Documentation/devicetree/bindings/arm/cpus.txt - maze/linux - Git at Google

 =================
 ARM CPUs bindings
 =================

 The device tree allows to describe the layout of CPUs in a system through
 the "cpus" node, which in turn contains a number of subnodes (ie "cpu")
 defining properties for every cpu.

 Bindings for CPU nodes follow the ePAPR v1.1 standard, available from:

 https://www.power.org/documentation/epapr-version-1-1/

 with updates for 32-bit and 64-bit ARM systems provided in this document.

 ================================
 Convention used in this document
 ================================

 This document follows the conventions described in the ePAPR v1.1, with
 the addition:

 - square brackets define bitfields, eg reg[7:0] value of the bitfield in
   the reg property contained in bits 7 down to 0

 =====================================
 cpus and cpu node bindings definition
 =====================================

 The ARM architecture, in accordance with the ePAPR, requires the cpus and cpu
 nodes to be present and contain the properties described below.

 - cpus node

 	Description: Container of cpu nodes

 	The node name must be "cpus".

 	A cpus node must define the following properties:

 	- #address-cells
 		Usage: required
 		Value type: <u32>

 		Definition depends on ARM architecture version and
 		configuration:

 			# On uniprocessor ARM architectures previous to v7
 			  value must be 1, to enable a simple enumeration
 			  scheme for processors that do not have a HW CPU
 			  identification register.
 			# On 32-bit ARM 11 MPcore, ARM v7 or later systems
 			  value must be 1, that corresponds to CPUID/MPIDR
 			  registers sizes.
 			# On ARM v8 64-bit systems value should be set to 2,
 			  that corresponds to the MPIDR_EL1 register size.
 			  If MPIDR_EL1[63:32] value is equal to 0 on all CPUs
 			  in the system, #address-cells can be set to 1, since
 			  MPIDR_EL1[63:32] bits are not used for CPUs
 			  identification.
 	- #size-cells
 		Usage: required
 		Value type: <u32>
 		Definition: must be set to 0

 - cpu node

 	Description: Describes a CPU in an ARM based system

 	PROPERTIES

 	- device_type
 		Usage: required
 		Value type: <string>
 		Definition: must be "cpu"
 	- reg
 		Usage and definition depend on ARM architecture version and
 		configuration:

 			# On uniprocessor ARM architectures previous to v7
 			  this property is required and must be set to 0.

 			# On ARM 11 MPcore based systems this property is
 			  required and matches the CPUID[11:0] register bits.

 			  Bits [11:0] in the reg cell must be set to
 			  bits [11:0] in CPU ID register.

 			  All other bits in the reg cell must be set to 0.

 			# On 32-bit ARM v7 or later systems this property is
 			  required and matches the CPU MPIDR[23:0] register
 			  bits.

 			  Bits [23:0] in the reg cell must be set to
 			  bits [23:0] in MPIDR.

 			  All other bits in the reg cell must be set to 0.

 			# On ARM v8 64-bit systems this property is required
 			  and matches the MPIDR_EL1 register affinity bits.

 			  * If cpus node's #address-cells property is set to 2

 			    The first reg cell bits [7:0] must be set to
 			    bits [39:32] of MPIDR_EL1.

 			    The second reg cell bits [23:0] must be set to
 			    bits [23:0] of MPIDR_EL1.

 			  * If cpus node's #address-cells property is set to 1

 			    The reg cell bits [23:0] must be set to bits [23:0]
 			    of MPIDR_EL1.

 			  All other bits in the reg cells must be set to 0.

 	- compatible:
 		Usage: required
 		Value type: <string>
 		Definition: should be one of:
 			    "arm,arm710t"
 			    "arm,arm720t"
 			    "arm,arm740t"
 			    "arm,arm7ej-s"
 			    "arm,arm7tdmi"
 			    "arm,arm7tdmi-s"
 			    "arm,arm9es"
 			    "arm,arm9ej-s"
 			    "arm,arm920t"
 			    "arm,arm922t"
 			    "arm,arm925"
 			    "arm,arm926e-s"
 			    "arm,arm926ej-s"
 			    "arm,arm940t"
 			    "arm,arm946e-s"
 			    "arm,arm966e-s"
 			    "arm,arm968e-s"
 			    "arm,arm9tdmi"
 			    "arm,arm1020e"
 			    "arm,arm1020t"
 			    "arm,arm1022e"
 			    "arm,arm1026ej-s"
 			    "arm,arm1136j-s"
 			    "arm,arm1136jf-s"
 			    "arm,arm1156t2-s"
 			    "arm,arm1156t2f-s"
 			    "arm,arm1176jzf"
 			    "arm,arm1176jz-s"
 			    "arm,arm1176jzf-s"
 			    "arm,arm11mpcore"
 			    "arm,cortex-a5"
 			    "arm,cortex-a7"
 			    "arm,cortex-a8"
 			    "arm,cortex-a9"
 			    "arm,cortex-a15"
 			    "arm,cortex-a53"
 			    "arm,cortex-a57"
 			    "arm,cortex-m0"
 			    "arm,cortex-m0+"
 			    "arm,cortex-m1"
 			    "arm,cortex-m3"
 			    "arm,cortex-m4"
 			    "arm,cortex-r4"
 			    "arm,cortex-r5"
 			    "arm,cortex-r7"
 			    "faraday,fa526"
 			    "intel,sa110"
 			    "intel,sa1100"
 			    "marvell,feroceon"
 			    "marvell,mohawk"
 			    "marvell,pj4a"
 			    "marvell,pj4b"
 			    "marvell,sheeva-v5"
 			    "qcom,krait"
 			    "qcom,scorpion"
 	- enable-method
 		Value type: <stringlist>
 		Usage and definition depend on ARM architecture version.
 			# On ARM v8 64-bit this property is required and must
 			  be one of:
 			     "spin-table"
 			     "psci"
 			# On ARM 32-bit systems this property is optional and
 			  can be one of:
 			    "qcom,gcc-msm8660"
 			    "qcom,kpss-acc-v1"
 			    "qcom,kpss-acc-v2"

 	- cpu-release-addr
 		Usage: required for systems that have an "enable-method"
 		       property value of "spin-table".
 		Value type: <prop-encoded-array>
 		Definition:
 			# On ARM v8 64-bit systems must be a two cell
 			  property identifying a 64-bit zero-initialised
 			  memory location.

 	- qcom,saw
 		Usage: required for systems that have an "enable-method"
 		       property value of "qcom,kpss-acc-v1" or
 		       "qcom,kpss-acc-v2"
 		Value type: <phandle>
 		Definition: Specifies the SAW[1] node associated with this CPU.

 	- qcom,acc
 		Usage: required for systems that have an "enable-method"
 		       property value of "qcom,kpss-acc-v1" or
 		       "qcom,kpss-acc-v2"
 		Value type: <phandle>
 		Definition: Specifies the ACC[2] node associated with this CPU.


 Example 1 (dual-cluster big.LITTLE system 32-bit):

 	cpus {
 		#size-cells = <0>;
 		#address-cells = <1>;

 		cpu@0 {
 			device_type = "cpu";
 			compatible = "arm,cortex-a15";
 			reg = <0x0>;
 		};

 		cpu@1 {
 			device_type = "cpu";
 			compatible = "arm,cortex-a15";
 			reg = <0x1>;
 		};

 		cpu@100 {
 			device_type = "cpu";
 			compatible = "arm,cortex-a7";
 			reg = <0x100>;
 		};

 		cpu@101 {
 			device_type = "cpu";
 			compatible = "arm,cortex-a7";
 			reg = <0x101>;
 		};
 	};

 Example 2 (Cortex-A8 uniprocessor 32-bit system):

 	cpus {
 		#size-cells = <0>;
 		#address-cells = <1>;

 		cpu@0 {
 			device_type = "cpu";
 			compatible = "arm,cortex-a8";
 			reg = <0x0>;
 		};
 	};

 Example 3 (ARM 926EJ-S uniprocessor 32-bit system):

 	cpus {
 		#size-cells = <0>;
 		#address-cells = <1>;

 		cpu@0 {
 			device_type = "cpu";
 			compatible = "arm,arm926ej-s";
 			reg = <0x0>;
 		};
 	};

 Example 4 (ARM Cortex-A57 64-bit system):

 cpus {
 	#size-cells = <0>;
 	#address-cells = <2>;

 	cpu@0 {
 		device_type = "cpu";
 		compatible = "arm,cortex-a57";
 		reg = <0x0 0x0>;
 		enable-method = "spin-table";
 		cpu-release-addr = <0 0x20000000>;
 	};

 	cpu@1 {
 		device_type = "cpu";
 		compatible = "arm,cortex-a57";
 		reg = <0x0 0x1>;
 		enable-method = "spin-table";
 		cpu-release-addr = <0 0x20000000>;
 	};

 	cpu@100 {
 		device_type = "cpu";
 		compatible = "arm,cortex-a57";
 		reg = <0x0 0x100>;
 		enable-method = "spin-table";
 		cpu-release-addr = <0 0x20000000>;
 	};

 	cpu@101 {
 		device_type = "cpu";
 		compatible = "arm,cortex-a57";
 		reg = <0x0 0x101>;
 		enable-method = "spin-table";
 		cpu-release-addr = <0 0x20000000>;
 	};

 	cpu@10000 {
 		device_type = "cpu";
 		compatible = "arm,cortex-a57";
 		reg = <0x0 0x10000>;
 		enable-method = "spin-table";
 		cpu-release-addr = <0 0x20000000>;
 	};

 	cpu@10001 {
 		device_type = "cpu";
 		compatible = "arm,cortex-a57";
 		reg = <0x0 0x10001>;
 		enable-method = "spin-table";
 		cpu-release-addr = <0 0x20000000>;
 	};

 	cpu@10100 {
 		device_type = "cpu";
 		compatible = "arm,cortex-a57";
 		reg = <0x0 0x10100>;
 		enable-method = "spin-table";
 		cpu-release-addr = <0 0x20000000>;
 	};

 	cpu@10101 {
 		device_type = "cpu";
 		compatible = "arm,cortex-a57";
 		reg = <0x0 0x10101>;
 		enable-method = "spin-table";
 		cpu-release-addr = <0 0x20000000>;
 	};

 	cpu@100000000 {
 		device_type = "cpu";
 		compatible = "arm,cortex-a57";
 		reg = <0x1 0x0>;
 		enable-method = "spin-table";
 		cpu-release-addr = <0 0x20000000>;
 	};

 	cpu@100000001 {
 		device_type = "cpu";
 		compatible = "arm,cortex-a57";
 		reg = <0x1 0x1>;
 		enable-method = "spin-table";
 		cpu-release-addr = <0 0x20000000>;
 	};

 	cpu@100000100 {
 		device_type = "cpu";
 		compatible = "arm,cortex-a57";
 		reg = <0x1 0x100>;
 		enable-method = "spin-table";
 		cpu-release-addr = <0 0x20000000>;
 	};

 	cpu@100000101 {
 		device_type = "cpu";
 		compatible = "arm,cortex-a57";
 		reg = <0x1 0x101>;
 		enable-method = "spin-table";
 		cpu-release-addr = <0 0x20000000>;
 	};

 	cpu@100010000 {
 		device_type = "cpu";
 		compatible = "arm,cortex-a57";
 		reg = <0x1 0x10000>;
 		enable-method = "spin-table";
 		cpu-release-addr = <0 0x20000000>;
 	};

 	cpu@100010001 {
 		device_type = "cpu";
 		compatible = "arm,cortex-a57";
 		reg = <0x1 0x10001>;
 		enable-method = "spin-table";
 		cpu-release-addr = <0 0x20000000>;
 	};

 	cpu@100010100 {
 		device_type = "cpu";
 		compatible = "arm,cortex-a57";
 		reg = <0x1 0x10100>;
 		enable-method = "spin-table";
 		cpu-release-addr = <0 0x20000000>;
 	};

 	cpu@100010101 {
 		device_type = "cpu";
 		compatible = "arm,cortex-a57";
 		reg = <0x1 0x10101>;
 		enable-method = "spin-table";
 		cpu-release-addr = <0 0x20000000>;
 	};
 };

 --
 [1] arm/msm/qcom,saw2.txt
 [2] arm/msm/qcom,kpss-acc.txt
	=================
	ARM CPUs bindings
	=================

	The device tree allows to describe the layout of CPUs in a system through
	the "cpus" node, which in turn contains a number of subnodes (ie "cpu")
	defining properties for every cpu.

	Bindings for CPU nodes follow the ePAPR v1.1 standard, available from:

	https://www.power.org/documentation/epapr-version-1-1/

	with updates for 32-bit and 64-bit ARM systems provided in this document.

	================================
	Convention used in this document
	================================

	This document follows the conventions described in the ePAPR v1.1, with
	the addition:

	- square brackets define bitfields, eg reg[7:0] value of the bitfield in
	the reg property contained in bits 7 down to 0

	=====================================
	cpus and cpu node bindings definition
	=====================================

	The ARM architecture, in accordance with the ePAPR, requires the cpus and cpu
	nodes to be present and contain the properties described below.

	- cpus node

	Description: Container of cpu nodes

	The node name must be "cpus".

	A cpus node must define the following properties:

	- #address-cells
	Usage: required
	Value type: <u32>

	Definition depends on ARM architecture version and
	configuration:

	# On uniprocessor ARM architectures previous to v7
	value must be 1, to enable a simple enumeration
	scheme for processors that do not have a HW CPU
	identification register.
	# On 32-bit ARM 11 MPcore, ARM v7 or later systems
	value must be 1, that corresponds to CPUID/MPIDR
	registers sizes.
	# On ARM v8 64-bit systems value should be set to 2,
	that corresponds to the MPIDR_EL1 register size.
	If MPIDR_EL1[63:32] value is equal to 0 on all CPUs
	in the system, #address-cells can be set to 1, since
	MPIDR_EL1[63:32] bits are not used for CPUs
	identification.
	- #size-cells
	Usage: required
	Value type: <u32>
	Definition: must be set to 0

	- cpu node

	Description: Describes a CPU in an ARM based system

	PROPERTIES

	- device_type
	Usage: required
	Value type: <string>
	Definition: must be "cpu"
	- reg
	Usage and definition depend on ARM architecture version and
	configuration:

	# On uniprocessor ARM architectures previous to v7
	this property is required and must be set to 0.

	# On ARM 11 MPcore based systems this property is
	required and matches the CPUID[11:0] register bits.

	Bits [11:0] in the reg cell must be set to
	bits [11:0] in CPU ID register.

	All other bits in the reg cell must be set to 0.

	# On 32-bit ARM v7 or later systems this property is
	required and matches the CPU MPIDR[23:0] register
	bits.

	Bits [23:0] in the reg cell must be set to
	bits [23:0] in MPIDR.

	All other bits in the reg cell must be set to 0.

	# On ARM v8 64-bit systems this property is required
	and matches the MPIDR_EL1 register affinity bits.

	* If cpus node's #address-cells property is set to 2

	The first reg cell bits [7:0] must be set to
	bits [39:32] of MPIDR_EL1.

	The second reg cell bits [23:0] must be set to
	bits [23:0] of MPIDR_EL1.

	* If cpus node's #address-cells property is set to 1

	The reg cell bits [23:0] must be set to bits [23:0]
	of MPIDR_EL1.

	All other bits in the reg cells must be set to 0.

	- compatible:
	Usage: required
	Value type: <string>
	Definition: should be one of:
	"arm,arm710t"
	"arm,arm720t"
	"arm,arm740t"
	"arm,arm7ej-s"
	"arm,arm7tdmi"
	"arm,arm7tdmi-s"
	"arm,arm9es"
	"arm,arm9ej-s"
	"arm,arm920t"
	"arm,arm922t"
	"arm,arm925"
	"arm,arm926e-s"
	"arm,arm926ej-s"
	"arm,arm940t"
	"arm,arm946e-s"
	"arm,arm966e-s"
	"arm,arm968e-s"
	"arm,arm9tdmi"
	"arm,arm1020e"
	"arm,arm1020t"
	"arm,arm1022e"
	"arm,arm1026ej-s"
	"arm,arm1136j-s"
	"arm,arm1136jf-s"
	"arm,arm1156t2-s"
	"arm,arm1156t2f-s"
	"arm,arm1176jzf"
	"arm,arm1176jz-s"
	"arm,arm1176jzf-s"
	"arm,arm11mpcore"
	"arm,cortex-a5"
	"arm,cortex-a7"
	"arm,cortex-a8"
	"arm,cortex-a9"
	"arm,cortex-a15"
	"arm,cortex-a53"
	"arm,cortex-a57"
	"arm,cortex-m0"
	"arm,cortex-m0+"
	"arm,cortex-m1"
	"arm,cortex-m3"
	"arm,cortex-m4"
	"arm,cortex-r4"
	"arm,cortex-r5"
	"arm,cortex-r7"
	"faraday,fa526"
	"intel,sa110"
	"intel,sa1100"
	"marvell,feroceon"
	"marvell,mohawk"
	"marvell,pj4a"
	"marvell,pj4b"
	"marvell,sheeva-v5"
	"qcom,krait"
	"qcom,scorpion"
	- enable-method
	Value type: <stringlist>
	Usage and definition depend on ARM architecture version.
	# On ARM v8 64-bit this property is required and must
	be one of:
	"spin-table"
	"psci"
	# On ARM 32-bit systems this property is optional and
	can be one of:
	"qcom,gcc-msm8660"
	"qcom,kpss-acc-v1"
	"qcom,kpss-acc-v2"

	- cpu-release-addr
	Usage: required for systems that have an "enable-method"
	property value of "spin-table".
	Value type: <prop-encoded-array>
	Definition:
	# On ARM v8 64-bit systems must be a two cell
	property identifying a 64-bit zero-initialised
	memory location.

	- qcom,saw
	Usage: required for systems that have an "enable-method"
	property value of "qcom,kpss-acc-v1" or
	"qcom,kpss-acc-v2"
	Value type: <phandle>
	Definition: Specifies the SAW[1] node associated with this CPU.

	- qcom,acc
	Usage: required for systems that have an "enable-method"
	property value of "qcom,kpss-acc-v1" or
	"qcom,kpss-acc-v2"
	Value type: <phandle>
	Definition: Specifies the ACC[2] node associated with this CPU.


	Example 1 (dual-cluster big.LITTLE system 32-bit):

	cpus {
	#size-cells = <0>;
	#address-cells = <1>;

	cpu@0 {
	device_type = "cpu";
	compatible = "arm,cortex-a15";
	reg = <0x0>;
	};

	cpu@1 {
	device_type = "cpu";
	compatible = "arm,cortex-a15";
	reg = <0x1>;
	};

	cpu@100 {
	device_type = "cpu";
	compatible = "arm,cortex-a7";
	reg = <0x100>;
	};

	cpu@101 {
	device_type = "cpu";
	compatible = "arm,cortex-a7";
	reg = <0x101>;
	};
	};

	Example 2 (Cortex-A8 uniprocessor 32-bit system):

	cpus {
	#size-cells = <0>;
	#address-cells = <1>;

	cpu@0 {
	device_type = "cpu";
	compatible = "arm,cortex-a8";
	reg = <0x0>;
	};
	};

	Example 3 (ARM 926EJ-S uniprocessor 32-bit system):

	cpus {
	#size-cells = <0>;
	#address-cells = <1>;

	cpu@0 {
	device_type = "cpu";
	compatible = "arm,arm926ej-s";
	reg = <0x0>;
	};
	};

	Example 4 (ARM Cortex-A57 64-bit system):

	cpus {
	#size-cells = <0>;
	#address-cells = <2>;

	cpu@0 {
	device_type = "cpu";
	compatible = "arm,cortex-a57";
	reg = <0x0 0x0>;
	enable-method = "spin-table";
	cpu-release-addr = <0 0x20000000>;
	};

	cpu@1 {
	device_type = "cpu";
	compatible = "arm,cortex-a57";
	reg = <0x0 0x1>;
	enable-method = "spin-table";
	cpu-release-addr = <0 0x20000000>;
	};

	cpu@100 {
	device_type = "cpu";
	compatible = "arm,cortex-a57";
	reg = <0x0 0x100>;
	enable-method = "spin-table";
	cpu-release-addr = <0 0x20000000>;
	};

	cpu@101 {
	device_type = "cpu";
	compatible = "arm,cortex-a57";
	reg = <0x0 0x101>;
	enable-method = "spin-table";
	cpu-release-addr = <0 0x20000000>;
	};

	cpu@10000 {
	device_type = "cpu";
	compatible = "arm,cortex-a57";
	reg = <0x0 0x10000>;
	enable-method = "spin-table";
	cpu-release-addr = <0 0x20000000>;
	};

	cpu@10001 {
	device_type = "cpu";
	compatible = "arm,cortex-a57";
	reg = <0x0 0x10001>;
	enable-method = "spin-table";
	cpu-release-addr = <0 0x20000000>;
	};

	cpu@10100 {
	device_type = "cpu";
	compatible = "arm,cortex-a57";
	reg = <0x0 0x10100>;
	enable-method = "spin-table";
	cpu-release-addr = <0 0x20000000>;
	};

	cpu@10101 {
	device_type = "cpu";
	compatible = "arm,cortex-a57";
	reg = <0x0 0x10101>;
	enable-method = "spin-table";
	cpu-release-addr = <0 0x20000000>;
	};

	cpu@100000000 {
	device_type = "cpu";
	compatible = "arm,cortex-a57";
	reg = <0x1 0x0>;
	enable-method = "spin-table";
	cpu-release-addr = <0 0x20000000>;
	};

	cpu@100000001 {
	device_type = "cpu";
	compatible = "arm,cortex-a57";
	reg = <0x1 0x1>;
	enable-method = "spin-table";
	cpu-release-addr = <0 0x20000000>;
	};

	cpu@100000100 {
	device_type = "cpu";
	compatible = "arm,cortex-a57";
	reg = <0x1 0x100>;
	enable-method = "spin-table";
	cpu-release-addr = <0 0x20000000>;
	};

	cpu@100000101 {
	device_type = "cpu";
	compatible = "arm,cortex-a57";
	reg = <0x1 0x101>;
	enable-method = "spin-table";
	cpu-release-addr = <0 0x20000000>;
	};

	cpu@100010000 {
	device_type = "cpu";
	compatible = "arm,cortex-a57";
	reg = <0x1 0x10000>;
	enable-method = "spin-table";
	cpu-release-addr = <0 0x20000000>;
	};

	cpu@100010001 {
	device_type = "cpu";
	compatible = "arm,cortex-a57";
	reg = <0x1 0x10001>;
	enable-method = "spin-table";
	cpu-release-addr = <0 0x20000000>;
	};

	cpu@100010100 {
	device_type = "cpu";
	compatible = "arm,cortex-a57";
	reg = <0x1 0x10100>;
	enable-method = "spin-table";
	cpu-release-addr = <0 0x20000000>;
	};

	cpu@100010101 {
	device_type = "cpu";
	compatible = "arm,cortex-a57";
	reg = <0x1 0x10101>;
	enable-method = "spin-table";
	cpu-release-addr = <0 0x20000000>;
	};
	};

	--
	[1] arm/msm/qcom,saw2.txt
	[2] arm/msm/qcom,kpss-acc.txt