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 #define PSCI_POWER_STATE_TYPE_STANDBY           0
  34 #define PSCI_POWER_STATE_TYPE_POWER_DOWN        1
  35
  36 struct psci_power_state {
  37         u16     id;
  38         u8      type;
  39         u8      affinity_level;
  40 };
  41
  42 struct psci_operations {
  43         int (*cpu_suspend)(struct psci_power_state state,
  44                            unsigned long entry_point);
  45         int (*cpu_off)(struct psci_power_state state);
  46         int (*cpu_on)(unsigned long cpuid, unsigned long entry_point);
  47         int (*migrate)(unsigned long cpuid);
  48         int (*affinity_info)(unsigned long target_affinity,
  49                         unsigned long lowest_affinity_level);
  50         int (*migrate_info_type)(void);
  51 };
  52
  53 static struct psci_operations psci_ops;
  54
  55 static int (*invoke_psci_fn)(u64, u64, u64, u64);
  56 typedef int (*psci_initcall_t)(const struct device_node *);
  57
  58 enum psci_function {
  59         PSCI_FN_CPU_SUSPEND,
  60         PSCI_FN_CPU_ON,
  61         PSCI_FN_CPU_OFF,
  62         PSCI_FN_MIGRATE,
  63         PSCI_FN_AFFINITY_INFO,
  64         PSCI_FN_MIGRATE_INFO_TYPE,
  65         PSCI_FN_MAX,
  66 };
  67
  68 static u32 psci_function_id[PSCI_FN_MAX];
  69
  70 static int psci_to_linux_errno(int errno)
  71 {
  72         switch (errno) {
  73         case PSCI_RET_SUCCESS:
  74                 return 0;
  75         case PSCI_RET_NOT_SUPPORTED:
  76                 return -EOPNOTSUPP;
  77         case PSCI_RET_INVALID_PARAMS:
  78                 return -EINVAL;
  79         case PSCI_RET_DENIED:
  80                 return -EPERM;
  81         };
  82
  83         return -EINVAL;
  84 }
  85
  86 static u32 psci_power_state_pack(struct psci_power_state state)
  87 {
  88         return ((state.id << PSCI_0_2_POWER_STATE_ID_SHIFT)
  89                         & PSCI_0_2_POWER_STATE_ID_MASK) |
  90                 ((state.type << PSCI_0_2_POWER_STATE_TYPE_SHIFT)
  91                  & PSCI_0_2_POWER_STATE_TYPE_MASK) |
  92                 ((state.affinity_level << PSCI_0_2_POWER_STATE_AFFL_SHIFT)
  93                  & PSCI_0_2_POWER_STATE_AFFL_MASK);
  94 }
  95
  96 /*
  97  * The following two functions are invoked via the invoke_psci_fn pointer
  98  * and will not be inlined, allowing us to piggyback on the AAPCS.
  99  */
 100 static noinline int __invoke_psci_fn_hvc(u64 function_id, u64 arg0, u64 arg1,
 101                                          u64 arg2)
 102 {
 103         asm volatile(
 104                         __asmeq("%0", "x0")
 105                         __asmeq("%1", "x1")
 106                         __asmeq("%2", "x2")
 107                         __asmeq("%3", "x3")
 108                         "hvc    #0\n"
 109                 : "+r" (function_id)
 110                 : "r" (arg0), "r" (arg1), "r" (arg2));
 111
 112         return function_id;
 113 }
 114
 115 static noinline int __invoke_psci_fn_smc(u64 function_id, u64 arg0, u64 arg1,
 116                                          u64 arg2)
 117 {
 118         asm volatile(
 119                         __asmeq("%0", "x0")
 120                         __asmeq("%1", "x1")
 121                         __asmeq("%2", "x2")
 122                         __asmeq("%3", "x3")
 123                         "smc    #0\n"
 124                 : "+r" (function_id)
 125                 : "r" (arg0), "r" (arg1), "r" (arg2));
 126
 127         return function_id;
 128 }
 129
 130 static int psci_get_version(void)
 131 {
 132         int err;
 133
 134         err = invoke_psci_fn(PSCI_0_2_FN_PSCI_VERSION, 0, 0, 0);
 135         return err;
 136 }
 137
 138 static int psci_cpu_suspend(struct psci_power_state state,
 139                             unsigned long entry_point)
 140 {
 141         int err;
 142         u32 fn, power_state;
 143
 144         fn = psci_function_id[PSCI_FN_CPU_SUSPEND];
 145         power_state = psci_power_state_pack(state);
 146         err = invoke_psci_fn(fn, power_state, entry_point, 0);
 147         return psci_to_linux_errno(err);
 148 }
 149
 150 static int psci_cpu_off(struct psci_power_state state)
 151 {
 152         int err;
 153         u32 fn, power_state;
 154
 155         fn = psci_function_id[PSCI_FN_CPU_OFF];
 156         power_state = psci_power_state_pack(state);
 157         err = invoke_psci_fn(fn, power_state, 0, 0);
 158         return psci_to_linux_errno(err);
 159 }
 160
 161 static int psci_cpu_on(unsigned long cpuid, unsigned long entry_point)
 162 {
 163         int err;
 164         u32 fn;
 165
 166         fn = psci_function_id[PSCI_FN_CPU_ON];
 167         err = invoke_psci_fn(fn, cpuid, entry_point, 0);
 168         return psci_to_linux_errno(err);
 169 }
 170
 171 static int psci_migrate(unsigned long cpuid)
 172 {
 173         int err;
 174         u32 fn;
 175
 176         fn = psci_function_id[PSCI_FN_MIGRATE];
 177         err = invoke_psci_fn(fn, cpuid, 0, 0);
 178         return psci_to_linux_errno(err);
 179 }
 180
 181 static int psci_affinity_info(unsigned long target_affinity,
 182                 unsigned long lowest_affinity_level)
 183 {
 184         int err;
 185         u32 fn;
 186
 187         fn = psci_function_id[PSCI_FN_AFFINITY_INFO];
 188         err = invoke_psci_fn(fn, target_affinity, lowest_affinity_level, 0);
 189         return err;
 190 }
 191
 192 static int psci_migrate_info_type(void)
 193 {
 194         int err;
 195         u32 fn;
 196
 197         fn = psci_function_id[PSCI_FN_MIGRATE_INFO_TYPE];
 198         err = invoke_psci_fn(fn, 0, 0, 0);
 199         return err;
 200 }
 201
 202 static int get_set_conduit_method(struct device_node *np)
 203 {
 204         const char *method;
 205
 206         pr_info("probing for conduit method from DT.\n");
 207
 208         if (of_property_read_string(np, "method", &method)) {
 209                 pr_warn("missing \"method\" property\n");
 210                 return -ENXIO;
 211         }
 212
 213         if (!strcmp("hvc", method)) {
 214                 invoke_psci_fn = __invoke_psci_fn_hvc;
 215         } else if (!strcmp("smc", method)) {
 216                 invoke_psci_fn = __invoke_psci_fn_smc;
 217         } else {
 218                 pr_warn("invalid \"method\" property: %s\n", method);
 219                 return -EINVAL;
 220         }
 221         return 0;
 222 }
 223
 224 static void psci_sys_reset(enum reboot_mode reboot_mode, const char *cmd)
 225 {
 226         invoke_psci_fn(PSCI_0_2_FN_SYSTEM_RESET, 0, 0, 0);
 227 }
 228
 229 static void psci_sys_poweroff(void)
 230 {
 231         invoke_psci_fn(PSCI_0_2_FN_SYSTEM_OFF, 0, 0, 0);
 232 }
 233
 234 /*
 235  * PSCI Function IDs for v0.2+ are well defined so use
 236  * standard values.
 237  */
 238 static int __init psci_0_2_init(struct device_node *np)
 239 {
 240         int err, ver;
 241
 242         err = get_set_conduit_method(np);
 243
 244         if (err)
 245                 goto out_put_node;
 246
 247         ver = psci_get_version();
 248
 249         if (ver == PSCI_RET_NOT_SUPPORTED) {
 250                 /* PSCI v0.2 mandates implementation of PSCI_ID_VERSION. */
 251                 pr_err("PSCI firmware does not comply with the v0.2 spec.\n");
 252                 err = -EOPNOTSUPP;
 253                 goto out_put_node;
 254         } else {
 255                 pr_info("PSCIv%d.%d detected in firmware.\n",
 256                                 PSCI_VERSION_MAJOR(ver),
 257                                 PSCI_VERSION_MINOR(ver));
 258
 259                 if (PSCI_VERSION_MAJOR(ver) == 0 &&
 260                                 PSCI_VERSION_MINOR(ver) < 2) {
 261                         err = -EINVAL;
 262                         pr_err("Conflicting PSCI version detected.\n");
 263                         goto out_put_node;
 264                 }
 265         }
 266
 267         pr_info("Using standard PSCI v0.2 function IDs\n");
 268         psci_function_id[PSCI_FN_CPU_SUSPEND] = PSCI_0_2_FN64_CPU_SUSPEND;
 269         psci_ops.cpu_suspend = psci_cpu_suspend;
 270
 271         psci_function_id[PSCI_FN_CPU_OFF] = PSCI_0_2_FN_CPU_OFF;
 272         psci_ops.cpu_off = psci_cpu_off;
 273
 274         psci_function_id[PSCI_FN_CPU_ON] = PSCI_0_2_FN64_CPU_ON;
 275         psci_ops.cpu_on = psci_cpu_on;
 276
 277         psci_function_id[PSCI_FN_MIGRATE] = PSCI_0_2_FN64_MIGRATE;
 278         psci_ops.migrate = psci_migrate;
 279
 280         psci_function_id[PSCI_FN_AFFINITY_INFO] = PSCI_0_2_FN64_AFFINITY_INFO;
 281         psci_ops.affinity_info = psci_affinity_info;
 282
 283         psci_function_id[PSCI_FN_MIGRATE_INFO_TYPE] =
 284                 PSCI_0_2_FN_MIGRATE_INFO_TYPE;
 285         psci_ops.migrate_info_type = psci_migrate_info_type;
 286
 287         arm_pm_restart = psci_sys_reset;
 288
 289         pm_power_off = psci_sys_poweroff;
 290
 291 out_put_node:
 292         of_node_put(np);
 293         return err;
 294 }
 295
 296 /*
 297  * PSCI < v0.2 get PSCI Function IDs via DT.
 298  */
 299 static int __init psci_0_1_init(struct device_node *np)
 300 {
 301         u32 id;
 302         int err;
 303
 304         err = get_set_conduit_method(np);
 305
 306         if (err)
 307                 goto out_put_node;
 308
 309         pr_info("Using PSCI v0.1 Function IDs from DT\n");
 310
 311         if (!of_property_read_u32(np, "cpu_suspend", &id)) {
 312                 psci_function_id[PSCI_FN_CPU_SUSPEND] = id;
 313                 psci_ops.cpu_suspend = psci_cpu_suspend;
 314         }
 315
 316         if (!of_property_read_u32(np, "cpu_off", &id)) {
 317                 psci_function_id[PSCI_FN_CPU_OFF] = id;
 318                 psci_ops.cpu_off = psci_cpu_off;
 319         }
 320
 321         if (!of_property_read_u32(np, "cpu_on", &id)) {
 322                 psci_function_id[PSCI_FN_CPU_ON] = id;
 323                 psci_ops.cpu_on = psci_cpu_on;
 324         }
 325
 326         if (!of_property_read_u32(np, "migrate", &id)) {
 327                 psci_function_id[PSCI_FN_MIGRATE] = id;
 328                 psci_ops.migrate = psci_migrate;
 329         }
 330
 331 out_put_node:
 332         of_node_put(np);
 333         return err;
 334 }
 335
 336 static const struct of_device_id psci_of_match[] __initconst = {
 337         { .compatible = "arm,psci",     .data = psci_0_1_init},
 338         { .compatible = "arm,psci-0.2", .data = psci_0_2_init},
 339         {},
 340 };
 341
 342 int __init psci_init(void)
 343 {
 344         struct device_node *np;
 345         const struct of_device_id *matched_np;
 346         psci_initcall_t init_fn;
 347
 348         np = of_find_matching_node_and_match(NULL, psci_of_match, &matched_np);
 349
 350         if (!np)
 351                 return -ENODEV;
 352
 353         init_fn = (psci_initcall_t)matched_np->data;
 354         return init_fn(np);
 355 }
 356
 357 #ifdef CONFIG_SMP
 358
 359 static int __init cpu_psci_cpu_init(struct device_node *dn, unsigned int cpu)
 360 {
 361         return 0;
 362 }
 363
 364 static int __init cpu_psci_cpu_prepare(unsigned int cpu)
 365 {
 366         if (!psci_ops.cpu_on) {
 367                 pr_err("no cpu_on method, not booting CPU%d\n", cpu);
 368                 return -ENODEV;
 369         }
 370
 371         return 0;
 372 }
 373
 374 static int cpu_psci_cpu_boot(unsigned int cpu)
 375 {
 376         int err = psci_ops.cpu_on(cpu_logical_map(cpu), __pa(secondary_entry));
 377         if (err)
 378                 pr_err("failed to boot CPU%d (%d)\n", cpu, err);
 379
 380         return err;
 381 }
 382
 383 #ifdef CONFIG_HOTPLUG_CPU
 384 static int cpu_psci_cpu_disable(unsigned int cpu)
 385 {
 386         /* Fail early if we don't have CPU_OFF support */
 387         if (!psci_ops.cpu_off)
 388                 return -EOPNOTSUPP;
 389         return 0;
 390 }
 391
 392 static void cpu_psci_cpu_die(unsigned int cpu)
 393 {
 394         int ret;
 395         /*
 396          * There are no known implementations of PSCI actually using the
 397          * power state field, pass a sensible default for now.
 398          */
 399         struct psci_power_state state = {
 400                 .type = PSCI_POWER_STATE_TYPE_POWER_DOWN,
 401         };
 402
 403         ret = psci_ops.cpu_off(state);
 404
 405         pr_crit("unable to power off CPU%u (%d)\n", cpu, ret);
 406 }
 407
 408 static int cpu_psci_cpu_kill(unsigned int cpu)
 409 {
 410         int err, i;
 411
 412         if (!psci_ops.affinity_info)
 413                 return 1;
 414         /*
 415          * cpu_kill could race with cpu_die and we can
 416          * potentially end up declaring this cpu undead
 417          * while it is dying. So, try again a few times.
 418          */
 419
 420         for (i = 0; i < 10; i++) {
 421                 err = psci_ops.affinity_info(cpu_logical_map(cpu), 0);
 422                 if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) {
 423                         pr_info("CPU%d killed.\n", cpu);
 424                         return 1;
 425                 }
 426
 427                 msleep(10);
 428                 pr_info("Retrying again to check for CPU kill\n");
 429         }
 430
 431         pr_warn("CPU%d may not have shut down cleanly (AFFINITY_INFO reports %d)\n",
 432                         cpu, err);
 433         /* Make op_cpu_kill() fail. */
 434         return 0;
 435 }
 436 #endif
 437 #endif
 438
 439 const struct cpu_operations cpu_psci_ops = {
 440         .name           = "psci",
 441 #ifdef CONFIG_SMP
 442         .cpu_init       = cpu_psci_cpu_init,
 443         .cpu_prepare    = cpu_psci_cpu_prepare,
 444         .cpu_boot       = cpu_psci_cpu_boot,
 445 #ifdef CONFIG_HOTPLUG_CPU
 446         .cpu_disable    = cpu_psci_cpu_disable,
 447         .cpu_die        = cpu_psci_cpu_die,
 448         .cpu_kill       = cpu_psci_cpu_kill,
 449 #endif
 450 #endif
 451 };
 452