linux/Documentation/devicetree/bindings/arm/cpus.yaml

# SPDX-License-Identifier: GPL-2.0
%YAML 1.2
---
$id: http://devicetree.org/schemas/arm/cpus.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#

title: ARM CPUs bindings

maintainers:
  - Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

description: |+
  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 Devicetree Specification, available from:

  https://www.devicetree.org/specifications/

  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 Devicetree
  Specification, 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 Devicetree Specification,
  requires the cpus and cpu nodes to be present and contain the properties
  described below.  

properties:
  reg:
    maxItems: 1
    description: |
      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:
    enum:
      - 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,armv8 # Only for s/w models
      - arm,cortex-a5
      - arm,cortex-a7
      - arm,cortex-a8
      - arm,cortex-a9
      - arm,cortex-a12
      - arm,cortex-a15
      - arm,cortex-a17
      - arm,cortex-a32
      - arm,cortex-a34
      - arm,cortex-a35
      - arm,cortex-a53
      - arm,cortex-a55
      - arm,cortex-a57
      - arm,cortex-a65
      - arm,cortex-a72
      - arm,cortex-a73
      - arm,cortex-a75
      - arm,cortex-a76
      - arm,cortex-a77
      - arm,cortex-m0
      - arm,cortex-m0+
      - arm,cortex-m1
      - arm,cortex-m3
      - arm,cortex-m4
      - arm,cortex-r4
      - arm,cortex-r5
      - arm,cortex-r7
      - arm,neoverse-e1
      - arm,neoverse-n1
      - brcm,brahma-b15
      - brcm,brahma-b53
      - brcm,vulcan
      - cavium,thunder
      - cavium,thunder2
      - faraday,fa526
      - intel,sa110
      - intel,sa1100
      - marvell,feroceon
      - marvell,mohawk
      - marvell,pj4a
      - marvell,pj4b
      - marvell,sheeva-v5
      - marvell,sheeva-v7
      - nvidia,tegra132-denver
      - nvidia,tegra186-denver
      - nvidia,tegra194-carmel
      - qcom,krait
      - qcom,kryo
      - qcom,kryo260
      - qcom,kryo280
      - qcom,kryo385
      - qcom,kryo485
      - qcom,scorpion

  enable-method:
    allOf:
      - $ref: '/schemas/types.yaml#/definitions/string'
      - oneOf:
          # On ARM v8 64-bit this property is required
          - enum:
              - psci
              - spin-table
          # On ARM 32-bit systems this property is optional
          - enum:
              - actions,s500-smp
              - allwinner,sun6i-a31
              - allwinner,sun8i-a23
              - allwinner,sun9i-a80-smp
              - allwinner,sun8i-a83t-smp
              - amlogic,meson8-smp
              - amlogic,meson8b-smp
              - arm,realview-smp
              - aspeed,ast2600-smp
              - brcm,bcm11351-cpu-method
              - brcm,bcm23550
              - brcm,bcm2836-smp
              - brcm,bcm63138
              - brcm,bcm-nsp-smp
              - brcm,brahma-b15
              - marvell,armada-375-smp
              - marvell,armada-380-smp
              - marvell,armada-390-smp
              - marvell,armada-xp-smp
              - marvell,98dx3236-smp
              - marvell,mmp3-smp
              - mediatek,mt6589-smp
              - mediatek,mt81xx-tz-smp
              - qcom,gcc-msm8660
              - qcom,kpss-acc-v1
              - qcom,kpss-acc-v2
              - renesas,apmu
              - renesas,r9a06g032-smp
              - rockchip,rk3036-smp
              - rockchip,rk3066-smp
              - socionext,milbeaut-m10v-smp
              - ste,dbx500-smp
              - ti,am3352
              - ti,am4372

  cpu-release-addr:
    $ref: '/schemas/types.yaml#/definitions/uint64'

    description:
      Required for systems that have an "enable-method"
        property value of "spin-table".
      On ARM v8 64-bit systems must be a two cell
        property identifying a 64-bit zero-initialised
        memory location.

  cpu-idle-states:
    $ref: '/schemas/types.yaml#/definitions/phandle-array'
    description: |
      List of phandles to idle state nodes supported
      by this cpu (see ./idle-states.yaml).      

  capacity-dmips-mhz:
    $ref: '/schemas/types.yaml#/definitions/uint32'
    description:
      u32 value representing CPU capacity (see ./cpu-capacity.txt) in
      DMIPS/MHz, relative to highest capacity-dmips-mhz
      in the system.

  dynamic-power-coefficient:
    $ref: '/schemas/types.yaml#/definitions/uint32'
    description:
      A u32 value that represents the running time dynamic
      power coefficient in units of uW/MHz/V^2. The
      coefficient can either be calculated from power
      measurements or derived by analysis.

      The dynamic power consumption of the CPU  is
      proportional to the square of the Voltage (V) and
      the clock frequency (f). The coefficient is used to
      calculate the dynamic power as below -

      Pdyn = dynamic-power-coefficient * V^2 * f

      where voltage is in V, frequency is in MHz.

  power-domains:
    $ref: '/schemas/types.yaml#/definitions/phandle-array'
    description:
      List of phandles and PM domain specifiers, as defined by bindings of the
      PM domain provider (see also ../power_domain.txt).

  power-domain-names:
    $ref: '/schemas/types.yaml#/definitions/string-array'
    description:
      A list of power domain name strings sorted in the same order as the
      power-domains property.

      For PSCI based platforms, the name corresponding to the index of the PSCI
      PM domain provider, must be "psci".

  qcom,saw:
    $ref: '/schemas/types.yaml#/definitions/phandle'
    description: |
      Specifies the SAW* node associated with this CPU.

      Required for systems that have an "enable-method" property
      value of "qcom,kpss-acc-v1" or "qcom,kpss-acc-v2"

      * arm/msm/qcom,saw2.txt      

  qcom,acc:
    $ref: '/schemas/types.yaml#/definitions/phandle'
    description: |
      Specifies the ACC* node associated with this CPU.

      Required for systems that have an "enable-method" property
      value of "qcom,kpss-acc-v1" or "qcom,kpss-acc-v2"

      * arm/msm/qcom,kpss-acc.txt      

  rockchip,pmu:
    $ref: '/schemas/types.yaml#/definitions/phandle'
    description: |
      Specifies the syscon node controlling the cpu core power domains.

      Optional for systems that have an "enable-method"
      property value of "rockchip,rk3066-smp"
      While optional, it is the preferred way to get access to
      the cpu-core power-domains.      

  secondary-boot-reg:
    $ref: '/schemas/types.yaml#/definitions/uint32'
    description: |
      Required for systems that have an "enable-method" property value of
      "brcm,bcm11351-cpu-method", "brcm,bcm23550" or "brcm,bcm-nsp-smp".

      This includes the following SoCs: |
      BCM11130, BCM11140, BCM11351, BCM28145, BCM28155, BCM21664, BCM23550
      BCM58522, BCM58525, BCM58535, BCM58622, BCM58623, BCM58625, BCM88312

      The secondary-boot-reg property is a u32 value that specifies the
      physical address of the register used to request the ROM holding pen
      code release a secondary CPU. The value written to the register is
      formed by encoding the target CPU id into the low bits of the
      physical start address it should jump to.      

if:
  # If the enable-method property contains one of those values
  properties:
    enable-method:
      contains:
        enum:
          - brcm,bcm11351-cpu-method
          - brcm,bcm23550
          - brcm,bcm-nsp-smp
  # and if enable-method is present
  required:
    - enable-method

then:
   required:
     - secondary-boot-reg

required:
  - device_type
  - reg
  - compatible

dependencies:
  rockchip,pmu: [enable-method]

examples:
  - |
    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>;
      };
    };    
...