root/kernel/power/suspend.c

DEFINITIONS

1. pm_suspend_default_s2idle
2. s2idle_set_ops
3. s2idle_begin
4. s2idle_enter
5. s2idle_loop
6. s2idle_wake
7. valid_state
8. pm_states_init
9. mem_sleep_default_setup
10. suspend_set_ops
11. suspend_valid_only_mem
12. sleep_state_supported
13. platform_suspend_prepare
14. platform_suspend_prepare_late
15. platform_suspend_prepare_noirq
16. platform_resume_noirq
17. platform_resume_early
18. platform_resume_finish
19. platform_suspend_begin
20. platform_resume_end
21. platform_recover
22. platform_suspend_again
23. suspend_test
24. suspend_prepare
25. arch_suspend_disable_irqs
26. arch_suspend_enable_irqs
27. suspend_enter
28. suspend_devices_and_enter
29. suspend_finish
30. enter_state
31. pm_suspend

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * kernel/power/suspend.c - Suspend to RAM and standby functionality.
   4  *
   5  * Copyright (c) 2003 Patrick Mochel
   6  * Copyright (c) 2003 Open Source Development Lab
   7  * Copyright (c) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
   8  */
   9 
  10 #define pr_fmt(fmt) "PM: " fmt
  11 
  12 #include <linux/string.h>
  13 #include <linux/delay.h>
  14 #include <linux/errno.h>
  15 #include <linux/init.h>
  16 #include <linux/console.h>
  17 #include <linux/cpu.h>
  18 #include <linux/cpuidle.h>
  19 #include <linux/gfp.h>
  20 #include <linux/io.h>
  21 #include <linux/kernel.h>
  22 #include <linux/list.h>
  23 #include <linux/mm.h>
  24 #include <linux/slab.h>
  25 #include <linux/export.h>
  26 #include <linux/suspend.h>
  27 #include <linux/syscore_ops.h>
  28 #include <linux/swait.h>
  29 #include <linux/ftrace.h>
  30 #include <trace/events/power.h>
  31 #include <linux/compiler.h>
  32 #include <linux/moduleparam.h>
  33 
  34 #include "power.h"
  35 
  36 const char * const pm_labels[] = {
  37         [PM_SUSPEND_TO_IDLE] = "freeze",
  38         [PM_SUSPEND_STANDBY] = "standby",
  39         [PM_SUSPEND_MEM] = "mem",
  40 };
  41 const char *pm_states[PM_SUSPEND_MAX];
  42 static const char * const mem_sleep_labels[] = {
  43         [PM_SUSPEND_TO_IDLE] = "s2idle",
  44         [PM_SUSPEND_STANDBY] = "shallow",
  45         [PM_SUSPEND_MEM] = "deep",
  46 };
  47 const char *mem_sleep_states[PM_SUSPEND_MAX];
  48 
  49 suspend_state_t mem_sleep_current = PM_SUSPEND_TO_IDLE;
  50 suspend_state_t mem_sleep_default = PM_SUSPEND_MAX;
  51 suspend_state_t pm_suspend_target_state;
  52 EXPORT_SYMBOL_GPL(pm_suspend_target_state);
  53 
  54 unsigned int pm_suspend_global_flags;
  55 EXPORT_SYMBOL_GPL(pm_suspend_global_flags);
  56 
  57 static const struct platform_suspend_ops *suspend_ops;
  58 static const struct platform_s2idle_ops *s2idle_ops;
  59 static DECLARE_SWAIT_QUEUE_HEAD(s2idle_wait_head);
  60 
  61 enum s2idle_states __read_mostly s2idle_state;
  62 static DEFINE_RAW_SPINLOCK(s2idle_lock);
  63 
  64 /**
  65  * pm_suspend_default_s2idle - Check if suspend-to-idle is the default suspend.
  66  *
  67  * Return 'true' if suspend-to-idle has been selected as the default system
  68  * suspend method.
  69  */
  70 bool pm_suspend_default_s2idle(void)
  71 {
  72         return mem_sleep_current == PM_SUSPEND_TO_IDLE;
  73 }
  74 EXPORT_SYMBOL_GPL(pm_suspend_default_s2idle);
  75 
  76 void s2idle_set_ops(const struct platform_s2idle_ops *ops)
  77 {
  78         lock_system_sleep();
  79         s2idle_ops = ops;
  80         unlock_system_sleep();
  81 }
  82 
  83 static void s2idle_begin(void)
  84 {
  85         s2idle_state = S2IDLE_STATE_NONE;
  86 }
  87 
  88 static void s2idle_enter(void)
  89 {
  90         trace_suspend_resume(TPS("machine_suspend"), PM_SUSPEND_TO_IDLE, true);
  91 
  92         raw_spin_lock_irq(&s2idle_lock);
  93         if (pm_wakeup_pending())
  94                 goto out;
  95 
  96         s2idle_state = S2IDLE_STATE_ENTER;
  97         raw_spin_unlock_irq(&s2idle_lock);
  98 
  99         get_online_cpus();
 100         cpuidle_resume();
 101 
 102         /* Push all the CPUs into the idle loop. */
 103         wake_up_all_idle_cpus();
 104         /* Make the current CPU wait so it can enter the idle loop too. */
 105         swait_event_exclusive(s2idle_wait_head,
 106                     s2idle_state == S2IDLE_STATE_WAKE);
 107 
 108         cpuidle_pause();
 109         put_online_cpus();
 110 
 111         raw_spin_lock_irq(&s2idle_lock);
 112 
 113  out:
 114         s2idle_state = S2IDLE_STATE_NONE;
 115         raw_spin_unlock_irq(&s2idle_lock);
 116 
 117         trace_suspend_resume(TPS("machine_suspend"), PM_SUSPEND_TO_IDLE, false);
 118 }
 119 
 120 static void s2idle_loop(void)
 121 {
 122         pm_pr_dbg("suspend-to-idle\n");
 123 
 124         /*
 125          * Suspend-to-idle equals:
 126          * frozen processes + suspended devices + idle processors.
 127          * Thus s2idle_enter() should be called right after all devices have
 128          * been suspended.
 129          *
 130          * Wakeups during the noirq suspend of devices may be spurious, so try
 131          * to avoid them upfront.
 132          */
 133         for (;;) {
 134                 if (s2idle_ops && s2idle_ops->wake) {
 135                         if (s2idle_ops->wake())
 136                                 break;
 137                 } else if (pm_wakeup_pending()) {
 138                         break;
 139                 }
 140 
 141                 pm_wakeup_clear(false);
 142 
 143                 s2idle_enter();
 144         }
 145 
 146         pm_pr_dbg("resume from suspend-to-idle\n");
 147 }
 148 
 149 void s2idle_wake(void)
 150 {
 151         unsigned long flags;
 152 
 153         raw_spin_lock_irqsave(&s2idle_lock, flags);
 154         if (s2idle_state > S2IDLE_STATE_NONE) {
 155                 s2idle_state = S2IDLE_STATE_WAKE;
 156                 swake_up_one(&s2idle_wait_head);
 157         }
 158         raw_spin_unlock_irqrestore(&s2idle_lock, flags);
 159 }
 160 EXPORT_SYMBOL_GPL(s2idle_wake);
 161 
 162 static bool valid_state(suspend_state_t state)
 163 {
 164         /*
 165          * PM_SUSPEND_STANDBY and PM_SUSPEND_MEM states need low level
 166          * support and need to be valid to the low level
 167          * implementation, no valid callback implies that none are valid.
 168          */
 169         return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
 170 }
 171 
 172 void __init pm_states_init(void)
 173 {
 174         /* "mem" and "freeze" are always present in /sys/power/state. */
 175         pm_states[PM_SUSPEND_MEM] = pm_labels[PM_SUSPEND_MEM];
 176         pm_states[PM_SUSPEND_TO_IDLE] = pm_labels[PM_SUSPEND_TO_IDLE];
 177         /*
 178          * Suspend-to-idle should be supported even without any suspend_ops,
 179          * initialize mem_sleep_states[] accordingly here.
 180          */
 181         mem_sleep_states[PM_SUSPEND_TO_IDLE] = mem_sleep_labels[PM_SUSPEND_TO_IDLE];
 182 }
 183 
 184 static int __init mem_sleep_default_setup(char *str)
 185 {
 186         suspend_state_t state;
 187 
 188         for (state = PM_SUSPEND_TO_IDLE; state <= PM_SUSPEND_MEM; state++)
 189                 if (mem_sleep_labels[state] &&
 190                     !strcmp(str, mem_sleep_labels[state])) {
 191                         mem_sleep_default = state;
 192                         break;
 193                 }
 194 
 195         return 1;
 196 }
 197 __setup("mem_sleep_default=", mem_sleep_default_setup);
 198 
 199 /**
 200  * suspend_set_ops - Set the global suspend method table.
 201  * @ops: Suspend operations to use.
 202  */
 203 void suspend_set_ops(const struct platform_suspend_ops *ops)
 204 {
 205         lock_system_sleep();
 206 
 207         suspend_ops = ops;
 208 
 209         if (valid_state(PM_SUSPEND_STANDBY)) {
 210                 mem_sleep_states[PM_SUSPEND_STANDBY] = mem_sleep_labels[PM_SUSPEND_STANDBY];
 211                 pm_states[PM_SUSPEND_STANDBY] = pm_labels[PM_SUSPEND_STANDBY];
 212                 if (mem_sleep_default == PM_SUSPEND_STANDBY)
 213                         mem_sleep_current = PM_SUSPEND_STANDBY;
 214         }
 215         if (valid_state(PM_SUSPEND_MEM)) {
 216                 mem_sleep_states[PM_SUSPEND_MEM] = mem_sleep_labels[PM_SUSPEND_MEM];
 217                 if (mem_sleep_default >= PM_SUSPEND_MEM)
 218                         mem_sleep_current = PM_SUSPEND_MEM;
 219         }
 220 
 221         unlock_system_sleep();
 222 }
 223 EXPORT_SYMBOL_GPL(suspend_set_ops);
 224 
 225 /**
 226  * suspend_valid_only_mem - Generic memory-only valid callback.
 227  *
 228  * Platform drivers that implement mem suspend only and only need to check for
 229  * that in their .valid() callback can use this instead of rolling their own
 230  * .valid() callback.
 231  */
 232 int suspend_valid_only_mem(suspend_state_t state)
 233 {
 234         return state == PM_SUSPEND_MEM;
 235 }
 236 EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
 237 
 238 static bool sleep_state_supported(suspend_state_t state)
 239 {
 240         return state == PM_SUSPEND_TO_IDLE || (suspend_ops && suspend_ops->enter);
 241 }
 242 
 243 static int platform_suspend_prepare(suspend_state_t state)
 244 {
 245         return state != PM_SUSPEND_TO_IDLE && suspend_ops->prepare ?
 246                 suspend_ops->prepare() : 0;
 247 }
 248 
 249 static int platform_suspend_prepare_late(suspend_state_t state)
 250 {
 251         return state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->prepare ?
 252                 s2idle_ops->prepare() : 0;
 253 }
 254 
 255 static int platform_suspend_prepare_noirq(suspend_state_t state)
 256 {
 257         if (state == PM_SUSPEND_TO_IDLE)
 258                 return s2idle_ops && s2idle_ops->prepare_late ?
 259                         s2idle_ops->prepare_late() : 0;
 260 
 261         return suspend_ops->prepare_late ? suspend_ops->prepare_late() : 0;
 262 }
 263 
 264 static void platform_resume_noirq(suspend_state_t state)
 265 {
 266         if (state == PM_SUSPEND_TO_IDLE) {
 267                 if (s2idle_ops && s2idle_ops->restore_early)
 268                         s2idle_ops->restore_early();
 269         } else if (suspend_ops->wake) {
 270                 suspend_ops->wake();
 271         }
 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         error = dpm_suspend_noirq(PMSG_SUSPEND);
 409         if (error) {
 410                 pr_err("noirq suspend of devices failed\n");
 411                 goto Platform_early_resume;
 412         }
 413         error = platform_suspend_prepare_noirq(state);
 414         if (error)
 415                 goto Platform_wake;
 416 
 417         if (suspend_test(TEST_PLATFORM))
 418                 goto Platform_wake;
 419 
 420         if (state == PM_SUSPEND_TO_IDLE) {
 421                 s2idle_loop();
 422                 goto Platform_wake;
 423         }
 424 
 425         error = suspend_disable_secondary_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         suspend_enable_secondary_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         if (state == PM_SUSPEND_TO_IDLE)
 487                 pm_set_suspend_no_platform();
 488 
 489         error = platform_suspend_begin(state);
 490         if (error)
 491                 goto Close;
 492 
 493         suspend_console();
 494         suspend_test_start();
 495         error = dpm_suspend_start(PMSG_SUSPEND);
 496         if (error) {
 497                 pr_err("Some devices failed to suspend, or early wake event detected\n");
 498                 goto Recover_platform;
 499         }
 500         suspend_test_finish("suspend devices");
 501         if (suspend_test(TEST_DEVICES))
 502                 goto Recover_platform;
 503 
 504         do {
 505                 error = suspend_enter(state, &wakeup);
 506         } while (!error && !wakeup && platform_suspend_again(state));
 507 
 508  Resume_devices:
 509         suspend_test_start();
 510         dpm_resume_end(PMSG_RESUME);
 511         suspend_test_finish("resume devices");
 512         trace_suspend_resume(TPS("resume_console"), state, true);
 513         resume_console();
 514         trace_suspend_resume(TPS("resume_console"), state, false);
 515 
 516  Close:
 517         platform_resume_end(state);
 518         pm_suspend_target_state = PM_SUSPEND_ON;
 519         return error;
 520 
 521  Recover_platform:
 522         platform_recover(state);
 523         goto Resume_devices;
 524 }
 525 
 526 /**
 527  * suspend_finish - Clean up before finishing the suspend sequence.
 528  *
 529  * Call platform code to clean up, restart processes, and free the console that
 530  * we've allocated. This routine is not called for hibernation.
 531  */
 532 static void suspend_finish(void)
 533 {
 534         suspend_thaw_processes();
 535         pm_notifier_call_chain(PM_POST_SUSPEND);
 536         pm_restore_console();
 537 }
 538 
 539 /**
 540  * enter_state - Do common work needed to enter system sleep state.
 541  * @state: System sleep state to enter.
 542  *
 543  * Make sure that no one else is trying to put the system into a sleep state.
 544  * Fail if that's not the case.  Otherwise, prepare for system suspend, make the
 545  * system enter the given sleep state and clean up after wakeup.
 546  */
 547 static int enter_state(suspend_state_t state)
 548 {
 549         int error;
 550 
 551         trace_suspend_resume(TPS("suspend_enter"), state, true);
 552         if (state == PM_SUSPEND_TO_IDLE) {
 553 #ifdef CONFIG_PM_DEBUG
 554                 if (pm_test_level != TEST_NONE && pm_test_level <= TEST_CPUS) {
 555                         pr_warn("Unsupported test mode for suspend to idle, please choose none/freezer/devices/platform.\n");
 556                         return -EAGAIN;
 557                 }
 558 #endif
 559         } else if (!valid_state(state)) {
 560                 return -EINVAL;
 561         }
 562         if (!mutex_trylock(&system_transition_mutex))
 563                 return -EBUSY;
 564 
 565         if (state == PM_SUSPEND_TO_IDLE)
 566                 s2idle_begin();
 567 
 568         if (!IS_ENABLED(CONFIG_SUSPEND_SKIP_SYNC)) {
 569                 trace_suspend_resume(TPS("sync_filesystems"), 0, true);
 570                 ksys_sync_helper();
 571                 trace_suspend_resume(TPS("sync_filesystems"), 0, false);
 572         }
 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(&system_transition_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);