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