# 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
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:
- apple,avalanche
- apple,blizzard
- apple,icestorm
- apple,firestorm
- 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-a78
- arm,cortex-a78ae
- arm,cortex-a78c
- arm,cortex-a510
- arm,cortex-a520
- arm,cortex-a710
- arm,cortex-a715
- arm,cortex-a720
- 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,cortex-r52
- arm,cortex-x1
- arm,cortex-x1c
- arm,cortex-x2
- arm,cortex-x3
- arm,cortex-x4
- arm,neoverse-e1
- arm,neoverse-n1
- arm,neoverse-n2
- arm,neoverse-v1
- 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,kryo240
- qcom,kryo250
- qcom,kryo260
- qcom,kryo280
- qcom,kryo360
- qcom,kryo385
- qcom,kryo468
- qcom,kryo485
- qcom,kryo560
- qcom,kryo570
- qcom,kryo660
- qcom,kryo685
- qcom,kryo780
- qcom,scorpion
enable-method:
$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
- qcom,msm8226-smp
- qcom,msm8909-smp
# Only valid on ARM 32-bit, see above for ARM v8 64-bit
- qcom,msm8916-smp
- 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:
oneOf:
- $ref: /schemas/types.yaml#/definitions/uint32
- $ref: /schemas/types.yaml#/definitions/uint64
description:
The DT specification defines this as 64-bit always, but some 32-bit Arm
systems have used a 32-bit value which must be supported.
Required for systems that have an "enable-method"
property value of "spin-table".
cpu-idle-states:
$ref: /schemas/types.yaml#/definitions/phandle-array
items:
maxItems: 1
description: |
List of phandles to idle state nodes supported
by this cpu (see ./idle-states.yaml).
capacity-dmips-mhz:
description:
u32 value representing CPU capacity (see ../cpu/cpu-capacity.txt) in
DMIPS/MHz, relative to highest capacity-dmips-mhz
in the system.
cci-control-port: true
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.
performance-domains:
maxItems: 1
description:
List of phandles and performance domain specifiers, as defined by
bindings of the performance domain provider. See also
dvfs/performance-domain.yaml.
power-domains:
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:
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", "qcom,kpss-acc-v2", "qcom,msm8226-smp" or
"qcom,msm8916-smp".
* 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]
additionalProperties: true
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>;
};
};
...