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         /*
 110          * Kick all CPUs to ensure that they resume their timers and restore
 111          * consistent system state.
 112          */
 113         wake_up_all_idle_cpus();
 114
 115         cpus_read_unlock();
 116
 117         raw_spin_lock_irq(&s2idle_lock);
 118
 119  out:
 120         s2idle_state = S2IDLE_STATE_NONE;
 121         raw_spin_unlock_irq(&s2idle_lock);
 122
 123         trace_suspend_resume(TPS("machine_suspend"), PM_SUSPEND_TO_IDLE, false);
 124 }
 125
 126 static void s2idle_loop(void)
 127 {
 128         pm_pr_dbg("suspend-to-idle\n");
 129
 130         /*
 131          * Suspend-to-idle equals:
 132          * frozen processes + suspended devices + idle processors.
 133          * Thus s2idle_enter() should be called right after all devices have
 134          * been suspended.
 135          *
 136          * Wakeups during the noirq suspend of devices may be spurious, so try
 137          * to avoid them upfront.
 138          */
 139         for (;;) {
 140                 if (s2idle_ops && s2idle_ops->wake) {
 141                         if (s2idle_ops->wake())
 142                                 break;
 143                 } else if (pm_wakeup_pending()) {
 144                         break;
 145                 }
 146
 147                 if (s2idle_ops && s2idle_ops->check)
 148                         s2idle_ops->check();
 149
 150                 s2idle_enter();
 151         }
 152
 153         pm_pr_dbg("resume from suspend-to-idle\n");
 154 }
 155
 156 void s2idle_wake(void)
 157 {
 158         unsigned long flags;
 159
 160         raw_spin_lock_irqsave(&s2idle_lock, flags);
 161         if (s2idle_state > S2IDLE_STATE_NONE) {
 162                 s2idle_state = S2IDLE_STATE_WAKE;
 163                 swake_up_one(&s2idle_wait_head);
 164         }
 165         raw_spin_unlock_irqrestore(&s2idle_lock, flags);
 166 }
 167 EXPORT_SYMBOL_GPL(s2idle_wake);
 168
 169 static bool valid_state(suspend_state_t state)
 170 {
 171         /*
 172          * The PM_SUSPEND_STANDBY and PM_SUSPEND_MEM states require low-level
 173          * support and need to be valid to the low-level implementation.
 174          *
 175          * No ->valid() or ->enter() callback implies that none are valid.
 176          */
 177         return suspend_ops && suspend_ops->valid && suspend_ops->valid(state) &&
 178                 suspend_ops->enter;
 179 }
 180
 181 void __init pm_states_init(void)
 182 {
 183         /* "mem" and "freeze" are always present in /sys/power/state. */
 184         pm_states[PM_SUSPEND_MEM] = pm_labels[PM_SUSPEND_MEM];
 185         pm_states[PM_SUSPEND_TO_IDLE] = pm_labels[PM_SUSPEND_TO_IDLE];
 186         /*
 187          * Suspend-to-idle should be supported even without any suspend_ops,
 188          * initialize mem_sleep_states[] accordingly here.
 189          */
 190         mem_sleep_states[PM_SUSPEND_TO_IDLE] = mem_sleep_labels[PM_SUSPEND_TO_IDLE];
 191 }
 192
 193 static int __init mem_sleep_default_setup(char *str)
 194 {
 195         suspend_state_t state;
 196
 197         for (state = PM_SUSPEND_TO_IDLE; state <= PM_SUSPEND_MEM; state++)
 198                 if (mem_sleep_labels[state] &&
 199                     !strcmp(str, mem_sleep_labels[state])) {
 200                         mem_sleep_default = state;
 201                         mem_sleep_current = state;
 202                         break;
 203                 }
 204
 205         return 1;
 206 }
 207 __setup("mem_sleep_default=", mem_sleep_default_setup);
 208
 209 /**
 210  * suspend_set_ops - Set the global suspend method table.
 211  * @ops: Suspend operations to use.
 212  */
 213 void suspend_set_ops(const struct platform_suspend_ops *ops)
 214 {
 215         unsigned int sleep_flags;
 216
 217         sleep_flags = lock_system_sleep();
 218
 219         suspend_ops = ops;
 220
 221         if (valid_state(PM_SUSPEND_STANDBY)) {
 222                 mem_sleep_states[PM_SUSPEND_STANDBY] = mem_sleep_labels[PM_SUSPEND_STANDBY];
 223                 pm_states[PM_SUSPEND_STANDBY] = pm_labels[PM_SUSPEND_STANDBY];
 224                 if (mem_sleep_default == PM_SUSPEND_STANDBY)
 225                         mem_sleep_current = PM_SUSPEND_STANDBY;
 226         }
 227         if (valid_state(PM_SUSPEND_MEM)) {
 228                 mem_sleep_states[PM_SUSPEND_MEM] = mem_sleep_labels[PM_SUSPEND_MEM];
 229                 if (mem_sleep_default >= PM_SUSPEND_MEM)
 230                         mem_sleep_current = PM_SUSPEND_MEM;
 231         }
 232
 233         unlock_system_sleep(sleep_flags);
 234 }
 235 EXPORT_SYMBOL_GPL(suspend_set_ops);
 236
 237 /**
 238  * suspend_valid_only_mem - Generic memory-only valid callback.
 239  * @state: Target system sleep state.
 240  *
 241  * Platform drivers that implement mem suspend only and only need to check for
 242  * that in their .valid() callback can use this instead of rolling their own
 243  * .valid() callback.
 244  */
 245 int suspend_valid_only_mem(suspend_state_t state)
 246 {
 247         return state == PM_SUSPEND_MEM;
 248 }
 249 EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
 250
 251 static bool sleep_state_supported(suspend_state_t state)
 252 {
 253         return state == PM_SUSPEND_TO_IDLE ||
 254                (valid_state(state) && !cxl_mem_active());
 255 }
 256
 257 static int platform_suspend_prepare(suspend_state_t state)
 258 {
 259         return state != PM_SUSPEND_TO_IDLE && suspend_ops->prepare ?
 260                 suspend_ops->prepare() : 0;
 261 }
 262
 263 static int platform_suspend_prepare_late(suspend_state_t state)
 264 {
 265         return state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->prepare ?
 266                 s2idle_ops->prepare() : 0;
 267 }
 268
 269 static int platform_suspend_prepare_noirq(suspend_state_t state)
 270 {
 271         if (state == PM_SUSPEND_TO_IDLE)
 272                 return s2idle_ops && s2idle_ops->prepare_late ?
 273                         s2idle_ops->prepare_late() : 0;
 274
 275         return suspend_ops->prepare_late ? 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) {
 281                 if (s2idle_ops && s2idle_ops->restore_early)
 282                         s2idle_ops->restore_early();
 283         } else if (suspend_ops->wake) {
 284                 suspend_ops->wake();
 285         }
 286 }
 287
 288 static void platform_resume_early(suspend_state_t state)
 289 {
 290         if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->restore)
 291                 s2idle_ops->restore();
 292 }
 293
 294 static void platform_resume_finish(suspend_state_t state)
 295 {
 296         if (state != PM_SUSPEND_TO_IDLE && suspend_ops->finish)
 297                 suspend_ops->finish();
 298 }
 299
 300 static int platform_suspend_begin(suspend_state_t state)
 301 {
 302         if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->begin)
 303                 return s2idle_ops->begin();
 304         else if (suspend_ops && suspend_ops->begin)
 305                 return suspend_ops->begin(state);
 306         else
 307                 return 0;
 308 }
 309
 310 static void platform_resume_end(suspend_state_t state)
 311 {
 312         if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->end)
 313                 s2idle_ops->end();
 314         else if (suspend_ops && suspend_ops->end)
 315                 suspend_ops->end();
 316 }
 317
 318 static void platform_recover(suspend_state_t state)
 319 {
 320         if (state != PM_SUSPEND_TO_IDLE && suspend_ops->recover)
 321                 suspend_ops->recover();
 322 }
 323
 324 static bool platform_suspend_again(suspend_state_t state)
 325 {
 326         return state != PM_SUSPEND_TO_IDLE && suspend_ops->suspend_again ?
 327                 suspend_ops->suspend_again() : false;
 328 }
 329
 330 #ifdef CONFIG_PM_DEBUG
 331 static unsigned int pm_test_delay = 5;
 332 module_param(pm_test_delay, uint, 0644);
 333 MODULE_PARM_DESC(pm_test_delay,
 334                  "Number of seconds to wait before resuming from suspend test");
 335 #endif
 336
 337 static int suspend_test(int level)
 338 {
 339 #ifdef CONFIG_PM_DEBUG
 340         if (pm_test_level == level) {
 341                 pr_info("suspend debug: Waiting for %d second(s).\n",
 342                                 pm_test_delay);
 343                 mdelay(pm_test_delay * 1000);
 344                 return 1;
 345         }
 346 #endif /* !CONFIG_PM_DEBUG */
 347         return 0;
 348 }
 349
 350 /**
 351  * suspend_prepare - Prepare for entering system sleep state.
 352  * @state: Target system sleep state.
 353  *
 354  * Common code run for every system sleep state that can be entered (except for
 355  * hibernation).  Run suspend notifiers, allocate the "suspend" console and
 356  * freeze processes.
 357  */
 358 static int suspend_prepare(suspend_state_t state)
 359 {
 360         int error;
 361
 362         if (!sleep_state_supported(state))
 363                 return -EPERM;
 364
 365         pm_prepare_console();
 366
 367         error = pm_notifier_call_chain_robust(PM_SUSPEND_PREPARE, PM_POST_SUSPEND);
 368         if (error)
 369                 goto Restore;
 370
 371         trace_suspend_resume(TPS("freeze_processes"), 0, true);
 372         error = suspend_freeze_processes();
 373         trace_suspend_resume(TPS("freeze_processes"), 0, false);
 374         if (!error)
 375                 return 0;
 376
 377         dpm_save_failed_step(SUSPEND_FREEZE);
 378         pm_notifier_call_chain(PM_POST_SUSPEND);
 379  Restore:
 380         pm_restore_console();
 381         return error;
 382 }
 383
 384 /* default implementation */
 385 void __weak arch_suspend_disable_irqs(void)
 386 {
 387         local_irq_disable();
 388 }
 389
 390 /* default implementation */
 391 void __weak arch_suspend_enable_irqs(void)
 392 {
 393         local_irq_enable();
 394 }
 395
 396 /**
 397  * suspend_enter - Make the system enter the given sleep state.
 398  * @state: System sleep state to enter.
 399  * @wakeup: Returns information that the sleep state should not be re-entered.
 400  *
 401  * This function should be called after devices have been suspended.
 402  */
 403 static int suspend_enter(suspend_state_t state, bool *wakeup)
 404 {
 405         int error;
 406
 407         error = platform_suspend_prepare(state);
 408         if (error)
 409                 goto Platform_finish;
 410
 411         error = dpm_suspend_late(PMSG_SUSPEND);
 412         if (error) {
 413                 pr_err("late suspend of devices failed\n");
 414                 goto Platform_finish;
 415         }
 416         error = platform_suspend_prepare_late(state);
 417         if (error)
 418                 goto Devices_early_resume;
 419
 420         error = dpm_suspend_noirq(PMSG_SUSPEND);
 421         if (error) {
 422                 pr_err("noirq suspend of devices failed\n");
 423                 goto Platform_early_resume;
 424         }
 425         error = platform_suspend_prepare_noirq(state);
 426         if (error)
 427                 goto Platform_wake;
 428
 429         if (suspend_test(TEST_PLATFORM))
 430                 goto Platform_wake;
 431
 432         if (state == PM_SUSPEND_TO_IDLE) {
 433                 s2idle_loop();
 434                 goto Platform_wake;
 435         }
 436
 437         error = pm_sleep_disable_secondary_cpus();
 438         if (error || suspend_test(TEST_CPUS))
 439                 goto Enable_cpus;
 440
 441         arch_suspend_disable_irqs();
 442         BUG_ON(!irqs_disabled());
 443
 444         system_state = SYSTEM_SUSPEND;
 445
 446         error = syscore_suspend();
 447         if (!error) {
 448                 *wakeup = pm_wakeup_pending();
 449                 if (!(suspend_test(TEST_CORE) || *wakeup)) {
 450                         trace_suspend_resume(TPS("machine_suspend"),
 451                                 state, true);
 452                         error = suspend_ops->enter(state);
 453                         trace_suspend_resume(TPS("machine_suspend"),
 454                                 state, false);
 455                 } else if (*wakeup) {
 456                         error = -EBUSY;
 457                 }
 458                 syscore_resume();
 459         }
 460
 461         system_state = SYSTEM_RUNNING;
 462
 463         arch_suspend_enable_irqs();
 464         BUG_ON(irqs_disabled());
 465
 466  Enable_cpus:
 467         pm_sleep_enable_secondary_cpus();
 468
 469  Platform_wake:
 470         platform_resume_noirq(state);
 471         dpm_resume_noirq(PMSG_RESUME);
 472
 473  Platform_early_resume:
 474         platform_resume_early(state);
 475
 476  Devices_early_resume:
 477         dpm_resume_early(PMSG_RESUME);
 478
 479  Platform_finish:
 480         platform_resume_finish(state);
 481         return error;
 482 }
 483
 484 /**
 485  * suspend_devices_and_enter - Suspend devices and enter system sleep state.
 486  * @state: System sleep state to enter.
 487  */
 488 int suspend_devices_and_enter(suspend_state_t state)
 489 {
 490         int error;
 491         bool wakeup = false;
 492
 493         if (!sleep_state_supported(state))
 494                 return -ENOSYS;
 495
 496         pm_suspend_target_state = state;
 497
 498         if (state == PM_SUSPEND_TO_IDLE)
 499                 pm_set_suspend_no_platform();
 500
 501         error = platform_suspend_begin(state);
 502         if (error)
 503                 goto Close;
 504
 505         suspend_console();
 506         suspend_test_start();
 507         error = dpm_suspend_start(PMSG_SUSPEND);
 508         if (error) {
 509                 pr_err("Some devices failed to suspend, or early wake event detected\n");
 510                 goto Recover_platform;
 511         }
 512         suspend_test_finish("suspend devices");
 513         if (suspend_test(TEST_DEVICES))
 514                 goto Recover_platform;
 515
 516         do {
 517                 error = suspend_enter(state, &wakeup);
 518         } while (!error && !wakeup && platform_suspend_again(state));
 519
 520  Resume_devices:
 521         suspend_test_start();
 522         dpm_resume_end(PMSG_RESUME);
 523         suspend_test_finish("resume devices");
 524         trace_suspend_resume(TPS("resume_console"), state, true);
 525         resume_console();
 526         trace_suspend_resume(TPS("resume_console"), state, false);
 527
 528  Close:
 529         platform_resume_end(state);
 530         pm_suspend_target_state = PM_SUSPEND_ON;
 531         return error;
 532
 533  Recover_platform:
 534         platform_recover(state);
 535         goto Resume_devices;
 536 }
 537
 538 /**
 539  * suspend_finish - Clean up before finishing the suspend sequence.
 540  *
 541  * Call platform code to clean up, restart processes, and free the console that
 542  * we've allocated. This routine is not called for hibernation.
 543  */
 544 static void suspend_finish(void)
 545 {
 546         suspend_thaw_processes();
 547         pm_notifier_call_chain(PM_POST_SUSPEND);
 548         pm_restore_console();
 549 }
 550
 551 /**
 552  * enter_state - Do common work needed to enter system sleep state.
 553  * @state: System sleep state to enter.
 554  *
 555  * Make sure that no one else is trying to put the system into a sleep state.
 556  * Fail if that's not the case.  Otherwise, prepare for system suspend, make the
 557  * system enter the given sleep state and clean up after wakeup.
 558  */
 559 static int enter_state(suspend_state_t state)
 560 {
 561         int error;
 562
 563         trace_suspend_resume(TPS("suspend_enter"), state, true);
 564         if (state == PM_SUSPEND_TO_IDLE) {
 565 #ifdef CONFIG_PM_DEBUG
 566                 if (pm_test_level != TEST_NONE && pm_test_level <= TEST_CPUS) {
 567                         pr_warn("Unsupported test mode for suspend to idle, please choose none/freezer/devices/platform.\n");
 568                         return -EAGAIN;
 569                 }
 570 #endif
 571         } else if (!valid_state(state)) {
 572                 return -EINVAL;
 573         }
 574         if (!mutex_trylock(&system_transition_mutex))
 575                 return -EBUSY;
 576
 577         if (state == PM_SUSPEND_TO_IDLE)
 578                 s2idle_begin();
 579
 580         if (sync_on_suspend_enabled) {
 581                 trace_suspend_resume(TPS("sync_filesystems"), 0, true);
 582                 ksys_sync_helper();
 583                 trace_suspend_resume(TPS("sync_filesystems"), 0, false);
 584         }
 585
 586         pm_pr_dbg("Preparing system for sleep (%s)\n", mem_sleep_labels[state]);
 587         pm_suspend_clear_flags();
 588         error = suspend_prepare(state);
 589         if (error)
 590                 goto Unlock;
 591
 592         if (suspend_test(TEST_FREEZER))
 593                 goto Finish;
 594
 595         trace_suspend_resume(TPS("suspend_enter"), state, false);
 596         pm_pr_dbg("Suspending system (%s)\n", mem_sleep_labels[state]);
 597         pm_restrict_gfp_mask();
 598         error = suspend_devices_and_enter(state);
 599         pm_restore_gfp_mask();
 600
 601  Finish:
 602         events_check_enabled = false;
 603         pm_pr_dbg("Finishing wakeup.\n");
 604         suspend_finish();
 605  Unlock:
 606         mutex_unlock(&system_transition_mutex);
 607         return error;
 608 }
 609
 610 /**
 611  * pm_suspend - Externally visible function for suspending the system.
 612  * @state: System sleep state to enter.
 613  *
 614  * Check if the value of @state represents one of the supported states,
 615  * execute enter_state() and update system suspend statistics.
 616  */
 617 int pm_suspend(suspend_state_t state)
 618 {
 619         int error;
 620
 621         if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
 622                 return -EINVAL;
 623
 624         pr_info("suspend entry (%s)\n", mem_sleep_labels[state]);
 625         error = enter_state(state);
 626         dpm_save_errno(error);
 627         pr_info("suspend exit\n");
 628         return error;
 629 }
 630 EXPORT_SYMBOL(pm_suspend);