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diff --git a/Documentation/devicetree/bindings/arm/cpus.txt b/Documentation/devicetree/bindings/arm/cpus.txt new file mode 100644 index 000000000..96dfccc0f --- /dev/null +++ b/Documentation/devicetree/bindings/arm/cpus.txt @@ -0,0 +1,490 @@ +================= +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 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. + +- 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-a12" + "arm,cortex-a15" + "arm,cortex-a17" + "arm,cortex-a53" + "arm,cortex-a57" + "arm,cortex-a72" + "arm,cortex-a73" + "arm,cortex-m0" + "arm,cortex-m0+" + "arm,cortex-m1" + "arm,cortex-m3" + "arm,cortex-m4" + "arm,cortex-r4" + "arm,cortex-r5" + "arm,cortex-r7" + "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" + "nvidia,tegra132-denver" + "nvidia,tegra186-denver" + "nvidia,tegra194-carmel" + "qcom,krait" + "qcom,kryo" + "qcom,kryo385" + "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: + "psci" + "spin-table" + # On ARM 32-bit systems this property is optional and + can be one of: + "actions,s500-smp" + "allwinner,sun6i-a31" + "allwinner,sun8i-a23" + "allwinner,sun9i-a80-smp" + "amlogic,meson8-smp" + "amlogic,meson8b-smp" + "arm,realview-smp" + "brcm,bcm11351-cpu-method" + "brcm,bcm23550" + "brcm,bcm2836-smp" + "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" + "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" + "ste,dbx500-smp" + + - 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. + + - cpu-idle-states + Usage: Optional + Value type: <prop-encoded-array> + Definition: + # List of phandles to idle state nodes supported + by this cpu [3]. + + - capacity-dmips-mhz + Usage: Optional + Value type: <u32> + Definition: + # u32 value representing CPU capacity [4] in + DMIPS/MHz, relative to highest capacity-dmips-mhz + in the system. + + - rockchip,pmu + Usage: 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. + Value type: <phandle> + Definition: Specifies the syscon node controlling the cpu core + power domains. + + - dynamic-power-coefficient + Usage: optional + Value type: <prop-encoded-array> + Definition: A u32 value that represents the running time dynamic + power coefficient in units of mW/MHz/uV^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 uV, frequency is in MHz. + +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 +[3] ARM Linux kernel documentation - idle states bindings + Documentation/devicetree/bindings/arm/idle-states.txt +[4] ARM Linux kernel documentation - cpu capacity bindings + Documentation/devicetree/bindings/arm/cpu-capacity.txt |