kernel/power/suspend.c

   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         cpus_read_lock();
 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         cpus_read_unlock();
 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                 s2idle_enter();
 142         }
 143
 144         pm_pr_dbg("resume from suspend-to-idle\n");
 145 }
 146
 147 void s2idle_wake(void)
 148 {
 149         unsigned long flags;
 150
 151         raw_spin_lock_irqsave(&s2idle_lock, flags);
 152         if (s2idle_state > S2IDLE_STATE_NONE) {
 153                 s2idle_state = S2IDLE_STATE_WAKE;
 154                 swake_up_one(&s2idle_wait_head);
 155         }
 156         raw_spin_unlock_irqrestore(&s2idle_lock, flags);
 157 }
 158 EXPORT_SYMBOL_GPL(s2idle_wake);
 159
 160 static bool valid_state(suspend_state_t state)
 161 {
 162         /*
 163          * PM_SUSPEND_STANDBY and PM_SUSPEND_MEM states need low level
 164          * support and need to be valid to the low level
 165          * implementation, no valid callback implies that none are valid.
 166          */
 167         return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
 168 }
 169
 170 void __init pm_states_init(void)
 171 {
 172         /* "mem" and "freeze" are always present in /sys/power/state. */
 173         pm_states[PM_SUSPEND_MEM] = pm_labels[PM_SUSPEND_MEM];
 174         pm_states[PM_SUSPEND_TO_IDLE] = pm_labels[PM_SUSPEND_TO_IDLE];
 175         /*
 176          * Suspend-to-idle should be supported even without any suspend_ops,
 177          * initialize mem_sleep_states[] accordingly here.
 178          */
 179         mem_sleep_states[PM_SUSPEND_TO_IDLE] = mem_sleep_labels[PM_SUSPEND_TO_IDLE];
 180 }
 181
 182 static int __init mem_sleep_default_setup(char *str)
 183 {
 184         suspend_state_t state;
 185
 186         for (state = PM_SUSPEND_TO_IDLE; state <= PM_SUSPEND_MEM; state++)
 187                 if (mem_sleep_labels[state] &&
 188                     !strcmp(str, mem_sleep_labels[state])) {
 189                         mem_sleep_default = state;
 190                         break;
 191                 }
 192
 193         return 1;
 194 }
 195 __setup("mem_sleep_default=", mem_sleep_default_setup);
 196
 197 /**
 198  * suspend_set_ops - Set the global suspend method table.
 199  * @ops: Suspend operations to use.
 200  */
 201 void suspend_set_ops(const struct platform_suspend_ops *ops)
 202 {
 203         lock_system_sleep();
 204
 205         suspend_ops = ops;
 206
 207         if (valid_state(PM_SUSPEND_STANDBY)) {
 208                 mem_sleep_states[PM_SUSPEND_STANDBY] = mem_sleep_labels[PM_SUSPEND_STANDBY];
 209                 pm_states[PM_SUSPEND_STANDBY] = pm_labels[PM_SUSPEND_STANDBY];
 210                 if (mem_sleep_default == PM_SUSPEND_STANDBY)
 211                         mem_sleep_current = PM_SUSPEND_STANDBY;
 212         }
 213         if (valid_state(PM_SUSPEND_MEM)) {
 214                 mem_sleep_states[PM_SUSPEND_MEM] = mem_sleep_labels[PM_SUSPEND_MEM];
 215                 if (mem_sleep_default >= PM_SUSPEND_MEM)
 216                         mem_sleep_current = PM_SUSPEND_MEM;
 217         }
 218
 219         unlock_system_sleep();
 220 }
 221 EXPORT_SYMBOL_GPL(suspend_set_ops);
 222
 223 /**
 224  * suspend_valid_only_mem - Generic memory-only valid callback.
 225  * @state: Target system sleep state.
 226  *
 227  * Platform drivers that implement mem suspend only and only need to check for
 228  * that in their .valid() callback can use this instead of rolling their own
 229  * .valid() callback.
 230  */
 231 int suspend_valid_only_mem(suspend_state_t state)
 232 {
 233         return state == PM_SUSPEND_MEM;
 234 }
 235 EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
 236
 237 static bool sleep_state_supported(suspend_state_t state)
 238 {
 239         return state == PM_SUSPEND_TO_IDLE || (suspend_ops && suspend_ops->enter);
 240 }
 241
 242 static int platform_suspend_prepare(suspend_state_t state)
 243 {
 244         return state != PM_SUSPEND_TO_IDLE && suspend_ops->prepare ?
 245                 suspend_ops->prepare() : 0;
 246 }
 247
 248 static int platform_suspend_prepare_late(suspend_state_t state)
 249 {
 250         return state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->prepare ?
 251                 s2idle_ops->prepare() : 0;
 252 }
 253
 254 static int platform_suspend_prepare_noirq(suspend_state_t state)
 255 {
 256         if (state == PM_SUSPEND_TO_IDLE)
 257                 return s2idle_ops && s2idle_ops->prepare_late ?
 258                         s2idle_ops->prepare_late() : 0;
 259
 260         return suspend_ops->prepare_late ? suspend_ops->prepare_late() : 0;
 261 }
 262
 263 static void platform_resume_noirq(suspend_state_t state)
 264 {
 265         if (state == PM_SUSPEND_TO_IDLE) {
 266                 if (s2idle_ops && s2idle_ops->restore_early)
 267                         s2idle_ops->restore_early();
 268         } else if (suspend_ops->wake) {
 269                 suspend_ops->wake();
 270         }
 271 }
 272
 273 static void platform_resume_early(suspend_state_t state)
 274 {
 275         if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->restore)
 276                 s2idle_ops->restore();
 277 }
 278
 279 static void platform_resume_finish(suspend_state_t state)
 280 {
 281         if (state != PM_SUSPEND_TO_IDLE && suspend_ops->finish)
 282                 suspend_ops->finish();
 283 }
 284
 285 static int platform_suspend_begin(suspend_state_t state)
 286 {
 287         if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->begin)
 288                 return s2idle_ops->begin();
 289         else if (suspend_ops && suspend_ops->begin)
 290                 return suspend_ops->begin(state);
 291         else
 292                 return 0;
 293 }
 294
 295 static void platform_resume_end(suspend_state_t state)
 296 {
 297         if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->end)
 298                 s2idle_ops->end();
 299         else if (suspend_ops && suspend_ops->end)
 300                 suspend_ops->end();
 301 }
 302
 303 static void platform_recover(suspend_state_t state)
 304 {
 305         if (state != PM_SUSPEND_TO_IDLE && suspend_ops->recover)
 306                 suspend_ops->recover();
 307 }
 308
 309 static bool platform_suspend_again(suspend_state_t state)
 310 {
 311         return state != PM_SUSPEND_TO_IDLE && suspend_ops->suspend_again ?
 312                 suspend_ops->suspend_again() : false;
 313 }
 314
 315 #ifdef CONFIG_PM_DEBUG
 316 static unsigned int pm_test_delay = 5;
 317 module_param(pm_test_delay, uint, 0644);
 318 MODULE_PARM_DESC(pm_test_delay,
 319                  "Number of seconds to wait before resuming from suspend test");
 320 #endif
 321
 322 static int suspend_test(int level)
 323 {
 324 #ifdef CONFIG_PM_DEBUG
 325         if (pm_test_level == level) {
 326                 pr_info("suspend debug: Waiting for %d second(s).\n",
 327                                 pm_test_delay);
 328                 mdelay(pm_test_delay * 1000);
 329                 return 1;
 330         }
 331 #endif /* !CONFIG_PM_DEBUG */
 332         return 0;
 333 }
 334
 335 /**
 336  * suspend_prepare - Prepare for entering system sleep state.
 337  * @state: Target 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;
 346
 347         if (!sleep_state_supported(state))
 348                 return -EPERM;
 349
 350         pm_prepare_console();
 351
 352         error = pm_notifier_call_chain_robust(PM_SUSPEND_PREPARE, PM_POST_SUSPEND);
 353         if (error)
 354                 goto Restore;
 355
 356         trace_suspend_resume(TPS("freeze_processes"), 0, true);
 357         error = suspend_freeze_processes();
 358         trace_suspend_resume(TPS("freeze_processes"), 0, false);
 359         if (!error)
 360                 return 0;
 361
 362         suspend_stats.failed_freeze++;
 363         dpm_save_failed_step(SUSPEND_FREEZE);
 364         pm_notifier_call_chain(PM_POST_SUSPEND);
 365  Restore:
 366         pm_restore_console();
 367         return error;
 368 }
 369
 370 /* default implementation */
 371 void __weak arch_suspend_disable_irqs(void)
 372 {
 373         local_irq_disable();
 374 }
 375
 376 /* default implementation */
 377 void __weak arch_suspend_enable_irqs(void)
 378 {
 379         local_irq_enable();
 380 }
 381
 382 /**
 383  * suspend_enter - Make the system enter the given sleep state.
 384  * @state: System sleep state to enter.
 385  * @wakeup: Returns information that the sleep state should not be re-entered.
 386  *
 387  * This function should be called after devices have been suspended.
 388  */
 389 static int suspend_enter(suspend_state_t state, bool *wakeup)
 390 {
 391         int error;
 392
 393         error = platform_suspend_prepare(state);
 394         if (error)
 395                 goto Platform_finish;
 396
 397         error = dpm_suspend_late(PMSG_SUSPEND);
 398         if (error) {
 399                 pr_err("late suspend of devices failed\n");
 400                 goto Platform_finish;
 401         }
 402         error = platform_suspend_prepare_late(state);
 403         if (error)
 404                 goto Devices_early_resume;
 405
 406         error = dpm_suspend_noirq(PMSG_SUSPEND);
 407         if (error) {
 408                 pr_err("noirq suspend of devices failed\n");
 409                 goto Platform_early_resume;
 410         }
 411         error = platform_suspend_prepare_noirq(state);
 412         if (error)
 413                 goto Platform_wake;
 414
 415         if (suspend_test(TEST_PLATFORM))
 416                 goto Platform_wake;
 417
 418         if (state == PM_SUSPEND_TO_IDLE) {
 419                 s2idle_loop();
 420                 goto Platform_wake;
 421         }
 422
 423         error = suspend_disable_secondary_cpus();
 424         if (error || suspend_test(TEST_CPUS))
 425                 goto Enable_cpus;
 426
 427         arch_suspend_disable_irqs();
 428         BUG_ON(!irqs_disabled());
 429
 430         system_state = SYSTEM_SUSPEND;
 431
 432         error = syscore_suspend();
 433         if (!error) {
 434                 *wakeup = pm_wakeup_pending();
 435                 if (!(suspend_test(TEST_CORE) || *wakeup)) {
 436                         trace_suspend_resume(TPS("machine_suspend"),
 437                                 state, true);
 438                         error = suspend_ops->enter(state);
 439                         trace_suspend_resume(TPS("machine_suspend"),
 440                                 state, false);
 441                 } else if (*wakeup) {
 442                         error = -EBUSY;
 443                 }
 444                 syscore_resume();
 445         }
 446
 447         system_state = SYSTEM_RUNNING;
 448
 449         arch_suspend_enable_irqs();
 450         BUG_ON(irqs_disabled());
 451
 452  Enable_cpus:
 453         suspend_enable_secondary_cpus();
 454
 455  Platform_wake:
 456         platform_resume_noirq(state);
 457         dpm_resume_noirq(PMSG_RESUME);
 458
 459  Platform_early_resume:
 460         platform_resume_early(state);
 461
 462  Devices_early_resume:
 463         dpm_resume_early(PMSG_RESUME);
 464
 465  Platform_finish:
 466         platform_resume_finish(state);
 467         return error;
 468 }
 469
 470 /**
 471  * suspend_devices_and_enter - Suspend devices and enter system sleep state.
 472  * @state: System sleep state to enter.
 473  */
 474 int suspend_devices_and_enter(suspend_state_t state)
 475 {
 476         int error;
 477         bool wakeup = false;
 478
 479         if (!sleep_state_supported(state))
 480                 return -ENOSYS;
 481
 482         pm_suspend_target_state = state;
 483
 484         if (state == PM_SUSPEND_TO_IDLE)
 485                 pm_set_suspend_no_platform();
 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(&system_transition_mutex))
 561                 return -EBUSY;
 562
 563         if (state == PM_SUSPEND_TO_IDLE)
 564                 s2idle_begin();
 565
 566         if (sync_on_suspend_enabled) {
 567                 trace_suspend_resume(TPS("sync_filesystems"), 0, true);
 568                 ksys_sync_helper();
 569                 trace_suspend_resume(TPS("sync_filesystems"), 0, false);
 570         }
 571
 572         pm_pr_dbg("Preparing system for sleep (%s)\n", mem_sleep_labels[state]);
 573         pm_suspend_clear_flags();
 574         error = suspend_prepare(state);
 575         if (error)
 576                 goto Unlock;
 577
 578         if (suspend_test(TEST_FREEZER))
 579                 goto Finish;
 580
 581         trace_suspend_resume(TPS("suspend_enter"), state, false);
 582         pm_pr_dbg("Suspending system (%s)\n", mem_sleep_labels[state]);
 583         pm_restrict_gfp_mask();
 584         error = suspend_devices_and_enter(state);
 585         pm_restore_gfp_mask();
 586
 587  Finish:
 588         events_check_enabled = false;
 589         pm_pr_dbg("Finishing wakeup.\n");
 590         suspend_finish();
 591  Unlock:
 592         mutex_unlock(&system_transition_mutex);
 593         return error;
 594 }
 595
 596 /**
 597  * pm_suspend - Externally visible function for suspending the system.
 598  * @state: System sleep state to enter.
 599  *
 600  * Check if the value of @state represents one of the supported states,
 601  * execute enter_state() and update system suspend statistics.
 602  */
 603 int pm_suspend(suspend_state_t state)
 604 {
 605         int error;
 606
 607         if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
 608                 return -EINVAL;
 609
 610         pr_info("suspend entry (%s)\n", mem_sleep_labels[state]);
 611         error = enter_state(state);
 612         if (error) {
 613                 suspend_stats.fail++;
 614                 dpm_save_failed_errno(error);
 615         } else {
 616                 suspend_stats.success++;
 617         }
 618         pr_info("suspend exit\n");
 619         return error;
 620 }
 621 EXPORT_SYMBOL(pm_suspend);