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 *pm_labels[] = { "mem", "standby", "freeze", NULL };
  36 const char *pm_states[PM_SUSPEND_MAX];
  37
  38 unsigned int pm_suspend_global_flags;
  39 EXPORT_SYMBOL_GPL(pm_suspend_global_flags);
  40
  41 static const struct platform_suspend_ops *suspend_ops;
  42 static const struct platform_freeze_ops *freeze_ops;
  43 static DECLARE_WAIT_QUEUE_HEAD(suspend_freeze_wait_head);
  44
  45 enum freeze_state __read_mostly suspend_freeze_state;
  46 static DEFINE_SPINLOCK(suspend_freeze_lock);
  47
  48 void freeze_set_ops(const struct platform_freeze_ops *ops)
  49 {
  50         lock_system_sleep();
  51         freeze_ops = ops;
  52         unlock_system_sleep();
  53 }
  54
  55 static void freeze_begin(void)
  56 {
  57         suspend_freeze_state = FREEZE_STATE_NONE;
  58 }
  59
  60 static void freeze_enter(void)
  61 {
  62         spin_lock_irq(&suspend_freeze_lock);
  63         if (pm_wakeup_pending())
  64                 goto out;
  65
  66         suspend_freeze_state = FREEZE_STATE_ENTER;
  67         spin_unlock_irq(&suspend_freeze_lock);
  68
  69         get_online_cpus();
  70         cpuidle_resume();
  71
  72         /* Push all the CPUs into the idle loop. */
  73         wake_up_all_idle_cpus();
  74         pr_debug("PM: suspend-to-idle\n");
  75         /* Make the current CPU wait so it can enter the idle loop too. */
  76         wait_event(suspend_freeze_wait_head,
  77                    suspend_freeze_state == FREEZE_STATE_WAKE);
  78         pr_debug("PM: resume from suspend-to-idle\n");
  79
  80         cpuidle_pause();
  81         put_online_cpus();
  82
  83         spin_lock_irq(&suspend_freeze_lock);
  84
  85  out:
  86         suspend_freeze_state = FREEZE_STATE_NONE;
  87         spin_unlock_irq(&suspend_freeze_lock);
  88 }
  89
  90 void freeze_wake(void)
  91 {
  92         unsigned long flags;
  93
  94         spin_lock_irqsave(&suspend_freeze_lock, flags);
  95         if (suspend_freeze_state > FREEZE_STATE_NONE) {
  96                 suspend_freeze_state = FREEZE_STATE_WAKE;
  97                 wake_up(&suspend_freeze_wait_head);
  98         }
  99         spin_unlock_irqrestore(&suspend_freeze_lock, flags);
 100 }
 101 EXPORT_SYMBOL_GPL(freeze_wake);
 102
 103 static bool valid_state(suspend_state_t state)
 104 {
 105         /*
 106          * PM_SUSPEND_STANDBY and PM_SUSPEND_MEM states need low level
 107          * support and need to be valid to the low level
 108          * implementation, no valid callback implies that none are valid.
 109          */
 110         return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
 111 }
 112
 113 /*
 114  * If this is set, the "mem" label always corresponds to the deepest sleep state
 115  * available, the "standby" label corresponds to the second deepest sleep state
 116  * available (if any), and the "freeze" label corresponds to the remaining
 117  * available sleep state (if there is one).
 118  */
 119 static bool relative_states;
 120
 121 void __init pm_states_init(void)
 122 {
 123         /*
 124          * freeze state should be supported even without any suspend_ops,
 125          * initialize pm_states accordingly here
 126          */
 127         pm_states[PM_SUSPEND_FREEZE] = pm_labels[relative_states ? 0 : 2];
 128 }
 129
 130 static int __init sleep_states_setup(char *str)
 131 {
 132         relative_states = !strncmp(str, "1", 1);
 133         return 1;
 134 }
 135
 136 __setup("relative_sleep_states=", sleep_states_setup);
 137
 138 /**
 139  * suspend_set_ops - Set the global suspend method table.
 140  * @ops: Suspend operations to use.
 141  */
 142 void suspend_set_ops(const struct platform_suspend_ops *ops)
 143 {
 144         suspend_state_t i;
 145         int j = 0;
 146
 147         lock_system_sleep();
 148
 149         suspend_ops = ops;
 150         for (i = PM_SUSPEND_MEM; i >= PM_SUSPEND_STANDBY; i--)
 151                 if (valid_state(i)) {
 152                         pm_states[i] = pm_labels[j++];
 153                 } else if (!relative_states) {
 154                         pm_states[i] = NULL;
 155                         j++;
 156                 }
 157
 158         pm_states[PM_SUSPEND_FREEZE] = pm_labels[j];
 159
 160         unlock_system_sleep();
 161 }
 162 EXPORT_SYMBOL_GPL(suspend_set_ops);
 163
 164 /**
 165  * suspend_valid_only_mem - Generic memory-only valid callback.
 166  *
 167  * Platform drivers that implement mem suspend only and only need to check for
 168  * that in their .valid() callback can use this instead of rolling their own
 169  * .valid() callback.
 170  */
 171 int suspend_valid_only_mem(suspend_state_t state)
 172 {
 173         return state == PM_SUSPEND_MEM;
 174 }
 175 EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
 176
 177 static bool sleep_state_supported(suspend_state_t state)
 178 {
 179         return state == PM_SUSPEND_FREEZE || (suspend_ops && suspend_ops->enter);
 180 }
 181
 182 static int platform_suspend_prepare(suspend_state_t state)
 183 {
 184         return state != PM_SUSPEND_FREEZE && suspend_ops->prepare ?
 185                 suspend_ops->prepare() : 0;
 186 }
 187
 188 static int platform_suspend_prepare_late(suspend_state_t state)
 189 {
 190         return state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->prepare ?
 191                 freeze_ops->prepare() : 0;
 192 }
 193
 194 static int platform_suspend_prepare_noirq(suspend_state_t state)
 195 {
 196         return state != PM_SUSPEND_FREEZE && suspend_ops->prepare_late ?
 197                 suspend_ops->prepare_late() : 0;
 198 }
 199
 200 static void platform_resume_noirq(suspend_state_t state)
 201 {
 202         if (state != PM_SUSPEND_FREEZE && suspend_ops->wake)
 203                 suspend_ops->wake();
 204 }
 205
 206 static void platform_resume_early(suspend_state_t state)
 207 {
 208         if (state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->restore)
 209                 freeze_ops->restore();
 210 }
 211
 212 static void platform_resume_finish(suspend_state_t state)
 213 {
 214         if (state != PM_SUSPEND_FREEZE && suspend_ops->finish)
 215                 suspend_ops->finish();
 216 }
 217
 218 static int platform_suspend_begin(suspend_state_t state)
 219 {
 220         if (state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->begin)
 221                 return freeze_ops->begin();
 222         else if (suspend_ops && suspend_ops->begin)
 223                 return suspend_ops->begin(state);
 224         else
 225                 return 0;
 226 }
 227
 228 static void platform_resume_end(suspend_state_t state)
 229 {
 230         if (state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->end)
 231                 freeze_ops->end();
 232         else if (suspend_ops && suspend_ops->end)
 233                 suspend_ops->end();
 234 }
 235
 236 static void platform_recover(suspend_state_t state)
 237 {
 238         if (state != PM_SUSPEND_FREEZE && suspend_ops->recover)
 239                 suspend_ops->recover();
 240 }
 241
 242 static bool platform_suspend_again(suspend_state_t state)
 243 {
 244         return state != PM_SUSPEND_FREEZE && suspend_ops->suspend_again ?
 245                 suspend_ops->suspend_again() : false;
 246 }
 247
 248 #ifdef CONFIG_PM_DEBUG
 249 static unsigned int pm_test_delay = 5;
 250 module_param(pm_test_delay, uint, 0644);
 251 MODULE_PARM_DESC(pm_test_delay,
 252                  "Number of seconds to wait before resuming from suspend test");
 253 #endif
 254
 255 static int suspend_test(int level)
 256 {
 257 #ifdef CONFIG_PM_DEBUG
 258         if (pm_test_level == level) {
 259                 pr_info("suspend debug: Waiting for %d second(s).\n",
 260                                 pm_test_delay);
 261                 mdelay(pm_test_delay * 1000);
 262                 return 1;
 263         }
 264 #endif /* !CONFIG_PM_DEBUG */
 265         return 0;
 266 }
 267
 268 /**
 269  * suspend_prepare - Prepare for entering system sleep state.
 270  *
 271  * Common code run for every system sleep state that can be entered (except for
 272  * hibernation).  Run suspend notifiers, allocate the "suspend" console and
 273  * freeze processes.
 274  */
 275 static int suspend_prepare(suspend_state_t state)
 276 {
 277         int error, nr_calls = 0;
 278
 279         if (!sleep_state_supported(state))
 280                 return -EPERM;
 281
 282         pm_prepare_console();
 283
 284         error = __pm_notifier_call_chain(PM_SUSPEND_PREPARE, -1, &nr_calls);
 285         if (error) {
 286                 nr_calls--;
 287                 goto Finish;
 288         }
 289
 290         trace_suspend_resume(TPS("freeze_processes"), 0, true);
 291         error = suspend_freeze_processes();
 292         trace_suspend_resume(TPS("freeze_processes"), 0, false);
 293         if (!error)
 294                 return 0;
 295
 296         suspend_stats.failed_freeze++;
 297         dpm_save_failed_step(SUSPEND_FREEZE);
 298  Finish:
 299         __pm_notifier_call_chain(PM_POST_SUSPEND, nr_calls, NULL);
 300         pm_restore_console();
 301         return error;
 302 }
 303
 304 /* default implementation */
 305 void __weak arch_suspend_disable_irqs(void)
 306 {
 307         local_irq_disable();
 308 }
 309
 310 /* default implementation */
 311 void __weak arch_suspend_enable_irqs(void)
 312 {
 313         local_irq_enable();
 314 }
 315
 316 /**
 317  * suspend_enter - Make the system enter the given sleep state.
 318  * @state: System sleep state to enter.
 319  * @wakeup: Returns information that the sleep state should not be re-entered.
 320  *
 321  * This function should be called after devices have been suspended.
 322  */
 323 static int suspend_enter(suspend_state_t state, bool *wakeup)
 324 {
 325         int error;
 326
 327         error = platform_suspend_prepare(state);
 328         if (error)
 329                 goto Platform_finish;
 330
 331         error = dpm_suspend_late(PMSG_SUSPEND);
 332         if (error) {
 333                 pr_err("PM: late suspend of devices failed\n");
 334                 goto Platform_finish;
 335         }
 336         error = platform_suspend_prepare_late(state);
 337         if (error)
 338                 goto Devices_early_resume;
 339
 340         error = dpm_suspend_noirq(PMSG_SUSPEND);
 341         if (error) {
 342                 pr_err("PM: noirq suspend of devices failed\n");
 343                 goto Platform_early_resume;
 344         }
 345         error = platform_suspend_prepare_noirq(state);
 346         if (error)
 347                 goto Platform_wake;
 348
 349         if (suspend_test(TEST_PLATFORM))
 350                 goto Platform_wake;
 351
 352         /*
 353          * PM_SUSPEND_FREEZE equals
 354          * frozen processes + suspended devices + idle processors.
 355          * Thus we should invoke freeze_enter() soon after
 356          * all the devices are suspended.
 357          */
 358         if (state == PM_SUSPEND_FREEZE) {
 359                 trace_suspend_resume(TPS("machine_suspend"), state, true);
 360                 freeze_enter();
 361                 trace_suspend_resume(TPS("machine_suspend"), state, false);
 362                 goto Platform_wake;
 363         }
 364
 365         error = disable_nonboot_cpus();
 366         if (error || suspend_test(TEST_CPUS))
 367                 goto Enable_cpus;
 368
 369         arch_suspend_disable_irqs();
 370         BUG_ON(!irqs_disabled());
 371
 372         error = syscore_suspend();
 373         if (!error) {
 374                 *wakeup = pm_wakeup_pending();
 375                 if (!(suspend_test(TEST_CORE) || *wakeup)) {
 376                         trace_suspend_resume(TPS("machine_suspend"),
 377                                 state, true);
 378                         error = suspend_ops->enter(state);
 379                         trace_suspend_resume(TPS("machine_suspend"),
 380                                 state, false);
 381                         events_check_enabled = false;
 382                 } else if (*wakeup) {
 383                         error = -EBUSY;
 384                 }
 385                 syscore_resume();
 386         }
 387
 388         arch_suspend_enable_irqs();
 389         BUG_ON(irqs_disabled());
 390
 391  Enable_cpus:
 392         enable_nonboot_cpus();
 393
 394  Platform_wake:
 395         platform_resume_noirq(state);
 396         dpm_resume_noirq(PMSG_RESUME);
 397
 398  Platform_early_resume:
 399         platform_resume_early(state);
 400
 401  Devices_early_resume:
 402         dpm_resume_early(PMSG_RESUME);
 403
 404  Platform_finish:
 405         platform_resume_finish(state);
 406         return error;
 407 }
 408
 409 /**
 410  * suspend_devices_and_enter - Suspend devices and enter system sleep state.
 411  * @state: System sleep state to enter.
 412  */
 413 int suspend_devices_and_enter(suspend_state_t state)
 414 {
 415         int error;
 416         bool wakeup = false;
 417
 418         if (!sleep_state_supported(state))
 419                 return -ENOSYS;
 420
 421         error = platform_suspend_begin(state);
 422         if (error)
 423                 goto Close;
 424
 425         suspend_console();
 426         suspend_test_start();
 427         error = dpm_suspend_start(PMSG_SUSPEND);
 428         if (error) {
 429                 pr_err("PM: Some devices failed to suspend, or early wake event detected\n");
 430                 goto Recover_platform;
 431         }
 432         suspend_test_finish("suspend devices");
 433         if (suspend_test(TEST_DEVICES))
 434                 goto Recover_platform;
 435
 436         do {
 437                 error = suspend_enter(state, &wakeup);
 438         } while (!error && !wakeup && platform_suspend_again(state));
 439
 440  Resume_devices:
 441         suspend_test_start();
 442         dpm_resume_end(PMSG_RESUME);
 443         suspend_test_finish("resume devices");
 444         trace_suspend_resume(TPS("resume_console"), state, true);
 445         resume_console();
 446         trace_suspend_resume(TPS("resume_console"), state, false);
 447
 448  Close:
 449         platform_resume_end(state);
 450         return error;
 451
 452  Recover_platform:
 453         platform_recover(state);
 454         goto Resume_devices;
 455 }
 456
 457 /**
 458  * suspend_finish - Clean up before finishing the suspend sequence.
 459  *
 460  * Call platform code to clean up, restart processes, and free the console that
 461  * we've allocated. This routine is not called for hibernation.
 462  */
 463 static void suspend_finish(void)
 464 {
 465         suspend_thaw_processes();
 466         pm_notifier_call_chain(PM_POST_SUSPEND);
 467         pm_restore_console();
 468 }
 469
 470 /**
 471  * enter_state - Do common work needed to enter system sleep state.
 472  * @state: System sleep state to enter.
 473  *
 474  * Make sure that no one else is trying to put the system into a sleep state.
 475  * Fail if that's not the case.  Otherwise, prepare for system suspend, make the
 476  * system enter the given sleep state and clean up after wakeup.
 477  */
 478 static int enter_state(suspend_state_t state)
 479 {
 480         int error;
 481
 482         trace_suspend_resume(TPS("suspend_enter"), state, true);
 483         if (state == PM_SUSPEND_FREEZE) {
 484 #ifdef CONFIG_PM_DEBUG
 485                 if (pm_test_level != TEST_NONE && pm_test_level <= TEST_CPUS) {
 486                         pr_warn("PM: Unsupported test mode for suspend to idle, please choose none/freezer/devices/platform.\n");
 487                         return -EAGAIN;
 488                 }
 489 #endif
 490         } else if (!valid_state(state)) {
 491                 return -EINVAL;
 492         }
 493         if (!mutex_trylock(&pm_mutex))
 494                 return -EBUSY;
 495
 496         if (state == PM_SUSPEND_FREEZE)
 497                 freeze_begin();
 498
 499 #ifndef CONFIG_SUSPEND_SKIP_SYNC
 500         trace_suspend_resume(TPS("sync_filesystems"), 0, true);
 501         pr_info("PM: Syncing filesystems ... ");
 502         sys_sync();
 503         pr_cont("done.\n");
 504         trace_suspend_resume(TPS("sync_filesystems"), 0, false);
 505 #endif
 506
 507         pr_debug("PM: Preparing system for sleep (%s)\n", pm_states[state]);
 508         pm_suspend_clear_flags();
 509         error = suspend_prepare(state);
 510         if (error)
 511                 goto Unlock;
 512
 513         if (suspend_test(TEST_FREEZER))
 514                 goto Finish;
 515
 516         trace_suspend_resume(TPS("suspend_enter"), state, false);
 517         pr_debug("PM: Suspending system (%s)\n", pm_states[state]);
 518         pm_restrict_gfp_mask();
 519         error = suspend_devices_and_enter(state);
 520         pm_restore_gfp_mask();
 521
 522  Finish:
 523         pr_debug("PM: Finishing wakeup.\n");
 524         suspend_finish();
 525  Unlock:
 526         mutex_unlock(&pm_mutex);
 527         return error;
 528 }
 529
 530 /**
 531  * pm_suspend - Externally visible function for suspending the system.
 532  * @state: System sleep state to enter.
 533  *
 534  * Check if the value of @state represents one of the supported states,
 535  * execute enter_state() and update system suspend statistics.
 536  */
 537 int pm_suspend(suspend_state_t state)
 538 {
 539         int error;
 540
 541         if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
 542                 return -EINVAL;
 543
 544         error = enter_state(state);
 545         if (error) {
 546                 suspend_stats.fail++;
 547                 dpm_save_failed_errno(error);
 548         } else {
 549                 suspend_stats.success++;
 550         }
 551         return error;
 552 }
 553 EXPORT_SYMBOL(pm_suspend);