linux/kernel/power/main.c
<<
>>
Prefs
   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/resume-trace.h>
  15#include <linux/workqueue.h>
  16#include <linux/debugfs.h>
  17#include <linux/seq_file.h>
  18
  19#include "power.h"
  20
  21DEFINE_MUTEX(pm_mutex);
  22
  23#ifdef CONFIG_PM_SLEEP
  24
  25/* Routines for PM-transition notifications */
  26
  27static BLOCKING_NOTIFIER_HEAD(pm_chain_head);
  28
  29int register_pm_notifier(struct notifier_block *nb)
  30{
  31        return blocking_notifier_chain_register(&pm_chain_head, nb);
  32}
  33EXPORT_SYMBOL_GPL(register_pm_notifier);
  34
  35int unregister_pm_notifier(struct notifier_block *nb)
  36{
  37        return blocking_notifier_chain_unregister(&pm_chain_head, nb);
  38}
  39EXPORT_SYMBOL_GPL(unregister_pm_notifier);
  40
  41int 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. */
  49int pm_async_enabled = 1;
  50
  51static 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
  57static 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 (strict_strtoul(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
  72power_attr(pm_async);
  73
  74#ifdef CONFIG_PM_DEBUG
  75int pm_test_level = TEST_NONE;
  76
  77static 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
  86static 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
 107static 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
 134power_attr(pm_test);
 135#endif /* CONFIG_PM_DEBUG */
 136
 137#ifdef CONFIG_DEBUG_FS
 138static 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
 158static 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
 214static int suspend_stats_open(struct inode *inode, struct file *file)
 215{
 216        return single_open(file, suspend_stats_show, NULL);
 217}
 218
 219static 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
 226static 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
 233late_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 */
 245bool pm_print_times_enabled;
 246
 247static 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
 253static 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
 269power_attr(pm_print_times);
 270
 271static inline void pm_print_times_init(void)
 272{
 273        pm_print_times_enabled = !!initcall_debug;
 274}
 275#else /* !CONFIG_PP_SLEEP_DEBUG */
 276static inline void pm_print_times_init(void) {}
 277#endif /* CONFIG_PM_SLEEP_DEBUG */
 278
 279struct kobject *power_kobj;
 280
 281/**
 282 *      state - control system power state.
 283 *
 284 *      show() returns what states are supported, which is hard-coded to
 285 *      'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
 286 *      'disk' (Suspend-to-Disk).
 287 *
 288 *      store() accepts one of those strings, translates it into the
 289 *      proper enumerated value, and initiates a suspend transition.
 290 */
 291static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
 292                          char *buf)
 293{
 294        char *s = buf;
 295#ifdef CONFIG_SUSPEND
 296        int i;
 297
 298        for (i = 0; i < PM_SUSPEND_MAX; i++) {
 299                if (pm_states[i] && valid_state(i))
 300                        s += sprintf(s,"%s ", pm_states[i]);
 301        }
 302#endif
 303#ifdef CONFIG_HIBERNATION
 304        s += sprintf(s, "%s\n", "disk");
 305#else
 306        if (s != buf)
 307                /* convert the last space to a newline */
 308                *(s-1) = '\n';
 309#endif
 310        return (s - buf);
 311}
 312
 313static suspend_state_t decode_state(const char *buf, size_t n)
 314{
 315#ifdef CONFIG_SUSPEND
 316        suspend_state_t state = PM_SUSPEND_STANDBY;
 317        const char * const *s;
 318#endif
 319        char *p;
 320        int len;
 321
 322        p = memchr(buf, '\n', n);
 323        len = p ? p - buf : n;
 324
 325        /* Check hibernation first. */
 326        if (len == 4 && !strncmp(buf, "disk", len))
 327                return PM_SUSPEND_MAX;
 328
 329#ifdef CONFIG_SUSPEND
 330        for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++)
 331                if (*s && len == strlen(*s) && !strncmp(buf, *s, len))
 332                        return state;
 333#endif
 334
 335        return PM_SUSPEND_ON;
 336}
 337
 338static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
 339                           const char *buf, size_t n)
 340{
 341        suspend_state_t state;
 342        int error;
 343
 344        error = pm_autosleep_lock();
 345        if (error)
 346                return error;
 347
 348        if (pm_autosleep_state() > PM_SUSPEND_ON) {
 349                error = -EBUSY;
 350                goto out;
 351        }
 352
 353        state = decode_state(buf, n);
 354        if (state < PM_SUSPEND_MAX)
 355                error = pm_suspend(state);
 356        else if (state == PM_SUSPEND_MAX)
 357                error = hibernate();
 358        else
 359                error = -EINVAL;
 360
 361 out:
 362        pm_autosleep_unlock();
 363        return error ? error : n;
 364}
 365
 366power_attr(state);
 367
 368#ifdef CONFIG_PM_SLEEP
 369/*
 370 * The 'wakeup_count' attribute, along with the functions defined in
 371 * drivers/base/power/wakeup.c, provides a means by which wakeup events can be
 372 * handled in a non-racy way.
 373 *
 374 * If a wakeup event occurs when the system is in a sleep state, it simply is
 375 * woken up.  In turn, if an event that would wake the system up from a sleep
 376 * state occurs when it is undergoing a transition to that sleep state, the
 377 * transition should be aborted.  Moreover, if such an event occurs when the
 378 * system is in the working state, an attempt to start a transition to the
 379 * given sleep state should fail during certain period after the detection of
 380 * the event.  Using the 'state' attribute alone is not sufficient to satisfy
 381 * these requirements, because a wakeup event may occur exactly when 'state'
 382 * is being written to and may be delivered to user space right before it is
 383 * frozen, so the event will remain only partially processed until the system is
 384 * woken up by another event.  In particular, it won't cause the transition to
 385 * a sleep state to be aborted.
 386 *
 387 * This difficulty may be overcome if user space uses 'wakeup_count' before
 388 * writing to 'state'.  It first should read from 'wakeup_count' and store
 389 * the read value.  Then, after carrying out its own preparations for the system
 390 * transition to a sleep state, it should write the stored value to
 391 * 'wakeup_count'.  If that fails, at least one wakeup event has occurred since
 392 * 'wakeup_count' was read and 'state' should not be written to.  Otherwise, it
 393 * is allowed to write to 'state', but the transition will be aborted if there
 394 * are any wakeup events detected after 'wakeup_count' was written to.
 395 */
 396
 397static ssize_t wakeup_count_show(struct kobject *kobj,
 398                                struct kobj_attribute *attr,
 399                                char *buf)
 400{
 401        unsigned int val;
 402
 403        return pm_get_wakeup_count(&val, true) ?
 404                sprintf(buf, "%u\n", val) : -EINTR;
 405}
 406
 407static ssize_t wakeup_count_store(struct kobject *kobj,
 408                                struct kobj_attribute *attr,
 409                                const char *buf, size_t n)
 410{
 411        unsigned int val;
 412        int error;
 413
 414        error = pm_autosleep_lock();
 415        if (error)
 416                return error;
 417
 418        if (pm_autosleep_state() > PM_SUSPEND_ON) {
 419                error = -EBUSY;
 420                goto out;
 421        }
 422
 423        error = -EINVAL;
 424        if (sscanf(buf, "%u", &val) == 1) {
 425                if (pm_save_wakeup_count(val))
 426                        error = n;
 427        }
 428
 429 out:
 430        pm_autosleep_unlock();
 431        return error;
 432}
 433
 434power_attr(wakeup_count);
 435
 436#ifdef CONFIG_PM_AUTOSLEEP
 437static ssize_t autosleep_show(struct kobject *kobj,
 438                              struct kobj_attribute *attr,
 439                              char *buf)
 440{
 441        suspend_state_t state = pm_autosleep_state();
 442
 443        if (state == PM_SUSPEND_ON)
 444                return sprintf(buf, "off\n");
 445
 446#ifdef CONFIG_SUSPEND
 447        if (state < PM_SUSPEND_MAX)
 448                return sprintf(buf, "%s\n", valid_state(state) ?
 449                                                pm_states[state] : "error");
 450#endif
 451#ifdef CONFIG_HIBERNATION
 452        return sprintf(buf, "disk\n");
 453#else
 454        return sprintf(buf, "error");
 455#endif
 456}
 457
 458static ssize_t autosleep_store(struct kobject *kobj,
 459                               struct kobj_attribute *attr,
 460                               const char *buf, size_t n)
 461{
 462        suspend_state_t state = decode_state(buf, n);
 463        int error;
 464
 465        if (state == PM_SUSPEND_ON
 466            && strcmp(buf, "off") && strcmp(buf, "off\n"))
 467                return -EINVAL;
 468
 469        error = pm_autosleep_set_state(state);
 470        return error ? error : n;
 471}
 472
 473power_attr(autosleep);
 474#endif /* CONFIG_PM_AUTOSLEEP */
 475
 476#ifdef CONFIG_PM_WAKELOCKS
 477static ssize_t wake_lock_show(struct kobject *kobj,
 478                              struct kobj_attribute *attr,
 479                              char *buf)
 480{
 481        return pm_show_wakelocks(buf, true);
 482}
 483
 484static ssize_t wake_lock_store(struct kobject *kobj,
 485                               struct kobj_attribute *attr,
 486                               const char *buf, size_t n)
 487{
 488        int error = pm_wake_lock(buf);
 489        return error ? error : n;
 490}
 491
 492power_attr(wake_lock);
 493
 494static ssize_t wake_unlock_show(struct kobject *kobj,
 495                                struct kobj_attribute *attr,
 496                                char *buf)
 497{
 498        return pm_show_wakelocks(buf, false);
 499}
 500
 501static ssize_t wake_unlock_store(struct kobject *kobj,
 502                                 struct kobj_attribute *attr,
 503                                 const char *buf, size_t n)
 504{
 505        int error = pm_wake_unlock(buf);
 506        return error ? error : n;
 507}
 508
 509power_attr(wake_unlock);
 510
 511#endif /* CONFIG_PM_WAKELOCKS */
 512#endif /* CONFIG_PM_SLEEP */
 513
 514#ifdef CONFIG_PM_TRACE
 515int pm_trace_enabled;
 516
 517static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr,
 518                             char *buf)
 519{
 520        return sprintf(buf, "%d\n", pm_trace_enabled);
 521}
 522
 523static ssize_t
 524pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr,
 525               const char *buf, size_t n)
 526{
 527        int val;
 528
 529        if (sscanf(buf, "%d", &val) == 1) {
 530                pm_trace_enabled = !!val;
 531                return n;
 532        }
 533        return -EINVAL;
 534}
 535
 536power_attr(pm_trace);
 537
 538static ssize_t pm_trace_dev_match_show(struct kobject *kobj,
 539                                       struct kobj_attribute *attr,
 540                                       char *buf)
 541{
 542        return show_trace_dev_match(buf, PAGE_SIZE);
 543}
 544
 545static ssize_t
 546pm_trace_dev_match_store(struct kobject *kobj, struct kobj_attribute *attr,
 547                         const char *buf, size_t n)
 548{
 549        return -EINVAL;
 550}
 551
 552power_attr(pm_trace_dev_match);
 553
 554#endif /* CONFIG_PM_TRACE */
 555
 556static struct attribute * g[] = {
 557        &state_attr.attr,
 558#ifdef CONFIG_PM_TRACE
 559        &pm_trace_attr.attr,
 560        &pm_trace_dev_match_attr.attr,
 561#endif
 562#ifdef CONFIG_PM_SLEEP
 563        &pm_async_attr.attr,
 564        &wakeup_count_attr.attr,
 565#ifdef CONFIG_PM_AUTOSLEEP
 566        &autosleep_attr.attr,
 567#endif
 568#ifdef CONFIG_PM_WAKELOCKS
 569        &wake_lock_attr.attr,
 570        &wake_unlock_attr.attr,
 571#endif
 572#ifdef CONFIG_PM_DEBUG
 573        &pm_test_attr.attr,
 574#endif
 575#ifdef CONFIG_PM_SLEEP_DEBUG
 576        &pm_print_times_attr.attr,
 577#endif
 578#endif
 579        NULL,
 580};
 581
 582static struct attribute_group attr_group = {
 583        .attrs = g,
 584};
 585
 586#ifdef CONFIG_PM_RUNTIME
 587struct workqueue_struct *pm_wq;
 588EXPORT_SYMBOL_GPL(pm_wq);
 589
 590static int __init pm_start_workqueue(void)
 591{
 592        pm_wq = alloc_workqueue("pm", WQ_FREEZABLE, 0);
 593
 594        return pm_wq ? 0 : -ENOMEM;
 595}
 596#else
 597static inline int pm_start_workqueue(void) { return 0; }
 598#endif
 599
 600static int __init pm_init(void)
 601{
 602        int error = pm_start_workqueue();
 603        if (error)
 604                return error;
 605        hibernate_image_size_init();
 606        hibernate_reserved_size_init();
 607        power_kobj = kobject_create_and_add("power", NULL);
 608        if (!power_kobj)
 609                return -ENOMEM;
 610        error = sysfs_create_group(power_kobj, &attr_group);
 611        if (error)
 612                return error;
 613        pm_print_times_init();
 614        return pm_autosleep_init();
 615}
 616
 617core_initcall(pm_init);
 618
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.