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