arch/arm64/kernel/psci.c

   1 /*
   2  * This program is free software; you can redistribute it and/or modify
   3  * it under the terms of the GNU General Public License version 2 as
   4  * published by the Free Software Foundation.
   5  *
   6  * This program is distributed in the hope that it will be useful,
   7  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   8  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   9  * GNU General Public License for more details.
  10  *
  11  * Copyright (C) 2013 ARM Limited
  12  *
  13  * Author: Will Deacon <will.deacon@arm.com>
  14  */
  15
  16 #define pr_fmt(fmt) "psci: " fmt
  17
  18 #include <linux/init.h>
  19 #include <linux/of.h>
  20 #include <linux/smp.h>
  21 #include <linux/reboot.h>
  22 #include <linux/pm.h>
  23 #include <linux/delay.h>
  24 #include <linux/slab.h>
  25 #include <uapi/linux/psci.h>
  26
  27 #include <asm/compiler.h>
  28 #include <asm/cpu_ops.h>
  29 #include <asm/errno.h>
  30 #include <asm/psci.h>
  31 #include <asm/smp_plat.h>
  32 #include <asm/suspend.h>
  33 #include <asm/system_misc.h>
  34
  35 #define PSCI_POWER_STATE_TYPE_STANDBY           0
  36 #define PSCI_POWER_STATE_TYPE_POWER_DOWN        1
  37
  38 struct psci_power_state {
  39         u16     id;
  40         u8      type;
  41         u8      affinity_level;
  42 };
  43
  44 struct psci_operations {
  45         int (*cpu_suspend)(struct psci_power_state state,
  46                            unsigned long entry_point);
  47         int (*cpu_off)(struct psci_power_state state);
  48         int (*cpu_on)(unsigned long cpuid, unsigned long entry_point);
  49         int (*migrate)(unsigned long cpuid);
  50         int (*affinity_info)(unsigned long target_affinity,
  51                         unsigned long lowest_affinity_level);
  52         int (*migrate_info_type)(void);
  53 };
  54
  55 static struct psci_operations psci_ops;
  56
  57 static int (*invoke_psci_fn)(u64, u64, u64, u64);
  58 typedef int (*psci_initcall_t)(const struct device_node *);
  59
  60 enum psci_function {
  61         PSCI_FN_CPU_SUSPEND,
  62         PSCI_FN_CPU_ON,
  63         PSCI_FN_CPU_OFF,
  64         PSCI_FN_MIGRATE,
  65         PSCI_FN_AFFINITY_INFO,
  66         PSCI_FN_MIGRATE_INFO_TYPE,
  67         PSCI_FN_MAX,
  68 };
  69
  70 static DEFINE_PER_CPU_READ_MOSTLY(struct psci_power_state *, psci_power_state);
  71
  72 static u32 psci_function_id[PSCI_FN_MAX];
  73
  74 static int psci_to_linux_errno(int errno)
  75 {
  76         switch (errno) {
  77         case PSCI_RET_SUCCESS:
  78                 return 0;
  79         case PSCI_RET_NOT_SUPPORTED:
  80                 return -EOPNOTSUPP;
  81         case PSCI_RET_INVALID_PARAMS:
  82                 return -EINVAL;
  83         case PSCI_RET_DENIED:
  84                 return -EPERM;
  85         };
  86
  87         return -EINVAL;
  88 }
  89
  90 static u32 psci_power_state_pack(struct psci_power_state state)
  91 {
  92         return ((state.id << PSCI_0_2_POWER_STATE_ID_SHIFT)
  93                         & PSCI_0_2_POWER_STATE_ID_MASK) |
  94                 ((state.type << PSCI_0_2_POWER_STATE_TYPE_SHIFT)
  95                  & PSCI_0_2_POWER_STATE_TYPE_MASK) |
  96                 ((state.affinity_level << PSCI_0_2_POWER_STATE_AFFL_SHIFT)
  97                  & PSCI_0_2_POWER_STATE_AFFL_MASK);
  98 }
  99
 100 static void psci_power_state_unpack(u32 power_state,
 101                                     struct psci_power_state *state)
 102 {
 103         state->id = (power_state & PSCI_0_2_POWER_STATE_ID_MASK) >>
 104                         PSCI_0_2_POWER_STATE_ID_SHIFT;
 105         state->type = (power_state & PSCI_0_2_POWER_STATE_TYPE_MASK) >>
 106                         PSCI_0_2_POWER_STATE_TYPE_SHIFT;
 107         state->affinity_level =
 108                         (power_state & PSCI_0_2_POWER_STATE_AFFL_MASK) >>
 109                         PSCI_0_2_POWER_STATE_AFFL_SHIFT;
 110 }
 111
 112 /*
 113  * The following two functions are invoked via the invoke_psci_fn pointer
 114  * and will not be inlined, allowing us to piggyback on the AAPCS.
 115  */
 116 static noinline int __invoke_psci_fn_hvc(u64 function_id, u64 arg0, u64 arg1,
 117                                          u64 arg2)
 118 {
 119         asm volatile(
 120                         __asmeq("%0", "x0")
 121                         __asmeq("%1", "x1")
 122                         __asmeq("%2", "x2")
 123                         __asmeq("%3", "x3")
 124                         "hvc    #0\n"
 125                 : "+r" (function_id)
 126                 : "r" (arg0), "r" (arg1), "r" (arg2));
 127
 128         return function_id;
 129 }
 130
 131 static noinline int __invoke_psci_fn_smc(u64 function_id, u64 arg0, u64 arg1,
 132                                          u64 arg2)
 133 {
 134         asm volatile(
 135                         __asmeq("%0", "x0")
 136                         __asmeq("%1", "x1")
 137                         __asmeq("%2", "x2")
 138                         __asmeq("%3", "x3")
 139                         "smc    #0\n"
 140                 : "+r" (function_id)
 141                 : "r" (arg0), "r" (arg1), "r" (arg2));
 142
 143         return function_id;
 144 }
 145
 146 static int psci_get_version(void)
 147 {
 148         int err;
 149
 150         err = invoke_psci_fn(PSCI_0_2_FN_PSCI_VERSION, 0, 0, 0);
 151         return err;
 152 }
 153
 154 static int psci_cpu_suspend(struct psci_power_state state,
 155                             unsigned long entry_point)
 156 {
 157         int err;
 158         u32 fn, power_state;
 159
 160         fn = psci_function_id[PSCI_FN_CPU_SUSPEND];
 161         power_state = psci_power_state_pack(state);
 162         err = invoke_psci_fn(fn, power_state, entry_point, 0);
 163         return psci_to_linux_errno(err);
 164 }
 165
 166 static int psci_cpu_off(struct psci_power_state state)
 167 {
 168         int err;
 169         u32 fn, power_state;
 170
 171         fn = psci_function_id[PSCI_FN_CPU_OFF];
 172         power_state = psci_power_state_pack(state);
 173         err = invoke_psci_fn(fn, power_state, 0, 0);
 174         return psci_to_linux_errno(err);
 175 }
 176
 177 static int psci_cpu_on(unsigned long cpuid, unsigned long entry_point)
 178 {
 179         int err;
 180         u32 fn;
 181
 182         fn = psci_function_id[PSCI_FN_CPU_ON];
 183         err = invoke_psci_fn(fn, cpuid, entry_point, 0);
 184         return psci_to_linux_errno(err);
 185 }
 186
 187 static int psci_migrate(unsigned long cpuid)
 188 {
 189         int err;
 190         u32 fn;
 191
 192         fn = psci_function_id[PSCI_FN_MIGRATE];
 193         err = invoke_psci_fn(fn, cpuid, 0, 0);
 194         return psci_to_linux_errno(err);
 195 }
 196
 197 static int psci_affinity_info(unsigned long target_affinity,
 198                 unsigned long lowest_affinity_level)
 199 {
 200         int err;
 201         u32 fn;
 202
 203         fn = psci_function_id[PSCI_FN_AFFINITY_INFO];
 204         err = invoke_psci_fn(fn, target_affinity, lowest_affinity_level, 0);
 205         return err;
 206 }
 207
 208 static int psci_migrate_info_type(void)
 209 {
 210         int err;
 211         u32 fn;
 212
 213         fn = psci_function_id[PSCI_FN_MIGRATE_INFO_TYPE];
 214         err = invoke_psci_fn(fn, 0, 0, 0);
 215         return err;
 216 }
 217
 218 static int __maybe_unused cpu_psci_cpu_init_idle(struct device_node *cpu_node,
 219                                                  unsigned int cpu)
 220 {
 221         int i, ret, count = 0;
 222         struct psci_power_state *psci_states;
 223         struct device_node *state_node;
 224
 225         /*
 226          * If the PSCI cpu_suspend function hook has not been initialized
 227          * idle states must not be enabled, so bail out
 228          */
 229         if (!psci_ops.cpu_suspend)
 230                 return -EOPNOTSUPP;
 231
 232         /* Count idle states */
 233         while ((state_node = of_parse_phandle(cpu_node, "cpu-idle-states",
 234                                               count))) {
 235                 count++;
 236                 of_node_put(state_node);
 237         }
 238
 239         if (!count)
 240                 return -ENODEV;
 241
 242         psci_states = kcalloc(count, sizeof(*psci_states), GFP_KERNEL);
 243         if (!psci_states)
 244                 return -ENOMEM;
 245
 246         for (i = 0; i < count; i++) {
 247                 u32 psci_power_state;
 248
 249                 state_node = of_parse_phandle(cpu_node, "cpu-idle-states", i);
 250
 251                 ret = of_property_read_u32(state_node,
 252                                            "arm,psci-suspend-param",
 253                                            &psci_power_state);
 254                 if (ret) {
 255                         pr_warn(" * %s missing arm,psci-suspend-param property\n",
 256                                 state_node->full_name);
 257                         of_node_put(state_node);
 258                         goto free_mem;
 259                 }
 260
 261                 of_node_put(state_node);
 262                 pr_debug("psci-power-state %#x index %d\n", psci_power_state,
 263                                                             i);
 264                 psci_power_state_unpack(psci_power_state, &psci_states[i]);
 265         }
 266         /* Idle states parsed correctly, initialize per-cpu pointer */
 267         per_cpu(psci_power_state, cpu) = psci_states;
 268         return 0;
 269
 270 free_mem:
 271         kfree(psci_states);
 272         return ret;
 273 }
 274
 275 static int get_set_conduit_method(struct device_node *np)
 276 {
 277         const char *method;
 278
 279         pr_info("probing for conduit method from DT.\n");
 280
 281         if (of_property_read_string(np, "method", &method)) {
 282                 pr_warn("missing \"method\" property\n");
 283                 return -ENXIO;
 284         }
 285
 286         if (!strcmp("hvc", method)) {
 287                 invoke_psci_fn = __invoke_psci_fn_hvc;
 288         } else if (!strcmp("smc", method)) {
 289                 invoke_psci_fn = __invoke_psci_fn_smc;
 290         } else {
 291                 pr_warn("invalid \"method\" property: %s\n", method);
 292                 return -EINVAL;
 293         }
 294         return 0;
 295 }
 296
 297 static void psci_sys_reset(enum reboot_mode reboot_mode, const char *cmd)
 298 {
 299         invoke_psci_fn(PSCI_0_2_FN_SYSTEM_RESET, 0, 0, 0);
 300 }
 301
 302 static void psci_sys_poweroff(void)
 303 {
 304         invoke_psci_fn(PSCI_0_2_FN_SYSTEM_OFF, 0, 0, 0);
 305 }
 306
 307 /*
 308  * PSCI Function IDs for v0.2+ are well defined so use
 309  * standard values.
 310  */
 311 static int __init psci_0_2_init(struct device_node *np)
 312 {
 313         int err, ver;
 314
 315         err = get_set_conduit_method(np);
 316
 317         if (err)
 318                 goto out_put_node;
 319
 320         ver = psci_get_version();
 321
 322         if (ver == PSCI_RET_NOT_SUPPORTED) {
 323                 /* PSCI v0.2 mandates implementation of PSCI_ID_VERSION. */
 324                 pr_err("PSCI firmware does not comply with the v0.2 spec.\n");
 325                 err = -EOPNOTSUPP;
 326                 goto out_put_node;
 327         } else {
 328                 pr_info("PSCIv%d.%d detected in firmware.\n",
 329                                 PSCI_VERSION_MAJOR(ver),
 330                                 PSCI_VERSION_MINOR(ver));
 331
 332                 if (PSCI_VERSION_MAJOR(ver) == 0 &&
 333                                 PSCI_VERSION_MINOR(ver) < 2) {
 334                         err = -EINVAL;
 335                         pr_err("Conflicting PSCI version detected.\n");
 336                         goto out_put_node;
 337                 }
 338         }
 339
 340         pr_info("Using standard PSCI v0.2 function IDs\n");
 341         psci_function_id[PSCI_FN_CPU_SUSPEND] = PSCI_0_2_FN64_CPU_SUSPEND;
 342         psci_ops.cpu_suspend = psci_cpu_suspend;
 343
 344         psci_function_id[PSCI_FN_CPU_OFF] = PSCI_0_2_FN_CPU_OFF;
 345         psci_ops.cpu_off = psci_cpu_off;
 346
 347         psci_function_id[PSCI_FN_CPU_ON] = PSCI_0_2_FN64_CPU_ON;
 348         psci_ops.cpu_on = psci_cpu_on;
 349
 350         psci_function_id[PSCI_FN_MIGRATE] = PSCI_0_2_FN64_MIGRATE;
 351         psci_ops.migrate = psci_migrate;
 352
 353         psci_function_id[PSCI_FN_AFFINITY_INFO] = PSCI_0_2_FN64_AFFINITY_INFO;
 354         psci_ops.affinity_info = psci_affinity_info;
 355
 356         psci_function_id[PSCI_FN_MIGRATE_INFO_TYPE] =
 357                 PSCI_0_2_FN_MIGRATE_INFO_TYPE;
 358         psci_ops.migrate_info_type = psci_migrate_info_type;
 359
 360         arm_pm_restart = psci_sys_reset;
 361
 362         pm_power_off = psci_sys_poweroff;
 363
 364 out_put_node:
 365         of_node_put(np);
 366         return err;
 367 }
 368
 369 /*
 370  * PSCI < v0.2 get PSCI Function IDs via DT.
 371  */
 372 static int __init psci_0_1_init(struct device_node *np)
 373 {
 374         u32 id;
 375         int err;
 376
 377         err = get_set_conduit_method(np);
 378
 379         if (err)
 380                 goto out_put_node;
 381
 382         pr_info("Using PSCI v0.1 Function IDs from DT\n");
 383
 384         if (!of_property_read_u32(np, "cpu_suspend", &id)) {
 385                 psci_function_id[PSCI_FN_CPU_SUSPEND] = id;
 386                 psci_ops.cpu_suspend = psci_cpu_suspend;
 387         }
 388
 389         if (!of_property_read_u32(np, "cpu_off", &id)) {
 390                 psci_function_id[PSCI_FN_CPU_OFF] = id;
 391                 psci_ops.cpu_off = psci_cpu_off;
 392         }
 393
 394         if (!of_property_read_u32(np, "cpu_on", &id)) {
 395                 psci_function_id[PSCI_FN_CPU_ON] = id;
 396                 psci_ops.cpu_on = psci_cpu_on;
 397         }
 398
 399         if (!of_property_read_u32(np, "migrate", &id)) {
 400                 psci_function_id[PSCI_FN_MIGRATE] = id;
 401                 psci_ops.migrate = psci_migrate;
 402         }
 403
 404 out_put_node:
 405         of_node_put(np);
 406         return err;
 407 }
 408
 409 static const struct of_device_id psci_of_match[] __initconst = {
 410         { .compatible = "arm,psci",     .data = psci_0_1_init},
 411         { .compatible = "arm,psci-0.2", .data = psci_0_2_init},
 412         {},
 413 };
 414
 415 int __init psci_init(void)
 416 {
 417         struct device_node *np;
 418         const struct of_device_id *matched_np;
 419         psci_initcall_t init_fn;
 420
 421         np = of_find_matching_node_and_match(NULL, psci_of_match, &matched_np);
 422
 423         if (!np)
 424                 return -ENODEV;
 425
 426         init_fn = (psci_initcall_t)matched_np->data;
 427         return init_fn(np);
 428 }
 429
 430 #ifdef CONFIG_SMP
 431
 432 static int __init cpu_psci_cpu_init(struct device_node *dn, unsigned int cpu)
 433 {
 434         return 0;
 435 }
 436
 437 static int __init cpu_psci_cpu_prepare(unsigned int cpu)
 438 {
 439         if (!psci_ops.cpu_on) {
 440                 pr_err("no cpu_on method, not booting CPU%d\n", cpu);
 441                 return -ENODEV;
 442         }
 443
 444         return 0;
 445 }
 446
 447 static int cpu_psci_cpu_boot(unsigned int cpu)
 448 {
 449         int err = psci_ops.cpu_on(cpu_logical_map(cpu), __pa(secondary_entry));
 450         if (err)
 451                 pr_err("failed to boot CPU%d (%d)\n", cpu, err);
 452
 453         return err;
 454 }
 455
 456 #ifdef CONFIG_HOTPLUG_CPU
 457 static int cpu_psci_cpu_disable(unsigned int cpu)
 458 {
 459         /* Fail early if we don't have CPU_OFF support */
 460         if (!psci_ops.cpu_off)
 461                 return -EOPNOTSUPP;
 462         return 0;
 463 }
 464
 465 static void cpu_psci_cpu_die(unsigned int cpu)
 466 {
 467         int ret;
 468         /*
 469          * There are no known implementations of PSCI actually using the
 470          * power state field, pass a sensible default for now.
 471          */
 472         struct psci_power_state state = {
 473                 .type = PSCI_POWER_STATE_TYPE_POWER_DOWN,
 474         };
 475
 476         ret = psci_ops.cpu_off(state);
 477
 478         pr_crit("unable to power off CPU%u (%d)\n", cpu, ret);
 479 }
 480
 481 static int cpu_psci_cpu_kill(unsigned int cpu)
 482 {
 483         int err, i;
 484
 485         if (!psci_ops.affinity_info)
 486                 return 1;
 487         /*
 488          * cpu_kill could race with cpu_die and we can
 489          * potentially end up declaring this cpu undead
 490          * while it is dying. So, try again a few times.
 491          */
 492
 493         for (i = 0; i < 10; i++) {
 494                 err = psci_ops.affinity_info(cpu_logical_map(cpu), 0);
 495                 if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) {
 496                         pr_info("CPU%d killed.\n", cpu);
 497                         return 1;
 498                 }
 499
 500                 msleep(10);
 501                 pr_info("Retrying again to check for CPU kill\n");
 502         }
 503
 504         pr_warn("CPU%d may not have shut down cleanly (AFFINITY_INFO reports %d)\n",
 505                         cpu, err);
 506         /* Make op_cpu_kill() fail. */
 507         return 0;
 508 }
 509 #endif
 510 #endif
 511
 512 static int psci_suspend_finisher(unsigned long index)
 513 {
 514         struct psci_power_state *state = __this_cpu_read(psci_power_state);
 515
 516         return psci_ops.cpu_suspend(state[index - 1],
 517                                     virt_to_phys(cpu_resume));
 518 }
 519
 520 static int __maybe_unused cpu_psci_cpu_suspend(unsigned long index)
 521 {
 522         int ret;
 523         struct psci_power_state *state = __this_cpu_read(psci_power_state);
 524         /*
 525          * idle state index 0 corresponds to wfi, should never be called
 526          * from the cpu_suspend operations
 527          */
 528         if (WARN_ON_ONCE(!index))
 529                 return -EINVAL;
 530
 531         if (state[index - 1].type == PSCI_POWER_STATE_TYPE_STANDBY)
 532                 ret = psci_ops.cpu_suspend(state[index - 1], 0);
 533         else
 534                 ret = __cpu_suspend(index, psci_suspend_finisher);
 535
 536         return ret;
 537 }
 538
 539 const struct cpu_operations cpu_psci_ops = {
 540         .name           = "psci",
 541 #ifdef CONFIG_CPU_IDLE
 542         .cpu_init_idle  = cpu_psci_cpu_init_idle,
 543         .cpu_suspend    = cpu_psci_cpu_suspend,
 544 #endif
 545 #ifdef CONFIG_SMP
 546         .cpu_init       = cpu_psci_cpu_init,
 547         .cpu_prepare    = cpu_psci_cpu_prepare,
 548         .cpu_boot       = cpu_psci_cpu_boot,
 549 #ifdef CONFIG_HOTPLUG_CPU
 550         .cpu_disable    = cpu_psci_cpu_disable,
 551         .cpu_die        = cpu_psci_cpu_die,
 552         .cpu_kill       = cpu_psci_cpu_kill,
 553 #endif
 554 #endif
 555 };
 556