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
 101         /* Push all the CPUs into the idle loop. */
 102         wake_up_all_idle_cpus();
 103         /* Make the current CPU wait so it can enter the idle loop too. */
 104         swait_event_exclusive(s2idle_wait_head,
 105                     s2idle_state == S2IDLE_STATE_WAKE);
 106
 107         cpus_read_unlock();
 108
 109         raw_spin_lock_irq(&s2idle_lock);
 110
 111  out:
 112         s2idle_state = S2IDLE_STATE_NONE;
 113         raw_spin_unlock_irq(&s2idle_lock);
 114
 115         trace_suspend_resume(TPS("machine_suspend"), PM_SUSPEND_TO_IDLE, false);
 116 }
 117
 118 static void s2idle_loop(void)
 119 {
 120         pm_pr_dbg("suspend-to-idle\n");
 121
 122         /*
 123          * Suspend-to-idle equals:
 124          * frozen processes + suspended devices + idle processors.
 125          * Thus s2idle_enter() should be called right after all devices have
 126          * been suspended.
 127          *
 128          * Wakeups during the noirq suspend of devices may be spurious, so try
 129          * to avoid them upfront.
 130          */
 131         for (;;) {
 132                 if (s2idle_ops && s2idle_ops->wake) {
 133                         if (s2idle_ops->wake())
 134                                 break;
 135                 } else if (pm_wakeup_pending()) {
 136                         break;
 137                 }
 138
 139                 s2idle_enter();
 140         }
 141
 142         pm_pr_dbg("resume from suspend-to-idle\n");
 143 }
 144
 145 void s2idle_wake(void)
 146 {
 147         unsigned long flags;
 148
 149         raw_spin_lock_irqsave(&s2idle_lock, flags);
 150         if (s2idle_state > S2IDLE_STATE_NONE) {
 151                 s2idle_state = S2IDLE_STATE_WAKE;
 152                 swake_up_one(&s2idle_wait_head);
 153         }
 154         raw_spin_unlock_irqrestore(&s2idle_lock, flags);
 155 }
 156 EXPORT_SYMBOL_GPL(s2idle_wake);
 157
 158 static bool valid_state(suspend_state_t state)
 159 {
 160         /*
 161          * The PM_SUSPEND_STANDBY and PM_SUSPEND_MEM states require low-level
 162          * support and need to be valid to the low-level implementation.
 163          *
 164          * No ->valid() or ->enter() callback implies that none are valid.
 165          */
 166         return suspend_ops && suspend_ops->valid && suspend_ops->valid(state) &&
 167                 suspend_ops->enter;
 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 ||
 240                (valid_state(state) && !cxl_mem_active());
 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  * @state: Target system sleep state.
 339  *
 340  * Common code run for every system sleep state that can be entered (except for
 341  * hibernation).  Run suspend notifiers, allocate the "suspend" console and
 342  * freeze processes.
 343  */
 344 static int suspend_prepare(suspend_state_t state)
 345 {
 346         int error;
 347
 348         if (!sleep_state_supported(state))
 349                 return -EPERM;
 350
 351         pm_prepare_console();
 352
 353         error = pm_notifier_call_chain_robust(PM_SUSPEND_PREPARE, PM_POST_SUSPEND);
 354         if (error)
 355                 goto Restore;
 356
 357         trace_suspend_resume(TPS("freeze_processes"), 0, true);
 358         error = suspend_freeze_processes();
 359         trace_suspend_resume(TPS("freeze_processes"), 0, false);
 360         if (!error)
 361                 return 0;
 362
 363         suspend_stats.failed_freeze++;
 364         dpm_save_failed_step(SUSPEND_FREEZE);
 365         pm_notifier_call_chain(PM_POST_SUSPEND);
 366  Restore:
 367         pm_restore_console();
 368         return error;
 369 }
 370
 371 /* default implementation */
 372 void __weak arch_suspend_disable_irqs(void)
 373 {
 374         local_irq_disable();
 375 }
 376
 377 /* default implementation */
 378 void __weak arch_suspend_enable_irqs(void)
 379 {
 380         local_irq_enable();
 381 }
 382
 383 /**
 384  * suspend_enter - Make the system enter the given sleep state.
 385  * @state: System sleep state to enter.
 386  * @wakeup: Returns information that the sleep state should not be re-entered.
 387  *
 388  * This function should be called after devices have been suspended.
 389  */
 390 static int suspend_enter(suspend_state_t state, bool *wakeup)
 391 {
 392         int error;
 393
 394         error = platform_suspend_prepare(state);
 395         if (error)
 396                 goto Platform_finish;
 397
 398         error = dpm_suspend_late(PMSG_SUSPEND);
 399         if (error) {
 400                 pr_err("late suspend of devices failed\n");
 401                 goto Platform_finish;
 402         }
 403         error = platform_suspend_prepare_late(state);
 404         if (error)
 405                 goto Devices_early_resume;
 406
 407         error = dpm_suspend_noirq(PMSG_SUSPEND);
 408         if (error) {
 409                 pr_err("noirq suspend of devices failed\n");
 410                 goto Platform_early_resume;
 411         }
 412         error = platform_suspend_prepare_noirq(state);
 413         if (error)
 414                 goto Platform_wake;
 415
 416         if (suspend_test(TEST_PLATFORM))
 417                 goto Platform_wake;
 418
 419         if (state == PM_SUSPEND_TO_IDLE) {
 420                 s2idle_loop();
 421                 goto Platform_wake;
 422         }
 423
 424         error = pm_sleep_disable_secondary_cpus();
 425         if (error || suspend_test(TEST_CPUS))
 426                 goto Enable_cpus;
 427
 428         arch_suspend_disable_irqs();
 429         BUG_ON(!irqs_disabled());
 430
 431         system_state = SYSTEM_SUSPEND;
 432
 433         error = syscore_suspend();
 434         if (!error) {
 435                 *wakeup = pm_wakeup_pending();
 436                 if (!(suspend_test(TEST_CORE) || *wakeup)) {
 437                         trace_suspend_resume(TPS("machine_suspend"),
 438                                 state, true);
 439                         error = suspend_ops->enter(state);
 440                         trace_suspend_resume(TPS("machine_suspend"),
 441                                 state, false);
 442                 } else if (*wakeup) {
 443                         error = -EBUSY;
 444                 }
 445                 syscore_resume();
 446         }
 447
 448         system_state = SYSTEM_RUNNING;
 449
 450         arch_suspend_enable_irqs();
 451         BUG_ON(irqs_disabled());
 452
 453  Enable_cpus:
 454         pm_sleep_enable_secondary_cpus();
 455
 456  Platform_wake:
 457         platform_resume_noirq(state);
 458         dpm_resume_noirq(PMSG_RESUME);
 459
 460  Platform_early_resume:
 461         platform_resume_early(state);
 462
 463  Devices_early_resume:
 464         dpm_resume_early(PMSG_RESUME);
 465
 466  Platform_finish:
 467         platform_resume_finish(state);
 468         return error;
 469 }
 470
 471 /**
 472  * suspend_devices_and_enter - Suspend devices and enter system sleep state.
 473  * @state: System sleep state to enter.
 474  */
 475 int suspend_devices_and_enter(suspend_state_t state)
 476 {
 477         int error;
 478         bool wakeup = false;
 479
 480         if (!sleep_state_supported(state))
 481                 return -ENOSYS;
 482
 483         pm_suspend_target_state = state;
 484
 485         if (state == PM_SUSPEND_TO_IDLE)
 486                 pm_set_suspend_no_platform();
 487
 488         error = platform_suspend_begin(state);
 489         if (error)
 490                 goto Close;
 491
 492         suspend_console();
 493         suspend_test_start();
 494         error = dpm_suspend_start(PMSG_SUSPEND);
 495         if (error) {
 496                 pr_err("Some devices failed to suspend, or early wake event detected\n");
 497                 goto Recover_platform;
 498         }
 499         suspend_test_finish("suspend devices");
 500         if (suspend_test(TEST_DEVICES))
 501                 goto Recover_platform;
 502
 503         do {
 504                 error = suspend_enter(state, &wakeup);
 505         } while (!error && !wakeup && platform_suspend_again(state));
 506
 507  Resume_devices:
 508         suspend_test_start();
 509         dpm_resume_end(PMSG_RESUME);
 510         suspend_test_finish("resume devices");
 511         trace_suspend_resume(TPS("resume_console"), state, true);
 512         resume_console();
 513         trace_suspend_resume(TPS("resume_console"), state, false);
 514
 515  Close:
 516         platform_resume_end(state);
 517         pm_suspend_target_state = PM_SUSPEND_ON;
 518         return error;
 519
 520  Recover_platform:
 521         platform_recover(state);
 522         goto Resume_devices;
 523 }
 524
 525 /**
 526  * suspend_finish - Clean up before finishing the suspend sequence.
 527  *
 528  * Call platform code to clean up, restart processes, and free the console that
 529  * we've allocated. This routine is not called for hibernation.
 530  */
 531 static void suspend_finish(void)
 532 {
 533         suspend_thaw_processes();
 534         pm_notifier_call_chain(PM_POST_SUSPEND);
 535         pm_restore_console();
 536 }
 537
 538 /**
 539  * enter_state - Do common work needed to enter system sleep state.
 540  * @state: System sleep state to enter.
 541  *
 542  * Make sure that no one else is trying to put the system into a sleep state.
 543  * Fail if that's not the case.  Otherwise, prepare for system suspend, make the
 544  * system enter the given sleep state and clean up after wakeup.
 545  */
 546 static int enter_state(suspend_state_t state)
 547 {
 548         int error;
 549
 550         trace_suspend_resume(TPS("suspend_enter"), state, true);
 551         if (state == PM_SUSPEND_TO_IDLE) {
 552 #ifdef CONFIG_PM_DEBUG
 553                 if (pm_test_level != TEST_NONE && pm_test_level <= TEST_CPUS) {
 554                         pr_warn("Unsupported test mode for suspend to idle, please choose none/freezer/devices/platform.\n");
 555                         return -EAGAIN;
 556                 }
 557 #endif
 558         } else if (!valid_state(state)) {
 559                 return -EINVAL;
 560         }
 561         if (!mutex_trylock(&system_transition_mutex))
 562                 return -EBUSY;
 563
 564         if (state == PM_SUSPEND_TO_IDLE)
 565                 s2idle_begin();
 566
 567         if (sync_on_suspend_enabled) {
 568                 trace_suspend_resume(TPS("sync_filesystems"), 0, true);
 569                 ksys_sync_helper();
 570                 trace_suspend_resume(TPS("sync_filesystems"), 0, false);
 571         }
 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);