Messages in this thread | | | Date | Tue, 26 Jul 2022 13:15:25 +0200 | Subject | Re: [PATCH 4/4] dt-bindings: firmware: Add Qualcomm UEFI Secure Application client | From | Maximilian Luz <> |
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Hi,
On 7/26/22 12:17, Krzysztof Kozlowski wrote: > On 24/07/2022 00:49, Maximilian Luz wrote: >> Add bindings for the Qualcomm Trusted Execution Environment (TrEE) UEFI >> Secure application (uefisecapp) client. >> >> Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com> >> --- >> .../firmware/qcom,tee-uefisecapp.yaml | 38 +++++++++++++++++++ >> MAINTAINERS | 1 + >> 2 files changed, 39 insertions(+) >> create mode 100644 Documentation/devicetree/bindings/firmware/qcom,tee-uefisecapp.yaml >> >> diff --git a/Documentation/devicetree/bindings/firmware/qcom,tee-uefisecapp.yaml b/Documentation/devicetree/bindings/firmware/qcom,tee-uefisecapp.yaml >> new file mode 100644 >> index 000000000000..9e5de1005d5c >> --- /dev/null >> +++ b/Documentation/devicetree/bindings/firmware/qcom,tee-uefisecapp.yaml >> @@ -0,0 +1,38 @@ >> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) >> +%YAML 1.2 >> +--- >> +$id: http://devicetree.org/schemas/soc/qcom/qcom,rpmh-rsc.yaml# > > Does not look like you tested the bindings. Please run `make > dt_binding_check` (see > Documentation/devicetree/bindings/writing-schema.rst for instructions).
Sorry, first time submitting a schema. Already saw the warning of Rob's bot and Will fix this in v2.
>> +$schema: http://devicetree.org/meta-schemas/core.yaml# >> + >> +title: Qualcomm Trusted Execution Environment UEFI Secure Application >> + >> +maintainers: >> + - Maximilian Luz <luzmaximilian@gmail.com> >> + >> +description: | >> + Various Qualcomm SoCs do not allow direct access to UEFI variables. Instead, >> + these need to be accessed via the UEFI Secure Application (uefisecapp), >> + residing in the Trusted Execution Environment (TrEE). These bindings mark the >> + presence of uefisecapp and allow the respective client driver to load and >> + install efivar operations, providing the kernel with access to UEFI >> + variables. >> + >> +properties: >> + compatible: >> + const: qcom,tee-uefisecapp > > Isn't this SoC-specific device? Generic compatibles are usually not > expected.
This is essentially software (kernel driver) talking to software (in the TrustZone), so I don't expect there to be anything SoC specific about it.
>> + >> +required: >> + - compatible >> + >> +additionalProperties: false >> + >> +examples: >> + - | >> + firmware { >> + scm { >> + compatible = "qcom,scm-sc8180x", "qcom,scm"; >> + }; >> + tee-uefisecapp { >> + compatible = "qcom,tee-uefisecapp"; > > You did not model here any dependency on SCM. This is not full > description of the firmware/hardware
How would I do that? A lot of other stuff also depends on SCM being present (e.g. qcom_q6v5_pas for loading mdt files) and I don't see them declare this in the device tree. As far as I can tell, SCM is pretty much expected to be there at all times (i.e. can't be unloaded) and drivers check for it when probing via qcom_scm_is_available(), deferring probe if not.
Don't take this as an excuse as in "I want to leave that out", it's just that I don't know how one would declare such a dependency explicitly. If you can tell me how to fix it, I'll include that for v2.
Regards, Max
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