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