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