ARM: dts: meson8: add support for booting the secondary CPU cores

Booting the secondary CPU cores involves the following nodes/devices:
- SCU (Snoop-Control-Unit, for which we already have a DT node)
- a reset line for each CPU core, provided by the reset-controller
  which is built into the clock-controller
- the PMU (power management unit) which controls the power of the CPU
  cores
- a range in the SRAM specifically reserved for booting secondary CPU
  cores
- the "enable-method" which activates booting the secondary CPU cores

This adds all required nodes and properties to boot the secondary CPU
cores.
Suggested-by: Carlo Caione <carlo@caione.org>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>

arch/arm/boot/dts/meson8.dtsi

@@ -45,6 +45,7 @@
 
 #include <dt-bindings/clock/meson8b-clkc.h>
 #include <dt-bindings/gpio/meson8-gpio.h>
+#include <dt-bindings/reset/amlogic,meson8b-clkc-reset.h>
 #include "meson.dtsi"
 
 / {
@@ -60,6 +61,8 @@ cpu@200 {
 			compatible = "arm,cortex-a9";
 			next-level-cache = <&L2>;
 			reg = <0x200>;
+			enable-method = "amlogic,meson8-smp";
+			resets = <&clkc CLKC_RESET_CPU0_SOFT_RESET>;
 		};
 
 		cpu@201 {
@@ -67,6 +70,8 @@ cpu@201 {
 			compatible = "arm,cortex-a9";
 			next-level-cache = <&L2>;
 			reg = <0x201>;
+			enable-method = "amlogic,meson8-smp";
+			resets = <&clkc CLKC_RESET_CPU1_SOFT_RESET>;
 		};
 
 		cpu@202 {
@@ -74,6 +79,8 @@ cpu@202 {
 			compatible = "arm,cortex-a9";
 			next-level-cache = <&L2>;
 			reg = <0x202>;
+			enable-method = "amlogic,meson8-smp";
+			resets = <&clkc CLKC_RESET_CPU2_SOFT_RESET>;
 		};
 
 		cpu@203 {
@@ -81,6 +88,8 @@ cpu@203 {
 			compatible = "arm,cortex-a9";
 			next-level-cache = <&L2>;
 			reg = <0x203>;
+			enable-method = "amlogic,meson8-smp";
+			resets = <&clkc CLKC_RESET_CPU3_SOFT_RESET>;
 		};
 	};
 
@@ -118,6 +127,11 @@ scu@c4300000 {
 }; /* end of / */
 
 &aobus {
+	pmu: pmu@e0 {
+		compatible = "amlogic,meson8-pmu", "syscon";
+		reg = <0xe0 0x8>;
+	};
+
 	pinctrl_aobus: pinctrl@84 {
 		compatible = "amlogic,meson8-aobus-pinctrl";
 		reg = <0x84 0xc>;
@@ -254,6 +268,13 @@ mux {
 	};
 };
 
+&ahb_sram {
+	smp-sram@1ff80 {
+		compatible = "amlogic,meson8-smp-sram";
+		reg = <0x1ff80 0x8>;
+	};
+};
+
 &ethmac {
 	clocks = <&clkc CLKID_ETH>;
 	clock-names = "stmmaceth";