firmware: scmi: Add OP-TEE transport
This change implements an SCMI transport for agent interfacing the
OP-TEE SCMI service. OP-TEE provides an SCMI PTA (Pseudo-TA) for
non-secure world to send SCMI messages over an identified channel.
The driver implemented here uses a SMT shared memory for passing
messages between client and server.
The implementation opens and releases channel resources for each
passed SCMI message so that resources allocated (sessions) or
registered (shared memory areas) in OP-TEE firmware are released for
example before relocation as the driver will likely allocate/register
them back when probed after relocation.
The integration of the driver using dedicated config switch
CONFIG_SCMI_AGENT_OPTEE is designed on the model posted to the
U-Boot ML by Patrick Delaunay [1].
Link: [1] https://lore.kernel.org/all/20211028191222.v3.4.Ib2e58ee67f4d023823d8b5404332dc4d7e847277@changeid/
Cc: Patrick Delaunay <patrick.delaunay@foss.st.com>
Cc: Wolfgang Denk <wd@denx.de>
Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>
Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
diff --git a/drivers/firmware/scmi/Kconfig b/drivers/firmware/scmi/Kconfig
index c33de87..8cf85f0 100644
--- a/drivers/firmware/scmi/Kconfig
+++ b/drivers/firmware/scmi/Kconfig
@@ -2,7 +2,7 @@
bool "Enable SCMI support"
select FIRMWARE
select OF_TRANSLATE
- depends on SANDBOX || DM_MAILBOX || ARM_SMCCC
+ depends on SANDBOX || DM_MAILBOX || ARM_SMCCC || OPTEE
help
System Control and Management Interface (SCMI) is a communication
protocol that defines standard interfaces for power, performance
@@ -14,7 +14,7 @@
or a companion host in the CPU system.
Communications between agent (client) and the SCMI server are
- based on message exchange. Messages can be exchange over tranport
+ based on message exchange. Messages can be exchanged over transport
channels as a mailbox device or an Arm SMCCC service with some
piece of identified shared memory.
@@ -33,3 +33,11 @@
help
Enable the SCMI communication channel based on Arm SMCCC service for
compatible "arm,scmi-smc".
+
+config SCMI_AGENT_OPTEE
+ bool "Enable SCMI agent OP-TEE"
+ depends on SCMI_FIRMWARE && OPTEE
+ default y
+ help
+ Enable the SCMI communication channel based on OP-TEE transport
+ for compatible "linaro,scmi-optee".