ARM: dts: Alpine platform binding documentation

Annapurna Labs Alpine Platform Device Tree Bindings

---------------------------------------------------------------

Boards in the Alpine family shall have the following properties:

* Required root node properties:

compatible: must contain "al,alpine"

* Example:

/ {

	model = "Annapurna Labs Alpine Dev Board";

	compatible = "al,alpine";

	...

}

* CPU node:

The Alpine platform includes cortex-a15 cores.

enable-method: must be "al,alpine-smp" to allow smp  [1]

Example:

cpus {

	#address-cells = <1>;

	#size-cells = <0>;

	enable-method = "al,alpine-smp";

	cpu@0 {

		compatible = "arm,cortex-a15";

		device_type = "cpu";

		reg = <0>;

	};

	cpu@1 {

		compatible = "arm,cortex-a15";

		device_type = "cpu";

		reg = <1>;

	};

	cpu@2 {

		compatible = "arm,cortex-a15";

		device_type = "cpu";

		reg = <2>;

	};

	cpu@3 {

		compatible = "arm,cortex-a15";

		device_type = "cpu";

		reg = <3>;

	};

};

* Alpine CPU resume registers

The CPU resume register are used to define required resume address after

reset.

Properties:

- compatible : Should contain "al,alpine-cpu-resume".

- reg : Offset and length of the register set for the device

Example:

cpu_resume {

	compatible = "al,alpine-cpu-resume";

	reg = <0xfbff5ed0 0x30>;

};

* Alpine System-Fabric Service Registers

The System-Fabric Service Registers allow various operation on CPU and

system fabric, like powering CPUs off.

Properties:

- compatible : Should contain "al,alpine-sysfabric-service" and "syscon".

- reg : Offset and length of the register set for the device

Example:

nb_service {

        compatible = "al,alpine-sysfabric-service", "syscon";

        reg = <0xfb070000 0x10000>;

};

[1] arm/cpu-enable-method/al,alpine-smp

========================================================

Secondary CPU enable-method "al,alpine-smp" binding

========================================================

This document describes the "al,alpine-smp" method for

enabling secondary CPUs. To apply to all CPUs, a single

"al,alpine-smp" enable method should be defined in the

"cpus" node.

Enable method name:	"al,alpine-smp"

Compatible machines:	"al,alpine"

Compatible CPUs:	"arm,cortex-a15"

Related properties:	(none)

Note:

This enable method requires valid nodes compatible with

"al,alpine-cpu-resume" and "al,alpine-nb-service"[1].

Example:

cpus {

	#address-cells = <1>;

	#size-cells = <0>;

	enable-method = "al,alpine-smp";

	cpu@0 {

		compatible = "arm,cortex-a15";

		device_type = "cpu";

		reg = <0>;

	};

	cpu@1 {

		compatible = "arm,cortex-a15";

		device_type = "cpu";

		reg = <1>;

	};

	cpu@2 {

		compatible = "arm,cortex-a15";

		device_type = "cpu";

		reg = <2>;

	};

	cpu@3 {

		compatible = "arm,cortex-a15";

		device_type = "cpu";

		reg = <3>;

	};

};

--

[1] arm/al,alpine.txt

adh	AD Holdings Plc.

adi	Analog Devices, Inc.

aeroflexgaisler	Aeroflex Gaisler AB

al	Annapurna Labs

allwinner	Allwinner Technology Co., Ltd.

alphascale	AlphaScale Integrated Circuits Systems, Inc.

altr	Altera Corp.