arm64: dts: mediatek: cherry: Enable the System Companion Processor

MT8195 features a SCP like some other older SoCs, and Cherry uses it
for various tasks. Add the required pin configuration and DMA pool
and enable the node.
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20220902081156.38526-2-angelogioacchino.delregno@collabora.comSigned-off-by: Matthias Brugger <matthias.bgg@gmail.com>

arch/arm64/boot/dts/mediatek/mt8195-cherry.dtsi

@@ -104,6 +104,18 @@ usb_vbus: regulator-5v0-usb-vbus {
 		enable-active-high;
 		regulator-always-on;
 	};
+
+	reserved_memory: reserved-memory {
+		#address-cells = <2>;
+		#size-cells = <2>;
+		ranges;
+
+		scp_mem: memory@50000000 {
+			compatible = "shared-dma-pool";
+			reg = <0 0x50000000 0 0x2900000>;
+			no-map;
+		};
+	};
 };
 
 &i2c0 {
@@ -600,6 +612,14 @@ pins-low-power-pupd {
 		};
 	};
 
+	scp_pins: scp-default-pins {
+		pins-vreq {
+			pinmux = <PINMUX_GPIO76__FUNC_SCP_VREQ_VAO>;
+			bias-disable;
+			input-enable;
+		};
+	};
+
 	spi0_pins: spi0-default-pins {
 		pins-cs-mosi-clk {
 			pinmux = <PINMUX_GPIO132__FUNC_SPIM0_CSB>,
@@ -643,6 +663,15 @@ &pmic {
 	interrupts-extended = <&pio 222 IRQ_TYPE_LEVEL_HIGH>;
 };
 
+&scp {
+	status = "okay";
+
+	firmware-name = "mediatek/mt8195/scp.img";
+	memory-region = <&scp_mem>;
+	pinctrl-names = "default";
+	pinctrl-0 = <&scp_pins>;
+};
+
 &spi0 {
 	status = "okay";