MSCC: add board support for the Ocelots based evaluation boards

Adding the support for 2 boards sharing common code for Ocelot chip:
PCB120 and PCB123

Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
diff --git a/arch/mips/dts/mscc,ocelot.dtsi b/arch/mips/dts/mscc,ocelot.dtsi
new file mode 100644
index 0000000..87b4736
--- /dev/null
+++ b/arch/mips/dts/mscc,ocelot.dtsi
@@ -0,0 +1,152 @@
+// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+/*
+ * Copyright (c) 2018 Microsemi Corporation
+ */
+
+/ {
+	#address-cells = <1>;
+	#size-cells = <1>;
+	compatible = "mscc,ocelot";
+
+	cpus {
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		cpu@0 {
+			compatible = "mips,mips24KEc";
+			device_type = "cpu";
+			clocks = <&cpu_clk>;
+			reg = <0>;
+		};
+	};
+
+	aliases {
+		serial0 = &uart0;
+	};
+
+	cpuintc: interrupt-controller@0 {
+		#address-cells = <0>;
+		#interrupt-cells = <1>;
+		interrupt-controller;
+		compatible = "mti,cpu-interrupt-controller";
+	};
+
+	cpu_clk: cpu-clock {
+		compatible = "fixed-clock";
+		#clock-cells = <0>;
+		clock-frequency = <500000000>;
+	};
+
+	ahb_clk: ahb-clk {
+		compatible = "fixed-clock";
+		#clock-cells = <0>;
+		clock-frequency = <250000000>;
+	};
+
+	ahb {
+		compatible = "simple-bus";
+		#address-cells = <1>;
+		#size-cells = <1>;
+		ranges = <0 0x70000000 0x2000000>;
+
+		interrupt-parent = <&intc>;
+
+		cpu_ctrl: syscon@0 {
+			compatible = "mscc,ocelot-cpu-syscon", "syscon";
+			reg = <0x0 0x2c>;
+		};
+
+		intc: interrupt-controller@70 {
+			compatible = "mscc,ocelot-icpu-intr";
+			reg = <0x70 0x70>;
+			#interrupt-cells = <1>;
+			interrupt-controller;
+			interrupt-parent = <&cpuintc>;
+			interrupts = <2>;
+		};
+
+		uart0: serial@100000 {
+			pinctrl-0 = <&uart_pins>;
+			pinctrl-names = "default";
+			compatible = "ns16550a";
+			reg = <0x100000 0x20>;
+			interrupts = <6>;
+			clocks = <&ahb_clk>;
+			reg-io-width = <4>;
+			reg-shift = <2>;
+
+			status = "disabled";
+		};
+
+		uart2: serial@100800 {
+			pinctrl-0 = <&uart2_pins>;
+			pinctrl-names = "default";
+			compatible = "ns16550a";
+			reg = <0x100800 0x20>;
+			interrupts = <7>;
+			clocks = <&ahb_clk>;
+			reg-io-width = <4>;
+			reg-shift = <2>;
+
+			status = "disabled";
+		};
+
+		spi0: spi-master@101000 {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			compatible = "snps,dw-apb-ssi";
+			reg = <0x101000 0x40>;
+			num-chipselect = <4>;
+			bus-num = <0>;
+			reg-io-width = <4>;
+			reg-shift = <2>;
+			spi-max-frequency = <18000000>; /* input clock */
+			clocks = <&ahb_clk>;
+
+			status = "disabled";
+		};
+
+		reset@1070008 {
+			compatible = "mscc,ocelot-chip-reset";
+			reg = <0x1070008 0x4>;
+		};
+
+		gpio: pinctrl@1070034 {
+			compatible = "mscc,ocelot-pinctrl";
+			reg = <0x1070034 0x68>;
+			gpio-controller;
+			#gpio-cells = <2>;
+			gpio-ranges = <&gpio 0 0 22>;
+
+			uart_pins: uart-pins {
+				pins = "GPIO_6", "GPIO_7";
+				function = "uart";
+			};
+
+			uart2_pins: uart2-pins {
+				pins = "GPIO_12", "GPIO_13";
+				function = "uart2";
+			};
+
+			spi_cs1_pin: spi-cs1-pin {
+				pins = "GPIO_8";
+				function = "si";
+			};
+
+			spi_cs2_pin: spi-cs2-pin {
+				pins = "GPIO_9";
+				function = "si";
+			};
+
+			spi_cs3_pin: spi-cs3-pin {
+				pins = "GPIO_16";
+				function = "si";
+			};
+
+			spi_cs4_pin: spi-cs4-pin {
+				pins = "GPIO_17";
+				function = "si";
+			};
+		};
+	};
+};