ARM: dts: sun8i: R40: Add PMU node

The ARM Cortex-A7 cores used in the Allwinner R40 SoC have their usual
Performance Monitoring Unit (PMU), which allows perf to use hardware
events.
The SoC integrator just needs to connect each per-core interrupt line
to the GIC. The R40 manual does not really mention those IRQ lines, but
experimentation in U-Boot shows that interrupts 152-155 are connected to
the four cores (similar to the A20).

Tested on a Bananapi M2 Berry, with perf and taskset to confirm the
association between cores and interrupts.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>

arch/arm/boot/dts/sun8i-r40.dtsi

@@ -78,25 +78,25 @@ cpus {
 		#address-cells = <1>;
 		#size-cells = <0>;
 
-		cpu@0 {
+		cpu0: cpu@0 {
 			compatible = "arm,cortex-a7";
 			device_type = "cpu";
 			reg = <0>;
 		};
 
-		cpu@1 {
+		cpu1: cpu@1 {
 			compatible = "arm,cortex-a7";
 			device_type = "cpu";
 			reg = <1>;
 		};
 
-		cpu@2 {
+		cpu2: cpu@2 {
 			compatible = "arm,cortex-a7";
 			device_type = "cpu";
 			reg = <2>;
 		};
 
-		cpu@3 {
+		cpu3: cpu@3 {
 			compatible = "arm,cortex-a7";
 			device_type = "cpu";
 			reg = <3>;
@@ -884,6 +884,15 @@ hdmi_phy: hdmi-phy@1ef0000 {
 		};
 	};
 
+	pmu {
+		compatible = "arm,cortex-a7-pmu";
+		interrupts = <GIC_SPI 120 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 121 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 122 IRQ_TYPE_LEVEL_HIGH>,
+			     <GIC_SPI 123 IRQ_TYPE_LEVEL_HIGH>;
+		interrupt-affinity = <&cpu0>, <&cpu1>, <&cpu2>, <&cpu3>;
+	};
+
 	timer {
 		compatible = "arm,armv7-timer";
 		interrupts = <GIC_PPI 13 (GIC_CPU_MASK_SIMPLE(4) | IRQ_TYPE_LEVEL_LOW)>,