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Message-ID: <2ed036b4-5a0a-f017-17e3-7922fcc2e8cc@pengutronix.de>
Date:   Tue, 8 Mar 2022 10:58:19 +0100
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Subject: Re: [Linux-stm32] [PATCH v2 12/13] ARM: dts: stm32: enable optee
 firmware and SCMI support on STM32MP13
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To:     Gabriel FERNANDEZ <gabriel.fernandez@foss.st.com>,
        Michael Turquette <mturquette@baylibre.com>,
        Stephen Boyd <sboyd@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        Alexandre Torgue <alexandre.torgue@foss.st.com>,
        Philipp Zabel <p.zabel@pengutronix.de>
Cc:     devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-stm32@st-md-mailman.stormreply.com,
        Pengutronix Kernel Team <kernel@pengutronix.de>,
        Etienne Carriere <etienne.carriere@linaro.org>
References: <20220225133137.813919-1-gabriel.fernandez@foss.st.com>
 <20220225133137.813919-13-gabriel.fernandez@foss.st.com>
 <1d90078d-e27f-539d-d010-78a3c4da565a@pengutronix.de>
 <65581f3a-3ae6-2dd3-7571-1e64982b5f50@foss.st.com>
From:   Ahmad Fatoum <a.fatoum@pengutronix.de>
In-Reply-To: <65581f3a-3ae6-2dd3-7571-1e64982b5f50@foss.st.com>
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Helo Gabriel,

On 03.03.22 14:09, Gabriel FERNANDEZ wrote:
> 
> On 2/25/22 16:13, Ahmad Fatoum wrote:
>> Hello Gabriel,
>>
>> On 25.02.22 14:31, gabriel.fernandez@foss.st.com wrote:
>>> From: Gabriel Fernandez <gabriel.fernandez@foss.st.com>
>>> +    firmware {
>>> +        optee {
>>> +            method = "smc";
>>> +            compatible = "linaro,optee-tz";
>>> +        };
>>> +
>>> +        scmi: scmi {
>>> +            compatible = "linaro,scmi-optee";
>> This compatible doesn't seem to be documented upstream. I am looking at v5.17-rc5.
>> Do you have a reference detailing the difference between this conduit and
>> plain arm,scmi-smc (as used with TF-A on the STM32MP151).
>>
>> Cheers,
>> Ahmad
> 
> Hi
> 
> Ahmad,
> 
> it's on going.
> 
> https://lore.kernel.org/linux-arm-kernel/20211029102118.GG6526@e120937-lin/T/#mf46c83f0aadce3061ee93fa22159405f38d881a0

I've found that thread in the meantime and got some clarification on why a new
transport for OP-TEE was added. One question I still have though is why make
this transport the default for STM32MP13x instead of using SCMI over SMC like
you do for STM32MP15x. OP-TEE could still be made to service SCMI over SMC
and it would allow people employing TF-A as SCMI provider an easier migration
to the newer SoC.

Cheers,
Ahmad

> 
>>
>>> +            #address-cells = <1>;
>>> +            #size-cells = <0>;
>>> +            linaro,optee-channel-id = <0>;
>>> +            shmem = <&scmi_shm>;
>>> +
>>> +            scmi_clk: protocol@14 {
>>> +                reg = <0x14>;
>>> +                #clock-cells = <1>;
>>> +            };
>>> +
>>> +            scmi_reset: protocol@16 {
>>> +                reg = <0x16>;
>>> +                #reset-cells = <1>;
>>> +            };
>>> +        };
>>> +    };
>>>       clocks {
>>>           clk_axi: clk-axi {
>>>               #clock-cells = <0>;
>>
> 


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