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Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/devicetree/bindings/arm/cpus.txt | 401 |
1 files changed, 354 insertions, 47 deletions
diff --git a/Documentation/devicetree/bindings/arm/cpus.txt b/Documentation/devicetree/bindings/arm/cpus.txt index f32494d..9130435 100644 --- a/Documentation/devicetree/bindings/arm/cpus.txt +++ b/Documentation/devicetree/bindings/arm/cpus.txt @@ -1,77 +1,384 @@ -* ARM CPUs binding description +================= +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 standard, available from: - -http://devicetree.org - -For the ARM architecture every CPU node must contain the following properties: - -- device_type: must be "cpu" -- reg: property matching the CPU MPIDR[23:0] register bits - reg[31:24] bits must be set to 0 -- compatible: should be one of: - "arm,arm1020" - "arm,arm1020e" - "arm,arm1022" - "arm,arm1026" - "arm,arm720" - "arm,arm740" - "arm,arm7tdmi" - "arm,arm920" - "arm,arm922" - "arm,arm925" - "arm,arm926" - "arm,arm940" - "arm,arm946" - "arm,arm9tdmi" - "arm,cortex-a5" - "arm,cortex-a7" - "arm,cortex-a8" - "arm,cortex-a9" - "arm,cortex-a15" - "arm,arm1136" - "arm,arm1156" - "arm,arm1176" - "arm,arm11mpcore" - "faraday,fa526" - "intel,sa110" - "intel,sa1100" - "marvell,feroceon" - "marvell,mohawk" - "marvell,xsc3" - "marvell,xscale" - -Example: +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. + + - 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. + +Example 1 (dual-cluster big.LITTLE system 32-bit): cpus { #size-cells = <0>; #address-cells = <1>; - CPU0: cpu@0 { + cpu@0 { device_type = "cpu"; compatible = "arm,cortex-a15"; reg = <0x0>; }; - CPU1: cpu@1 { + cpu@1 { device_type = "cpu"; compatible = "arm,cortex-a15"; reg = <0x1>; }; - CPU2: cpu@100 { + cpu@100 { device_type = "cpu"; compatible = "arm,cortex-a7"; reg = <0x100>; }; - CPU3: cpu@101 { + 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>; + }; +}; |
