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/swait.h>
  31 #include <linux/ftrace.h>
  32 #include <trace/events/power.h>
  33 #include <linux/compiler.h>
  34 #include <linux/moduleparam.h>
  35
  36 #include "power.h"
  37
  38 const char * const pm_labels[] = {
  39         [PM_SUSPEND_TO_IDLE] = "freeze",
  40         [PM_SUSPEND_STANDBY] = "standby",
  41         [PM_SUSPEND_MEM] = "mem",
  42 };
  43 const char *pm_states[PM_SUSPEND_MAX];
  44 static const char * const mem_sleep_labels[] = {
  45         [PM_SUSPEND_TO_IDLE] = "s2idle",
  46         [PM_SUSPEND_STANDBY] = "shallow",
  47         [PM_SUSPEND_MEM] = "deep",
  48 };
  49 const char *mem_sleep_states[PM_SUSPEND_MAX];
  50
  51 suspend_state_t mem_sleep_current = PM_SUSPEND_TO_IDLE;
  52 suspend_state_t mem_sleep_default = PM_SUSPEND_MAX;
  53 suspend_state_t pm_suspend_target_state;
  54 EXPORT_SYMBOL_GPL(pm_suspend_target_state);
  55
  56 unsigned int pm_suspend_global_flags;
  57 EXPORT_SYMBOL_GPL(pm_suspend_global_flags);
  58
  59 static const struct platform_suspend_ops *suspend_ops;
  60 static const struct platform_s2idle_ops *s2idle_ops;
  61 static DECLARE_SWAIT_QUEUE_HEAD(s2idle_wait_head);
  62
  63 enum s2idle_states __read_mostly s2idle_state;
  64 static DEFINE_RAW_SPINLOCK(s2idle_lock);
  65
  66 bool pm_suspend_via_s2idle(void)
  67 {
  68         return mem_sleep_current == PM_SUSPEND_TO_IDLE;
  69 }
  70 EXPORT_SYMBOL_GPL(pm_suspend_via_s2idle);
  71
  72 void s2idle_set_ops(const struct platform_s2idle_ops *ops)
  73 {
  74         lock_system_sleep();
  75         s2idle_ops = ops;
  76         unlock_system_sleep();
  77 }
  78
  79 static void s2idle_begin(void)
  80 {
  81         s2idle_state = S2IDLE_STATE_NONE;
  82 }
  83
  84 static void s2idle_enter(void)
  85 {
  86         trace_suspend_resume(TPS("machine_suspend"), PM_SUSPEND_TO_IDLE, true);
  87
  88         raw_spin_lock_irq(&s2idle_lock);
  89         if (pm_wakeup_pending())
  90                 goto out;
  91
  92         s2idle_state = S2IDLE_STATE_ENTER;
  93         raw_spin_unlock_irq(&s2idle_lock);
  94
  95         get_online_cpus();
  96         cpuidle_resume();
  97
  98         /* Push all the CPUs into the idle loop. */
  99         wake_up_all_idle_cpus();
 100         /* Make the current CPU wait so it can enter the idle loop too. */
 101         swait_event_exclusive(s2idle_wait_head,
 102                     s2idle_state == S2IDLE_STATE_WAKE);
 103
 104         cpuidle_pause();
 105         put_online_cpus();
 106
 107         raw_spin_lock_irq(&s2idle_lock);
 108
 109  out:
 110         s2idle_state = S2IDLE_STATE_NONE;
 111         raw_spin_unlock_irq(&s2idle_lock);
 112
 113         trace_suspend_resume(TPS("machine_suspend"), PM_SUSPEND_TO_IDLE, false);
 114 }
 115
 116 static void s2idle_loop(void)
 117 {
 118         pm_pr_dbg("suspend-to-idle\n");
 119
 120         for (;;) {
 121                 int error;
 122
 123                 dpm_noirq_begin();
 124
 125                 /*
 126                  * Suspend-to-idle equals
 127                  * frozen processes + suspended devices + idle processors.
 128                  * Thus s2idle_enter() should be called right after
 129                  * all devices have been suspended.
 130                  *
 131                  * Wakeups during the noirq suspend of devices may be spurious,
 132                  * so prevent them from terminating the loop right away.
 133                  */
 134                 error = dpm_noirq_suspend_devices(PMSG_SUSPEND);
 135                 if (!error)
 136                         s2idle_enter();
 137                 else if (error == -EBUSY && pm_wakeup_pending())
 138                         error = 0;
 139
 140                 if (!error && s2idle_ops && s2idle_ops->wake)
 141                         s2idle_ops->wake();
 142
 143                 dpm_noirq_resume_devices(PMSG_RESUME);
 144
 145                 dpm_noirq_end();
 146
 147                 if (error)
 148                         break;
 149
 150                 if (s2idle_ops && s2idle_ops->sync)
 151                         s2idle_ops->sync();
 152
 153                 if (pm_wakeup_pending())
 154                         break;
 155
 156                 pm_wakeup_clear(false);
 157         }
 158
 159         pm_pr_dbg("resume from suspend-to-idle\n");
 160 }
 161
 162 void s2idle_wake(void)
 163 {
 164         unsigned long flags;
 165
 166         raw_spin_lock_irqsave(&s2idle_lock, flags);
 167         if (s2idle_state > S2IDLE_STATE_NONE) {
 168                 s2idle_state = S2IDLE_STATE_WAKE;
 169                 swake_up_one(&s2idle_wait_head);
 170         }
 171         raw_spin_unlock_irqrestore(&s2idle_lock, flags);
 172 }
 173 EXPORT_SYMBOL_GPL(s2idle_wake);
 174
 175 static bool valid_state(suspend_state_t state)
 176 {
 177         /*
 178          * PM_SUSPEND_STANDBY and PM_SUSPEND_MEM states need low level
 179          * support and need to be valid to the low level
 180          * implementation, no valid callback implies that none are valid.
 181          */
 182         return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
 183 }
 184
 185 void __init pm_states_init(void)
 186 {
 187         /* "mem" and "freeze" are always present in /sys/power/state. */
 188         pm_states[PM_SUSPEND_MEM] = pm_labels[PM_SUSPEND_MEM];
 189         pm_states[PM_SUSPEND_TO_IDLE] = pm_labels[PM_SUSPEND_TO_IDLE];
 190         /*
 191          * Suspend-to-idle should be supported even without any suspend_ops,
 192          * initialize mem_sleep_states[] accordingly here.
 193          */
 194         mem_sleep_states[PM_SUSPEND_TO_IDLE] = mem_sleep_labels[PM_SUSPEND_TO_IDLE];
 195 }
 196
 197 static int __init mem_sleep_default_setup(char *str)
 198 {
 199         suspend_state_t state;
 200
 201         for (state = PM_SUSPEND_TO_IDLE; state <= PM_SUSPEND_MEM; state++)
 202                 if (mem_sleep_labels[state] &&
 203                     !strcmp(str, mem_sleep_labels[state])) {
 204                         mem_sleep_default = state;
 205                         break;
 206                 }
 207
 208         return 1;
 209 }
 210 __setup("mem_sleep_default=", mem_sleep_default_setup);
 211
 212 /**
 213  * suspend_set_ops - Set the global suspend method table.
 214  * @ops: Suspend operations to use.
 215  */
 216 void suspend_set_ops(const struct platform_suspend_ops *ops)
 217 {
 218         lock_system_sleep();
 219
 220         suspend_ops = ops;
 221
 222         if (valid_state(PM_SUSPEND_STANDBY)) {
 223                 mem_sleep_states[PM_SUSPEND_STANDBY] = mem_sleep_labels[PM_SUSPEND_STANDBY];
 224                 pm_states[PM_SUSPEND_STANDBY] = pm_labels[PM_SUSPEND_STANDBY];
 225                 if (mem_sleep_default == PM_SUSPEND_STANDBY)
 226                         mem_sleep_current = PM_SUSPEND_STANDBY;
 227         }
 228         if (valid_state(PM_SUSPEND_MEM)) {
 229                 mem_sleep_states[PM_SUSPEND_MEM] = mem_sleep_labels[PM_SUSPEND_MEM];
 230                 if (mem_sleep_default >= PM_SUSPEND_MEM)
 231                         mem_sleep_current = PM_SUSPEND_MEM;
 232         }
 233
 234         unlock_system_sleep();
 235 }
 236 EXPORT_SYMBOL_GPL(suspend_set_ops);
 237
 238 /**
 239  * suspend_valid_only_mem - Generic memory-only valid callback.
 240  *
 241  * Platform drivers that implement mem suspend only and only need to check for
 242  * that in their .valid() callback can use this instead of rolling their own
 243  * .valid() callback.
 244  */
 245 int suspend_valid_only_mem(suspend_state_t state)
 246 {
 247         return state == PM_SUSPEND_MEM;
 248 }
 249 EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
 250
 251 static bool sleep_state_supported(suspend_state_t state)
 252 {
 253         return state == PM_SUSPEND_TO_IDLE || (suspend_ops && suspend_ops->enter);
 254 }
 255
 256 static int platform_suspend_prepare(suspend_state_t state)
 257 {
 258         return state != PM_SUSPEND_TO_IDLE && suspend_ops->prepare ?
 259                 suspend_ops->prepare() : 0;
 260 }
 261
 262 static int platform_suspend_prepare_late(suspend_state_t state)
 263 {
 264         return state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->prepare ?
 265                 s2idle_ops->prepare() : 0;
 266 }
 267
 268 static int platform_suspend_prepare_noirq(suspend_state_t state)
 269 {
 270         return state != PM_SUSPEND_TO_IDLE && suspend_ops->prepare_late ?
 271                 suspend_ops->prepare_late() : 0;
 272 }
 273
 274 static void platform_resume_noirq(suspend_state_t state)
 275 {
 276         if (state != PM_SUSPEND_TO_IDLE && suspend_ops->wake)
 277                 suspend_ops->wake();
 278 }
 279
 280 static void platform_resume_early(suspend_state_t state)
 281 {
 282         if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->restore)
 283                 s2idle_ops->restore();
 284 }
 285
 286 static void platform_resume_finish(suspend_state_t state)
 287 {
 288         if (state != PM_SUSPEND_TO_IDLE && suspend_ops->finish)
 289                 suspend_ops->finish();
 290 }
 291
 292 static int platform_suspend_begin(suspend_state_t state)
 293 {
 294         if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->begin)
 295                 return s2idle_ops->begin();
 296         else if (suspend_ops && suspend_ops->begin)
 297                 return suspend_ops->begin(state);
 298         else
 299                 return 0;
 300 }
 301
 302 static void platform_resume_end(suspend_state_t state)
 303 {
 304         if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->end)
 305                 s2idle_ops->end();
 306         else if (suspend_ops && suspend_ops->end)
 307                 suspend_ops->end();
 308 }
 309
 310 static void platform_recover(suspend_state_t state)
 311 {
 312         if (state != PM_SUSPEND_TO_IDLE && suspend_ops->recover)
 313                 suspend_ops->recover();
 314 }
 315
 316 static bool platform_suspend_again(suspend_state_t state)
 317 {
 318         return state != PM_SUSPEND_TO_IDLE && suspend_ops->suspend_again ?
 319                 suspend_ops->suspend_again() : false;
 320 }
 321
 322 #ifdef CONFIG_PM_DEBUG
 323 static unsigned int pm_test_delay = 5;
 324 module_param(pm_test_delay, uint, 0644);
 325 MODULE_PARM_DESC(pm_test_delay,
 326                  "Number of seconds to wait before resuming from suspend test");
 327 #endif
 328
 329 static int suspend_test(int level)
 330 {
 331 #ifdef CONFIG_PM_DEBUG
 332         if (pm_test_level == level) {
 333                 pr_info("suspend debug: Waiting for %d second(s).\n",
 334                                 pm_test_delay);
 335                 mdelay(pm_test_delay * 1000);
 336                 return 1;
 337         }
 338 #endif /* !CONFIG_PM_DEBUG */
 339         return 0;
 340 }
 341
 342 /**
 343  * suspend_prepare - Prepare for entering system sleep state.
 344  *
 345  * Common code run for every system sleep state that can be entered (except for
 346  * hibernation).  Run suspend notifiers, allocate the "suspend" console and
 347  * freeze processes.
 348  */
 349 static int suspend_prepare(suspend_state_t state)
 350 {
 351         int error, nr_calls = 0;
 352
 353         if (!sleep_state_supported(state))
 354                 return -EPERM;
 355
 356         pm_prepare_console();
 357
 358         error = __pm_notifier_call_chain(PM_SUSPEND_PREPARE, -1, &nr_calls);
 359         if (error) {
 360                 nr_calls--;
 361                 goto Finish;
 362         }
 363
 364         trace_suspend_resume(TPS("freeze_processes"), 0, true);
 365         error = suspend_freeze_processes();
 366         trace_suspend_resume(TPS("freeze_processes"), 0, false);
 367         if (!error)
 368                 return 0;
 369
 370         suspend_stats.failed_freeze++;
 371         dpm_save_failed_step(SUSPEND_FREEZE);
 372  Finish:
 373         __pm_notifier_call_chain(PM_POST_SUSPEND, nr_calls, NULL);
 374         pm_restore_console();
 375         return error;
 376 }
 377
 378 /* default implementation */
 379 void __weak arch_suspend_disable_irqs(void)
 380 {
 381         local_irq_disable();
 382 }
 383
 384 /* default implementation */
 385 void __weak arch_suspend_enable_irqs(void)
 386 {
 387         local_irq_enable();
 388 }
 389
 390 /**
 391  * suspend_enter - Make the system enter the given sleep state.
 392  * @state: System sleep state to enter.
 393  * @wakeup: Returns information that the sleep state should not be re-entered.
 394  *
 395  * This function should be called after devices have been suspended.
 396  */
 397 static int suspend_enter(suspend_state_t state, bool *wakeup)
 398 {
 399         int error;
 400
 401         error = platform_suspend_prepare(state);
 402         if (error)
 403                 goto Platform_finish;
 404
 405         error = dpm_suspend_late(PMSG_SUSPEND);
 406         if (error) {
 407                 pr_err("late suspend of devices failed\n");
 408                 goto Platform_finish;
 409         }
 410         error = platform_suspend_prepare_late(state);
 411         if (error)
 412                 goto Devices_early_resume;
 413
 414         if (state == PM_SUSPEND_TO_IDLE && pm_test_level != TEST_PLATFORM) {
 415                 s2idle_loop();
 416                 goto Platform_early_resume;
 417         }
 418
 419         error = dpm_suspend_noirq(PMSG_SUSPEND);
 420         if (error) {
 421                 pr_err("noirq suspend of devices failed\n");
 422                 goto Platform_early_resume;
 423         }
 424         error = platform_suspend_prepare_noirq(state);
 425         if (error)
 426                 goto Platform_wake;
 427
 428         if (suspend_test(TEST_PLATFORM))
 429                 goto Platform_wake;
 430
 431         error = disable_nonboot_cpus();
 432         if (error || suspend_test(TEST_CPUS))
 433                 goto Enable_cpus;
 434
 435         arch_suspend_disable_irqs();
 436         BUG_ON(!irqs_disabled());
 437
 438         system_state = SYSTEM_SUSPEND;
 439
 440         error = syscore_suspend();
 441         if (!error) {
 442                 *wakeup = pm_wakeup_pending();
 443                 if (!(suspend_test(TEST_CORE) || *wakeup)) {
 444                         trace_suspend_resume(TPS("machine_suspend"),
 445                                 state, true);
 446                         error = suspend_ops->enter(state);
 447                         trace_suspend_resume(TPS("machine_suspend"),
 448                                 state, false);
 449                 } else if (*wakeup) {
 450                         error = -EBUSY;
 451                 }
 452                 syscore_resume();
 453         }
 454
 455         system_state = SYSTEM_RUNNING;
 456
 457         arch_suspend_enable_irqs();
 458         BUG_ON(irqs_disabled());
 459
 460  Enable_cpus:
 461         enable_nonboot_cpus();
 462
 463  Platform_wake:
 464         platform_resume_noirq(state);
 465         dpm_resume_noirq(PMSG_RESUME);
 466
 467  Platform_early_resume:
 468         platform_resume_early(state);
 469
 470  Devices_early_resume:
 471         dpm_resume_early(PMSG_RESUME);
 472
 473  Platform_finish:
 474         platform_resume_finish(state);
 475         return error;
 476 }
 477
 478 /**
 479  * suspend_devices_and_enter - Suspend devices and enter system sleep state.
 480  * @state: System sleep state to enter.
 481  */
 482 int suspend_devices_and_enter(suspend_state_t state)
 483 {
 484         int error;
 485         bool wakeup = false;
 486
 487         if (!sleep_state_supported(state))
 488                 return -ENOSYS;
 489
 490         pm_suspend_target_state = state;
 491
 492         error = platform_suspend_begin(state);
 493         if (error)
 494                 goto Close;
 495
 496         suspend_console();
 497         suspend_test_start();
 498         error = dpm_suspend_start(PMSG_SUSPEND);
 499         if (error) {
 500                 pr_err("Some devices failed to suspend, or early wake event detected\n");
 501                 goto Recover_platform;
 502         }
 503         suspend_test_finish("suspend devices");
 504         if (suspend_test(TEST_DEVICES))
 505                 goto Recover_platform;
 506
 507         do {
 508                 error = suspend_enter(state, &wakeup);
 509         } while (!error && !wakeup && platform_suspend_again(state));
 510
 511  Resume_devices:
 512         suspend_test_start();
 513         dpm_resume_end(PMSG_RESUME);
 514         suspend_test_finish("resume devices");
 515         trace_suspend_resume(TPS("resume_console"), state, true);
 516         resume_console();
 517         trace_suspend_resume(TPS("resume_console"), state, false);
 518
 519  Close:
 520         platform_resume_end(state);
 521         pm_suspend_target_state = PM_SUSPEND_ON;
 522         return error;
 523
 524  Recover_platform:
 525         platform_recover(state);
 526         goto Resume_devices;
 527 }
 528
 529 /**
 530  * suspend_finish - Clean up before finishing the suspend sequence.
 531  *
 532  * Call platform code to clean up, restart processes, and free the console that
 533  * we've allocated. This routine is not called for hibernation.
 534  */
 535 static void suspend_finish(void)
 536 {
 537         suspend_thaw_processes();
 538         pm_notifier_call_chain(PM_POST_SUSPEND);
 539         pm_restore_console();
 540 }
 541
 542 /**
 543  * enter_state - Do common work needed to enter system sleep state.
 544  * @state: System sleep state to enter.
 545  *
 546  * Make sure that no one else is trying to put the system into a sleep state.
 547  * Fail if that's not the case.  Otherwise, prepare for system suspend, make the
 548  * system enter the given sleep state and clean up after wakeup.
 549  */
 550 static int enter_state(suspend_state_t state)
 551 {
 552         int error;
 553
 554         trace_suspend_resume(TPS("suspend_enter"), state, true);
 555         if (state == PM_SUSPEND_TO_IDLE) {
 556 #ifdef CONFIG_PM_DEBUG
 557                 if (pm_test_level != TEST_NONE && pm_test_level <= TEST_CPUS) {
 558                         pr_warn("Unsupported test mode for suspend to idle, please choose none/freezer/devices/platform.\n");
 559                         return -EAGAIN;
 560                 }
 561 #endif
 562         } else if (!valid_state(state)) {
 563                 return -EINVAL;
 564         }
 565         if (!mutex_trylock(&system_transition_mutex))
 566                 return -EBUSY;
 567
 568         if (state == PM_SUSPEND_TO_IDLE)
 569                 s2idle_begin();
 570
 571 #ifndef CONFIG_SUSPEND_SKIP_SYNC
 572         trace_suspend_resume(TPS("sync_filesystems"), 0, true);
 573         pr_info("Syncing filesystems ... ");
 574         ksys_sync();
 575         pr_cont("done.\n");
 576         trace_suspend_resume(TPS("sync_filesystems"), 0, false);
 577 #endif
 578
 579         pm_pr_dbg("Preparing system for sleep (%s)\n", mem_sleep_labels[state]);
 580         pm_suspend_clear_flags();
 581         error = suspend_prepare(state);
 582         if (error)
 583                 goto Unlock;
 584
 585         if (suspend_test(TEST_FREEZER))
 586                 goto Finish;
 587
 588         trace_suspend_resume(TPS("suspend_enter"), state, false);
 589         pm_pr_dbg("Suspending system (%s)\n", mem_sleep_labels[state]);
 590         pm_restrict_gfp_mask();
 591         error = suspend_devices_and_enter(state);
 592         pm_restore_gfp_mask();
 593
 594  Finish:
 595         events_check_enabled = false;
 596         pm_pr_dbg("Finishing wakeup.\n");
 597         suspend_finish();
 598  Unlock:
 599         mutex_unlock(&system_transition_mutex);
 600         return error;
 601 }
 602
 603 /**
 604  * pm_suspend - Externally visible function for suspending the system.
 605  * @state: System sleep state to enter.
 606  *
 607  * Check if the value of @state represents one of the supported states,
 608  * execute enter_state() and update system suspend statistics.
 609  */
 610 int pm_suspend(suspend_state_t state)
 611 {
 612         int error;
 613
 614         if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
 615                 return -EINVAL;
 616
 617         pr_info("suspend entry (%s)\n", mem_sleep_labels[state]);
 618         error = enter_state(state);
 619         if (error) {
 620                 suspend_stats.fail++;
 621                 dpm_save_failed_errno(error);
 622         } else {
 623                 suspend_stats.success++;
 624         }
 625         pr_info("suspend exit\n");
 626         return error;
 627 }
 628 EXPORT_SYMBOL(pm_suspend);