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