Documentation/devicetree/bindings/arm/cpus.txt

   1 =================
   2 ARM CPUs bindings
   3 =================
   4
   5 The device tree allows to describe the layout of CPUs in a system through
   6 the "cpus" node, which in turn contains a number of subnodes (ie "cpu")
   7 defining properties for every cpu.
   8
   9 Bindings for CPU nodes follow the ePAPR v1.1 standard, available from:
  10
  11 https://www.power.org/documentation/epapr-version-1-1/
  12
  13 with updates for 32-bit and 64-bit ARM systems provided in this document.
  14
  15 ================================
  16 Convention used in this document
  17 ================================
  18
  19 This document follows the conventions described in the ePAPR v1.1, with
  20 the addition:
  21
  22 - square brackets define bitfields, eg reg[7:0] value of the bitfield in
  23   the reg property contained in bits 7 down to 0
  24
  25 =====================================
  26 cpus and cpu node bindings definition
  27 =====================================
  28
  29 The ARM architecture, in accordance with the ePAPR, requires the cpus and cpu
  30 nodes to be present and contain the properties described below.
  31
  32 - cpus node
  33
  34         Description: Container of cpu nodes
  35
  36         The node name must be "cpus".
  37
  38         A cpus node must define the following properties:
  39
  40         - #address-cells
  41                 Usage: required
  42                 Value type: <u32>
  43
  44                 Definition depends on ARM architecture version and
  45                 configuration:
  46
  47                         # On uniprocessor ARM architectures previous to v7
  48                           value must be 1, to enable a simple enumeration
  49                           scheme for processors that do not have a HW CPU
  50                           identification register.
  51                         # On 32-bit ARM 11 MPcore, ARM v7 or later systems
  52                           value must be 1, that corresponds to CPUID/MPIDR
  53                           registers sizes.
  54                         # On ARM v8 64-bit systems value should be set to 2,
  55                           that corresponds to the MPIDR_EL1 register size.
  56                           If MPIDR_EL1[63:32] value is equal to 0 on all CPUs
  57                           in the system, #address-cells can be set to 1, since
  58                           MPIDR_EL1[63:32] bits are not used for CPUs
  59                           identification.
  60         - #size-cells
  61                 Usage: required
  62                 Value type: <u32>
  63                 Definition: must be set to 0
  64
  65 - cpu node
  66
  67         Description: Describes a CPU in an ARM based system
  68
  69         PROPERTIES
  70
  71         - device_type
  72                 Usage: required
  73                 Value type: <string>
  74                 Definition: must be "cpu"
  75         - reg
  76                 Usage and definition depend on ARM architecture version and
  77                 configuration:
  78
  79                         # On uniprocessor ARM architectures previous to v7
  80                           this property is required and must be set to 0.
  81
  82                         # On ARM 11 MPcore based systems this property is
  83                           required and matches the CPUID[11:0] register bits.
  84
  85                           Bits [11:0] in the reg cell must be set to
  86                           bits [11:0] in CPU ID register.
  87
  88                           All other bits in the reg cell must be set to 0.
  89
  90                         # On 32-bit ARM v7 or later systems this property is
  91                           required and matches the CPU MPIDR[23:0] register
  92                           bits.
  93
  94                           Bits [23:0] in the reg cell must be set to
  95                           bits [23:0] in MPIDR.
  96
  97                           All other bits in the reg cell must be set to 0.
  98
  99                         # On ARM v8 64-bit systems this property is required
 100                           and matches the MPIDR_EL1 register affinity bits.
 101
 102                           * If cpus node's #address-cells property is set to 2
 103
 104                             The first reg cell bits [7:0] must be set to
 105                             bits [39:32] of MPIDR_EL1.
 106
 107                             The second reg cell bits [23:0] must be set to
 108                             bits [23:0] of MPIDR_EL1.
 109
 110                           * If cpus node's #address-cells property is set to 1
 111
 112                             The reg cell bits [23:0] must be set to bits [23:0]
 113                             of MPIDR_EL1.
 114
 115                           All other bits in the reg cells must be set to 0.
 116
 117         - compatible:
 118                 Usage: required
 119                 Value type: <string>
 120                 Definition: should be one of:
 121                             "arm,arm710t"
 122                             "arm,arm720t"
 123                             "arm,arm740t"
 124                             "arm,arm7ej-s"
 125                             "arm,arm7tdmi"
 126                             "arm,arm7tdmi-s"
 127                             "arm,arm9es"
 128                             "arm,arm9ej-s"
 129                             "arm,arm920t"
 130                             "arm,arm922t"
 131                             "arm,arm925"
 132                             "arm,arm926e-s"
 133                             "arm,arm926ej-s"
 134                             "arm,arm940t"
 135                             "arm,arm946e-s"
 136                             "arm,arm966e-s"
 137                             "arm,arm968e-s"
 138                             "arm,arm9tdmi"
 139                             "arm,arm1020e"
 140                             "arm,arm1020t"
 141                             "arm,arm1022e"
 142                             "arm,arm1026ej-s"
 143                             "arm,arm1136j-s"
 144                             "arm,arm1136jf-s"
 145                             "arm,arm1156t2-s"
 146                             "arm,arm1156t2f-s"
 147                             "arm,arm1176jzf"
 148                             "arm,arm1176jz-s"
 149                             "arm,arm1176jzf-s"
 150                             "arm,arm11mpcore"
 151                             "arm,cortex-a5"
 152                             "arm,cortex-a7"
 153                             "arm,cortex-a8"
 154                             "arm,cortex-a9"
 155                             "arm,cortex-a15"
 156                             "arm,cortex-a53"
 157                             "arm,cortex-a57"
 158                             "arm,cortex-m0"
 159                             "arm,cortex-m0+"
 160                             "arm,cortex-m1"
 161                             "arm,cortex-m3"
 162                             "arm,cortex-m4"
 163                             "arm,cortex-r4"
 164                             "arm,cortex-r5"
 165                             "arm,cortex-r7"
 166                             "faraday,fa526"
 167                             "intel,sa110"
 168                             "intel,sa1100"
 169                             "marvell,feroceon"
 170                             "marvell,mohawk"
 171                             "marvell,pj4a"
 172                             "marvell,pj4b"
 173                             "marvell,sheeva-v5"
 174                             "qcom,krait"
 175                             "qcom,scorpion"
 176         - enable-method
 177                 Value type: <stringlist>
 178                 Usage and definition depend on ARM architecture version.
 179                         # On ARM v8 64-bit this property is required and must
 180                           be one of:
 181                              "spin-table"
 182                              "psci"
 183                         # On ARM 32-bit systems this property is optional.
 184
 185         - cpu-release-addr
 186                 Usage: required for systems that have an "enable-method"
 187                        property value of "spin-table".
 188                 Value type: <prop-encoded-array>
 189                 Definition:
 190                         # On ARM v8 64-bit systems must be a two cell
 191                           property identifying a 64-bit zero-initialised
 192                           memory location.
 193
 194 Example 1 (dual-cluster big.LITTLE system 32-bit):
 195
 196         cpus {
 197                 #size-cells = <0>;
 198                 #address-cells = <1>;
 199
 200                 cpu@0 {
 201                         device_type = "cpu";
 202                         compatible = "arm,cortex-a15";
 203                         reg = <0x0>;
 204                 };
 205
 206                 cpu@1 {
 207                         device_type = "cpu";
 208                         compatible = "arm,cortex-a15";
 209                         reg = <0x1>;
 210                 };
 211
 212                 cpu@100 {
 213                         device_type = "cpu";
 214                         compatible = "arm,cortex-a7";
 215                         reg = <0x100>;
 216                 };
 217
 218                 cpu@101 {
 219                         device_type = "cpu";
 220                         compatible = "arm,cortex-a7";
 221                         reg = <0x101>;
 222                 };
 223         };
 224
 225 Example 2 (Cortex-A8 uniprocessor 32-bit system):
 226
 227         cpus {
 228                 #size-cells = <0>;
 229                 #address-cells = <1>;
 230
 231                 cpu@0 {
 232                         device_type = "cpu";
 233                         compatible = "arm,cortex-a8";
 234                         reg = <0x0>;
 235                 };
 236         };
 237
 238 Example 3 (ARM 926EJ-S uniprocessor 32-bit system):
 239
 240         cpus {
 241                 #size-cells = <0>;
 242                 #address-cells = <1>;
 243
 244                 cpu@0 {
 245                         device_type = "cpu";
 246                         compatible = "arm,arm926ej-s";
 247                         reg = <0x0>;
 248                 };
 249         };
 250
 251 Example 4 (ARM Cortex-A57 64-bit system):
 252
 253 cpus {
 254         #size-cells = <0>;
 255         #address-cells = <2>;
 256
 257         cpu@0 {
 258                 device_type = "cpu";
 259                 compatible = "arm,cortex-a57";
 260                 reg = <0x0 0x0>;
 261                 enable-method = "spin-table";
 262                 cpu-release-addr = <0 0x20000000>;
 263         };
 264
 265         cpu@1 {
 266                 device_type = "cpu";
 267                 compatible = "arm,cortex-a57";
 268                 reg = <0x0 0x1>;
 269                 enable-method = "spin-table";
 270                 cpu-release-addr = <0 0x20000000>;
 271         };
 272
 273         cpu@100 {
 274                 device_type = "cpu";
 275                 compatible = "arm,cortex-a57";
 276                 reg = <0x0 0x100>;
 277                 enable-method = "spin-table";
 278                 cpu-release-addr = <0 0x20000000>;
 279         };
 280
 281         cpu@101 {
 282                 device_type = "cpu";
 283                 compatible = "arm,cortex-a57";
 284                 reg = <0x0 0x101>;
 285                 enable-method = "spin-table";
 286                 cpu-release-addr = <0 0x20000000>;
 287         };
 288
 289         cpu@10000 {
 290                 device_type = "cpu";
 291                 compatible = "arm,cortex-a57";
 292                 reg = <0x0 0x10000>;
 293                 enable-method = "spin-table";
 294                 cpu-release-addr = <0 0x20000000>;
 295         };
 296
 297         cpu@10001 {
 298                 device_type = "cpu";
 299                 compatible = "arm,cortex-a57";
 300                 reg = <0x0 0x10001>;
 301                 enable-method = "spin-table";
 302                 cpu-release-addr = <0 0x20000000>;
 303         };
 304
 305         cpu@10100 {
 306                 device_type = "cpu";
 307                 compatible = "arm,cortex-a57";
 308                 reg = <0x0 0x10100>;
 309                 enable-method = "spin-table";
 310                 cpu-release-addr = <0 0x20000000>;
 311         };
 312
 313         cpu@10101 {
 314                 device_type = "cpu";
 315                 compatible = "arm,cortex-a57";
 316                 reg = <0x0 0x10101>;
 317                 enable-method = "spin-table";
 318                 cpu-release-addr = <0 0x20000000>;
 319         };
 320
 321         cpu@100000000 {
 322                 device_type = "cpu";
 323                 compatible = "arm,cortex-a57";
 324                 reg = <0x1 0x0>;
 325                 enable-method = "spin-table";
 326                 cpu-release-addr = <0 0x20000000>;
 327         };
 328
 329         cpu@100000001 {
 330                 device_type = "cpu";
 331                 compatible = "arm,cortex-a57";
 332                 reg = <0x1 0x1>;
 333                 enable-method = "spin-table";
 334                 cpu-release-addr = <0 0x20000000>;
 335         };
 336
 337         cpu@100000100 {
 338                 device_type = "cpu";
 339                 compatible = "arm,cortex-a57";
 340                 reg = <0x1 0x100>;
 341                 enable-method = "spin-table";
 342                 cpu-release-addr = <0 0x20000000>;
 343         };
 344
 345         cpu@100000101 {
 346                 device_type = "cpu";
 347                 compatible = "arm,cortex-a57";
 348                 reg = <0x1 0x101>;
 349                 enable-method = "spin-table";
 350                 cpu-release-addr = <0 0x20000000>;
 351         };
 352
 353         cpu@100010000 {
 354                 device_type = "cpu";
 355                 compatible = "arm,cortex-a57";
 356                 reg = <0x1 0x10000>;
 357                 enable-method = "spin-table";
 358                 cpu-release-addr = <0 0x20000000>;
 359         };
 360
 361         cpu@100010001 {
 362                 device_type = "cpu";
 363                 compatible = "arm,cortex-a57";
 364                 reg = <0x1 0x10001>;
 365                 enable-method = "spin-table";
 366                 cpu-release-addr = <0 0x20000000>;
 367         };
 368
 369         cpu@100010100 {
 370                 device_type = "cpu";
 371                 compatible = "arm,cortex-a57";
 372                 reg = <0x1 0x10100>;
 373                 enable-method = "spin-table";
 374                 cpu-release-addr = <0 0x20000000>;
 375         };
 376
 377         cpu@100010101 {
 378                 device_type = "cpu";
 379                 compatible = "arm,cortex-a57";
 380                 reg = <0x1 0x10101>;
 381                 enable-method = "spin-table";
 382                 cpu-release-addr = <0 0x20000000>;
 383         };
 384 };