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         unsigned int sleep_flags;
  79
  80         sleep_flags = lock_system_sleep();
  81         s2idle_ops = ops;
  82         unlock_system_sleep(sleep_flags);
  83 }
  84
  85 static void s2idle_begin(void)
  86 {
  87         s2idle_state = S2IDLE_STATE_NONE;
  88 }
  89
  90 static void s2idle_enter(void)
  91 {
  92         trace_suspend_resume(TPS("machine_suspend"), PM_SUSPEND_TO_IDLE, true);
  93
  94         raw_spin_lock_irq(&s2idle_lock);
  95         if (pm_wakeup_pending())
  96                 goto out;
  97
  98         s2idle_state = S2IDLE_STATE_ENTER;
  99         raw_spin_unlock_irq(&s2idle_lock);
 100
 101         cpus_read_lock();
 102
 103         /* Push all the CPUs into the idle loop. */
 104         wake_up_all_idle_cpus();
 105         /* Make the current CPU wait so it can enter the idle loop too. */
 106         swait_event_exclusive(s2idle_wait_head,
 107                     s2idle_state == S2IDLE_STATE_WAKE);
 108
 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                 if (s2idle_ops && s2idle_ops->check)
 142                         s2idle_ops->check();
 143
 144                 s2idle_enter();
 145         }
 146
 147         pm_pr_dbg("resume from suspend-to-idle\n");
 148 }
 149
 150 void s2idle_wake(void)
 151 {
 152         unsigned long flags;
 153
 154         raw_spin_lock_irqsave(&s2idle_lock, flags);
 155         if (s2idle_state > S2IDLE_STATE_NONE) {
 156                 s2idle_state = S2IDLE_STATE_WAKE;
 157                 swake_up_one(&s2idle_wait_head);
 158         }
 159         raw_spin_unlock_irqrestore(&s2idle_lock, flags);
 160 }
 161 EXPORT_SYMBOL_GPL(s2idle_wake);
 162
 163 static bool valid_state(suspend_state_t state)
 164 {
 165         /*
 166          * The PM_SUSPEND_STANDBY and PM_SUSPEND_MEM states require low-level
 167          * support and need to be valid to the low-level implementation.
 168          *
 169          * No ->valid() or ->enter() callback implies that none are valid.
 170          */
 171         return suspend_ops && suspend_ops->valid && suspend_ops->valid(state) &&
 172                 suspend_ops->enter;
 173 }
 174
 175 void __init pm_states_init(void)
 176 {
 177         /* "mem" and "freeze" are always present in /sys/power/state. */
 178         pm_states[PM_SUSPEND_MEM] = pm_labels[PM_SUSPEND_MEM];
 179         pm_states[PM_SUSPEND_TO_IDLE] = pm_labels[PM_SUSPEND_TO_IDLE];
 180         /*
 181          * Suspend-to-idle should be supported even without any suspend_ops,
 182          * initialize mem_sleep_states[] accordingly here.
 183          */
 184         mem_sleep_states[PM_SUSPEND_TO_IDLE] = mem_sleep_labels[PM_SUSPEND_TO_IDLE];
 185 }
 186
 187 static int __init mem_sleep_default_setup(char *str)
 188 {
 189         suspend_state_t state;
 190
 191         for (state = PM_SUSPEND_TO_IDLE; state <= PM_SUSPEND_MEM; state++)
 192                 if (mem_sleep_labels[state] &&
 193                     !strcmp(str, mem_sleep_labels[state])) {
 194                         mem_sleep_default = state;
 195                         break;
 196                 }
 197
 198         return 1;
 199 }
 200 __setup("mem_sleep_default=", mem_sleep_default_setup);
 201
 202 /**
 203  * suspend_set_ops - Set the global suspend method table.
 204  * @ops: Suspend operations to use.
 205  */
 206 void suspend_set_ops(const struct platform_suspend_ops *ops)
 207 {
 208         unsigned int sleep_flags;
 209
 210         sleep_flags = lock_system_sleep();
 211
 212         suspend_ops = ops;
 213
 214         if (valid_state(PM_SUSPEND_STANDBY)) {
 215                 mem_sleep_states[PM_SUSPEND_STANDBY] = mem_sleep_labels[PM_SUSPEND_STANDBY];
 216                 pm_states[PM_SUSPEND_STANDBY] = pm_labels[PM_SUSPEND_STANDBY];
 217                 if (mem_sleep_default == PM_SUSPEND_STANDBY)
 218                         mem_sleep_current = PM_SUSPEND_STANDBY;
 219         }
 220         if (valid_state(PM_SUSPEND_MEM)) {
 221                 mem_sleep_states[PM_SUSPEND_MEM] = mem_sleep_labels[PM_SUSPEND_MEM];
 222                 if (mem_sleep_default >= PM_SUSPEND_MEM)
 223                         mem_sleep_current = PM_SUSPEND_MEM;
 224         }
 225
 226         unlock_system_sleep(sleep_flags);
 227 }
 228 EXPORT_SYMBOL_GPL(suspend_set_ops);
 229
 230 /**
 231  * suspend_valid_only_mem - Generic memory-only valid callback.
 232  * @state: Target system sleep state.
 233  *
 234  * Platform drivers that implement mem suspend only and only need to check for
 235  * that in their .valid() callback can use this instead of rolling their own
 236  * .valid() callback.
 237  */
 238 int suspend_valid_only_mem(suspend_state_t state)
 239 {
 240         return state == PM_SUSPEND_MEM;
 241 }
 242 EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
 243
 244 static bool sleep_state_supported(suspend_state_t state)
 245 {
 246         return state == PM_SUSPEND_TO_IDLE ||
 247                (valid_state(state) && !cxl_mem_active());
 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         if (state == PM_SUSPEND_TO_IDLE)
 265                 return s2idle_ops && s2idle_ops->prepare_late ?
 266                         s2idle_ops->prepare_late() : 0;
 267
 268         return suspend_ops->prepare_late ? suspend_ops->prepare_late() : 0;
 269 }
 270
 271 static void platform_resume_noirq(suspend_state_t state)
 272 {
 273         if (state == PM_SUSPEND_TO_IDLE) {
 274                 if (s2idle_ops && s2idle_ops->restore_early)
 275                         s2idle_ops->restore_early();
 276         } else if (suspend_ops->wake) {
 277                 suspend_ops->wake();
 278         }
 279 }
 280
 281 static void platform_resume_early(suspend_state_t state)
 282 {
 283         if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->restore)
 284                 s2idle_ops->restore();
 285 }
 286
 287 static void platform_resume_finish(suspend_state_t state)
 288 {
 289         if (state != PM_SUSPEND_TO_IDLE && suspend_ops->finish)
 290                 suspend_ops->finish();
 291 }
 292
 293 static int platform_suspend_begin(suspend_state_t state)
 294 {
 295         if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->begin)
 296                 return s2idle_ops->begin();
 297         else if (suspend_ops && suspend_ops->begin)
 298                 return suspend_ops->begin(state);
 299         else
 300                 return 0;
 301 }
 302
 303 static void platform_resume_end(suspend_state_t state)
 304 {
 305         if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->end)
 306                 s2idle_ops->end();
 307         else if (suspend_ops && suspend_ops->end)
 308                 suspend_ops->end();
 309 }
 310
 311 static void platform_recover(suspend_state_t state)
 312 {
 313         if (state != PM_SUSPEND_TO_IDLE && suspend_ops->recover)
 314                 suspend_ops->recover();
 315 }
 316
 317 static bool platform_suspend_again(suspend_state_t state)
 318 {
 319         return state != PM_SUSPEND_TO_IDLE && suspend_ops->suspend_again ?
 320                 suspend_ops->suspend_again() : false;
 321 }
 322
 323 #ifdef CONFIG_PM_DEBUG
 324 static unsigned int pm_test_delay = 5;
 325 module_param(pm_test_delay, uint, 0644);
 326 MODULE_PARM_DESC(pm_test_delay,
 327                  "Number of seconds to wait before resuming from suspend test");
 328 #endif
 329
 330 static int suspend_test(int level)
 331 {
 332 #ifdef CONFIG_PM_DEBUG
 333         if (pm_test_level == level) {
 334                 pr_info("suspend debug: Waiting for %d second(s).\n",
 335                                 pm_test_delay);
 336                 mdelay(pm_test_delay * 1000);
 337                 return 1;
 338         }
 339 #endif /* !CONFIG_PM_DEBUG */
 340         return 0;
 341 }
 342
 343 /**
 344  * suspend_prepare - Prepare for entering system sleep state.
 345  * @state: Target system sleep state.
 346  *
 347  * Common code run for every system sleep state that can be entered (except for
 348  * hibernation).  Run suspend notifiers, allocate the "suspend" console and
 349  * freeze processes.
 350  */
 351 static int suspend_prepare(suspend_state_t state)
 352 {
 353         int error;
 354
 355         if (!sleep_state_supported(state))
 356                 return -EPERM;
 357
 358         pm_prepare_console();
 359
 360         error = pm_notifier_call_chain_robust(PM_SUSPEND_PREPARE, PM_POST_SUSPEND);
 361         if (error)
 362                 goto Restore;
 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         dpm_save_failed_step(SUSPEND_FREEZE);
 371         pm_notifier_call_chain(PM_POST_SUSPEND);
 372  Restore:
 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         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         if (state == PM_SUSPEND_TO_IDLE) {
 426                 s2idle_loop();
 427                 goto Platform_wake;
 428         }
 429
 430         error = pm_sleep_disable_secondary_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         system_state = SYSTEM_SUSPEND;
 438
 439         error = syscore_suspend();
 440         if (!error) {
 441                 *wakeup = pm_wakeup_pending();
 442                 if (!(suspend_test(TEST_CORE) || *wakeup)) {
 443                         trace_suspend_resume(TPS("machine_suspend"),
 444                                 state, true);
 445                         error = suspend_ops->enter(state);
 446                         trace_suspend_resume(TPS("machine_suspend"),
 447                                 state, false);
 448                 } else if (*wakeup) {
 449                         error = -EBUSY;
 450                 }
 451                 syscore_resume();
 452         }
 453
 454         system_state = SYSTEM_RUNNING;
 455
 456         arch_suspend_enable_irqs();
 457         BUG_ON(irqs_disabled());
 458
 459  Enable_cpus:
 460         pm_sleep_enable_secondary_cpus();
 461
 462  Platform_wake:
 463         platform_resume_noirq(state);
 464         dpm_resume_noirq(PMSG_RESUME);
 465
 466  Platform_early_resume:
 467         platform_resume_early(state);
 468
 469  Devices_early_resume:
 470         dpm_resume_early(PMSG_RESUME);
 471
 472  Platform_finish:
 473         platform_resume_finish(state);
 474         return error;
 475 }
 476
 477 /**
 478  * suspend_devices_and_enter - Suspend devices and enter system sleep state.
 479  * @state: System sleep state to enter.
 480  */
 481 int suspend_devices_and_enter(suspend_state_t state)
 482 {
 483         int error;
 484         bool wakeup = false;
 485
 486         if (!sleep_state_supported(state))
 487                 return -ENOSYS;
 488
 489         pm_suspend_target_state = state;
 490
 491         if (state == PM_SUSPEND_TO_IDLE)
 492                 pm_set_suspend_no_platform();
 493
 494         error = platform_suspend_begin(state);
 495         if (error)
 496                 goto Close;
 497
 498         suspend_console();
 499         suspend_test_start();
 500         error = dpm_suspend_start(PMSG_SUSPEND);
 501         if (error) {
 502                 pr_err("Some devices failed to suspend, or early wake event detected\n");
 503                 goto Recover_platform;
 504         }
 505         suspend_test_finish("suspend devices");
 506         if (suspend_test(TEST_DEVICES))
 507                 goto Recover_platform;
 508
 509         do {
 510                 error = suspend_enter(state, &wakeup);
 511         } while (!error && !wakeup && platform_suspend_again(state));
 512
 513  Resume_devices:
 514         suspend_test_start();
 515         dpm_resume_end(PMSG_RESUME);
 516         suspend_test_finish("resume devices");
 517         trace_suspend_resume(TPS("resume_console"), state, true);
 518         resume_console();
 519         trace_suspend_resume(TPS("resume_console"), state, false);
 520
 521  Close:
 522         platform_resume_end(state);
 523         pm_suspend_target_state = PM_SUSPEND_ON;
 524         return error;
 525
 526  Recover_platform:
 527         platform_recover(state);
 528         goto Resume_devices;
 529 }
 530
 531 /**
 532  * suspend_finish - Clean up before finishing the suspend sequence.
 533  *
 534  * Call platform code to clean up, restart processes, and free the console that
 535  * we've allocated. This routine is not called for hibernation.
 536  */
 537 static void suspend_finish(void)
 538 {
 539         suspend_thaw_processes();
 540         pm_notifier_call_chain(PM_POST_SUSPEND);
 541         pm_restore_console();
 542 }
 543
 544 /**
 545  * enter_state - Do common work needed to enter system sleep state.
 546  * @state: System sleep state to enter.
 547  *
 548  * Make sure that no one else is trying to put the system into a sleep state.
 549  * Fail if that's not the case.  Otherwise, prepare for system suspend, make the
 550  * system enter the given sleep state and clean up after wakeup.
 551  */
 552 static int enter_state(suspend_state_t state)
 553 {
 554         int error;
 555
 556         trace_suspend_resume(TPS("suspend_enter"), state, true);
 557         if (state == PM_SUSPEND_TO_IDLE) {
 558 #ifdef CONFIG_PM_DEBUG
 559                 if (pm_test_level != TEST_NONE && pm_test_level <= TEST_CPUS) {
 560                         pr_warn("Unsupported test mode for suspend to idle, please choose none/freezer/devices/platform.\n");
 561                         return -EAGAIN;
 562                 }
 563 #endif
 564         } else if (!valid_state(state)) {
 565                 return -EINVAL;
 566         }
 567         if (!mutex_trylock(&system_transition_mutex))
 568                 return -EBUSY;
 569
 570         if (state == PM_SUSPEND_TO_IDLE)
 571                 s2idle_begin();
 572
 573         if (sync_on_suspend_enabled) {
 574                 trace_suspend_resume(TPS("sync_filesystems"), 0, true);
 575                 ksys_sync_helper();
 576                 trace_suspend_resume(TPS("sync_filesystems"), 0, false);
 577         }
 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);