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