Documentation: driver-api: add stratix10 service layer

Add Intel Stratix10 service layer driver document

Signed-off-by: Richard Gong <richard.gong@intel.com>
Signed-off-by: Alan Tull <atull@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/driver-api/firmware/other_interfaces.rst

@@ -13,3 +13,33 @@ EDD Interfaces
 .. kernel-doc:: drivers/firmware/edd.c
    :internal:
 
+Intel Stratix10 SoC Service Layer
+---------------------------------
+Some features of the Intel Stratix10 SoC require a level of privilege
+higher than the kernel is granted. Such secure features include
+FPGA programming. In terms of the ARMv8 architecture, the kernel runs
+at Exception Level 1 (EL1), access to the features requires
+Exception Level 3 (EL3).
+
+The Intel Stratix10 SoC service layer provides an in kernel API for
+drivers to request access to the secure features. The requests are queued
+and processed one by one. ARM’s SMCCC is used to pass the execution
+of the requests on to a secure monitor (EL3).
+
+.. kernel-doc:: include/linux/firmware/intel/stratix10-svc-client.h
+   :functions: stratix10_svc_command_code
+
+.. kernel-doc:: include/linux/firmware/intel/stratix10-svc-client.h
+   :functions: stratix10_svc_client_msg
+
+.. kernel-doc:: include/linux/firmware/intel/stratix10-svc-client.h
+   :functions: stratix10_svc_command_reconfig_payload
+
+.. kernel-doc:: include/linux/firmware/intel/stratix10-svc-client.h
+   :functions: stratix10_svc_cb_data
+
+.. kernel-doc:: include/linux/firmware/intel/stratix10-svc-client.h
+   :functions: stratix10_svc_client
+
+.. kernel-doc:: drivers/firmware/stratix10-svc.c
+   :export: