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 #include <linux/string.h>
  12 #include <linux/delay.h>
  13 #include <linux/errno.h>
  14 #include <linux/init.h>
  15 #include <linux/console.h>
  16 #include <linux/cpu.h>
  17 #include <linux/cpuidle.h>
  18 #include <linux/syscalls.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/ftrace.h>
  29 #include <trace/events/power.h>
  30 #include <linux/compiler.h>
  31 #include <linux/moduleparam.h>
  32
  33 #include "power.h"
  34
  35 const char * const pm_labels[] = {
  36         [PM_SUSPEND_FREEZE] = "freeze",
  37         [PM_SUSPEND_STANDBY] = "standby",
  38         [PM_SUSPEND_MEM] = "mem",
  39 };
  40 const char *pm_states[PM_SUSPEND_MAX];
  41 static const char * const mem_sleep_labels[] = {
  42         [PM_SUSPEND_FREEZE] = "s2idle",
  43         [PM_SUSPEND_STANDBY] = "shallow",
  44         [PM_SUSPEND_MEM] = "deep",
  45 };
  46 const char *mem_sleep_states[PM_SUSPEND_MAX];
  47
  48 suspend_state_t mem_sleep_current = PM_SUSPEND_FREEZE;
  49 static suspend_state_t mem_sleep_default = PM_SUSPEND_MEM;
  50
  51 unsigned int pm_suspend_global_flags;
  52 EXPORT_SYMBOL_GPL(pm_suspend_global_flags);
  53
  54 static const struct platform_suspend_ops *suspend_ops;
  55 static const struct platform_freeze_ops *freeze_ops;
  56 static DECLARE_WAIT_QUEUE_HEAD(suspend_freeze_wait_head);
  57
  58 enum freeze_state __read_mostly suspend_freeze_state;
  59 static DEFINE_SPINLOCK(suspend_freeze_lock);
  60
  61 void freeze_set_ops(const struct platform_freeze_ops *ops)
  62 {
  63         lock_system_sleep();
  64         freeze_ops = ops;
  65         unlock_system_sleep();
  66 }
  67
  68 static void freeze_begin(void)
  69 {
  70         suspend_freeze_state = FREEZE_STATE_NONE;
  71 }
  72
  73 static void freeze_enter(void)
  74 {
  75         trace_suspend_resume(TPS("machine_suspend"), PM_SUSPEND_FREEZE, true);
  76
  77         spin_lock_irq(&suspend_freeze_lock);
  78         if (pm_wakeup_pending())
  79                 goto out;
  80
  81         suspend_freeze_state = FREEZE_STATE_ENTER;
  82         spin_unlock_irq(&suspend_freeze_lock);
  83
  84         get_online_cpus();
  85         cpuidle_resume();
  86
  87         /* Push all the CPUs into the idle loop. */
  88         wake_up_all_idle_cpus();
  89         /* Make the current CPU wait so it can enter the idle loop too. */
  90         wait_event(suspend_freeze_wait_head,
  91                    suspend_freeze_state == FREEZE_STATE_WAKE);
  92
  93         cpuidle_pause();
  94         put_online_cpus();
  95
  96         spin_lock_irq(&suspend_freeze_lock);
  97
  98  out:
  99         suspend_freeze_state = FREEZE_STATE_NONE;
 100         spin_unlock_irq(&suspend_freeze_lock);
 101
 102         trace_suspend_resume(TPS("machine_suspend"), PM_SUSPEND_FREEZE, false);
 103 }
 104
 105 static void s2idle_loop(void)
 106 {
 107         pr_debug("PM: suspend-to-idle\n");
 108
 109         do {
 110                 freeze_enter();
 111
 112                 if (freeze_ops && freeze_ops->wake)
 113                         freeze_ops->wake();
 114
 115                 dpm_resume_noirq(PMSG_RESUME);
 116                 if (freeze_ops && freeze_ops->sync)
 117                         freeze_ops->sync();
 118
 119                 if (pm_wakeup_pending())
 120                         break;
 121
 122                 pm_wakeup_clear(false);
 123         } while (!dpm_suspend_noirq(PMSG_SUSPEND));
 124
 125         pr_debug("PM: resume from suspend-to-idle\n");
 126 }
 127
 128 void freeze_wake(void)
 129 {
 130         unsigned long flags;
 131
 132         spin_lock_irqsave(&suspend_freeze_lock, flags);
 133         if (suspend_freeze_state > FREEZE_STATE_NONE) {
 134                 suspend_freeze_state = FREEZE_STATE_WAKE;
 135                 wake_up(&suspend_freeze_wait_head);
 136         }
 137         spin_unlock_irqrestore(&suspend_freeze_lock, flags);
 138 }
 139 EXPORT_SYMBOL_GPL(freeze_wake);
 140
 141 static bool valid_state(suspend_state_t state)
 142 {
 143         /*
 144          * PM_SUSPEND_STANDBY and PM_SUSPEND_MEM states need low level
 145          * support and need to be valid to the low level
 146          * implementation, no valid callback implies that none are valid.
 147          */
 148         return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
 149 }
 150
 151 void __init pm_states_init(void)
 152 {
 153         /* "mem" and "freeze" are always present in /sys/power/state. */
 154         pm_states[PM_SUSPEND_MEM] = pm_labels[PM_SUSPEND_MEM];
 155         pm_states[PM_SUSPEND_FREEZE] = pm_labels[PM_SUSPEND_FREEZE];
 156         /*
 157          * Suspend-to-idle should be supported even without any suspend_ops,
 158          * initialize mem_sleep_states[] accordingly here.
 159          */
 160         mem_sleep_states[PM_SUSPEND_FREEZE] = mem_sleep_labels[PM_SUSPEND_FREEZE];
 161 }
 162
 163 static int __init mem_sleep_default_setup(char *str)
 164 {
 165         suspend_state_t state;
 166
 167         for (state = PM_SUSPEND_FREEZE; state <= PM_SUSPEND_MEM; state++)
 168                 if (mem_sleep_labels[state] &&
 169                     !strcmp(str, mem_sleep_labels[state])) {
 170                         mem_sleep_default = state;
 171                         break;
 172                 }
 173
 174         return 1;
 175 }
 176 __setup("mem_sleep_default=", mem_sleep_default_setup);
 177
 178 /**
 179  * suspend_set_ops - Set the global suspend method table.
 180  * @ops: Suspend operations to use.
 181  */
 182 void suspend_set_ops(const struct platform_suspend_ops *ops)
 183 {
 184         lock_system_sleep();
 185
 186         suspend_ops = ops;
 187
 188         if (valid_state(PM_SUSPEND_STANDBY)) {
 189                 mem_sleep_states[PM_SUSPEND_STANDBY] = mem_sleep_labels[PM_SUSPEND_STANDBY];
 190                 pm_states[PM_SUSPEND_STANDBY] = pm_labels[PM_SUSPEND_STANDBY];
 191                 if (mem_sleep_default == PM_SUSPEND_STANDBY)
 192                         mem_sleep_current = PM_SUSPEND_STANDBY;
 193         }
 194         if (valid_state(PM_SUSPEND_MEM)) {
 195                 mem_sleep_states[PM_SUSPEND_MEM] = mem_sleep_labels[PM_SUSPEND_MEM];
 196                 if (mem_sleep_default == PM_SUSPEND_MEM)
 197                         mem_sleep_current = PM_SUSPEND_MEM;
 198         }
 199
 200         unlock_system_sleep();
 201 }
 202 EXPORT_SYMBOL_GPL(suspend_set_ops);
 203
 204 /**
 205  * suspend_valid_only_mem - Generic memory-only valid callback.
 206  *
 207  * Platform drivers that implement mem suspend only and only need to check for
 208  * that in their .valid() callback can use this instead of rolling their own
 209  * .valid() callback.
 210  */
 211 int suspend_valid_only_mem(suspend_state_t state)
 212 {
 213         return state == PM_SUSPEND_MEM;
 214 }
 215 EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
 216
 217 static bool sleep_state_supported(suspend_state_t state)
 218 {
 219         return state == PM_SUSPEND_FREEZE || (suspend_ops && suspend_ops->enter);
 220 }
 221
 222 static int platform_suspend_prepare(suspend_state_t state)
 223 {
 224         return state != PM_SUSPEND_FREEZE && suspend_ops->prepare ?
 225                 suspend_ops->prepare() : 0;
 226 }
 227
 228 static int platform_suspend_prepare_late(suspend_state_t state)
 229 {
 230         return state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->prepare ?
 231                 freeze_ops->prepare() : 0;
 232 }
 233
 234 static int platform_suspend_prepare_noirq(suspend_state_t state)
 235 {
 236         return state != PM_SUSPEND_FREEZE && suspend_ops->prepare_late ?
 237                 suspend_ops->prepare_late() : 0;
 238 }
 239
 240 static void platform_resume_noirq(suspend_state_t state)
 241 {
 242         if (state != PM_SUSPEND_FREEZE && suspend_ops->wake)
 243                 suspend_ops->wake();
 244 }
 245
 246 static void platform_resume_early(suspend_state_t state)
 247 {
 248         if (state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->restore)
 249                 freeze_ops->restore();
 250 }
 251
 252 static void platform_resume_finish(suspend_state_t state)
 253 {
 254         if (state != PM_SUSPEND_FREEZE && suspend_ops->finish)
 255                 suspend_ops->finish();
 256 }
 257
 258 static int platform_suspend_begin(suspend_state_t state)
 259 {
 260         if (state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->begin)
 261                 return freeze_ops->begin();
 262         else if (suspend_ops && suspend_ops->begin)
 263                 return suspend_ops->begin(state);
 264         else
 265                 return 0;
 266 }
 267
 268 static void platform_resume_end(suspend_state_t state)
 269 {
 270         if (state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->end)
 271                 freeze_ops->end();
 272         else if (suspend_ops && suspend_ops->end)
 273                 suspend_ops->end();
 274 }
 275
 276 static void platform_recover(suspend_state_t state)
 277 {
 278         if (state != PM_SUSPEND_FREEZE && suspend_ops->recover)
 279                 suspend_ops->recover();
 280 }
 281
 282 static bool platform_suspend_again(suspend_state_t state)
 283 {
 284         return state != PM_SUSPEND_FREEZE && suspend_ops->suspend_again ?
 285                 suspend_ops->suspend_again() : false;
 286 }
 287
 288 #ifdef CONFIG_PM_DEBUG
 289 static unsigned int pm_test_delay = 5;
 290 module_param(pm_test_delay, uint, 0644);
 291 MODULE_PARM_DESC(pm_test_delay,
 292                  "Number of seconds to wait before resuming from suspend test");
 293 #endif
 294
 295 static int suspend_test(int level)
 296 {
 297 #ifdef CONFIG_PM_DEBUG
 298         if (pm_test_level == level) {
 299                 pr_info("suspend debug: Waiting for %d second(s).\n",
 300                                 pm_test_delay);
 301                 mdelay(pm_test_delay * 1000);
 302                 return 1;
 303         }
 304 #endif /* !CONFIG_PM_DEBUG */
 305         return 0;
 306 }
 307
 308 /**
 309  * suspend_prepare - Prepare for entering system sleep state.
 310  *
 311  * Common code run for every system sleep state that can be entered (except for
 312  * hibernation).  Run suspend notifiers, allocate the "suspend" console and
 313  * freeze processes.
 314  */
 315 static int suspend_prepare(suspend_state_t state)
 316 {
 317         int error, nr_calls = 0;
 318
 319         if (!sleep_state_supported(state))
 320                 return -EPERM;
 321
 322         pm_prepare_console();
 323
 324         error = __pm_notifier_call_chain(PM_SUSPEND_PREPARE, -1, &nr_calls);
 325         if (error) {
 326                 nr_calls--;
 327                 goto Finish;
 328         }
 329
 330         trace_suspend_resume(TPS("freeze_processes"), 0, true);
 331         error = suspend_freeze_processes();
 332         trace_suspend_resume(TPS("freeze_processes"), 0, false);
 333         if (!error)
 334                 return 0;
 335
 336         suspend_stats.failed_freeze++;
 337         dpm_save_failed_step(SUSPEND_FREEZE);
 338  Finish:
 339         __pm_notifier_call_chain(PM_POST_SUSPEND, nr_calls, NULL);
 340         pm_restore_console();
 341         return error;
 342 }
 343
 344 /* default implementation */
 345 void __weak arch_suspend_disable_irqs(void)
 346 {
 347         local_irq_disable();
 348 }
 349
 350 /* default implementation */
 351 void __weak arch_suspend_enable_irqs(void)
 352 {
 353         local_irq_enable();
 354 }
 355
 356 /**
 357  * suspend_enter - Make the system enter the given sleep state.
 358  * @state: System sleep state to enter.
 359  * @wakeup: Returns information that the sleep state should not be re-entered.
 360  *
 361  * This function should be called after devices have been suspended.
 362  */
 363 static int suspend_enter(suspend_state_t state, bool *wakeup)
 364 {
 365         int error;
 366
 367         error = platform_suspend_prepare(state);
 368         if (error)
 369                 goto Platform_finish;
 370
 371         error = dpm_suspend_late(PMSG_SUSPEND);
 372         if (error) {
 373                 pr_err("PM: late suspend of devices failed\n");
 374                 goto Platform_finish;
 375         }
 376         error = platform_suspend_prepare_late(state);
 377         if (error)
 378                 goto Devices_early_resume;
 379
 380         error = dpm_suspend_noirq(PMSG_SUSPEND);
 381         if (error) {
 382                 pr_err("PM: noirq suspend of devices failed\n");
 383                 goto Platform_early_resume;
 384         }
 385         error = platform_suspend_prepare_noirq(state);
 386         if (error)
 387                 goto Platform_wake;
 388
 389         if (suspend_test(TEST_PLATFORM))
 390                 goto Platform_wake;
 391
 392         /*
 393          * PM_SUSPEND_FREEZE equals
 394          * frozen processes + suspended devices + idle processors.
 395          * Thus we should invoke freeze_enter() soon after
 396          * all the devices are suspended.
 397          */
 398         if (state == PM_SUSPEND_FREEZE) {
 399                 s2idle_loop();
 400                 goto Platform_early_resume;
 401         }
 402
 403         error = disable_nonboot_cpus();
 404         if (error || suspend_test(TEST_CPUS))
 405                 goto Enable_cpus;
 406
 407         arch_suspend_disable_irqs();
 408         BUG_ON(!irqs_disabled());
 409
 410         error = syscore_suspend();
 411         if (!error) {
 412                 *wakeup = pm_wakeup_pending();
 413                 if (!(suspend_test(TEST_CORE) || *wakeup)) {
 414                         trace_suspend_resume(TPS("machine_suspend"),
 415                                 state, true);
 416                         error = suspend_ops->enter(state);
 417                         trace_suspend_resume(TPS("machine_suspend"),
 418                                 state, false);
 419                         events_check_enabled = false;
 420                 } else if (*wakeup) {
 421                         error = -EBUSY;
 422                 }
 423                 syscore_resume();
 424         }
 425
 426         arch_suspend_enable_irqs();
 427         BUG_ON(irqs_disabled());
 428
 429  Enable_cpus:
 430         enable_nonboot_cpus();
 431
 432  Platform_wake:
 433         platform_resume_noirq(state);
 434         dpm_resume_noirq(PMSG_RESUME);
 435
 436  Platform_early_resume:
 437         platform_resume_early(state);
 438
 439  Devices_early_resume:
 440         dpm_resume_early(PMSG_RESUME);
 441
 442  Platform_finish:
 443         platform_resume_finish(state);
 444         return error;
 445 }
 446
 447 /**
 448  * suspend_devices_and_enter - Suspend devices and enter system sleep state.
 449  * @state: System sleep state to enter.
 450  */
 451 int suspend_devices_and_enter(suspend_state_t state)
 452 {
 453         int error;
 454         bool wakeup = false;
 455
 456         if (!sleep_state_supported(state))
 457                 return -ENOSYS;
 458
 459         error = platform_suspend_begin(state);
 460         if (error)
 461                 goto Close;
 462
 463         suspend_console();
 464         suspend_test_start();
 465         error = dpm_suspend_start(PMSG_SUSPEND);
 466         if (error) {
 467                 pr_err("PM: Some devices failed to suspend, or early wake event detected\n");
 468                 goto Recover_platform;
 469         }
 470         suspend_test_finish("suspend devices");
 471         if (suspend_test(TEST_DEVICES))
 472                 goto Recover_platform;
 473
 474         do {
 475                 error = suspend_enter(state, &wakeup);
 476         } while (!error && !wakeup && platform_suspend_again(state));
 477
 478  Resume_devices:
 479         suspend_test_start();
 480         dpm_resume_end(PMSG_RESUME);
 481         suspend_test_finish("resume devices");
 482         trace_suspend_resume(TPS("resume_console"), state, true);
 483         resume_console();
 484         trace_suspend_resume(TPS("resume_console"), state, false);
 485
 486  Close:
 487         platform_resume_end(state);
 488         return error;
 489
 490  Recover_platform:
 491         platform_recover(state);
 492         goto Resume_devices;
 493 }
 494
 495 /**
 496  * suspend_finish - Clean up before finishing the suspend sequence.
 497  *
 498  * Call platform code to clean up, restart processes, and free the console that
 499  * we've allocated. This routine is not called for hibernation.
 500  */
 501 static void suspend_finish(void)
 502 {
 503         suspend_thaw_processes();
 504         pm_notifier_call_chain(PM_POST_SUSPEND);
 505         pm_restore_console();
 506 }
 507
 508 /**
 509  * enter_state - Do common work needed to enter system sleep state.
 510  * @state: System sleep state to enter.
 511  *
 512  * Make sure that no one else is trying to put the system into a sleep state.
 513  * Fail if that's not the case.  Otherwise, prepare for system suspend, make the
 514  * system enter the given sleep state and clean up after wakeup.
 515  */
 516 static int enter_state(suspend_state_t state)
 517 {
 518         int error;
 519
 520         trace_suspend_resume(TPS("suspend_enter"), state, true);
 521         if (state == PM_SUSPEND_FREEZE) {
 522 #ifdef CONFIG_PM_DEBUG
 523                 if (pm_test_level != TEST_NONE && pm_test_level <= TEST_CPUS) {
 524                         pr_warn("PM: Unsupported test mode for suspend to idle, please choose none/freezer/devices/platform.\n");
 525                         return -EAGAIN;
 526                 }
 527 #endif
 528         } else if (!valid_state(state)) {
 529                 return -EINVAL;
 530         }
 531         if (!mutex_trylock(&pm_mutex))
 532                 return -EBUSY;
 533
 534         if (state == PM_SUSPEND_FREEZE)
 535                 freeze_begin();
 536
 537 #ifndef CONFIG_SUSPEND_SKIP_SYNC
 538         trace_suspend_resume(TPS("sync_filesystems"), 0, true);
 539         pr_info("PM: Syncing filesystems ... ");
 540         sys_sync();
 541         pr_cont("done.\n");
 542         trace_suspend_resume(TPS("sync_filesystems"), 0, false);
 543 #endif
 544
 545         pr_debug("PM: Preparing system for sleep (%s)\n", pm_states[state]);
 546         pm_suspend_clear_flags();
 547         error = suspend_prepare(state);
 548         if (error)
 549                 goto Unlock;
 550
 551         if (suspend_test(TEST_FREEZER))
 552                 goto Finish;
 553
 554         trace_suspend_resume(TPS("suspend_enter"), state, false);
 555         pr_debug("PM: Suspending system (%s)\n", pm_states[state]);
 556         pm_restrict_gfp_mask();
 557         error = suspend_devices_and_enter(state);
 558         pm_restore_gfp_mask();
 559
 560  Finish:
 561         pr_debug("PM: Finishing wakeup.\n");
 562         suspend_finish();
 563  Unlock:
 564         mutex_unlock(&pm_mutex);
 565         return error;
 566 }
 567
 568 /**
 569  * pm_suspend - Externally visible function for suspending the system.
 570  * @state: System sleep state to enter.
 571  *
 572  * Check if the value of @state represents one of the supported states,
 573  * execute enter_state() and update system suspend statistics.
 574  */
 575 int pm_suspend(suspend_state_t state)
 576 {
 577         int error;
 578
 579         if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
 580                 return -EINVAL;
 581
 582         error = enter_state(state);
 583         if (error) {
 584                 suspend_stats.fail++;
 585                 dpm_save_failed_errno(error);
 586         } else {
 587                 suspend_stats.success++;
 588         }
 589         return error;
 590 }
 591 EXPORT_SYMBOL(pm_suspend);