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 suspend_state_t pm_suspend_target_state;
  51 EXPORT_SYMBOL_GPL(pm_suspend_target_state);
  52
  53 unsigned int pm_suspend_global_flags;
  54 EXPORT_SYMBOL_GPL(pm_suspend_global_flags);
  55
  56 static const struct platform_suspend_ops *suspend_ops;
  57 static const struct platform_freeze_ops *freeze_ops;
  58 static DECLARE_WAIT_QUEUE_HEAD(suspend_freeze_wait_head);
  59
  60 enum freeze_state __read_mostly suspend_freeze_state;
  61 static DEFINE_SPINLOCK(suspend_freeze_lock);
  62
  63 void freeze_set_ops(const struct platform_freeze_ops *ops)
  64 {
  65         lock_system_sleep();
  66         freeze_ops = ops;
  67         unlock_system_sleep();
  68 }
  69
  70 static void freeze_begin(void)
  71 {
  72         suspend_freeze_state = FREEZE_STATE_NONE;
  73 }
  74
  75 static void freeze_enter(void)
  76 {
  77         trace_suspend_resume(TPS("machine_suspend"), PM_SUSPEND_FREEZE, true);
  78
  79         spin_lock_irq(&suspend_freeze_lock);
  80         if (pm_wakeup_pending())
  81                 goto out;
  82
  83         suspend_freeze_state = FREEZE_STATE_ENTER;
  84         spin_unlock_irq(&suspend_freeze_lock);
  85
  86         get_online_cpus();
  87         cpuidle_resume();
  88
  89         /* Push all the CPUs into the idle loop. */
  90         wake_up_all_idle_cpus();
  91         /* Make the current CPU wait so it can enter the idle loop too. */
  92         wait_event(suspend_freeze_wait_head,
  93                    suspend_freeze_state == FREEZE_STATE_WAKE);
  94
  95         cpuidle_pause();
  96         put_online_cpus();
  97
  98         spin_lock_irq(&suspend_freeze_lock);
  99
 100  out:
 101         suspend_freeze_state = FREEZE_STATE_NONE;
 102         spin_unlock_irq(&suspend_freeze_lock);
 103
 104         trace_suspend_resume(TPS("machine_suspend"), PM_SUSPEND_FREEZE, false);
 105 }
 106
 107 static void s2idle_loop(void)
 108 {
 109         pm_pr_dbg("suspend-to-idle\n");
 110
 111         for (;;) {
 112                 int error;
 113
 114                 dpm_noirq_begin();
 115
 116                 /*
 117                  * Suspend-to-idle equals
 118                  * frozen processes + suspended devices + idle processors.
 119                  * Thus freeze_enter() should be called right after
 120                  * all devices have been suspended.
 121                  */
 122                 error = dpm_noirq_suspend_devices(PMSG_SUSPEND);
 123                 if (!error)
 124                         freeze_enter();
 125
 126                 dpm_noirq_resume_devices(PMSG_RESUME);
 127                 if (error && (error != -EBUSY || !pm_wakeup_pending())) {
 128                         dpm_noirq_end();
 129                         break;
 130                 }
 131
 132                 if (freeze_ops && freeze_ops->wake)
 133                         freeze_ops->wake();
 134
 135                 dpm_noirq_end();
 136
 137                 if (freeze_ops && freeze_ops->sync)
 138                         freeze_ops->sync();
 139
 140                 if (pm_wakeup_pending())
 141                         break;
 142
 143                 pm_wakeup_clear(false);
 144         }
 145
 146         pm_pr_dbg("resume from suspend-to-idle\n");
 147 }
 148
 149 void freeze_wake(void)
 150 {
 151         unsigned long flags;
 152
 153         spin_lock_irqsave(&suspend_freeze_lock, flags);
 154         if (suspend_freeze_state > FREEZE_STATE_NONE) {
 155                 suspend_freeze_state = FREEZE_STATE_WAKE;
 156                 wake_up(&suspend_freeze_wait_head);
 157         }
 158         spin_unlock_irqrestore(&suspend_freeze_lock, flags);
 159 }
 160 EXPORT_SYMBOL_GPL(freeze_wake);
 161
 162 static bool valid_state(suspend_state_t state)
 163 {
 164         /*
 165          * PM_SUSPEND_STANDBY and PM_SUSPEND_MEM states need low level
 166          * support and need to be valid to the low level
 167          * implementation, no valid callback implies that none are valid.
 168          */
 169         return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
 170 }
 171
 172 void __init pm_states_init(void)
 173 {
 174         /* "mem" and "freeze" are always present in /sys/power/state. */
 175         pm_states[PM_SUSPEND_MEM] = pm_labels[PM_SUSPEND_MEM];
 176         pm_states[PM_SUSPEND_FREEZE] = pm_labels[PM_SUSPEND_FREEZE];
 177         /*
 178          * Suspend-to-idle should be supported even without any suspend_ops,
 179          * initialize mem_sleep_states[] accordingly here.
 180          */
 181         mem_sleep_states[PM_SUSPEND_FREEZE] = mem_sleep_labels[PM_SUSPEND_FREEZE];
 182 }
 183
 184 static int __init mem_sleep_default_setup(char *str)
 185 {
 186         suspend_state_t state;
 187
 188         for (state = PM_SUSPEND_FREEZE; state <= PM_SUSPEND_MEM; state++)
 189                 if (mem_sleep_labels[state] &&
 190                     !strcmp(str, mem_sleep_labels[state])) {
 191                         mem_sleep_default = state;
 192                         break;
 193                 }
 194
 195         return 1;
 196 }
 197 __setup("mem_sleep_default=", mem_sleep_default_setup);
 198
 199 /**
 200  * suspend_set_ops - Set the global suspend method table.
 201  * @ops: Suspend operations to use.
 202  */
 203 void suspend_set_ops(const struct platform_suspend_ops *ops)
 204 {
 205         lock_system_sleep();
 206
 207         suspend_ops = ops;
 208
 209         if (valid_state(PM_SUSPEND_STANDBY)) {
 210                 mem_sleep_states[PM_SUSPEND_STANDBY] = mem_sleep_labels[PM_SUSPEND_STANDBY];
 211                 pm_states[PM_SUSPEND_STANDBY] = pm_labels[PM_SUSPEND_STANDBY];
 212                 if (mem_sleep_default == PM_SUSPEND_STANDBY)
 213                         mem_sleep_current = PM_SUSPEND_STANDBY;
 214         }
 215         if (valid_state(PM_SUSPEND_MEM)) {
 216                 mem_sleep_states[PM_SUSPEND_MEM] = mem_sleep_labels[PM_SUSPEND_MEM];
 217                 if (mem_sleep_default == PM_SUSPEND_MEM)
 218                         mem_sleep_current = PM_SUSPEND_MEM;
 219         }
 220
 221         unlock_system_sleep();
 222 }
 223 EXPORT_SYMBOL_GPL(suspend_set_ops);
 224
 225 /**
 226  * suspend_valid_only_mem - Generic memory-only valid callback.
 227  *
 228  * Platform drivers that implement mem suspend only and only need to check for
 229  * that in their .valid() callback can use this instead of rolling their own
 230  * .valid() callback.
 231  */
 232 int suspend_valid_only_mem(suspend_state_t state)
 233 {
 234         return state == PM_SUSPEND_MEM;
 235 }
 236 EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
 237
 238 static bool sleep_state_supported(suspend_state_t state)
 239 {
 240         return state == PM_SUSPEND_FREEZE || (suspend_ops && suspend_ops->enter);
 241 }
 242
 243 static int platform_suspend_prepare(suspend_state_t state)
 244 {
 245         return state != PM_SUSPEND_FREEZE && suspend_ops->prepare ?
 246                 suspend_ops->prepare() : 0;
 247 }
 248
 249 static int platform_suspend_prepare_late(suspend_state_t state)
 250 {
 251         return state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->prepare ?
 252                 freeze_ops->prepare() : 0;
 253 }
 254
 255 static int platform_suspend_prepare_noirq(suspend_state_t state)
 256 {
 257         return state != PM_SUSPEND_FREEZE && suspend_ops->prepare_late ?
 258                 suspend_ops->prepare_late() : 0;
 259 }
 260
 261 static void platform_resume_noirq(suspend_state_t state)
 262 {
 263         if (state != PM_SUSPEND_FREEZE && suspend_ops->wake)
 264                 suspend_ops->wake();
 265 }
 266
 267 static void platform_resume_early(suspend_state_t state)
 268 {
 269         if (state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->restore)
 270                 freeze_ops->restore();
 271 }
 272
 273 static void platform_resume_finish(suspend_state_t state)
 274 {
 275         if (state != PM_SUSPEND_FREEZE && suspend_ops->finish)
 276                 suspend_ops->finish();
 277 }
 278
 279 static int platform_suspend_begin(suspend_state_t state)
 280 {
 281         if (state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->begin)
 282                 return freeze_ops->begin();
 283         else if (suspend_ops && suspend_ops->begin)
 284                 return suspend_ops->begin(state);
 285         else
 286                 return 0;
 287 }
 288
 289 static void platform_resume_end(suspend_state_t state)
 290 {
 291         if (state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->end)
 292                 freeze_ops->end();
 293         else if (suspend_ops && suspend_ops->end)
 294                 suspend_ops->end();
 295 }
 296
 297 static void platform_recover(suspend_state_t state)
 298 {
 299         if (state != PM_SUSPEND_FREEZE && suspend_ops->recover)
 300                 suspend_ops->recover();
 301 }
 302
 303 static bool platform_suspend_again(suspend_state_t state)
 304 {
 305         return state != PM_SUSPEND_FREEZE && suspend_ops->suspend_again ?
 306                 suspend_ops->suspend_again() : false;
 307 }
 308
 309 #ifdef CONFIG_PM_DEBUG
 310 static unsigned int pm_test_delay = 5;
 311 module_param(pm_test_delay, uint, 0644);
 312 MODULE_PARM_DESC(pm_test_delay,
 313                  "Number of seconds to wait before resuming from suspend test");
 314 #endif
 315
 316 static int suspend_test(int level)
 317 {
 318 #ifdef CONFIG_PM_DEBUG
 319         if (pm_test_level == level) {
 320                 pr_info("suspend debug: Waiting for %d second(s).\n",
 321                                 pm_test_delay);
 322                 mdelay(pm_test_delay * 1000);
 323                 return 1;
 324         }
 325 #endif /* !CONFIG_PM_DEBUG */
 326         return 0;
 327 }
 328
 329 /**
 330  * suspend_prepare - Prepare for entering system sleep state.
 331  *
 332  * Common code run for every system sleep state that can be entered (except for
 333  * hibernation).  Run suspend notifiers, allocate the "suspend" console and
 334  * freeze processes.
 335  */
 336 static int suspend_prepare(suspend_state_t state)
 337 {
 338         int error, nr_calls = 0;
 339
 340         if (!sleep_state_supported(state))
 341                 return -EPERM;
 342
 343         pm_prepare_console();
 344
 345         error = __pm_notifier_call_chain(PM_SUSPEND_PREPARE, -1, &nr_calls);
 346         if (error) {
 347                 nr_calls--;
 348                 goto Finish;
 349         }
 350
 351         trace_suspend_resume(TPS("freeze_processes"), 0, true);
 352         error = suspend_freeze_processes();
 353         trace_suspend_resume(TPS("freeze_processes"), 0, false);
 354         if (!error)
 355                 return 0;
 356
 357         suspend_stats.failed_freeze++;
 358         dpm_save_failed_step(SUSPEND_FREEZE);
 359  Finish:
 360         __pm_notifier_call_chain(PM_POST_SUSPEND, nr_calls, NULL);
 361         pm_restore_console();
 362         return error;
 363 }
 364
 365 /* default implementation */
 366 void __weak arch_suspend_disable_irqs(void)
 367 {
 368         local_irq_disable();
 369 }
 370
 371 /* default implementation */
 372 void __weak arch_suspend_enable_irqs(void)
 373 {
 374         local_irq_enable();
 375 }
 376
 377 /**
 378  * suspend_enter - Make the system enter the given sleep state.
 379  * @state: System sleep state to enter.
 380  * @wakeup: Returns information that the sleep state should not be re-entered.
 381  *
 382  * This function should be called after devices have been suspended.
 383  */
 384 static int suspend_enter(suspend_state_t state, bool *wakeup)
 385 {
 386         int error;
 387
 388         error = platform_suspend_prepare(state);
 389         if (error)
 390                 goto Platform_finish;
 391
 392         error = dpm_suspend_late(PMSG_SUSPEND);
 393         if (error) {
 394                 pr_err("PM: late suspend of devices failed\n");
 395                 goto Platform_finish;
 396         }
 397         error = platform_suspend_prepare_late(state);
 398         if (error)
 399                 goto Devices_early_resume;
 400
 401         if (state == PM_SUSPEND_FREEZE && pm_test_level != TEST_PLATFORM) {
 402                 s2idle_loop();
 403                 goto Platform_early_resume;
 404         }
 405
 406         error = dpm_suspend_noirq(PMSG_SUSPEND);
 407         if (error) {
 408                 pr_err("PM: noirq suspend of devices failed\n");
 409                 goto Platform_early_resume;
 410         }
 411         error = platform_suspend_prepare_noirq(state);
 412         if (error)
 413                 goto Platform_wake;
 414
 415         if (suspend_test(TEST_PLATFORM))
 416                 goto Platform_wake;
 417
 418         error = disable_nonboot_cpus();
 419         if (error || suspend_test(TEST_CPUS))
 420                 goto Enable_cpus;
 421
 422         arch_suspend_disable_irqs();
 423         BUG_ON(!irqs_disabled());
 424
 425         error = syscore_suspend();
 426         if (!error) {
 427                 *wakeup = pm_wakeup_pending();
 428                 if (!(suspend_test(TEST_CORE) || *wakeup)) {
 429                         trace_suspend_resume(TPS("machine_suspend"),
 430                                 state, true);
 431                         error = suspend_ops->enter(state);
 432                         trace_suspend_resume(TPS("machine_suspend"),
 433                                 state, false);
 434                         events_check_enabled = false;
 435                 } else if (*wakeup) {
 436                         error = -EBUSY;
 437                 }
 438                 syscore_resume();
 439         }
 440
 441         arch_suspend_enable_irqs();
 442         BUG_ON(irqs_disabled());
 443
 444  Enable_cpus:
 445         enable_nonboot_cpus();
 446
 447  Platform_wake:
 448         platform_resume_noirq(state);
 449         dpm_resume_noirq(PMSG_RESUME);
 450
 451  Platform_early_resume:
 452         platform_resume_early(state);
 453
 454  Devices_early_resume:
 455         dpm_resume_early(PMSG_RESUME);
 456
 457  Platform_finish:
 458         platform_resume_finish(state);
 459         return error;
 460 }
 461
 462 /**
 463  * suspend_devices_and_enter - Suspend devices and enter system sleep state.
 464  * @state: System sleep state to enter.
 465  */
 466 int suspend_devices_and_enter(suspend_state_t state)
 467 {
 468         int error;
 469         bool wakeup = false;
 470
 471         if (!sleep_state_supported(state))
 472                 return -ENOSYS;
 473
 474         pm_suspend_target_state = state;
 475
 476         error = platform_suspend_begin(state);
 477         if (error)
 478                 goto Close;
 479
 480         suspend_console();
 481         suspend_test_start();
 482         error = dpm_suspend_start(PMSG_SUSPEND);
 483         if (error) {
 484                 pr_err("PM: Some devices failed to suspend, or early wake event detected\n");
 485                 goto Recover_platform;
 486         }
 487         suspend_test_finish("suspend devices");
 488         if (suspend_test(TEST_DEVICES))
 489                 goto Recover_platform;
 490
 491         do {
 492                 error = suspend_enter(state, &wakeup);
 493         } while (!error && !wakeup && platform_suspend_again(state));
 494
 495  Resume_devices:
 496         suspend_test_start();
 497         dpm_resume_end(PMSG_RESUME);
 498         suspend_test_finish("resume devices");
 499         trace_suspend_resume(TPS("resume_console"), state, true);
 500         resume_console();
 501         trace_suspend_resume(TPS("resume_console"), state, false);
 502
 503  Close:
 504         platform_resume_end(state);
 505         pm_suspend_target_state = PM_SUSPEND_ON;
 506         return error;
 507
 508  Recover_platform:
 509         platform_recover(state);
 510         goto Resume_devices;
 511 }
 512
 513 /**
 514  * suspend_finish - Clean up before finishing the suspend sequence.
 515  *
 516  * Call platform code to clean up, restart processes, and free the console that
 517  * we've allocated. This routine is not called for hibernation.
 518  */
 519 static void suspend_finish(void)
 520 {
 521         suspend_thaw_processes();
 522         pm_notifier_call_chain(PM_POST_SUSPEND);
 523         pm_restore_console();
 524 }
 525
 526 /**
 527  * enter_state - Do common work needed to enter system sleep state.
 528  * @state: System sleep state to enter.
 529  *
 530  * Make sure that no one else is trying to put the system into a sleep state.
 531  * Fail if that's not the case.  Otherwise, prepare for system suspend, make the
 532  * system enter the given sleep state and clean up after wakeup.
 533  */
 534 static int enter_state(suspend_state_t state)
 535 {
 536         int error;
 537
 538         trace_suspend_resume(TPS("suspend_enter"), state, true);
 539         if (state == PM_SUSPEND_FREEZE) {
 540 #ifdef CONFIG_PM_DEBUG
 541                 if (pm_test_level != TEST_NONE && pm_test_level <= TEST_CPUS) {
 542                         pr_warn("PM: Unsupported test mode for suspend to idle, please choose none/freezer/devices/platform.\n");
 543                         return -EAGAIN;
 544                 }
 545 #endif
 546         } else if (!valid_state(state)) {
 547                 return -EINVAL;
 548         }
 549         if (!mutex_trylock(&pm_mutex))
 550                 return -EBUSY;
 551
 552         if (state == PM_SUSPEND_FREEZE)
 553                 freeze_begin();
 554
 555 #ifndef CONFIG_SUSPEND_SKIP_SYNC
 556         trace_suspend_resume(TPS("sync_filesystems"), 0, true);
 557         pr_info("PM: Syncing filesystems ... ");
 558         sys_sync();
 559         pr_cont("done.\n");
 560         trace_suspend_resume(TPS("sync_filesystems"), 0, false);
 561 #endif
 562
 563         pm_pr_dbg("Preparing system for sleep (%s)\n", pm_states[state]);
 564         pm_suspend_clear_flags();
 565         error = suspend_prepare(state);
 566         if (error)
 567                 goto Unlock;
 568
 569         if (suspend_test(TEST_FREEZER))
 570                 goto Finish;
 571
 572         trace_suspend_resume(TPS("suspend_enter"), state, false);
 573         pm_pr_dbg("Suspending system (%s)\n", pm_states[state]);
 574         pm_restrict_gfp_mask();
 575         error = suspend_devices_and_enter(state);
 576         pm_restore_gfp_mask();
 577
 578  Finish:
 579         pm_pr_dbg("Finishing wakeup.\n");
 580         suspend_finish();
 581  Unlock:
 582         mutex_unlock(&pm_mutex);
 583         return error;
 584 }
 585
 586 /**
 587  * pm_suspend - Externally visible function for suspending the system.
 588  * @state: System sleep state to enter.
 589  *
 590  * Check if the value of @state represents one of the supported states,
 591  * execute enter_state() and update system suspend statistics.
 592  */
 593 int pm_suspend(suspend_state_t state)
 594 {
 595         int error;
 596
 597         if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
 598                 return -EINVAL;
 599
 600         pr_info("PM: suspend entry (%s)\n", pm_states[state]);
 601         error = enter_state(state);
 602         if (error) {
 603                 suspend_stats.fail++;
 604                 dpm_save_failed_errno(error);
 605         } else {
 606                 suspend_stats.success++;
 607         }
 608         pr_info("PM: suspend exit\n");
 609         return error;
 610 }
 611 EXPORT_SYMBOL(pm_suspend);