kernel/power/suspend.c

   1 /*
   2  * kernel/power/suspend.c - Suspend to RAM and standby functionality.
   3  *
   4  * Copyright (c) 2003 Patrick Mochel
   5  * Copyright (c) 2003 Open Source Development Lab
   6  * Copyright (c) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
   7  *
   8  * This file is released under the GPLv2.
   9  */
  10
  11 #define pr_fmt(fmt) "PM: " fmt
  12
  13 #include <linux/string.h>
  14 #include <linux/delay.h>
  15 #include <linux/errno.h>
  16 #include <linux/init.h>
  17 #include <linux/console.h>
  18 #include <linux/cpu.h>
  19 #include <linux/cpuidle.h>
  20 #include <linux/syscalls.h>
  21 #include <linux/gfp.h>
  22 #include <linux/io.h>
  23 #include <linux/kernel.h>
  24 #include <linux/list.h>
  25 #include <linux/mm.h>
  26 #include <linux/slab.h>
  27 #include <linux/export.h>
  28 #include <linux/suspend.h>
  29 #include <linux/syscore_ops.h>
  30 #include <linux/ftrace.h>
  31 #include <trace/events/power.h>
  32 #include <linux/compiler.h>
  33 #include <linux/moduleparam.h>
  34
  35 #include "power.h"
  36
  37 const char * const pm_labels[] = {
  38         [PM_SUSPEND_TO_IDLE] = "freeze",
  39         [PM_SUSPEND_STANDBY] = "standby",
  40         [PM_SUSPEND_MEM] = "mem",
  41 };
  42 const char *pm_states[PM_SUSPEND_MAX];
  43 static const char * const mem_sleep_labels[] = {
  44         [PM_SUSPEND_TO_IDLE] = "s2idle",
  45         [PM_SUSPEND_STANDBY] = "shallow",
  46         [PM_SUSPEND_MEM] = "deep",
  47 };
  48 const char *mem_sleep_states[PM_SUSPEND_MAX];
  49
  50 suspend_state_t mem_sleep_current = PM_SUSPEND_TO_IDLE;
  51 suspend_state_t mem_sleep_default = PM_SUSPEND_MAX;
  52 suspend_state_t pm_suspend_target_state;
  53 EXPORT_SYMBOL_GPL(pm_suspend_target_state);
  54
  55 unsigned int pm_suspend_global_flags;
  56 EXPORT_SYMBOL_GPL(pm_suspend_global_flags);
  57
  58 static const struct platform_suspend_ops *suspend_ops;
  59 static const struct platform_s2idle_ops *s2idle_ops;
  60 static DECLARE_WAIT_QUEUE_HEAD(s2idle_wait_head);
  61
  62 enum s2idle_states __read_mostly s2idle_state;
  63 static DEFINE_SPINLOCK(s2idle_lock);
  64
  65 bool pm_suspend_via_s2idle(void)
  66 {
  67         return mem_sleep_current == PM_SUSPEND_TO_IDLE;
  68 }
  69 EXPORT_SYMBOL_GPL(pm_suspend_via_s2idle);
  70
  71 void s2idle_set_ops(const struct platform_s2idle_ops *ops)
  72 {
  73         lock_system_sleep();
  74         s2idle_ops = ops;
  75         unlock_system_sleep();
  76 }
  77
  78 static void s2idle_begin(void)
  79 {
  80         s2idle_state = S2IDLE_STATE_NONE;
  81 }
  82
  83 static void s2idle_enter(void)
  84 {
  85         trace_suspend_resume(TPS("machine_suspend"), PM_SUSPEND_TO_IDLE, true);
  86
  87         spin_lock_irq(&s2idle_lock);
  88         if (pm_wakeup_pending())
  89                 goto out;
  90
  91         s2idle_state = S2IDLE_STATE_ENTER;
  92         spin_unlock_irq(&s2idle_lock);
  93
  94         get_online_cpus();
  95         cpuidle_resume();
  96
  97         /* Push all the CPUs into the idle loop. */
  98         wake_up_all_idle_cpus();
  99         /* Make the current CPU wait so it can enter the idle loop too. */
 100         wait_event(s2idle_wait_head,
 101                    s2idle_state == S2IDLE_STATE_WAKE);
 102
 103         cpuidle_pause();
 104         put_online_cpus();
 105
 106         spin_lock_irq(&s2idle_lock);
 107
 108  out:
 109         s2idle_state = S2IDLE_STATE_NONE;
 110         spin_unlock_irq(&s2idle_lock);
 111
 112         trace_suspend_resume(TPS("machine_suspend"), PM_SUSPEND_TO_IDLE, false);
 113 }
 114
 115 static void s2idle_loop(void)
 116 {
 117         pm_pr_dbg("suspend-to-idle\n");
 118
 119         for (;;) {
 120                 int error;
 121
 122                 dpm_noirq_begin();
 123
 124                 /*
 125                  * Suspend-to-idle equals
 126                  * frozen processes + suspended devices + idle processors.
 127                  * Thus s2idle_enter() should be called right after
 128                  * all devices have been suspended.
 129                  *
 130                  * Wakeups during the noirq suspend of devices may be spurious,
 131                  * so prevent them from terminating the loop right away.
 132                  */
 133                 error = dpm_noirq_suspend_devices(PMSG_SUSPEND);
 134                 if (!error)
 135                         s2idle_enter();
 136                 else if (error == -EBUSY && pm_wakeup_pending())
 137                         error = 0;
 138
 139                 if (!error && s2idle_ops && s2idle_ops->wake)
 140                         s2idle_ops->wake();
 141
 142                 dpm_noirq_resume_devices(PMSG_RESUME);
 143
 144                 dpm_noirq_end();
 145
 146                 if (error)
 147                         break;
 148
 149                 if (s2idle_ops && s2idle_ops->sync)
 150                         s2idle_ops->sync();
 151
 152                 if (pm_wakeup_pending())
 153                         break;
 154
 155                 pm_wakeup_clear(false);
 156         }
 157
 158         pm_pr_dbg("resume from suspend-to-idle\n");
 159 }
 160
 161 void s2idle_wake(void)
 162 {
 163         unsigned long flags;
 164
 165         spin_lock_irqsave(&s2idle_lock, flags);
 166         if (s2idle_state > S2IDLE_STATE_NONE) {
 167                 s2idle_state = S2IDLE_STATE_WAKE;
 168                 wake_up(&s2idle_wait_head);
 169         }
 170         spin_unlock_irqrestore(&s2idle_lock, flags);
 171 }
 172 EXPORT_SYMBOL_GPL(s2idle_wake);
 173
 174 static bool valid_state(suspend_state_t state)
 175 {
 176         /*
 177          * PM_SUSPEND_STANDBY and PM_SUSPEND_MEM states need low level
 178          * support and need to be valid to the low level
 179          * implementation, no valid callback implies that none are valid.
 180          */
 181         return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
 182 }
 183
 184 void __init pm_states_init(void)
 185 {
 186         /* "mem" and "freeze" are always present in /sys/power/state. */
 187         pm_states[PM_SUSPEND_MEM] = pm_labels[PM_SUSPEND_MEM];
 188         pm_states[PM_SUSPEND_TO_IDLE] = pm_labels[PM_SUSPEND_TO_IDLE];
 189         /*
 190          * Suspend-to-idle should be supported even without any suspend_ops,
 191          * initialize mem_sleep_states[] accordingly here.
 192          */
 193         mem_sleep_states[PM_SUSPEND_TO_IDLE] = mem_sleep_labels[PM_SUSPEND_TO_IDLE];
 194 }
 195
 196 static int __init mem_sleep_default_setup(char *str)
 197 {
 198         suspend_state_t state;
 199
 200         for (state = PM_SUSPEND_TO_IDLE; state <= PM_SUSPEND_MEM; state++)
 201                 if (mem_sleep_labels[state] &&
 202                     !strcmp(str, mem_sleep_labels[state])) {
 203                         mem_sleep_default = state;
 204                         break;
 205                 }
 206
 207         return 1;
 208 }
 209 __setup("mem_sleep_default=", mem_sleep_default_setup);
 210
 211 /**
 212  * suspend_set_ops - Set the global suspend method table.
 213  * @ops: Suspend operations to use.
 214  */
 215 void suspend_set_ops(const struct platform_suspend_ops *ops)
 216 {
 217         lock_system_sleep();
 218
 219         suspend_ops = ops;
 220
 221         if (valid_state(PM_SUSPEND_STANDBY)) {
 222                 mem_sleep_states[PM_SUSPEND_STANDBY] = mem_sleep_labels[PM_SUSPEND_STANDBY];
 223                 pm_states[PM_SUSPEND_STANDBY] = pm_labels[PM_SUSPEND_STANDBY];
 224                 if (mem_sleep_default == PM_SUSPEND_STANDBY)
 225                         mem_sleep_current = PM_SUSPEND_STANDBY;
 226         }
 227         if (valid_state(PM_SUSPEND_MEM)) {
 228                 mem_sleep_states[PM_SUSPEND_MEM] = mem_sleep_labels[PM_SUSPEND_MEM];
 229                 if (mem_sleep_default >= PM_SUSPEND_MEM)
 230                         mem_sleep_current = PM_SUSPEND_MEM;
 231         }
 232
 233         unlock_system_sleep();
 234 }
 235 EXPORT_SYMBOL_GPL(suspend_set_ops);
 236
 237 /**
 238  * suspend_valid_only_mem - Generic memory-only valid callback.
 239  *
 240  * Platform drivers that implement mem suspend only and only need to check for
 241  * that in their .valid() callback can use this instead of rolling their own
 242  * .valid() callback.
 243  */
 244 int suspend_valid_only_mem(suspend_state_t state)
 245 {
 246         return state == PM_SUSPEND_MEM;
 247 }
 248 EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
 249
 250 static bool sleep_state_supported(suspend_state_t state)
 251 {
 252         return state == PM_SUSPEND_TO_IDLE || (suspend_ops && suspend_ops->enter);
 253 }
 254
 255 static int platform_suspend_prepare(suspend_state_t state)
 256 {
 257         return state != PM_SUSPEND_TO_IDLE && suspend_ops->prepare ?
 258                 suspend_ops->prepare() : 0;
 259 }
 260
 261 static int platform_suspend_prepare_late(suspend_state_t state)
 262 {
 263         return state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->prepare ?
 264                 s2idle_ops->prepare() : 0;
 265 }
 266
 267 static int platform_suspend_prepare_noirq(suspend_state_t state)
 268 {
 269         return state != PM_SUSPEND_TO_IDLE && suspend_ops->prepare_late ?
 270                 suspend_ops->prepare_late() : 0;
 271 }
 272
 273 static void platform_resume_noirq(suspend_state_t state)
 274 {
 275         if (state != PM_SUSPEND_TO_IDLE && suspend_ops->wake)
 276                 suspend_ops->wake();
 277 }
 278
 279 static void platform_resume_early(suspend_state_t state)
 280 {
 281         if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->restore)
 282                 s2idle_ops->restore();
 283 }
 284
 285 static void platform_resume_finish(suspend_state_t state)
 286 {
 287         if (state != PM_SUSPEND_TO_IDLE && suspend_ops->finish)
 288                 suspend_ops->finish();
 289 }
 290
 291 static int platform_suspend_begin(suspend_state_t state)
 292 {
 293         if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->begin)
 294                 return s2idle_ops->begin();
 295         else if (suspend_ops && suspend_ops->begin)
 296                 return suspend_ops->begin(state);
 297         else
 298                 return 0;
 299 }
 300
 301 static void platform_resume_end(suspend_state_t state)
 302 {
 303         if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->end)
 304                 s2idle_ops->end();
 305         else if (suspend_ops && suspend_ops->end)
 306                 suspend_ops->end();
 307 }
 308
 309 static void platform_recover(suspend_state_t state)
 310 {
 311         if (state != PM_SUSPEND_TO_IDLE && suspend_ops->recover)
 312                 suspend_ops->recover();
 313 }
 314
 315 static bool platform_suspend_again(suspend_state_t state)
 316 {
 317         return state != PM_SUSPEND_TO_IDLE && suspend_ops->suspend_again ?
 318                 suspend_ops->suspend_again() : false;
 319 }
 320
 321 #ifdef CONFIG_PM_DEBUG
 322 static unsigned int pm_test_delay = 5;
 323 module_param(pm_test_delay, uint, 0644);
 324 MODULE_PARM_DESC(pm_test_delay,
 325                  "Number of seconds to wait before resuming from suspend test");
 326 #endif
 327
 328 static int suspend_test(int level)
 329 {
 330 #ifdef CONFIG_PM_DEBUG
 331         if (pm_test_level == level) {
 332                 pr_info("suspend debug: Waiting for %d second(s).\n",
 333                                 pm_test_delay);
 334                 mdelay(pm_test_delay * 1000);
 335                 return 1;
 336         }
 337 #endif /* !CONFIG_PM_DEBUG */
 338         return 0;
 339 }
 340
 341 /**
 342  * suspend_prepare - Prepare for entering system sleep state.
 343  *
 344  * Common code run for every system sleep state that can be entered (except for
 345  * hibernation).  Run suspend notifiers, allocate the "suspend" console and
 346  * freeze processes.
 347  */
 348 static int suspend_prepare(suspend_state_t state)
 349 {
 350         int error, nr_calls = 0;
 351
 352         if (!sleep_state_supported(state))
 353                 return -EPERM;
 354
 355         pm_prepare_console();
 356
 357         error = __pm_notifier_call_chain(PM_SUSPEND_PREPARE, -1, &nr_calls);
 358         if (error) {
 359                 nr_calls--;
 360                 goto Finish;
 361         }
 362
 363         trace_suspend_resume(TPS("freeze_processes"), 0, true);
 364         error = suspend_freeze_processes();
 365         trace_suspend_resume(TPS("freeze_processes"), 0, false);
 366         if (!error)
 367                 return 0;
 368
 369         suspend_stats.failed_freeze++;
 370         dpm_save_failed_step(SUSPEND_FREEZE);
 371  Finish:
 372         __pm_notifier_call_chain(PM_POST_SUSPEND, nr_calls, NULL);
 373         pm_restore_console();
 374         return error;
 375 }
 376
 377 /* default implementation */
 378 void __weak arch_suspend_disable_irqs(void)
 379 {
 380         local_irq_disable();
 381 }
 382
 383 /* default implementation */
 384 void __weak arch_suspend_enable_irqs(void)
 385 {
 386         local_irq_enable();
 387 }
 388
 389 /**
 390  * suspend_enter - Make the system enter the given sleep state.
 391  * @state: System sleep state to enter.
 392  * @wakeup: Returns information that the sleep state should not be re-entered.
 393  *
 394  * This function should be called after devices have been suspended.
 395  */
 396 static int suspend_enter(suspend_state_t state, bool *wakeup)
 397 {
 398         int error;
 399
 400         error = platform_suspend_prepare(state);
 401         if (error)
 402                 goto Platform_finish;
 403
 404         error = dpm_suspend_late(PMSG_SUSPEND);
 405         if (error) {
 406                 pr_err("late suspend of devices failed\n");
 407                 goto Platform_finish;
 408         }
 409         error = platform_suspend_prepare_late(state);
 410         if (error)
 411                 goto Devices_early_resume;
 412
 413         if (state == PM_SUSPEND_TO_IDLE && pm_test_level != TEST_PLATFORM) {
 414                 s2idle_loop();
 415                 goto Platform_early_resume;
 416         }
 417
 418         error = dpm_suspend_noirq(PMSG_SUSPEND);
 419         if (error) {
 420                 pr_err("noirq suspend of devices failed\n");
 421                 goto Platform_early_resume;
 422         }
 423         error = platform_suspend_prepare_noirq(state);
 424         if (error)
 425                 goto Platform_wake;
 426
 427         if (suspend_test(TEST_PLATFORM))
 428                 goto Platform_wake;
 429
 430         error = disable_nonboot_cpus();
 431         if (error || suspend_test(TEST_CPUS))
 432                 goto Enable_cpus;
 433
 434         arch_suspend_disable_irqs();
 435         BUG_ON(!irqs_disabled());
 436
 437         error = syscore_suspend();
 438         if (!error) {
 439                 *wakeup = pm_wakeup_pending();
 440                 if (!(suspend_test(TEST_CORE) || *wakeup)) {
 441                         trace_suspend_resume(TPS("machine_suspend"),
 442                                 state, true);
 443                         error = suspend_ops->enter(state);
 444                         trace_suspend_resume(TPS("machine_suspend"),
 445                                 state, false);
 446                 } else if (*wakeup) {
 447                         error = -EBUSY;
 448                 }
 449                 syscore_resume();
 450         }
 451
 452         arch_suspend_enable_irqs();
 453         BUG_ON(irqs_disabled());
 454
 455  Enable_cpus:
 456         enable_nonboot_cpus();
 457
 458  Platform_wake:
 459         platform_resume_noirq(state);
 460         dpm_resume_noirq(PMSG_RESUME);
 461
 462  Platform_early_resume:
 463         platform_resume_early(state);
 464
 465  Devices_early_resume:
 466         dpm_resume_early(PMSG_RESUME);
 467
 468  Platform_finish:
 469         platform_resume_finish(state);
 470         return error;
 471 }
 472
 473 /**
 474  * suspend_devices_and_enter - Suspend devices and enter system sleep state.
 475  * @state: System sleep state to enter.
 476  */
 477 int suspend_devices_and_enter(suspend_state_t state)
 478 {
 479         int error;
 480         bool wakeup = false;
 481
 482         if (!sleep_state_supported(state))
 483                 return -ENOSYS;
 484
 485         pm_suspend_target_state = state;
 486
 487         error = platform_suspend_begin(state);
 488         if (error)
 489                 goto Close;
 490
 491         suspend_console();
 492         suspend_test_start();
 493         error = dpm_suspend_start(PMSG_SUSPEND);
 494         if (error) {
 495                 pr_err("Some devices failed to suspend, or early wake event detected\n");
 496                 goto Recover_platform;
 497         }
 498         suspend_test_finish("suspend devices");
 499         if (suspend_test(TEST_DEVICES))
 500                 goto Recover_platform;
 501
 502         do {
 503                 error = suspend_enter(state, &wakeup);
 504         } while (!error && !wakeup && platform_suspend_again(state));
 505
 506  Resume_devices:
 507         suspend_test_start();
 508         dpm_resume_end(PMSG_RESUME);
 509         suspend_test_finish("resume devices");
 510         trace_suspend_resume(TPS("resume_console"), state, true);
 511         resume_console();
 512         trace_suspend_resume(TPS("resume_console"), state, false);
 513
 514  Close:
 515         platform_resume_end(state);
 516         pm_suspend_target_state = PM_SUSPEND_ON;
 517         return error;
 518
 519  Recover_platform:
 520         platform_recover(state);
 521         goto Resume_devices;
 522 }
 523
 524 /**
 525  * suspend_finish - Clean up before finishing the suspend sequence.
 526  *
 527  * Call platform code to clean up, restart processes, and free the console that
 528  * we've allocated. This routine is not called for hibernation.
 529  */
 530 static void suspend_finish(void)
 531 {
 532         suspend_thaw_processes();
 533         pm_notifier_call_chain(PM_POST_SUSPEND);
 534         pm_restore_console();
 535 }
 536
 537 /**
 538  * enter_state - Do common work needed to enter system sleep state.
 539  * @state: System sleep state to enter.
 540  *
 541  * Make sure that no one else is trying to put the system into a sleep state.
 542  * Fail if that's not the case.  Otherwise, prepare for system suspend, make the
 543  * system enter the given sleep state and clean up after wakeup.
 544  */
 545 static int enter_state(suspend_state_t state)
 546 {
 547         int error;
 548
 549         trace_suspend_resume(TPS("suspend_enter"), state, true);
 550         if (state == PM_SUSPEND_TO_IDLE) {
 551 #ifdef CONFIG_PM_DEBUG
 552                 if (pm_test_level != TEST_NONE && pm_test_level <= TEST_CPUS) {
 553                         pr_warn("Unsupported test mode for suspend to idle, please choose none/freezer/devices/platform.\n");
 554                         return -EAGAIN;
 555                 }
 556 #endif
 557         } else if (!valid_state(state)) {
 558                 return -EINVAL;
 559         }
 560         if (!mutex_trylock(&pm_mutex))
 561                 return -EBUSY;
 562
 563         if (state == PM_SUSPEND_TO_IDLE)
 564                 s2idle_begin();
 565
 566 #ifndef CONFIG_SUSPEND_SKIP_SYNC
 567         trace_suspend_resume(TPS("sync_filesystems"), 0, true);
 568         pr_info("Syncing filesystems ... ");
 569         ksys_sync();
 570         pr_cont("done.\n");
 571         trace_suspend_resume(TPS("sync_filesystems"), 0, false);
 572 #endif
 573
 574         pm_pr_dbg("Preparing system for sleep (%s)\n", mem_sleep_labels[state]);
 575         pm_suspend_clear_flags();
 576         error = suspend_prepare(state);
 577         if (error)
 578                 goto Unlock;
 579
 580         if (suspend_test(TEST_FREEZER))
 581                 goto Finish;
 582
 583         trace_suspend_resume(TPS("suspend_enter"), state, false);
 584         pm_pr_dbg("Suspending system (%s)\n", mem_sleep_labels[state]);
 585         pm_restrict_gfp_mask();
 586         error = suspend_devices_and_enter(state);
 587         pm_restore_gfp_mask();
 588
 589  Finish:
 590         events_check_enabled = false;
 591         pm_pr_dbg("Finishing wakeup.\n");
 592         suspend_finish();
 593  Unlock:
 594         mutex_unlock(&pm_mutex);
 595         return error;
 596 }
 597
 598 /**
 599  * pm_suspend - Externally visible function for suspending the system.
 600  * @state: System sleep state to enter.
 601  *
 602  * Check if the value of @state represents one of the supported states,
 603  * execute enter_state() and update system suspend statistics.
 604  */
 605 int pm_suspend(suspend_state_t state)
 606 {
 607         int error;
 608
 609         if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
 610                 return -EINVAL;
 611
 612         pr_info("suspend entry (%s)\n", mem_sleep_labels[state]);
 613         error = enter_state(state);
 614         if (error) {
 615                 suspend_stats.fail++;
 616                 dpm_save_failed_errno(error);
 617         } else {
 618                 suspend_stats.success++;
 619         }
 620         pr_info("suspend exit\n");
 621         return error;
 622 }
 623 EXPORT_SYMBOL(pm_suspend);