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/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
  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 (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
  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         mutex_lock(&pm_mutex);
 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         mutex_unlock(&pm_mutex);
 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"
 169                         "%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_noirq",
 176                                 suspend_stats.failed_suspend_noirq,
 177                         "failed_resume", suspend_stats.failed_resume,
 178                         "failed_resume_noirq",
 179                                 suspend_stats.failed_resume_noirq);
 180         seq_printf(s,   "failures:\n  last_failed_dev:\t%-s\n",
 181                         suspend_stats.failed_devs[last_dev]);
 182         for (i = 1; i < REC_FAILED_NUM; i++) {
 183                 index = last_dev + REC_FAILED_NUM - i;
 184                 index %= REC_FAILED_NUM;
 185                 seq_printf(s, "\t\t\t%-s\n",
 186                         suspend_stats.failed_devs[index]);
 187         }
 188         seq_printf(s,   "  last_failed_errno:\t%-d\n",
 189                         suspend_stats.errno[last_errno]);
 190         for (i = 1; i < REC_FAILED_NUM; i++) {
 191                 index = last_errno + REC_FAILED_NUM - i;
 192                 index %= REC_FAILED_NUM;
 193                 seq_printf(s, "\t\t\t%-d\n",
 194                         suspend_stats.errno[index]);
 195         }
 196         seq_printf(s,   "  last_failed_step:\t%-s\n",
 197                         suspend_step_name(
 198                                 suspend_stats.failed_steps[last_step]));
 199         for (i = 1; i < REC_FAILED_NUM; i++) {
 200                 index = last_step + REC_FAILED_NUM - i;
 201                 index %= REC_FAILED_NUM;
 202                 seq_printf(s, "\t\t\t%-s\n",
 203                         suspend_step_name(
 204                                 suspend_stats.failed_steps[index]));
 205         }
 206
 207         return 0;
 208 }
 209
 210 static int suspend_stats_open(struct inode *inode, struct file *file)
 211 {
 212         return single_open(file, suspend_stats_show, NULL);
 213 }
 214
 215 static const struct file_operations suspend_stats_operations = {
 216         .open           = suspend_stats_open,
 217         .read           = seq_read,
 218         .llseek         = seq_lseek,
 219         .release        = single_release,
 220 };
 221
 222 static int __init pm_debugfs_init(void)
 223 {
 224         debugfs_create_file("suspend_stats", S_IFREG | S_IRUGO,
 225                         NULL, NULL, &suspend_stats_operations);
 226         return 0;
 227 }
 228
 229 late_initcall(pm_debugfs_init);
 230 #endif /* CONFIG_DEBUG_FS */
 231
 232 #endif /* CONFIG_PM_SLEEP */
 233
 234 struct kobject *power_kobj;
 235
 236 /**
 237  *      state - control system power state.
 238  *
 239  *      show() returns what states are supported, which is hard-coded to
 240  *      'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
 241  *      'disk' (Suspend-to-Disk).
 242  *
 243  *      store() accepts one of those strings, translates it into the
 244  *      proper enumerated value, and initiates a suspend transition.
 245  */
 246 static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
 247                           char *buf)
 248 {
 249         char *s = buf;
 250 #ifdef CONFIG_SUSPEND
 251         int i;
 252
 253         for (i = 0; i < PM_SUSPEND_MAX; i++) {
 254                 if (pm_states[i] && valid_state(i))
 255                         s += sprintf(s,"%s ", pm_states[i]);
 256         }
 257 #endif
 258 #ifdef CONFIG_HIBERNATION
 259         s += sprintf(s, "%s\n", "disk");
 260 #else
 261         if (s != buf)
 262                 /* convert the last space to a newline */
 263                 *(s-1) = '\n';
 264 #endif
 265         return (s - buf);
 266 }
 267
 268 static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
 269                            const char *buf, size_t n)
 270 {
 271 #ifdef CONFIG_SUSPEND
 272         suspend_state_t state = PM_SUSPEND_STANDBY;
 273         const char * const *s;
 274 #endif
 275         char *p;
 276         int len;
 277         int error = -EINVAL;
 278
 279         p = memchr(buf, '\n', n);
 280         len = p ? p - buf : n;
 281
 282         /* First, check if we are requested to hibernate */
 283         if (len == 4 && !strncmp(buf, "disk", len)) {
 284                 error = hibernate();
 285   goto Exit;
 286         }
 287
 288 #ifdef CONFIG_SUSPEND
 289         for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
 290                 if (*s && len == strlen(*s) && !strncmp(buf, *s, len))
 291                         break;
 292         }
 293         if (state < PM_SUSPEND_MAX && *s) {
 294                 error = enter_state(state);
 295                 if (error) {
 296                         suspend_stats.fail++;
 297                         dpm_save_failed_errno(error);
 298                 } else
 299                         suspend_stats.success++;
 300         }
 301 #endif
 302
 303  Exit:
 304         return error ? error : n;
 305 }
 306
 307 power_attr(state);
 308
 309 #ifdef CONFIG_PM_SLEEP
 310 /*
 311  * The 'wakeup_count' attribute, along with the functions defined in
 312  * drivers/base/power/wakeup.c, provides a means by which wakeup events can be
 313  * handled in a non-racy way.
 314  *
 315  * If a wakeup event occurs when the system is in a sleep state, it simply is
 316  * woken up.  In turn, if an event that would wake the system up from a sleep
 317  * state occurs when it is undergoing a transition to that sleep state, the
 318  * transition should be aborted.  Moreover, if such an event occurs when the
 319  * system is in the working state, an attempt to start a transition to the
 320  * given sleep state should fail during certain period after the detection of
 321  * the event.  Using the 'state' attribute alone is not sufficient to satisfy
 322  * these requirements, because a wakeup event may occur exactly when 'state'
 323  * is being written to and may be delivered to user space right before it is
 324  * frozen, so the event will remain only partially processed until the system is
 325  * woken up by another event.  In particular, it won't cause the transition to
 326  * a sleep state to be aborted.
 327  *
 328  * This difficulty may be overcome if user space uses 'wakeup_count' before
 329  * writing to 'state'.  It first should read from 'wakeup_count' and store
 330  * the read value.  Then, after carrying out its own preparations for the system
 331  * transition to a sleep state, it should write the stored value to
 332  * 'wakeup_count'.  If that fails, at least one wakeup event has occurred since
 333  * 'wakeup_count' was read and 'state' should not be written to.  Otherwise, it
 334  * is allowed to write to 'state', but the transition will be aborted if there
 335  * are any wakeup events detected after 'wakeup_count' was written to.
 336  */
 337
 338 static ssize_t wakeup_count_show(struct kobject *kobj,
 339                                 struct kobj_attribute *attr,
 340                                 char *buf)
 341 {
 342         unsigned int val;
 343
 344         return pm_get_wakeup_count(&val) ? sprintf(buf, "%u\n", val) : -EINTR;
 345 }
 346
 347 static ssize_t wakeup_count_store(struct kobject *kobj,
 348                                 struct kobj_attribute *attr,
 349                                 const char *buf, size_t n)
 350 {
 351         unsigned int val;
 352
 353         if (sscanf(buf, "%u", &val) == 1) {
 354                 if (pm_save_wakeup_count(val))
 355                         return n;
 356         }
 357         return -EINVAL;
 358 }
 359
 360 power_attr(wakeup_count);
 361 #endif /* CONFIG_PM_SLEEP */
 362
 363 #ifdef CONFIG_PM_TRACE
 364 int pm_trace_enabled;
 365
 366 static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr,
 367                              char *buf)
 368 {
 369         return sprintf(buf, "%d\n", pm_trace_enabled);
 370 }
 371
 372 static ssize_t
 373 pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr,
 374                const char *buf, size_t n)
 375 {
 376         int val;
 377
 378         if (sscanf(buf, "%d", &val) == 1) {
 379                 pm_trace_enabled = !!val;
 380                 return n;
 381         }
 382         return -EINVAL;
 383 }
 384
 385 power_attr(pm_trace);
 386
 387 static ssize_t pm_trace_dev_match_show(struct kobject *kobj,
 388                                        struct kobj_attribute *attr,
 389                                        char *buf)
 390 {
 391         return show_trace_dev_match(buf, PAGE_SIZE);
 392 }
 393
 394 static ssize_t
 395 pm_trace_dev_match_store(struct kobject *kobj, struct kobj_attribute *attr,
 396                          const char *buf, size_t n)
 397 {
 398         return -EINVAL;
 399 }
 400
 401 power_attr(pm_trace_dev_match);
 402
 403 #endif /* CONFIG_PM_TRACE */
 404
 405 static struct attribute * g[] = {
 406         &state_attr.attr,
 407 #ifdef CONFIG_PM_TRACE
 408         &pm_trace_attr.attr,
 409         &pm_trace_dev_match_attr.attr,
 410 #endif
 411 #ifdef CONFIG_PM_SLEEP
 412         &pm_async_attr.attr,
 413         &wakeup_count_attr.attr,
 414 #ifdef CONFIG_PM_DEBUG
 415         &pm_test_attr.attr,
 416 #endif
 417 #endif
 418         NULL,
 419 };
 420
 421 static struct attribute_group attr_group = {
 422         .attrs = g,
 423 };
 424
 425 #ifdef CONFIG_PM_RUNTIME
 426 struct workqueue_struct *pm_wq;
 427 EXPORT_SYMBOL_GPL(pm_wq);
 428
 429 static int __init pm_start_workqueue(void)
 430 {
 431         pm_wq = alloc_workqueue("pm", WQ_FREEZABLE, 0);
 432
 433         return pm_wq ? 0 : -ENOMEM;
 434 }
 435 #else
 436 static inline int pm_start_workqueue(void) { return 0; }
 437 #endif
 438
 439 static int __init pm_init(void)
 440 {
 441         int error = pm_start_workqueue();
 442         if (error)
 443                 return error;
 444         hibernate_image_size_init();
 445         hibernate_reserved_size_init();
 446         power_kobj = kobject_create_and_add("power", NULL);
 447         if (!power_kobj)
 448                 return -ENOMEM;
 449         return sysfs_create_group(power_kobj, &attr_group);
 450 }
 451
 452 core_initcall(pm_init);