* ARM Generic Interrupt Controller, version 3

AArch64 SMP cores are often associated with a GICv3, providing Private
Peripheral Interrupts (PPI), Shared Peripheral Interrupts (SPI),
Software Generated Interrupts (SGI), and Locality-specific Peripheral
Interrupts (LPI).

Main node required properties:

- compatible : should at least contain  "arm,gic-v3".
- interrupt-controller : Identifies the node as an interrupt controller
- #interrupt-cells : Specifies the number of cells needed to encode an
  interrupt source. Must be a single cell with a value of at least 3.

  The 1st cell is the interrupt type; 0 for SPI interrupts, 1 for PPI
  interrupts. Other values are reserved for future use.

  The 2nd cell contains the interrupt number for the interrupt type.
  SPI interrupts are in the range [0-987]. PPI interrupts are in the
  range [0-15].

  The 3rd cell is the flags, encoded as follows:
	bits[3:0] trigger type and level flags.
		1 = edge triggered
		4 = level triggered

  Cells 4 and beyond are reserved for future use. When the 1st cell
  has a value of 0 or 1, cells 4 and beyond act as padding, and may be
  ignored. It is recommended that padding cells have a value of 0.

- reg : Specifies base physical address(s) and size of the GIC
  registers, in the following order:
  - GIC Distributor interface (GICD)
  - GIC Redistributors (GICR), one range per redistributor region
  - GIC CPU interface (GICC)
  - GIC Hypervisor interface (GICH)
  - GIC Virtual CPU interface (GICV)

  GICC, GICH and GICV are optional.

- interrupts : Interrupt source of the VGIC maintenance interrupt.

Optional

- redistributor-stride : If using padding pages, specifies the stride
  of consecutive redistributors. Must be a multiple of 64kB.

- #redistributor-regions: The number of independent contiguous regions
  occupied by the redistributors. Required if more than one such
  region is present.

Sub-nodes:

GICv3 has one or more Interrupt Translation Services (ITS) that are
used to route Message Signalled Interrupts (MSI) to the CPUs.

These nodes must have the following properties:
- compatible : Should at least contain  "arm,gic-v3-its".
- msi-controller : Boolean property. Identifies the node as an MSI controller
- #msi-cells: Must be <1>. The single msi-cell is the DeviceID of the device
  which will generate the MSI.
- reg: Specifies the base physical address and size of the ITS
  registers.

The main GIC node must contain the appropriate #address-cells,
#size-cells and ranges properties for the reg property of all ITS
nodes.

Examples:

	gic: interrupt-controller@2cf00000 {
		compatible = "arm,gic-v3";
		#interrupt-cells = <3>;
		#address-cells = <2>;
		#size-cells = <2>;
		ranges;
		interrupt-controller;
		reg = <0x0 0x2f000000 0 0x10000>,	// GICD
		      <0x0 0x2f100000 0 0x200000>,	// GICR
		      <0x0 0x2c000000 0 0x2000>,	// GICC
		      <0x0 0x2c010000 0 0x2000>,	// GICH
		      <0x0 0x2c020000 0 0x2000>;	// GICV
		interrupts = <1 9 4>;

		gic-its@2c200000 {
			compatible = "arm,gic-v3-its";
			msi-controller;
			#msi-cells = <1>;
			reg = <0x0 0x2c200000 0 0x200000>;
		};
	};

	gic: interrupt-controller@2c010000 {
		compatible = "arm,gic-v3";
		#interrupt-cells = <3>;
		#address-cells = <2>;
		#size-cells = <2>;
		ranges;
		interrupt-controller;
		redistributor-stride = <0x0 0x40000>;	// 256kB stride
		#redistributor-regions = <2>;
		reg = <0x0 0x2c010000 0 0x10000>,	// GICD
		      <0x0 0x2d000000 0 0x800000>,	// GICR 1: CPUs 0-31
		      <0x0 0x2e000000 0 0x800000>;	// GICR 2: CPUs 32-63
		      <0x0 0x2c040000 0 0x2000>,	// GICC
		      <0x0 0x2c060000 0 0x2000>,	// GICH
		      <0x0 0x2c080000 0 0x2000>;	// GICV
		interrupts = <1 9 4>;

		gic-its@2c200000 {
			compatible = "arm,gic-v3-its";
			msi-controller;
			#msi-cells = <1>;
			reg = <0x0 0x2c200000 0 0x200000>;
		};

		gic-its@2c400000 {
			compatible = "arm,gic-v3-its";
			msi-controller;
			#msi-cells = <1>;
			reg = <0x0 0x2c400000 0 0x200000>;
		};
	};
