Changes SCMI optee transport to call tee_client_system_session()
to request optee driver to provision an entry context in OP-TEE
for processing OP-TEE messages. This prevents possible deadlock
in case OP-TEE threads are all consumed while these may be waiting
for a clock or regulator to be enable which SCMI OP-TEE service which
requires a free thread context to execute.

Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>
---
No change since v7

No change since v6

Changes since v5:
- Applied Sudeep's review tag

Changes since v4:
- Updated to new API function tee_client_system_session() introduced
  in patch v5 2/3.

No change since v3

Changes since v2:
- Fixed syntax issues (missing ';' chars), reported by kernel test robot.

Changes since v1:
- Updated to use new tee API functions tee_client_request_system_context()
  and tee_client_release_system_context().
---
 drivers/firmware/arm_scmi/optee.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/firmware/arm_scmi/optee.c b/drivers/firmware/arm_scmi/optee.c
index e123de6e8c67..25bfb465484d 100644
--- a/drivers/firmware/arm_scmi/optee.c
+++ b/drivers/firmware/arm_scmi/optee.c
@@ -440,6 +440,10 @@ static int scmi_optee_chan_setup(struct scmi_chan_info *cinfo, struct device *de
 	if (ret)
 		goto err_free_shm;
 
+	ret = tee_client_system_session(scmi_optee_private->tee_ctx, channel->tee_session);
+	if (ret)
+		dev_warn(dev, "Could not switch to system session, do best effort\n");
+
 	ret = get_channel(channel);
 	if (ret)
 		goto err_close_sess;
-- 
2.25.1

On Tue, 16 May 2023 at 18:24, Etienne Carriere
<etienne.carriere@linaro.org> wrote:
>
> Changes SCMI optee transport to call tee_client_system_session()
> to request optee driver to provision an entry context in OP-TEE
> for processing OP-TEE messages. This prevents possible deadlock
> in case OP-TEE threads are all consumed while these may be waiting
> for a clock or regulator to be enable which SCMI OP-TEE service which
> requires a free thread context to execute.
>
> Acked-by: Sudeep Holla <sudeep.holla@arm.com>
> Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>
> ---
> No change since v7
>

Reviewed-by: Sumit Garg <sumit.garg@linaro.org>

-Sumit

> No change since v6
>
> Changes since v5:
> - Applied Sudeep's review tag
>
> Changes since v4:
> - Updated to new API function tee_client_system_session() introduced
>   in patch v5 2/3.
>
> No change since v3
>
> Changes since v2:
> - Fixed syntax issues (missing ';' chars), reported by kernel test robot.
>
> Changes since v1:
> - Updated to use new tee API functions tee_client_request_system_context()
>   and tee_client_release_system_context().
> ---
>  drivers/firmware/arm_scmi/optee.c | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/drivers/firmware/arm_scmi/optee.c b/drivers/firmware/arm_scmi/optee.c
> index e123de6e8c67..25bfb465484d 100644
> --- a/drivers/firmware/arm_scmi/optee.c
> +++ b/drivers/firmware/arm_scmi/optee.c
> @@ -440,6 +440,10 @@ static int scmi_optee_chan_setup(struct scmi_chan_info *cinfo, struct device *de
>         if (ret)
>                 goto err_free_shm;
>
> +       ret = tee_client_system_session(scmi_optee_private->tee_ctx, channel->tee_session);
> +       if (ret)
> +               dev_warn(dev, "Could not switch to system session, do best effort\n");
> +
>         ret = get_channel(channel);
>         if (ret)
>                 goto err_close_sess;
> --
> 2.25.1
>