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References: <20230130094157.1082712-1-etienne.carriere@linaro.org> <20230130094157.1082712-2-etienne.carriere@linaro.org>
In-Reply-To: <20230130094157.1082712-2-etienne.carriere@linaro.org>
From:   Sumit Garg <sumit.garg@linaro.org>
Date:   Tue, 7 Feb 2023 15:29:44 +0530
Message-ID: <CAFA6WYMDP88=3+NnrwTm_u99M-1BZe5ob-bo4mQDRA=QZ9xQXw@mail.gmail.com>
Subject: Re: [PATCH 2/2] firmware: arm_scmi: optee: use optee system invocation
To:     Etienne Carriere <etienne.carriere@linaro.org>
Cc:     linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        Jens Wiklander <jens.wiklander@linaro.org>,
        Sudeep Holla <sudeep.holla@arm.com>,
        Cristian Marussi <cristian.marussi@arm.com>
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On Mon, 30 Jan 2023 at 15:12, Etienne Carriere
<etienne.carriere@linaro.org> wrote:
>
> Changes SCMI optee transport to enable sys_service capability of
> its tee context to leverage provisioned system resources in OP-TEE
> preventing possible deadlock.
>
> Such deadlock could happen when many Linux clients invoke OP-TEE are
> are all suspended waiting for an OP-TEE RPC request access an SCMI
> resource through the SCMI OP-TEE PTA service.
>
> Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>
> ---
>  drivers/firmware/arm_scmi/optee.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/drivers/firmware/arm_scmi/optee.c b/drivers/firmware/arm_scmi/optee.c
> index 2a7aeab40e54..91840345e946 100644
> --- a/drivers/firmware/arm_scmi/optee.c
> +++ b/drivers/firmware/arm_scmi/optee.c
> @@ -559,6 +559,9 @@ static int scmi_optee_service_probe(struct device *dev)
>         if (IS_ERR(tee_ctx))
>                 return -ENODEV;
>
> +       /* SCMI agent can used TEE system service resources */
> +       tee_ctx->sys_service = true;
> +

As per the other thread for patch #1, this feature will only be
available with OP-TEE supporting TEE_GEN_CAP_REG_MEM. Can we add a
corresponding conditional check here?

-Sumit

>         agent = devm_kzalloc(dev, sizeof(*agent), GFP_KERNEL);
>         if (!agent) {
>                 ret = -ENOMEM;
> --
> 2.25.1
>