kernel/power/suspend.c

   1 /*
   2  * kernel/power/suspend.c - Suspend to RAM and standby functionality.
   3  *
   4  * Copyright (c) 2003 Patrick Mochel
   5  * Copyright (c) 2003 Open Source Development Lab
   6  * Copyright (c) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
   7  *
   8  * This file is released under the GPLv2.
   9  */
  10
  11 #define pr_fmt(fmt) "PM: " fmt
  12
  13 #include <linux/string.h>
  14 #include <linux/delay.h>
  15 #include <linux/errno.h>
  16 #include <linux/init.h>
  17 #include <linux/console.h>
  18 #include <linux/cpu.h>
  19 #include <linux/cpuidle.h>
  20 #include <linux/syscalls.h>
  21 #include <linux/gfp.h>
  22 #include <linux/io.h>
  23 #include <linux/kernel.h>
  24 #include <linux/list.h>
  25 #include <linux/mm.h>
  26 #include <linux/slab.h>
  27 #include <linux/export.h>
  28 #include <linux/suspend.h>
  29 #include <linux/syscore_ops.h>
  30 #include <linux/ftrace.h>
  31 #include <trace/events/power.h>
  32 #include <linux/compiler.h>
  33 #include <linux/moduleparam.h>
  34
  35 #include "power.h"
  36
  37 const char * const pm_labels[] = {
  38         [PM_SUSPEND_TO_IDLE] = "freeze",
  39         [PM_SUSPEND_STANDBY] = "standby",
  40         [PM_SUSPEND_MEM] = "mem",
  41 };
  42 const char *pm_states[PM_SUSPEND_MAX];
  43 static const char * const mem_sleep_labels[] = {
  44         [PM_SUSPEND_TO_IDLE] = "s2idle",
  45         [PM_SUSPEND_STANDBY] = "shallow",
  46         [PM_SUSPEND_MEM] = "deep",
  47 };
  48 const char *mem_sleep_states[PM_SUSPEND_MAX];
  49
  50 suspend_state_t mem_sleep_current = PM_SUSPEND_TO_IDLE;
  51 suspend_state_t mem_sleep_default = PM_SUSPEND_MAX;
  52 suspend_state_t pm_suspend_target_state;
  53 EXPORT_SYMBOL_GPL(pm_suspend_target_state);
  54
  55 unsigned int pm_suspend_global_flags;
  56 EXPORT_SYMBOL_GPL(pm_suspend_global_flags);
  57
  58 static const struct platform_suspend_ops *suspend_ops;
  59 static const struct platform_s2idle_ops *s2idle_ops;
  60 static DECLARE_WAIT_QUEUE_HEAD(s2idle_wait_head);
  61
  62 enum s2idle_states __read_mostly s2idle_state;
  63 static DEFINE_SPINLOCK(s2idle_lock);
  64
  65 void s2idle_set_ops(const struct platform_s2idle_ops *ops)
  66 {
  67         lock_system_sleep();
  68         s2idle_ops = ops;
  69         unlock_system_sleep();
  70 }
  71
  72 static void s2idle_begin(void)
  73 {
  74         s2idle_state = S2IDLE_STATE_NONE;
  75 }
  76
  77 static void s2idle_enter(void)
  78 {
  79         trace_suspend_resume(TPS("machine_suspend"), PM_SUSPEND_TO_IDLE, true);
  80
  81         spin_lock_irq(&s2idle_lock);
  82         if (pm_wakeup_pending())
  83                 goto out;
  84
  85         s2idle_state = S2IDLE_STATE_ENTER;
  86         spin_unlock_irq(&s2idle_lock);
  87
  88         get_online_cpus();
  89         cpuidle_resume();
  90
  91         /* Push all the CPUs into the idle loop. */
  92         wake_up_all_idle_cpus();
  93         /* Make the current CPU wait so it can enter the idle loop too. */
  94         wait_event(s2idle_wait_head,
  95                    s2idle_state == S2IDLE_STATE_WAKE);
  96
  97         cpuidle_pause();
  98         put_online_cpus();
  99
 100         spin_lock_irq(&s2idle_lock);
 101
 102  out:
 103         s2idle_state = S2IDLE_STATE_NONE;
 104         spin_unlock_irq(&s2idle_lock);
 105
 106         trace_suspend_resume(TPS("machine_suspend"), PM_SUSPEND_TO_IDLE, false);
 107 }
 108
 109 static void s2idle_loop(void)
 110 {
 111         pm_pr_dbg("suspend-to-idle\n");
 112
 113         for (;;) {
 114                 int error;
 115
 116                 dpm_noirq_begin();
 117
 118                 /*
 119                  * Suspend-to-idle equals
 120                  * frozen processes + suspended devices + idle processors.
 121                  * Thus s2idle_enter() should be called right after
 122                  * all devices have been suspended.
 123                  */
 124                 error = dpm_noirq_suspend_devices(PMSG_SUSPEND);
 125                 if (!error)
 126                         s2idle_enter();
 127
 128                 dpm_noirq_resume_devices(PMSG_RESUME);
 129                 if (error && (error != -EBUSY || !pm_wakeup_pending())) {
 130                         dpm_noirq_end();
 131                         break;
 132                 }
 133
 134                 if (s2idle_ops && s2idle_ops->wake)
 135                         s2idle_ops->wake();
 136
 137                 dpm_noirq_end();
 138
 139                 if (s2idle_ops && s2idle_ops->sync)
 140                         s2idle_ops->sync();
 141
 142                 if (pm_wakeup_pending())
 143                         break;
 144
 145                 pm_wakeup_clear(false);
 146         }
 147
 148         pm_pr_dbg("resume from suspend-to-idle\n");
 149 }
 150
 151 void s2idle_wake(void)
 152 {
 153         unsigned long flags;
 154
 155         spin_lock_irqsave(&s2idle_lock, flags);
 156         if (s2idle_state > S2IDLE_STATE_NONE) {
 157                 s2idle_state = S2IDLE_STATE_WAKE;
 158                 wake_up(&s2idle_wait_head);
 159         }
 160         spin_unlock_irqrestore(&s2idle_lock, flags);
 161 }
 162 EXPORT_SYMBOL_GPL(s2idle_wake);
 163
 164 static bool valid_state(suspend_state_t state)
 165 {
 166         /*
 167          * PM_SUSPEND_STANDBY and PM_SUSPEND_MEM states need low level
 168          * support and need to be valid to the low level
 169          * implementation, no valid callback implies that none are valid.
 170          */
 171         return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
 172 }
 173
 174 void __init pm_states_init(void)
 175 {
 176         /* "mem" and "freeze" are always present in /sys/power/state. */
 177         pm_states[PM_SUSPEND_MEM] = pm_labels[PM_SUSPEND_MEM];
 178         pm_states[PM_SUSPEND_TO_IDLE] = pm_labels[PM_SUSPEND_TO_IDLE];
 179         /*
 180          * Suspend-to-idle should be supported even without any suspend_ops,
 181          * initialize mem_sleep_states[] accordingly here.
 182          */
 183         mem_sleep_states[PM_SUSPEND_TO_IDLE] = mem_sleep_labels[PM_SUSPEND_TO_IDLE];
 184 }
 185
 186 static int __init mem_sleep_default_setup(char *str)
 187 {
 188         suspend_state_t state;
 189
 190         for (state = PM_SUSPEND_TO_IDLE; state <= PM_SUSPEND_MEM; state++)
 191                 if (mem_sleep_labels[state] &&
 192                     !strcmp(str, mem_sleep_labels[state])) {
 193                         mem_sleep_default = state;
 194                         break;
 195                 }
 196
 197         return 1;
 198 }
 199 __setup("mem_sleep_default=", mem_sleep_default_setup);
 200
 201 /**
 202  * suspend_set_ops - Set the global suspend method table.
 203  * @ops: Suspend operations to use.
 204  */
 205 void suspend_set_ops(const struct platform_suspend_ops *ops)
 206 {
 207         lock_system_sleep();
 208
 209         suspend_ops = ops;
 210
 211         if (valid_state(PM_SUSPEND_STANDBY)) {
 212                 mem_sleep_states[PM_SUSPEND_STANDBY] = mem_sleep_labels[PM_SUSPEND_STANDBY];
 213                 pm_states[PM_SUSPEND_STANDBY] = pm_labels[PM_SUSPEND_STANDBY];
 214                 if (mem_sleep_default == PM_SUSPEND_STANDBY)
 215                         mem_sleep_current = PM_SUSPEND_STANDBY;
 216         }
 217         if (valid_state(PM_SUSPEND_MEM)) {
 218                 mem_sleep_states[PM_SUSPEND_MEM] = mem_sleep_labels[PM_SUSPEND_MEM];
 219                 if (mem_sleep_default >= PM_SUSPEND_MEM)
 220                         mem_sleep_current = PM_SUSPEND_MEM;
 221         }
 222
 223         unlock_system_sleep();
 224 }
 225 EXPORT_SYMBOL_GPL(suspend_set_ops);
 226
 227 /**
 228  * suspend_valid_only_mem - Generic memory-only valid callback.
 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 || (suspend_ops && suspend_ops->enter);
 243 }
 244
 245 static int platform_suspend_prepare(suspend_state_t state)
 246 {
 247         return state != PM_SUSPEND_TO_IDLE && suspend_ops->prepare ?
 248                 suspend_ops->prepare() : 0;
 249 }
 250
 251 static int platform_suspend_prepare_late(suspend_state_t state)
 252 {
 253         return state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->prepare ?
 254                 s2idle_ops->prepare() : 0;
 255 }
 256
 257 static int platform_suspend_prepare_noirq(suspend_state_t state)
 258 {
 259         return state != PM_SUSPEND_TO_IDLE && suspend_ops->prepare_late ?
 260                 suspend_ops->prepare_late() : 0;
 261 }
 262
 263 static void platform_resume_noirq(suspend_state_t state)
 264 {
 265         if (state != PM_SUSPEND_TO_IDLE && suspend_ops->wake)
 266                 suspend_ops->wake();
 267 }
 268
 269 static void platform_resume_early(suspend_state_t state)
 270 {
 271         if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->restore)
 272                 s2idle_ops->restore();
 273 }
 274
 275 static void platform_resume_finish(suspend_state_t state)
 276 {
 277         if (state != PM_SUSPEND_TO_IDLE && suspend_ops->finish)
 278                 suspend_ops->finish();
 279 }
 280
 281 static int platform_suspend_begin(suspend_state_t state)
 282 {
 283         if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->begin)
 284                 return s2idle_ops->begin();
 285         else if (suspend_ops && suspend_ops->begin)
 286                 return suspend_ops->begin(state);
 287         else
 288                 return 0;
 289 }
 290
 291 static void platform_resume_end(suspend_state_t state)
 292 {
 293         if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->end)
 294                 s2idle_ops->end();
 295         else if (suspend_ops && suspend_ops->end)
 296                 suspend_ops->end();
 297 }
 298
 299 static void platform_recover(suspend_state_t state)
 300 {
 301         if (state != PM_SUSPEND_TO_IDLE && suspend_ops->recover)
 302                 suspend_ops->recover();
 303 }
 304
 305 static bool platform_suspend_again(suspend_state_t state)
 306 {
 307         return state != PM_SUSPEND_TO_IDLE && suspend_ops->suspend_again ?
 308                 suspend_ops->suspend_again() : false;
 309 }
 310
 311 #ifdef CONFIG_PM_DEBUG
 312 static unsigned int pm_test_delay = 5;
 313 module_param(pm_test_delay, uint, 0644);
 314 MODULE_PARM_DESC(pm_test_delay,
 315                  "Number of seconds to wait before resuming from suspend test");
 316 #endif
 317
 318 static int suspend_test(int level)
 319 {
 320 #ifdef CONFIG_PM_DEBUG
 321         if (pm_test_level == level) {
 322                 pr_info("suspend debug: Waiting for %d second(s).\n",
 323                                 pm_test_delay);
 324                 mdelay(pm_test_delay * 1000);
 325                 return 1;
 326         }
 327 #endif /* !CONFIG_PM_DEBUG */
 328         return 0;
 329 }
 330
 331 /**
 332  * suspend_prepare - Prepare for entering system sleep state.
 333  *
 334  * Common code run for every system sleep state that can be entered (except for
 335  * hibernation).  Run suspend notifiers, allocate the "suspend" console and
 336  * freeze processes.
 337  */
 338 static int suspend_prepare(suspend_state_t state)
 339 {
 340         int error, nr_calls = 0;
 341
 342         if (!sleep_state_supported(state))
 343                 return -EPERM;
 344
 345         pm_prepare_console();
 346
 347         error = __pm_notifier_call_chain(PM_SUSPEND_PREPARE, -1, &nr_calls);
 348         if (error) {
 349                 nr_calls--;
 350                 goto Finish;
 351         }
 352
 353         trace_suspend_resume(TPS("freeze_processes"), 0, true);
 354         error = suspend_freeze_processes();
 355         trace_suspend_resume(TPS("freeze_processes"), 0, false);
 356         if (!error)
 357                 return 0;
 358
 359         suspend_stats.failed_freeze++;
 360         dpm_save_failed_step(SUSPEND_FREEZE);
 361  Finish:
 362         __pm_notifier_call_chain(PM_POST_SUSPEND, nr_calls, NULL);
 363         pm_restore_console();
 364         return error;
 365 }
 366
 367 /* default implementation */
 368 void __weak arch_suspend_disable_irqs(void)
 369 {
 370         local_irq_disable();
 371 }
 372
 373 /* default implementation */
 374 void __weak arch_suspend_enable_irqs(void)
 375 {
 376         local_irq_enable();
 377 }
 378
 379 /**
 380  * suspend_enter - Make the system enter the given sleep state.
 381  * @state: System sleep state to enter.
 382  * @wakeup: Returns information that the sleep state should not be re-entered.
 383  *
 384  * This function should be called after devices have been suspended.
 385  */
 386 static int suspend_enter(suspend_state_t state, bool *wakeup)
 387 {
 388         int error;
 389
 390         error = platform_suspend_prepare(state);
 391         if (error)
 392                 goto Platform_finish;
 393
 394         error = dpm_suspend_late(PMSG_SUSPEND);
 395         if (error) {
 396                 pr_err("late suspend of devices failed\n");
 397                 goto Platform_finish;
 398         }
 399         error = platform_suspend_prepare_late(state);
 400         if (error)
 401                 goto Devices_early_resume;
 402
 403         if (state == PM_SUSPEND_TO_IDLE && pm_test_level != TEST_PLATFORM) {
 404                 s2idle_loop();
 405                 goto Platform_early_resume;
 406         }
 407
 408         error = dpm_suspend_noirq(PMSG_SUSPEND);
 409         if (error) {
 410                 pr_err("noirq suspend of devices failed\n");
 411                 goto Platform_early_resume;
 412         }
 413         error = platform_suspend_prepare_noirq(state);
 414         if (error)
 415                 goto Platform_wake;
 416
 417         if (suspend_test(TEST_PLATFORM))
 418                 goto Platform_wake;
 419
 420         error = disable_nonboot_cpus();
 421         if (error || suspend_test(TEST_CPUS))
 422                 goto Enable_cpus;
 423
 424         arch_suspend_disable_irqs();
 425         BUG_ON(!irqs_disabled());
 426
 427         error = syscore_suspend();
 428         if (!error) {
 429                 *wakeup = pm_wakeup_pending();
 430                 if (!(suspend_test(TEST_CORE) || *wakeup)) {
 431                         trace_suspend_resume(TPS("machine_suspend"),
 432                                 state, true);
 433                         error = suspend_ops->enter(state);
 434                         trace_suspend_resume(TPS("machine_suspend"),
 435                                 state, false);
 436                         events_check_enabled = false;
 437                 } else if (*wakeup) {
 438                         error = -EBUSY;
 439                 }
 440                 syscore_resume();
 441         }
 442
 443         arch_suspend_enable_irqs();
 444         BUG_ON(irqs_disabled());
 445
 446  Enable_cpus:
 447         enable_nonboot_cpus();
 448
 449  Platform_wake:
 450         platform_resume_noirq(state);
 451         dpm_resume_noirq(PMSG_RESUME);
 452
 453  Platform_early_resume:
 454         platform_resume_early(state);
 455
 456  Devices_early_resume:
 457         dpm_resume_early(PMSG_RESUME);
 458
 459  Platform_finish:
 460         platform_resume_finish(state);
 461         return error;
 462 }
 463
 464 /**
 465  * suspend_devices_and_enter - Suspend devices and enter system sleep state.
 466  * @state: System sleep state to enter.
 467  */
 468 int suspend_devices_and_enter(suspend_state_t state)
 469 {
 470         int error;
 471         bool wakeup = false;
 472
 473         if (!sleep_state_supported(state))
 474                 return -ENOSYS;
 475
 476         pm_suspend_target_state = state;
 477
 478         error = platform_suspend_begin(state);
 479         if (error)
 480                 goto Close;
 481
 482         suspend_console();
 483         suspend_test_start();
 484         error = dpm_suspend_start(PMSG_SUSPEND);
 485         if (error) {
 486                 pr_err("Some devices failed to suspend, or early wake event detected\n");
 487                 goto Recover_platform;
 488         }
 489         suspend_test_finish("suspend devices");
 490         if (suspend_test(TEST_DEVICES))
 491                 goto Recover_platform;
 492
 493         do {
 494                 error = suspend_enter(state, &wakeup);
 495         } while (!error && !wakeup && platform_suspend_again(state));
 496
 497  Resume_devices:
 498         suspend_test_start();
 499         dpm_resume_end(PMSG_RESUME);
 500         suspend_test_finish("resume devices");
 501         trace_suspend_resume(TPS("resume_console"), state, true);
 502         resume_console();
 503         trace_suspend_resume(TPS("resume_console"), state, false);
 504
 505  Close:
 506         platform_resume_end(state);
 507         pm_suspend_target_state = PM_SUSPEND_ON;
 508         return error;
 509
 510  Recover_platform:
 511         platform_recover(state);
 512         goto Resume_devices;
 513 }
 514
 515 /**
 516  * suspend_finish - Clean up before finishing the suspend sequence.
 517  *
 518  * Call platform code to clean up, restart processes, and free the console that
 519  * we've allocated. This routine is not called for hibernation.
 520  */
 521 static void suspend_finish(void)
 522 {
 523         suspend_thaw_processes();
 524         pm_notifier_call_chain(PM_POST_SUSPEND);
 525         pm_restore_console();
 526 }
 527
 528 /**
 529  * enter_state - Do common work needed to enter system sleep state.
 530  * @state: System sleep state to enter.
 531  *
 532  * Make sure that no one else is trying to put the system into a sleep state.
 533  * Fail if that's not the case.  Otherwise, prepare for system suspend, make the
 534  * system enter the given sleep state and clean up after wakeup.
 535  */
 536 static int enter_state(suspend_state_t state)
 537 {
 538         int error;
 539
 540         trace_suspend_resume(TPS("suspend_enter"), state, true);
 541         if (state == PM_SUSPEND_TO_IDLE) {
 542 #ifdef CONFIG_PM_DEBUG
 543                 if (pm_test_level != TEST_NONE && pm_test_level <= TEST_CPUS) {
 544                         pr_warn("Unsupported test mode for suspend to idle, please choose none/freezer/devices/platform.\n");
 545                         return -EAGAIN;
 546                 }
 547 #endif
 548         } else if (!valid_state(state)) {
 549                 return -EINVAL;
 550         }
 551         if (!mutex_trylock(&pm_mutex))
 552                 return -EBUSY;
 553
 554         if (state == PM_SUSPEND_TO_IDLE)
 555                 s2idle_begin();
 556
 557 #ifndef CONFIG_SUSPEND_SKIP_SYNC
 558         trace_suspend_resume(TPS("sync_filesystems"), 0, true);
 559         pr_info("Syncing filesystems ... ");
 560         sys_sync();
 561         pr_cont("done.\n");
 562         trace_suspend_resume(TPS("sync_filesystems"), 0, false);
 563 #endif
 564
 565         pm_pr_dbg("Preparing system for sleep (%s)\n", mem_sleep_labels[state]);
 566         pm_suspend_clear_flags();
 567         error = suspend_prepare(state);
 568         if (error)
 569                 goto Unlock;
 570
 571         if (suspend_test(TEST_FREEZER))
 572                 goto Finish;
 573
 574         trace_suspend_resume(TPS("suspend_enter"), state, false);
 575         pm_pr_dbg("Suspending system (%s)\n", mem_sleep_labels[state]);
 576         pm_restrict_gfp_mask();
 577         error = suspend_devices_and_enter(state);
 578         pm_restore_gfp_mask();
 579
 580  Finish:
 581         pm_pr_dbg("Finishing wakeup.\n");
 582         suspend_finish();
 583  Unlock:
 584         mutex_unlock(&pm_mutex);
 585         return error;
 586 }
 587
 588 /**
 589  * pm_suspend - Externally visible function for suspending the system.
 590  * @state: System sleep state to enter.
 591  *
 592  * Check if the value of @state represents one of the supported states,
 593  * execute enter_state() and update system suspend statistics.
 594  */
 595 int pm_suspend(suspend_state_t state)
 596 {
 597         int error;
 598
 599         if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
 600                 return -EINVAL;
 601
 602         pr_info("suspend entry (%s)\n", mem_sleep_labels[state]);
 603         error = enter_state(state);
 604         if (error) {
 605                 suspend_stats.fail++;
 606                 dpm_save_failed_errno(error);
 607         } else {
 608                 suspend_stats.success++;
 609         }
 610         pr_info("suspend exit\n");
 611         return error;
 612 }
 613 EXPORT_SYMBOL(pm_suspend);