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         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         for (;;) {
 125                 int error;
 126
 127                 dpm_noirq_begin();
 128
 129                 /*
 130                  * Suspend-to-idle equals
 131                  * frozen processes + suspended devices + idle processors.
 132                  * Thus s2idle_enter() should be called right after
 133                  * all devices have been suspended.
 134                  *
 135                  * Wakeups during the noirq suspend of devices may be spurious,
 136                  * so prevent them from terminating the loop right away.
 137                  */
 138                 error = dpm_noirq_suspend_devices(PMSG_SUSPEND);
 139                 if (!error)
 140                         s2idle_enter();
 141                 else if (error == -EBUSY && pm_wakeup_pending())
 142                         error = 0;
 143
 144                 if (!error && s2idle_ops && s2idle_ops->wake)
 145                         s2idle_ops->wake();
 146
 147                 dpm_noirq_resume_devices(PMSG_RESUME);
 148
 149                 dpm_noirq_end();
 150
 151                 if (error)
 152                         break;
 153
 154                 if (s2idle_ops && s2idle_ops->sync)
 155                         s2idle_ops->sync();
 156
 157                 if (pm_wakeup_pending())
 158                         break;
 159
 160                 pm_wakeup_clear(false);
 161         }
 162
 163         pm_pr_dbg("resume from suspend-to-idle\n");
 164 }
 165
 166 void s2idle_wake(void)
 167 {
 168         unsigned long flags;
 169
 170         raw_spin_lock_irqsave(&s2idle_lock, flags);
 171         if (s2idle_state > S2IDLE_STATE_NONE) {
 172                 s2idle_state = S2IDLE_STATE_WAKE;
 173                 swake_up_one(&s2idle_wait_head);
 174         }
 175         raw_spin_unlock_irqrestore(&s2idle_lock, flags);
 176 }
 177 EXPORT_SYMBOL_GPL(s2idle_wake);
 178
 179 static bool valid_state(suspend_state_t state)
 180 {
 181         /*
 182          * PM_SUSPEND_STANDBY and PM_SUSPEND_MEM states need low level
 183          * support and need to be valid to the low level
 184          * implementation, no valid callback implies that none are valid.
 185          */
 186         return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
 187 }
 188
 189 void __init pm_states_init(void)
 190 {
 191         /* "mem" and "freeze" are always present in /sys/power/state. */
 192         pm_states[PM_SUSPEND_MEM] = pm_labels[PM_SUSPEND_MEM];
 193         pm_states[PM_SUSPEND_TO_IDLE] = pm_labels[PM_SUSPEND_TO_IDLE];
 194         /*
 195          * Suspend-to-idle should be supported even without any suspend_ops,
 196          * initialize mem_sleep_states[] accordingly here.
 197          */
 198         mem_sleep_states[PM_SUSPEND_TO_IDLE] = mem_sleep_labels[PM_SUSPEND_TO_IDLE];
 199 }
 200
 201 static int __init mem_sleep_default_setup(char *str)
 202 {
 203         suspend_state_t state;
 204
 205         for (state = PM_SUSPEND_TO_IDLE; state <= PM_SUSPEND_MEM; state++)
 206                 if (mem_sleep_labels[state] &&
 207                     !strcmp(str, mem_sleep_labels[state])) {
 208                         mem_sleep_default = state;
 209                         break;
 210                 }
 211
 212         return 1;
 213 }
 214 __setup("mem_sleep_default=", mem_sleep_default_setup);
 215
 216 /**
 217  * suspend_set_ops - Set the global suspend method table.
 218  * @ops: Suspend operations to use.
 219  */
 220 void suspend_set_ops(const struct platform_suspend_ops *ops)
 221 {
 222         lock_system_sleep();
 223
 224         suspend_ops = ops;
 225
 226         if (valid_state(PM_SUSPEND_STANDBY)) {
 227                 mem_sleep_states[PM_SUSPEND_STANDBY] = mem_sleep_labels[PM_SUSPEND_STANDBY];
 228                 pm_states[PM_SUSPEND_STANDBY] = pm_labels[PM_SUSPEND_STANDBY];
 229                 if (mem_sleep_default == PM_SUSPEND_STANDBY)
 230                         mem_sleep_current = PM_SUSPEND_STANDBY;
 231         }
 232         if (valid_state(PM_SUSPEND_MEM)) {
 233                 mem_sleep_states[PM_SUSPEND_MEM] = mem_sleep_labels[PM_SUSPEND_MEM];
 234                 if (mem_sleep_default >= PM_SUSPEND_MEM)
 235                         mem_sleep_current = PM_SUSPEND_MEM;
 236         }
 237
 238         unlock_system_sleep();
 239 }
 240 EXPORT_SYMBOL_GPL(suspend_set_ops);
 241
 242 /**
 243  * suspend_valid_only_mem - Generic memory-only valid callback.
 244  *
 245  * Platform drivers that implement mem suspend only and only need to check for
 246  * that in their .valid() callback can use this instead of rolling their own
 247  * .valid() callback.
 248  */
 249 int suspend_valid_only_mem(suspend_state_t state)
 250 {
 251         return state == PM_SUSPEND_MEM;
 252 }
 253 EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
 254
 255 static bool sleep_state_supported(suspend_state_t state)
 256 {
 257         return state == PM_SUSPEND_TO_IDLE || (suspend_ops && suspend_ops->enter);
 258 }
 259
 260 static int platform_suspend_prepare(suspend_state_t state)
 261 {
 262         return state != PM_SUSPEND_TO_IDLE && suspend_ops->prepare ?
 263                 suspend_ops->prepare() : 0;
 264 }
 265
 266 static int platform_suspend_prepare_late(suspend_state_t state)
 267 {
 268         return state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->prepare ?
 269                 s2idle_ops->prepare() : 0;
 270 }
 271
 272 static int platform_suspend_prepare_noirq(suspend_state_t state)
 273 {
 274         return state != PM_SUSPEND_TO_IDLE && suspend_ops->prepare_late ?
 275                 suspend_ops->prepare_late() : 0;
 276 }
 277
 278 static void platform_resume_noirq(suspend_state_t state)
 279 {
 280         if (state != PM_SUSPEND_TO_IDLE && suspend_ops->wake)
 281                 suspend_ops->wake();
 282 }
 283
 284 static void platform_resume_early(suspend_state_t state)
 285 {
 286         if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->restore)
 287                 s2idle_ops->restore();
 288 }
 289
 290 static void platform_resume_finish(suspend_state_t state)
 291 {
 292         if (state != PM_SUSPEND_TO_IDLE && suspend_ops->finish)
 293                 suspend_ops->finish();
 294 }
 295
 296 static int platform_suspend_begin(suspend_state_t state)
 297 {
 298         if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->begin)
 299                 return s2idle_ops->begin();
 300         else if (suspend_ops && suspend_ops->begin)
 301                 return suspend_ops->begin(state);
 302         else
 303                 return 0;
 304 }
 305
 306 static void platform_resume_end(suspend_state_t state)
 307 {
 308         if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->end)
 309                 s2idle_ops->end();
 310         else if (suspend_ops && suspend_ops->end)
 311                 suspend_ops->end();
 312 }
 313
 314 static void platform_recover(suspend_state_t state)
 315 {
 316         if (state != PM_SUSPEND_TO_IDLE && suspend_ops->recover)
 317                 suspend_ops->recover();
 318 }
 319
 320 static bool platform_suspend_again(suspend_state_t state)
 321 {
 322         return state != PM_SUSPEND_TO_IDLE && suspend_ops->suspend_again ?
 323                 suspend_ops->suspend_again() : false;
 324 }
 325
 326 #ifdef CONFIG_PM_DEBUG
 327 static unsigned int pm_test_delay = 5;
 328 module_param(pm_test_delay, uint, 0644);
 329 MODULE_PARM_DESC(pm_test_delay,
 330                  "Number of seconds to wait before resuming from suspend test");
 331 #endif
 332
 333 static int suspend_test(int level)
 334 {
 335 #ifdef CONFIG_PM_DEBUG
 336         if (pm_test_level == level) {
 337                 pr_info("suspend debug: Waiting for %d second(s).\n",
 338                                 pm_test_delay);
 339                 mdelay(pm_test_delay * 1000);
 340                 return 1;
 341         }
 342 #endif /* !CONFIG_PM_DEBUG */
 343         return 0;
 344 }
 345
 346 /**
 347  * suspend_prepare - Prepare for entering system sleep state.
 348  *
 349  * Common code run for every system sleep state that can be entered (except for
 350  * hibernation).  Run suspend notifiers, allocate the "suspend" console and
 351  * freeze processes.
 352  */
 353 static int suspend_prepare(suspend_state_t state)
 354 {
 355         int error, nr_calls = 0;
 356
 357         if (!sleep_state_supported(state))
 358                 return -EPERM;
 359
 360         pm_prepare_console();
 361
 362         error = __pm_notifier_call_chain(PM_SUSPEND_PREPARE, -1, &nr_calls);
 363         if (error) {
 364                 nr_calls--;
 365                 goto Finish;
 366         }
 367
 368         trace_suspend_resume(TPS("freeze_processes"), 0, true);
 369         error = suspend_freeze_processes();
 370         trace_suspend_resume(TPS("freeze_processes"), 0, false);
 371         if (!error)
 372                 return 0;
 373
 374         suspend_stats.failed_freeze++;
 375         dpm_save_failed_step(SUSPEND_FREEZE);
 376  Finish:
 377         __pm_notifier_call_chain(PM_POST_SUSPEND, nr_calls, NULL);
 378         pm_restore_console();
 379         return error;
 380 }
 381
 382 /* default implementation */
 383 void __weak arch_suspend_disable_irqs(void)
 384 {
 385         local_irq_disable();
 386 }
 387
 388 /* default implementation */
 389 void __weak arch_suspend_enable_irqs(void)
 390 {
 391         local_irq_enable();
 392 }
 393
 394 /**
 395  * suspend_enter - Make the system enter the given sleep state.
 396  * @state: System sleep state to enter.
 397  * @wakeup: Returns information that the sleep state should not be re-entered.
 398  *
 399  * This function should be called after devices have been suspended.
 400  */
 401 static int suspend_enter(suspend_state_t state, bool *wakeup)
 402 {
 403         int error;
 404
 405         error = platform_suspend_prepare(state);
 406         if (error)
 407                 goto Platform_finish;
 408
 409         error = dpm_suspend_late(PMSG_SUSPEND);
 410         if (error) {
 411                 pr_err("late suspend of devices failed\n");
 412                 goto Platform_finish;
 413         }
 414         error = platform_suspend_prepare_late(state);
 415         if (error)
 416                 goto Devices_early_resume;
 417
 418         if (state == PM_SUSPEND_TO_IDLE && pm_test_level != TEST_PLATFORM) {
 419                 s2idle_loop();
 420                 goto Platform_early_resume;
 421         }
 422
 423         error = dpm_suspend_noirq(PMSG_SUSPEND);
 424         if (error) {
 425                 pr_err("noirq suspend of devices failed\n");
 426                 goto Platform_early_resume;
 427         }
 428         error = platform_suspend_prepare_noirq(state);
 429         if (error)
 430                 goto Platform_wake;
 431
 432         if (suspend_test(TEST_PLATFORM))
 433                 goto Platform_wake;
 434
 435         error = suspend_disable_secondary_cpus();
 436         if (error || suspend_test(TEST_CPUS))
 437                 goto Enable_cpus;
 438
 439         arch_suspend_disable_irqs();
 440         BUG_ON(!irqs_disabled());
 441
 442         system_state = SYSTEM_SUSPEND;
 443
 444         error = syscore_suspend();
 445         if (!error) {
 446                 *wakeup = pm_wakeup_pending();
 447                 if (!(suspend_test(TEST_CORE) || *wakeup)) {
 448                         trace_suspend_resume(TPS("machine_suspend"),
 449                                 state, true);
 450                         error = suspend_ops->enter(state);
 451                         trace_suspend_resume(TPS("machine_suspend"),
 452                                 state, false);
 453                 } else if (*wakeup) {
 454                         error = -EBUSY;
 455                 }
 456                 syscore_resume();
 457         }
 458
 459         system_state = SYSTEM_RUNNING;
 460
 461         arch_suspend_enable_irqs();
 462         BUG_ON(irqs_disabled());
 463
 464  Enable_cpus:
 465         suspend_enable_secondary_cpus();
 466
 467  Platform_wake:
 468         platform_resume_noirq(state);
 469         dpm_resume_noirq(PMSG_RESUME);
 470
 471  Platform_early_resume:
 472         platform_resume_early(state);
 473
 474  Devices_early_resume:
 475         dpm_resume_early(PMSG_RESUME);
 476
 477  Platform_finish:
 478         platform_resume_finish(state);
 479         return error;
 480 }
 481
 482 /**
 483  * suspend_devices_and_enter - Suspend devices and enter system sleep state.
 484  * @state: System sleep state to enter.
 485  */
 486 int suspend_devices_and_enter(suspend_state_t state)
 487 {
 488         int error;
 489         bool wakeup = false;
 490
 491         if (!sleep_state_supported(state))
 492                 return -ENOSYS;
 493
 494         pm_suspend_target_state = state;
 495
 496         if (state == PM_SUSPEND_TO_IDLE)
 497                 pm_set_suspend_no_platform();
 498
 499         error = platform_suspend_begin(state);
 500         if (error)
 501                 goto Close;
 502
 503         suspend_console();
 504         suspend_test_start();
 505         error = dpm_suspend_start(PMSG_SUSPEND);
 506         if (error) {
 507                 pr_err("Some devices failed to suspend, or early wake event detected\n");
 508                 goto Recover_platform;
 509         }
 510         suspend_test_finish("suspend devices");
 511         if (suspend_test(TEST_DEVICES))
 512                 goto Recover_platform;
 513
 514         do {
 515                 error = suspend_enter(state, &wakeup);
 516         } while (!error && !wakeup && platform_suspend_again(state));
 517
 518  Resume_devices:
 519         suspend_test_start();
 520         dpm_resume_end(PMSG_RESUME);
 521         suspend_test_finish("resume devices");
 522         trace_suspend_resume(TPS("resume_console"), state, true);
 523         resume_console();
 524         trace_suspend_resume(TPS("resume_console"), state, false);
 525
 526  Close:
 527         platform_resume_end(state);
 528         pm_suspend_target_state = PM_SUSPEND_ON;
 529         return error;
 530
 531  Recover_platform:
 532         platform_recover(state);
 533         goto Resume_devices;
 534 }
 535
 536 /**
 537  * suspend_finish - Clean up before finishing the suspend sequence.
 538  *
 539  * Call platform code to clean up, restart processes, and free the console that
 540  * we've allocated. This routine is not called for hibernation.
 541  */
 542 static void suspend_finish(void)
 543 {
 544         suspend_thaw_processes();
 545         pm_notifier_call_chain(PM_POST_SUSPEND);
 546         pm_restore_console();
 547 }
 548
 549 /**
 550  * enter_state - Do common work needed to enter system sleep state.
 551  * @state: System sleep state to enter.
 552  *
 553  * Make sure that no one else is trying to put the system into a sleep state.
 554  * Fail if that's not the case.  Otherwise, prepare for system suspend, make the
 555  * system enter the given sleep state and clean up after wakeup.
 556  */
 557 static int enter_state(suspend_state_t state)
 558 {
 559         int error;
 560
 561         trace_suspend_resume(TPS("suspend_enter"), state, true);
 562         if (state == PM_SUSPEND_TO_IDLE) {
 563 #ifdef CONFIG_PM_DEBUG
 564                 if (pm_test_level != TEST_NONE && pm_test_level <= TEST_CPUS) {
 565                         pr_warn("Unsupported test mode for suspend to idle, please choose none/freezer/devices/platform.\n");
 566                         return -EAGAIN;
 567                 }
 568 #endif
 569         } else if (!valid_state(state)) {
 570                 return -EINVAL;
 571         }
 572         if (!mutex_trylock(&system_transition_mutex))
 573                 return -EBUSY;
 574
 575         if (state == PM_SUSPEND_TO_IDLE)
 576                 s2idle_begin();
 577
 578         if (!IS_ENABLED(CONFIG_SUSPEND_SKIP_SYNC)) {
 579                 trace_suspend_resume(TPS("sync_filesystems"), 0, true);
 580                 ksys_sync_helper();
 581                 trace_suspend_resume(TPS("sync_filesystems"), 0, false);
 582         }
 583
 584         pm_pr_dbg("Preparing system for sleep (%s)\n", mem_sleep_labels[state]);
 585         pm_suspend_clear_flags();
 586         error = suspend_prepare(state);
 587         if (error)
 588                 goto Unlock;
 589
 590         if (suspend_test(TEST_FREEZER))
 591                 goto Finish;
 592
 593         trace_suspend_resume(TPS("suspend_enter"), state, false);
 594         pm_pr_dbg("Suspending system (%s)\n", mem_sleep_labels[state]);
 595         pm_restrict_gfp_mask();
 596         error = suspend_devices_and_enter(state);
 597         pm_restore_gfp_mask();
 598
 599  Finish:
 600         events_check_enabled = false;
 601         pm_pr_dbg("Finishing wakeup.\n");
 602         suspend_finish();
 603  Unlock:
 604         mutex_unlock(&system_transition_mutex);
 605         return error;
 606 }
 607
 608 /**
 609  * pm_suspend - Externally visible function for suspending the system.
 610  * @state: System sleep state to enter.
 611  *
 612  * Check if the value of @state represents one of the supported states,
 613  * execute enter_state() and update system suspend statistics.
 614  */
 615 int pm_suspend(suspend_state_t state)
 616 {
 617         int error;
 618
 619         if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
 620                 return -EINVAL;
 621
 622         pr_info("suspend entry (%s)\n", mem_sleep_labels[state]);
 623         error = enter_state(state);
 624         if (error) {
 625                 suspend_stats.fail++;
 626                 dpm_save_failed_errno(error);
 627         } else {
 628                 suspend_stats.success++;
 629         }
 630         pr_info("suspend exit\n");
 631         return error;
 632 }
 633 EXPORT_SYMBOL(pm_suspend);