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

[Heinrich Schuchardt <xypron.glpk@gmx.de>]

On 8/26/23 11:06, Sughosh Ganu 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.

We should have a test for the new functionality. E.g. add some
superfluous properties and nodes to arch/sandbox/dts/test.dts, delete
them via the DT_PURGE macro, and check that the device-tree passed to an
EFI binary does not contain these properties and nodes.

Best regards

Heinrich

>
> 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
>