linux-kernel - Re: [PATCH v5 1/2] dt-bindings: arm: optee: add interrupt controller properties

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Message-ID: <4529262a-59c2-1610-2d7f-d2e3529bf867@linaro.org>
Date:   Tue, 16 May 2023 10:03:46 +0200
From:   Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To:     Etienne Carriere <etienne.carriere@...aro.org>,
        linux-kernel@...r.kernel.org, Rob Herring <robh+dt@...nel.org>
Cc:     devicetree@...r.kernel.org, op-tee@...ts.trustedfirmware.org,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Jonathan Cameron <Jonathan.Cameron@...wei.com>,
        Jens Wiklander <jens.wiklander@...aro.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Marc Zyngier <maz@...nel.org>,
        Sumit Garg <sumit.garg@...aro.org>,
        Pascal Paillet <p.paillet@...s.st.com>
Subject: Re: [PATCH v5 1/2] dt-bindings: arm: optee: add interrupt controller
 properties

On 16/05/2023 08:02, Etienne Carriere wrote:
> Dear all,
> 
> On Sat, 6 May 2023 at 09:33, Etienne Carriere
> <etienne.carriere@...aro.org> wrote:
>>
>> Adds an optional interrupt controller property to optee firmware node
>> in the DT bindings. Optee driver may embeds an irqchip exposing
>> OP-TEE interrupt events notified by the TEE world. Optee registers up
>> to 1 interrupt controller and identifies each line with a line
>> number from 0 to UINT16_MAX.
>>
>> The identifiers and meaning of the interrupt line number are specific
>> to the platform and shall be found in the OP-TEE platform documentation.
>>
>> In the example shown in optee DT binding documentation, the platform SCMI
>> device controlled by Linux scmi driver uses optee interrupt irq 5 as
>> signal to trigger processing of an asynchronous incoming SCMI message
>> in the scope of a CPU DVFS control. A platform can have several SCMI
>> channels driven this way. Optee irqs also permit small embedded devices
>> to share e.g. a gpio expander, a group of wakeup sources, etc... between
>> OP-TEE world (for sensitive services) and Linux world (for non-sensitive
>> services). The physical controller is driven from the TEE which exposes
>> some controls to Linux kernel.
>>
>> Cc: Jens Wiklander <jens.wiklander@...aro.org>
>> Cc: Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>
>> Cc: Marc Zyngier <maz@...nel.org>
>> Cc: Rob Herring <robh+dt@...nel.org>
>> Cc: Sumit Garg <sumit.garg@...aro.org>
>> Co-developed-by: Pascal Paillet <p.paillet@...s.st.com>
>> Signed-off-by: Pascal Paillet <p.paillet@...s.st.com>
>> Signed-off-by: Etienne Carriere <etienne.carriere@...aro.org>
>> ---
> 
> Any feedback on this change proposal?

Rob had here several comments, so I will defer it to him.

I don't get why this is not part of linaro,scmi-optee driver directly. I
think it's the only valid use case because the others like GPIO
expanders seem  a stretch.


Best regards,
Krzysztof