version of the software for validation,
so patches-on-top aren't out of the question.

-- 
Tom
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