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