firmware: arm_scmi: optee: use optee system invocation

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.

Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Cristian Marussi <cristian.marussi@arm.com>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Reviewed-by: Sumit Garg <sumit.garg@linaro.org>
Signed-off-by: Etienne Carriere <etienne.carriere@foss.st.com>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>

diff --git a/drivers/firmware/arm_scmi/optee.c b/drivers/firmware/arm_scmi/optee.c
index e123de6e8c67a9719542666bd93116fe9cc41347..25bfb465484d089479b4a48b4526a4473bac00f0 100644 (file)
--- 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;