[PATCH 1/6] dt-bindings: firmware: Add arm,errata-management

[Rob Herring]

On Thu, 30 Mar 2023 17:51:23 +0100, James Morse wrote:
> The Errata Management SMCCC interface allows firmware to advertise whether
> the OS is affected by an erratum, or if a higher exception level has
> mitigated the issue. This allows properties of the device that are not
> discoverable by the OS to be described. e.g. some errata depend on the
> behaviour of the interconnect, which is not visible to the OS.
> 
> Deployed devices may find it significantly harder to update EL3
> firmware than the device tree. Erratum workarounds typically have to
> fail safe, and assume the platform is affected putting correctness
> above performance.
> 
> Instead of adding a device-tree entry for any CPU errata that is
> relevant (or not) to the platform, allow the device-tree to describe
> firmware's responses for the SMCCC interface. This could be used as
> the data source for the firmware interface, or be parsed by the OS if
> the firmware interface is missing.
> 
> Most errata can be detected from CPU id registers. These mechanisms
> are only needed for the rare cases that external knowledge is needed.
> 
> Suggested-by: Andre Przywara <andre.przywara at arm.com>
> Signed-off-by: James Morse <james.morse at arm.com>
> ---
>  .../devicetree/bindings/arm/cpus.yaml         |  5 ++
>  .../firmware/arm,errata-management.yaml       | 77 +++++++++++++++++++
>  2 files changed, 82 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/firmware/arm,errata-management.yaml
> 

My bot found errors running 'make DT_CHECKER_FLAGS=-m dt_binding_check'
on your patch (DT_CHECKER_FLAGS is new in v5.13):

yamllint warnings/errors:
./Documentation/devicetree/bindings/firmware/arm,errata-management.yaml:48:5: [warning] wrong indentation: expected 6 but found 4 (indentation)
./Documentation/devicetree/bindings/firmware/arm,errata-management.yaml:50:5: [warning] wrong indentation: expected 6 but found 4 (indentation)
./Documentation/devicetree/bindings/firmware/arm,errata-management.yaml:52:5: [warning] wrong indentation: expected 6 but found 4 (indentation)

dtschema/dtc warnings/errors:

doc reference errors (make refcheckdocs):

See https://patchwork.ozlabs.org/project/devicetree-bindings/patch/20230330165128.3237939-2-james.morse@arm.com

The base for the series is generally the latest rc1. A different dependency
should be noted in *this* patch.

If you already ran 'make dt_binding_check' and didn't see the above
error(s), then make sure 'yamllint' is installed and dt-schema is up to
date:

pip3 install dtschema --upgrade

Please check and re-submit after running the above command yourself. Note
that DT_SCHEMA_FILES can be set to your schema file to speed up checking
your schema. However, it must be unset to test all examples with your schema.