dt-bindings, firmware: add Intel Stratix10 service layer binding

Add a device tree binding for the Intel Stratix10 service layer driver
Signed-off-by: Richard Gong <richard.gong@intel.com>
Signed-off-by: Alan Tull <atull@kernel.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Moritz Fischer <mdf@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/firmware/intel,stratix10-svc.txt

+Intel Service Layer Driver for Stratix10 SoC
+============================================
+Intel Stratix10 SoC is composed of a 64 bit quad-core ARM Cortex A53 hard
+processor system (HPS) and Secure Device Manager (SDM). When the FPGA is
+configured from HPS, there needs to be a way for HPS to notify SDM the
+location and size of the configuration data. Then SDM will get the
+configuration data from that location and perform the FPGA configuration.
+
+To meet the whole system security needs and support virtual machine requesting
+communication with SDM, only the secure world of software (EL3, Exception
+Layer 3) can interface with SDM. All software entities running on other
+exception layers must channel through the EL3 software whenever it needs
+service from SDM.
+
+Intel Stratix10 service layer driver, running at privileged exception level
+(EL1, Exception Layer 1), interfaces with the service providers and provides
+the services for FPGA configuration, QSPI, Crypto and warm reset. Service layer
+driver also manages secure monitor call (SMC) to communicate with secure monitor
+code running in EL3.
+
+Required properties:
+-------------------
+The svc node has the following mandatory properties, must be located under
+the firmware node.
+
+- compatible: "intel,stratix10-svc"
+- method: smc or hvc
+        smc - Secure Monitor Call
+        hvc - Hypervisor Call
+- memory-region:
+	phandle to the reserved memory node. See
+	Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
+	for details
+
+Example:
+-------
+
+	reserved-memory {
+                #address-cells = <2>;
+                #size-cells = <2>;
+                ranges;
+
+                service_reserved: svcbuffer@0 {
+                        compatible = "shared-dma-pool";
+                        reg = <0x0 0x0 0x0 0x1000000>;
+                        alignment = <0x1000>;
+                        no-map;
+                };
+        };
+
+	firmware {
+		svc {
+			compatible = "intel,stratix10-svc";
+			method = "smc";
+			memory-region = <&service_reserved>;
+		};
+	};