kernel/power/main.c

   1 /*
   2  * kernel/power/main.c - PM subsystem core functionality.
   3  *
   4  * Copyright (c) 2003 Patrick Mochel
   5  * Copyright (c) 2003 Open Source Development Lab
   6  *
   7  * This file is released under the GPLv2
   8  *
   9  */
  10
  11 #include <linux/export.h>
  12 #include <linux/kobject.h>
  13 #include <linux/string.h>
  14 #include <linux/pm-trace.h>
  15 #include <linux/workqueue.h>
  16 #include <linux/debugfs.h>
  17 #include <linux/seq_file.h>
  18
  19 #include "power.h"
  20
  21 DEFINE_MUTEX(pm_mutex);
  22
  23 #ifdef CONFIG_PM_SLEEP
  24
  25 /* Routines for PM-transition notifications */
  26
  27 static BLOCKING_NOTIFIER_HEAD(pm_chain_head);
  28
  29 int register_pm_notifier(struct notifier_block *nb)
  30 {
  31         return blocking_notifier_chain_register(&pm_chain_head, nb);
  32 }
  33 EXPORT_SYMBOL_GPL(register_pm_notifier);
  34
  35 int unregister_pm_notifier(struct notifier_block *nb)
  36 {
  37         return blocking_notifier_chain_unregister(&pm_chain_head, nb);
  38 }
  39 EXPORT_SYMBOL_GPL(unregister_pm_notifier);
  40
  41 int __pm_notifier_call_chain(unsigned long val, int nr_to_call, int *nr_calls)
  42 {
  43         int ret;
  44
  45         ret = __blocking_notifier_call_chain(&pm_chain_head, val, NULL,
  46                                                 nr_to_call, nr_calls);
  47
  48         return notifier_to_errno(ret);
  49 }
  50 int pm_notifier_call_chain(unsigned long val)
  51 {
  52         return __pm_notifier_call_chain(val, -1, NULL);
  53 }
  54
  55 /* If set, devices may be suspended and resumed asynchronously. */
  56 int pm_async_enabled = 1;
  57
  58 static ssize_t pm_async_show(struct kobject *kobj, struct kobj_attribute *attr,
  59                              char *buf)
  60 {
  61         return sprintf(buf, "%d\n", pm_async_enabled);
  62 }
  63
  64 static ssize_t pm_async_store(struct kobject *kobj, struct kobj_attribute *attr,
  65                               const char *buf, size_t n)
  66 {
  67         unsigned long val;
  68
  69         if (kstrtoul(buf, 10, &val))
  70                 return -EINVAL;
  71
  72         if (val > 1)
  73                 return -EINVAL;
  74
  75         pm_async_enabled = val;
  76         return n;
  77 }
  78
  79 power_attr(pm_async);
  80
  81 #ifdef CONFIG_PM_DEBUG
  82 int pm_test_level = TEST_NONE;
  83
  84 static const char * const pm_tests[__TEST_AFTER_LAST] = {
  85         [TEST_NONE] = "none",
  86         [TEST_CORE] = "core",
  87         [TEST_CPUS] = "processors",
  88         [TEST_PLATFORM] = "platform",
  89         [TEST_DEVICES] = "devices",
  90         [TEST_FREEZER] = "freezer",
  91 };
  92
  93 static ssize_t pm_test_show(struct kobject *kobj, struct kobj_attribute *attr,
  94                                 char *buf)
  95 {
  96         char *s = buf;
  97         int level;
  98
  99         for (level = TEST_FIRST; level <= TEST_MAX; level++)
 100                 if (pm_tests[level]) {
 101                         if (level == pm_test_level)
 102                                 s += sprintf(s, "[%s] ", pm_tests[level]);
 103                         else
 104                                 s += sprintf(s, "%s ", pm_tests[level]);
 105                 }
 106
 107         if (s != buf)
 108                 /* convert the last space to a newline */
 109                 *(s-1) = '\n';
 110
 111         return (s - buf);
 112 }
 113
 114 static ssize_t pm_test_store(struct kobject *kobj, struct kobj_attribute *attr,
 115                                 const char *buf, size_t n)
 116 {
 117         const char * const *s;
 118         int level;
 119         char *p;
 120         int len;
 121         int error = -EINVAL;
 122
 123         p = memchr(buf, '\n', n);
 124         len = p ? p - buf : n;
 125
 126         lock_system_sleep();
 127
 128         level = TEST_FIRST;
 129         for (s = &pm_tests[level]; level <= TEST_MAX; s++, level++)
 130                 if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) {
 131                         pm_test_level = level;
 132                         error = 0;
 133                         break;
 134                 }
 135
 136         unlock_system_sleep();
 137
 138         return error ? error : n;
 139 }
 140
 141 power_attr(pm_test);
 142 #endif /* CONFIG_PM_DEBUG */
 143
 144 #ifdef CONFIG_DEBUG_FS
 145 static char *suspend_step_name(enum suspend_stat_step step)
 146 {
 147         switch (step) {
 148         case SUSPEND_FREEZE:
 149                 return "freeze";
 150         case SUSPEND_PREPARE:
 151                 return "prepare";
 152         case SUSPEND_SUSPEND:
 153                 return "suspend";
 154         case SUSPEND_SUSPEND_NOIRQ:
 155                 return "suspend_noirq";
 156         case SUSPEND_RESUME_NOIRQ:
 157                 return "resume_noirq";
 158         case SUSPEND_RESUME:
 159                 return "resume";
 160         default:
 161                 return "";
 162         }
 163 }
 164
 165 static int suspend_stats_show(struct seq_file *s, void *unused)
 166 {
 167         int i, index, last_dev, last_errno, last_step;
 168
 169         last_dev = suspend_stats.last_failed_dev + REC_FAILED_NUM - 1;
 170         last_dev %= REC_FAILED_NUM;
 171         last_errno = suspend_stats.last_failed_errno + REC_FAILED_NUM - 1;
 172         last_errno %= REC_FAILED_NUM;
 173         last_step = suspend_stats.last_failed_step + REC_FAILED_NUM - 1;
 174         last_step %= REC_FAILED_NUM;
 175         seq_printf(s, "%s: %d\n%s: %d\n%s: %d\n%s: %d\n%s: %d\n"
 176                         "%s: %d\n%s: %d\n%s: %d\n%s: %d\n%s: %d\n",
 177                         "success", suspend_stats.success,
 178                         "fail", suspend_stats.fail,
 179                         "failed_freeze", suspend_stats.failed_freeze,
 180                         "failed_prepare", suspend_stats.failed_prepare,
 181                         "failed_suspend", suspend_stats.failed_suspend,
 182                         "failed_suspend_late",
 183                                 suspend_stats.failed_suspend_late,
 184                         "failed_suspend_noirq",
 185                                 suspend_stats.failed_suspend_noirq,
 186                         "failed_resume", suspend_stats.failed_resume,
 187                         "failed_resume_early",
 188                                 suspend_stats.failed_resume_early,
 189                         "failed_resume_noirq",
 190                                 suspend_stats.failed_resume_noirq);
 191         seq_printf(s,   "failures:\n  last_failed_dev:\t%-s\n",
 192                         suspend_stats.failed_devs[last_dev]);
 193         for (i = 1; i < REC_FAILED_NUM; i++) {
 194                 index = last_dev + REC_FAILED_NUM - i;
 195                 index %= REC_FAILED_NUM;
 196                 seq_printf(s, "\t\t\t%-s\n",
 197                         suspend_stats.failed_devs[index]);
 198         }
 199         seq_printf(s,   "  last_failed_errno:\t%-d\n",
 200                         suspend_stats.errno[last_errno]);
 201         for (i = 1; i < REC_FAILED_NUM; i++) {
 202                 index = last_errno + REC_FAILED_NUM - i;
 203                 index %= REC_FAILED_NUM;
 204                 seq_printf(s, "\t\t\t%-d\n",
 205                         suspend_stats.errno[index]);
 206         }
 207         seq_printf(s,   "  last_failed_step:\t%-s\n",
 208                         suspend_step_name(
 209                                 suspend_stats.failed_steps[last_step]));
 210         for (i = 1; i < REC_FAILED_NUM; i++) {
 211                 index = last_step + REC_FAILED_NUM - i;
 212                 index %= REC_FAILED_NUM;
 213                 seq_printf(s, "\t\t\t%-s\n",
 214                         suspend_step_name(
 215                                 suspend_stats.failed_steps[index]));
 216         }
 217
 218         return 0;
 219 }
 220
 221 static int suspend_stats_open(struct inode *inode, struct file *file)
 222 {
 223         return single_open(file, suspend_stats_show, NULL);
 224 }
 225
 226 static const struct file_operations suspend_stats_operations = {
 227         .open           = suspend_stats_open,
 228         .read           = seq_read,
 229         .llseek         = seq_lseek,
 230         .release        = single_release,
 231 };
 232
 233 static int __init pm_debugfs_init(void)
 234 {
 235         debugfs_create_file("suspend_stats", S_IFREG | S_IRUGO,
 236                         NULL, NULL, &suspend_stats_operations);
 237         return 0;
 238 }
 239
 240 late_initcall(pm_debugfs_init);
 241 #endif /* CONFIG_DEBUG_FS */
 242
 243 #endif /* CONFIG_PM_SLEEP */
 244
 245 #ifdef CONFIG_PM_SLEEP_DEBUG
 246 /*
 247  * pm_print_times: print time taken by devices to suspend and resume.
 248  *
 249  * show() returns whether printing of suspend and resume times is enabled.
 250  * store() accepts 0 or 1.  0 disables printing and 1 enables it.
 251  */
 252 bool pm_print_times_enabled;
 253
 254 static ssize_t pm_print_times_show(struct kobject *kobj,
 255                                    struct kobj_attribute *attr, char *buf)
 256 {
 257         return sprintf(buf, "%d\n", pm_print_times_enabled);
 258 }
 259
 260 static ssize_t pm_print_times_store(struct kobject *kobj,
 261                                     struct kobj_attribute *attr,
 262                                     const char *buf, size_t n)
 263 {
 264         unsigned long val;
 265
 266         if (kstrtoul(buf, 10, &val))
 267                 return -EINVAL;
 268
 269         if (val > 1)
 270                 return -EINVAL;
 271
 272         pm_print_times_enabled = !!val;
 273         return n;
 274 }
 275
 276 power_attr(pm_print_times);
 277
 278 static inline void pm_print_times_init(void)
 279 {
 280         pm_print_times_enabled = !!initcall_debug;
 281 }
 282
 283 static ssize_t pm_wakeup_irq_show(struct kobject *kobj,
 284                                         struct kobj_attribute *attr,
 285                                         char *buf)
 286 {
 287         return pm_wakeup_irq ? sprintf(buf, "%u\n", pm_wakeup_irq) : -ENODATA;
 288 }
 289
 290 power_attr_ro(pm_wakeup_irq);
 291
 292 #else /* !CONFIG_PM_SLEEP_DEBUG */
 293 static inline void pm_print_times_init(void) {}
 294 #endif /* CONFIG_PM_SLEEP_DEBUG */
 295
 296 struct kobject *power_kobj;
 297
 298 /**
 299  * state - control system sleep states.
 300  *
 301  * show() returns available sleep state labels, which may be "mem", "standby",
 302  * "freeze" and "disk" (hibernation).  See Documentation/power/states.txt for a
 303  * description of what they mean.
 304  *
 305  * store() accepts one of those strings, translates it into the proper
 306  * enumerated value, and initiates a suspend transition.
 307  */
 308 static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
 309                           char *buf)
 310 {
 311         char *s = buf;
 312 #ifdef CONFIG_SUSPEND
 313         suspend_state_t i;
 314
 315         for (i = PM_SUSPEND_MIN; i < PM_SUSPEND_MAX; i++)
 316                 if (pm_states[i])
 317                         s += sprintf(s,"%s ", pm_states[i]);
 318
 319 #endif
 320         if (hibernation_available())
 321                 s += sprintf(s, "disk ");
 322         if (s != buf)
 323                 /* convert the last space to a newline */
 324                 *(s-1) = '\n';
 325         return (s - buf);
 326 }
 327
 328 static suspend_state_t decode_state(const char *buf, size_t n)
 329 {
 330 #ifdef CONFIG_SUSPEND
 331         suspend_state_t state;
 332 #endif
 333         char *p;
 334         int len;
 335
 336         p = memchr(buf, '\n', n);
 337         len = p ? p - buf : n;
 338
 339         /* Check hibernation first. */
 340         if (len == 4 && !strncmp(buf, "disk", len))
 341                 return PM_SUSPEND_MAX;
 342
 343 #ifdef CONFIG_SUSPEND
 344         for (state = PM_SUSPEND_MIN; state < PM_SUSPEND_MAX; state++) {
 345                 const char *label = pm_states[state];
 346
 347                 if (label && len == strlen(label) && !strncmp(buf, label, len))
 348                         return state;
 349         }
 350 #endif
 351
 352         return PM_SUSPEND_ON;
 353 }
 354
 355 static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
 356                            const char *buf, size_t n)
 357 {
 358         suspend_state_t state;
 359         int error;
 360
 361         error = pm_autosleep_lock();
 362         if (error)
 363                 return error;
 364
 365         if (pm_autosleep_state() > PM_SUSPEND_ON) {
 366                 error = -EBUSY;
 367                 goto out;
 368         }
 369
 370         state = decode_state(buf, n);
 371         if (state < PM_SUSPEND_MAX)
 372                 error = pm_suspend(state);
 373         else if (state == PM_SUSPEND_MAX)
 374                 error = hibernate();
 375         else
 376                 error = -EINVAL;
 377
 378  out:
 379         pm_autosleep_unlock();
 380         return error ? error : n;
 381 }
 382
 383 power_attr(state);
 384
 385 #ifdef CONFIG_PM_SLEEP
 386 /*
 387  * The 'wakeup_count' attribute, along with the functions defined in
 388  * drivers/base/power/wakeup.c, provides a means by which wakeup events can be
 389  * handled in a non-racy way.
 390  *
 391  * If a wakeup event occurs when the system is in a sleep state, it simply is
 392  * woken up.  In turn, if an event that would wake the system up from a sleep
 393  * state occurs when it is undergoing a transition to that sleep state, the
 394  * transition should be aborted.  Moreover, if such an event occurs when the
 395  * system is in the working state, an attempt to start a transition to the
 396  * given sleep state should fail during certain period after the detection of
 397  * the event.  Using the 'state' attribute alone is not sufficient to satisfy
 398  * these requirements, because a wakeup event may occur exactly when 'state'
 399  * is being written to and may be delivered to user space right before it is
 400  * frozen, so the event will remain only partially processed until the system is
 401  * woken up by another event.  In particular, it won't cause the transition to
 402  * a sleep state to be aborted.
 403  *
 404  * This difficulty may be overcome if user space uses 'wakeup_count' before
 405  * writing to 'state'.  It first should read from 'wakeup_count' and store
 406  * the read value.  Then, after carrying out its own preparations for the system
 407  * transition to a sleep state, it should write the stored value to
 408  * 'wakeup_count'.  If that fails, at least one wakeup event has occurred since
 409  * 'wakeup_count' was read and 'state' should not be written to.  Otherwise, it
 410  * is allowed to write to 'state', but the transition will be aborted if there
 411  * are any wakeup events detected after 'wakeup_count' was written to.
 412  */
 413
 414 static ssize_t wakeup_count_show(struct kobject *kobj,
 415                                 struct kobj_attribute *attr,
 416                                 char *buf)
 417 {
 418         unsigned int val;
 419
 420         return pm_get_wakeup_count(&val, true) ?
 421                 sprintf(buf, "%u\n", val) : -EINTR;
 422 }
 423
 424 static ssize_t wakeup_count_store(struct kobject *kobj,
 425                                 struct kobj_attribute *attr,
 426                                 const char *buf, size_t n)
 427 {
 428         unsigned int val;
 429         int error;
 430
 431         error = pm_autosleep_lock();
 432         if (error)
 433                 return error;
 434
 435         if (pm_autosleep_state() > PM_SUSPEND_ON) {
 436                 error = -EBUSY;
 437                 goto out;
 438         }
 439
 440         error = -EINVAL;
 441         if (sscanf(buf, "%u", &val) == 1) {
 442                 if (pm_save_wakeup_count(val))
 443                         error = n;
 444                 else
 445                         pm_print_active_wakeup_sources();
 446         }
 447
 448  out:
 449         pm_autosleep_unlock();
 450         return error;
 451 }
 452
 453 power_attr(wakeup_count);
 454
 455 #ifdef CONFIG_PM_AUTOSLEEP
 456 static ssize_t autosleep_show(struct kobject *kobj,
 457                               struct kobj_attribute *attr,
 458                               char *buf)
 459 {
 460         suspend_state_t state = pm_autosleep_state();
 461
 462         if (state == PM_SUSPEND_ON)
 463                 return sprintf(buf, "off\n");
 464
 465 #ifdef CONFIG_SUSPEND
 466         if (state < PM_SUSPEND_MAX)
 467                 return sprintf(buf, "%s\n", pm_states[state] ?
 468                                         pm_states[state] : "error");
 469 #endif
 470 #ifdef CONFIG_HIBERNATION
 471         return sprintf(buf, "disk\n");
 472 #else
 473         return sprintf(buf, "error");
 474 #endif
 475 }
 476
 477 static ssize_t autosleep_store(struct kobject *kobj,
 478                                struct kobj_attribute *attr,
 479                                const char *buf, size_t n)
 480 {
 481         suspend_state_t state = decode_state(buf, n);
 482         int error;
 483
 484         if (state == PM_SUSPEND_ON
 485             && strcmp(buf, "off") && strcmp(buf, "off\n"))
 486                 return -EINVAL;
 487
 488         error = pm_autosleep_set_state(state);
 489         return error ? error : n;
 490 }
 491
 492 power_attr(autosleep);
 493 #endif /* CONFIG_PM_AUTOSLEEP */
 494
 495 #ifdef CONFIG_PM_WAKELOCKS
 496 static ssize_t wake_lock_show(struct kobject *kobj,
 497                               struct kobj_attribute *attr,
 498                               char *buf)
 499 {
 500         return pm_show_wakelocks(buf, true);
 501 }
 502
 503 static ssize_t wake_lock_store(struct kobject *kobj,
 504                                struct kobj_attribute *attr,
 505                                const char *buf, size_t n)
 506 {
 507         int error = pm_wake_lock(buf);
 508         return error ? error : n;
 509 }
 510
 511 power_attr(wake_lock);
 512
 513 static ssize_t wake_unlock_show(struct kobject *kobj,
 514                                 struct kobj_attribute *attr,
 515                                 char *buf)
 516 {
 517         return pm_show_wakelocks(buf, false);
 518 }
 519
 520 static ssize_t wake_unlock_store(struct kobject *kobj,
 521                                  struct kobj_attribute *attr,
 522                                  const char *buf, size_t n)
 523 {
 524         int error = pm_wake_unlock(buf);
 525         return error ? error : n;
 526 }
 527
 528 power_attr(wake_unlock);
 529
 530 #endif /* CONFIG_PM_WAKELOCKS */
 531 #endif /* CONFIG_PM_SLEEP */
 532
 533 #ifdef CONFIG_PM_TRACE
 534 int pm_trace_enabled;
 535
 536 static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr,
 537                              char *buf)
 538 {
 539         return sprintf(buf, "%d\n", pm_trace_enabled);
 540 }
 541
 542 static ssize_t
 543 pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr,
 544                const char *buf, size_t n)
 545 {
 546         int val;
 547
 548         if (sscanf(buf, "%d", &val) == 1) {
 549                 pm_trace_enabled = !!val;
 550                 if (pm_trace_enabled) {
 551                         pr_warn("PM: Enabling pm_trace changes system date and time during resume.\n"
 552                                 "PM: Correct system time has to be restored manually after resume.\n");
 553                 }
 554                 return n;
 555         }
 556         return -EINVAL;
 557 }
 558
 559 power_attr(pm_trace);
 560
 561 static ssize_t pm_trace_dev_match_show(struct kobject *kobj,
 562                                        struct kobj_attribute *attr,
 563                                        char *buf)
 564 {
 565         return show_trace_dev_match(buf, PAGE_SIZE);
 566 }
 567
 568 power_attr_ro(pm_trace_dev_match);
 569
 570 #endif /* CONFIG_PM_TRACE */
 571
 572 #ifdef CONFIG_FREEZER
 573 static ssize_t pm_freeze_timeout_show(struct kobject *kobj,
 574                                       struct kobj_attribute *attr, char *buf)
 575 {
 576         return sprintf(buf, "%u\n", freeze_timeout_msecs);
 577 }
 578
 579 static ssize_t pm_freeze_timeout_store(struct kobject *kobj,
 580                                        struct kobj_attribute *attr,
 581                                        const char *buf, size_t n)
 582 {
 583         unsigned long val;
 584
 585         if (kstrtoul(buf, 10, &val))
 586                 return -EINVAL;
 587
 588         freeze_timeout_msecs = val;
 589         return n;
 590 }
 591
 592 power_attr(pm_freeze_timeout);
 593
 594 #endif  /* CONFIG_FREEZER*/
 595
 596 static struct attribute * g[] = {
 597         &state_attr.attr,
 598 #ifdef CONFIG_PM_TRACE
 599         &pm_trace_attr.attr,
 600         &pm_trace_dev_match_attr.attr,
 601 #endif
 602 #ifdef CONFIG_PM_SLEEP
 603         &pm_async_attr.attr,
 604         &wakeup_count_attr.attr,
 605 #ifdef CONFIG_PM_AUTOSLEEP
 606         &autosleep_attr.attr,
 607 #endif
 608 #ifdef CONFIG_PM_WAKELOCKS
 609         &wake_lock_attr.attr,
 610         &wake_unlock_attr.attr,
 611 #endif
 612 #ifdef CONFIG_PM_DEBUG
 613         &pm_test_attr.attr,
 614 #endif
 615 #ifdef CONFIG_PM_SLEEP_DEBUG
 616         &pm_print_times_attr.attr,
 617         &pm_wakeup_irq_attr.attr,
 618 #endif
 619 #endif
 620 #ifdef CONFIG_FREEZER
 621         &pm_freeze_timeout_attr.attr,
 622 #endif
 623         NULL,
 624 };
 625
 626 static struct attribute_group attr_group = {
 627         .attrs = g,
 628 };
 629
 630 struct workqueue_struct *pm_wq;
 631 EXPORT_SYMBOL_GPL(pm_wq);
 632
 633 static int __init pm_start_workqueue(void)
 634 {
 635         pm_wq = alloc_workqueue("pm", WQ_FREEZABLE, 0);
 636
 637         return pm_wq ? 0 : -ENOMEM;
 638 }
 639
 640 static int __init pm_init(void)
 641 {
 642         int error = pm_start_workqueue();
 643         if (error)
 644                 return error;
 645         hibernate_image_size_init();
 646         hibernate_reserved_size_init();
 647         pm_states_init();
 648         power_kobj = kobject_create_and_add("power", NULL);
 649         if (!power_kobj)
 650                 return -ENOMEM;
 651         error = sysfs_create_group(power_kobj, &attr_group);
 652         if (error)
 653                 return error;
 654         pm_print_times_init();
 655         return pm_autosleep_init();
 656 }
 657
 658 core_initcall(pm_init);