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 <uapi/linux/psci.h>
  25
  26 #include <asm/compiler.h>
  27 #include <asm/cpu_ops.h>
  28 #include <asm/errno.h>
  29 #include <asm/psci.h>
  30 #include <asm/smp_plat.h>
  31 #include <asm/system_misc.h>
  32
  33 #if 0 /* move to asm/psci.h for public export */
  34 #define PSCI_POWER_STATE_TYPE_STANDBY           0
  35 #define PSCI_POWER_STATE_TYPE_POWER_DOWN        1
  36
  37 struct psci_power_state {
  38         u16     id;
  39         u8      type;
  40         u8      affinity_level;
  41 };
  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 #endif //#if 0 /* move to asm/psci.h for public export */
  55
  56 struct psci_operations psci_ops;
  57
  58 static int (*invoke_psci_fn)(u64, u64, u64, u64);
  59 typedef int (*psci_initcall_t)(const struct device_node *);
  60
  61 enum psci_function {
  62         PSCI_FN_CPU_SUSPEND,
  63         PSCI_FN_CPU_ON,
  64         PSCI_FN_CPU_OFF,
  65         PSCI_FN_MIGRATE,
  66         PSCI_FN_AFFINITY_INFO,
  67         PSCI_FN_MIGRATE_INFO_TYPE,
  68         PSCI_FN_MAX,
  69 };
  70
  71 static u32 psci_function_id[PSCI_FN_MAX];
  72
  73 static int psci_to_linux_errno(int errno)
  74 {
  75         switch (errno) {
  76         case PSCI_RET_SUCCESS:
  77                 return 0;
  78         case PSCI_RET_NOT_SUPPORTED:
  79                 return -EOPNOTSUPP;
  80         case PSCI_RET_INVALID_PARAMS:
  81                 return -EINVAL;
  82         case PSCI_RET_DENIED:
  83                 return -EPERM;
  84         };
  85
  86         return -EINVAL;
  87 }
  88
  89 static u32 psci_power_state_pack(struct psci_power_state state)
  90 {
  91         return ((state.id << PSCI_0_2_POWER_STATE_ID_SHIFT)
  92                         & PSCI_0_2_POWER_STATE_ID_MASK) |
  93                 ((state.type << PSCI_0_2_POWER_STATE_TYPE_SHIFT)
  94                  & PSCI_0_2_POWER_STATE_TYPE_MASK) |
  95                 ((state.affinity_level << PSCI_0_2_POWER_STATE_AFFL_SHIFT)
  96                  & PSCI_0_2_POWER_STATE_AFFL_MASK);
  97 }
  98
  99 /*
 100  * The following two functions are invoked via the invoke_psci_fn pointer
 101  * and will not be inlined, allowing us to piggyback on the AAPCS.
 102  */
 103 static noinline int __invoke_psci_fn_hvc(u64 function_id, u64 arg0, u64 arg1,
 104                                          u64 arg2)
 105 {
 106         asm volatile(
 107                         __asmeq("%0", "x0")
 108                         __asmeq("%1", "x1")
 109                         __asmeq("%2", "x2")
 110                         __asmeq("%3", "x3")
 111                         "hvc    #0\n"
 112                 : "+r" (function_id)
 113                 : "r" (arg0), "r" (arg1), "r" (arg2));
 114
 115         return function_id;
 116 }
 117
 118 static noinline int __invoke_psci_fn_smc(u64 function_id, u64 arg0, u64 arg1,
 119                                          u64 arg2)
 120 {
 121         asm volatile(
 122                         __asmeq("%0", "x0")
 123                         __asmeq("%1", "x1")
 124                         __asmeq("%2", "x2")
 125                         __asmeq("%3", "x3")
 126                         "smc    #0\n"
 127                 : "+r" (function_id)
 128                 : "r" (arg0), "r" (arg1), "r" (arg2));
 129
 130         return function_id;
 131 }
 132
 133 static int psci_get_version(void)
 134 {
 135         int err;
 136
 137         err = invoke_psci_fn(PSCI_0_2_FN_PSCI_VERSION, 0, 0, 0);
 138         return err;
 139 }
 140
 141 static int psci_cpu_suspend(struct psci_power_state state,
 142                             unsigned long entry_point)
 143 {
 144         int err;
 145         u32 fn, power_state;
 146
 147         fn = psci_function_id[PSCI_FN_CPU_SUSPEND];
 148         power_state = psci_power_state_pack(state);
 149         err = invoke_psci_fn(fn, power_state, entry_point, 0);
 150         return psci_to_linux_errno(err);
 151 }
 152
 153 static int psci_cpu_off(struct psci_power_state state)
 154 {
 155         int err;
 156         u32 fn, power_state;
 157
 158         fn = psci_function_id[PSCI_FN_CPU_OFF];
 159         power_state = psci_power_state_pack(state);
 160         err = invoke_psci_fn(fn, power_state, 0, 0);
 161         return psci_to_linux_errno(err);
 162 }
 163
 164 static int psci_cpu_on(unsigned long cpuid, unsigned long entry_point)
 165 {
 166         int err;
 167         u32 fn;
 168
 169         fn = psci_function_id[PSCI_FN_CPU_ON];
 170         err = invoke_psci_fn(fn, cpuid, entry_point, 0);
 171         return psci_to_linux_errno(err);
 172 }
 173
 174 static int psci_migrate(unsigned long cpuid)
 175 {
 176         int err;
 177         u32 fn;
 178
 179         fn = psci_function_id[PSCI_FN_MIGRATE];
 180         err = invoke_psci_fn(fn, cpuid, 0, 0);
 181         return psci_to_linux_errno(err);
 182 }
 183
 184 static int psci_affinity_info(unsigned long target_affinity,
 185                 unsigned long lowest_affinity_level)
 186 {
 187         int err;
 188         u32 fn;
 189
 190         fn = psci_function_id[PSCI_FN_AFFINITY_INFO];
 191         err = invoke_psci_fn(fn, target_affinity, lowest_affinity_level, 0);
 192         return err;
 193 }
 194
 195 static int psci_migrate_info_type(void)
 196 {
 197         int err;
 198         u32 fn;
 199
 200         fn = psci_function_id[PSCI_FN_MIGRATE_INFO_TYPE];
 201         err = invoke_psci_fn(fn, 0, 0, 0);
 202         return err;
 203 }
 204
 205 static int get_set_conduit_method(struct device_node *np)
 206 {
 207         const char *method;
 208
 209         pr_info("probing for conduit method from DT.\n");
 210
 211         if (of_property_read_string(np, "method", &method)) {
 212                 pr_warn("missing \"method\" property\n");
 213                 return -ENXIO;
 214         }
 215
 216         if (!strcmp("hvc", method)) {
 217                 invoke_psci_fn = __invoke_psci_fn_hvc;
 218         } else if (!strcmp("smc", method)) {
 219                 invoke_psci_fn = __invoke_psci_fn_smc;
 220         } else {
 221                 pr_warn("invalid \"method\" property: %s\n", method);
 222                 return -EINVAL;
 223         }
 224         return 0;
 225 }
 226
 227 static void psci_sys_reset(enum reboot_mode reboot_mode, const char *cmd)
 228 {
 229         invoke_psci_fn(PSCI_0_2_FN_SYSTEM_RESET, 0, 0, 0);
 230 }
 231
 232 static void psci_sys_poweroff(void)
 233 {
 234         invoke_psci_fn(PSCI_0_2_FN_SYSTEM_OFF, 0, 0, 0);
 235 }
 236
 237 /*
 238  * PSCI Function IDs for v0.2+ are well defined so use
 239  * standard values.
 240  */
 241 static int psci_0_2_init(struct device_node *np)
 242 {
 243         int err, ver;
 244
 245         err = get_set_conduit_method(np);
 246
 247         if (err)
 248                 goto out_put_node;
 249
 250         ver = psci_get_version();
 251
 252         if (ver == PSCI_RET_NOT_SUPPORTED) {
 253                 /* PSCI v0.2 mandates implementation of PSCI_ID_VERSION. */
 254                 pr_err("PSCI firmware does not comply with the v0.2 spec.\n");
 255                 err = -EOPNOTSUPP;
 256                 goto out_put_node;
 257         } else {
 258                 pr_info("PSCIv%d.%d detected in firmware.\n",
 259                                 PSCI_VERSION_MAJOR(ver),
 260                                 PSCI_VERSION_MINOR(ver));
 261
 262                 if (PSCI_VERSION_MAJOR(ver) == 0 &&
 263                                 PSCI_VERSION_MINOR(ver) < 2) {
 264                         err = -EINVAL;
 265                         pr_err("Conflicting PSCI version detected.\n");
 266                         goto out_put_node;
 267                 }
 268         }
 269
 270         pr_info("Using standard PSCI v0.2 function IDs\n");
 271         psci_function_id[PSCI_FN_CPU_SUSPEND] = PSCI_0_2_FN64_CPU_SUSPEND;
 272         psci_ops.cpu_suspend = psci_cpu_suspend;
 273
 274         psci_function_id[PSCI_FN_CPU_OFF] = PSCI_0_2_FN_CPU_OFF;
 275         psci_ops.cpu_off = psci_cpu_off;
 276
 277         psci_function_id[PSCI_FN_CPU_ON] = PSCI_0_2_FN64_CPU_ON;
 278         psci_ops.cpu_on = psci_cpu_on;
 279
 280         psci_function_id[PSCI_FN_MIGRATE] = PSCI_0_2_FN64_MIGRATE;
 281         psci_ops.migrate = psci_migrate;
 282
 283         psci_function_id[PSCI_FN_AFFINITY_INFO] = PSCI_0_2_FN64_AFFINITY_INFO;
 284         psci_ops.affinity_info = psci_affinity_info;
 285
 286         psci_function_id[PSCI_FN_MIGRATE_INFO_TYPE] =
 287                 PSCI_0_2_FN_MIGRATE_INFO_TYPE;
 288         psci_ops.migrate_info_type = psci_migrate_info_type;
 289
 290         arm_pm_restart = psci_sys_reset;
 291
 292         pm_power_off = psci_sys_poweroff;
 293
 294 out_put_node:
 295         of_node_put(np);
 296         return err;
 297 }
 298
 299 /*
 300  * PSCI < v0.2 get PSCI Function IDs via DT.
 301  */
 302 static int psci_0_1_init(struct device_node *np)
 303 {
 304         u32 id;
 305         int err;
 306
 307         err = get_set_conduit_method(np);
 308
 309         if (err)
 310                 goto out_put_node;
 311
 312         pr_info("Using PSCI v0.1 Function IDs from DT\n");
 313
 314         if (!of_property_read_u32(np, "cpu_suspend", &id)) {
 315                 psci_function_id[PSCI_FN_CPU_SUSPEND] = id;
 316                 psci_ops.cpu_suspend = psci_cpu_suspend;
 317         }
 318
 319         if (!of_property_read_u32(np, "cpu_off", &id)) {
 320                 psci_function_id[PSCI_FN_CPU_OFF] = id;
 321                 psci_ops.cpu_off = psci_cpu_off;
 322         }
 323
 324         if (!of_property_read_u32(np, "cpu_on", &id)) {
 325                 psci_function_id[PSCI_FN_CPU_ON] = id;
 326                 psci_ops.cpu_on = psci_cpu_on;
 327         }
 328
 329         if (!of_property_read_u32(np, "migrate", &id)) {
 330                 psci_function_id[PSCI_FN_MIGRATE] = id;
 331                 psci_ops.migrate = psci_migrate;
 332         }
 333
 334 out_put_node:
 335         of_node_put(np);
 336         return err;
 337 }
 338
 339 static const struct of_device_id psci_of_match[] __initconst = {
 340         { .compatible = "arm,psci",     .data = psci_0_1_init},
 341         { .compatible = "arm,psci-0.2", .data = psci_0_2_init},
 342         {},
 343 };
 344
 345 int __init psci_init(void)
 346 {
 347         struct device_node *np;
 348         const struct of_device_id *matched_np;
 349         psci_initcall_t init_fn;
 350
 351         np = of_find_matching_node_and_match(NULL, psci_of_match, &matched_np);
 352
 353         if (!np)
 354                 return -ENODEV;
 355
 356         init_fn = (psci_initcall_t)matched_np->data;
 357         return init_fn(np);
 358 }
 359
 360 #ifdef CONFIG_SMP
 361
 362 static int __init cpu_psci_cpu_init(struct device_node *dn, unsigned int cpu)
 363 {
 364         return 0;
 365 }
 366
 367 static int __init cpu_psci_cpu_prepare(unsigned int cpu)
 368 {
 369         if (!psci_ops.cpu_on) {
 370                 pr_err("no cpu_on method, not booting CPU%d\n", cpu);
 371                 return -ENODEV;
 372         }
 373
 374         return 0;
 375 }
 376
 377 static int cpu_psci_cpu_boot(unsigned int cpu)
 378 {
 379         int err = psci_ops.cpu_on(cpu_logical_map(cpu), __pa(secondary_entry));
 380         if (err)
 381                 pr_err("failed to boot CPU%d (%d)\n", cpu, err);
 382
 383         return err;
 384 }
 385
 386 #ifdef CONFIG_HOTPLUG_CPU
 387 static int cpu_psci_cpu_disable(unsigned int cpu)
 388 {
 389         /* Fail early if we don't have CPU_OFF support */
 390         if (!psci_ops.cpu_off)
 391                 return -EOPNOTSUPP;
 392         return 0;
 393 }
 394
 395 static void cpu_psci_cpu_die(unsigned int cpu)
 396 {
 397         int ret;
 398         /*
 399          * There are no known implementations of PSCI actually using the
 400          * power state field, pass a sensible default for now.
 401          */
 402         struct psci_power_state state = {
 403                 .type = PSCI_POWER_STATE_TYPE_POWER_DOWN,
 404         };
 405
 406         ret = psci_ops.cpu_off(state);
 407
 408         pr_crit("unable to power off CPU%u (%d)\n", cpu, ret);
 409 }
 410
 411 static int cpu_psci_cpu_kill(unsigned int cpu)
 412 {
 413         int err, i;
 414
 415         if (!psci_ops.affinity_info)
 416                 return 1;
 417         /*
 418          * cpu_kill could race with cpu_die and we can
 419          * potentially end up declaring this cpu undead
 420          * while it is dying. So, try again a few times.
 421          */
 422
 423         for (i = 0; i < 10; i++) {
 424                 err = psci_ops.affinity_info(cpu_logical_map(cpu), 0);
 425                 if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) {
 426                         pr_info("CPU%d killed.\n", cpu);
 427                         return 1;
 428                 }
 429
 430                 msleep(10);
 431                 pr_info("Retrying again to check for CPU kill\n");
 432         }
 433
 434         pr_warn("CPU%d may not have shut down cleanly (AFFINITY_INFO reports %d)\n",
 435                         cpu, err);
 436         /* Make op_cpu_kill() fail. */
 437         return 0;
 438 }
 439 #endif
 440
 441 const struct cpu_operations cpu_psci_ops = {
 442         .name           = "psci",
 443         .cpu_init       = cpu_psci_cpu_init,
 444         .cpu_prepare    = cpu_psci_cpu_prepare,
 445         .cpu_boot       = cpu_psci_cpu_boot,
 446 #ifdef CONFIG_HOTPLUG_CPU
 447         .cpu_disable    = cpu_psci_cpu_disable,
 448         .cpu_die        = cpu_psci_cpu_die,
 449         .cpu_kill       = cpu_psci_cpu_kill,
 450 #endif
 451 };
 452
 453 #endif