2 * kernel/power/main.c - PM subsystem core functionality.
4 * Copyright (c) 2003 Patrick Mochel
5 * Copyright (c) 2003 Open Source Development Lab
7 * This file is released under the GPLv2
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>
21 DEFINE_MUTEX(pm_mutex);
23 #ifdef CONFIG_PM_SLEEP
25 /* Routines for PM-transition notifications */
27 static BLOCKING_NOTIFIER_HEAD(pm_chain_head);
29 int register_pm_notifier(struct notifier_block *nb)
31 return blocking_notifier_chain_register(&pm_chain_head, nb);
33 EXPORT_SYMBOL_GPL(register_pm_notifier);
35 int unregister_pm_notifier(struct notifier_block *nb)
37 return blocking_notifier_chain_unregister(&pm_chain_head, nb);
39 EXPORT_SYMBOL_GPL(unregister_pm_notifier);
41 int pm_notifier_call_chain(unsigned long val)
43 int ret = blocking_notifier_call_chain(&pm_chain_head, val, NULL);
45 return notifier_to_errno(ret);
48 /* If set, devices may be suspended and resumed asynchronously. */
49 int pm_async_enabled = 1;
51 static ssize_t pm_async_show(struct kobject *kobj, struct kobj_attribute *attr,
54 return sprintf(buf, "%d\n", pm_async_enabled);
57 static ssize_t pm_async_store(struct kobject *kobj, struct kobj_attribute *attr,
58 const char *buf, size_t n)
62 if (strict_strtoul(buf, 10, &val))
68 pm_async_enabled = val;
74 #ifdef CONFIG_PM_DEBUG
75 int pm_test_level = TEST_NONE;
77 static const char * const pm_tests[__TEST_AFTER_LAST] = {
80 [TEST_CPUS] = "processors",
81 [TEST_PLATFORM] = "platform",
82 [TEST_DEVICES] = "devices",
83 [TEST_FREEZER] = "freezer",
86 static ssize_t pm_test_show(struct kobject *kobj, struct kobj_attribute *attr,
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]);
97 s += sprintf(s, "%s ", pm_tests[level]);
101 /* convert the last space to a newline */
107 static ssize_t pm_test_store(struct kobject *kobj, struct kobj_attribute *attr,
108 const char *buf, size_t n)
110 const char * const *s;
116 p = memchr(buf, '\n', n);
117 len = p ? p - buf : n;
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;
129 unlock_system_sleep();
131 return error ? error : n;
135 #endif /* CONFIG_PM_DEBUG */
137 #ifdef CONFIG_DEBUG_FS
138 static char *suspend_step_name(enum suspend_stat_step step)
143 case SUSPEND_PREPARE:
145 case SUSPEND_SUSPEND:
147 case SUSPEND_SUSPEND_NOIRQ:
148 return "suspend_noirq";
149 case SUSPEND_RESUME_NOIRQ:
150 return "resume_noirq";
158 static int suspend_stats_show(struct seq_file *s, void *unused)
160 int i, index, last_dev, last_errno, last_step;
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]);
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]);
196 seq_printf(s, " last_failed_step:\t%-s\n",
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",
204 suspend_stats.failed_steps[index]));
210 static int suspend_stats_open(struct inode *inode, struct file *file)
212 return single_open(file, suspend_stats_show, NULL);
215 static const struct file_operations suspend_stats_operations = {
216 .open = suspend_stats_open,
219 .release = single_release,
222 static int __init pm_debugfs_init(void)
224 debugfs_create_file("suspend_stats", S_IFREG | S_IRUGO,
225 NULL, NULL, &suspend_stats_operations);
229 late_initcall(pm_debugfs_init);
230 #endif /* CONFIG_DEBUG_FS */
232 #endif /* CONFIG_PM_SLEEP */
234 struct kobject *power_kobj;
237 * state - control system power state.
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).
243 * store() accepts one of those strings, translates it into the
244 * proper enumerated value, and initiates a suspend transition.
246 static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
250 #ifdef CONFIG_SUSPEND
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]);
258 #ifdef CONFIG_HIBERNATION
259 s += sprintf(s, "%s\n", "disk");
262 /* convert the last space to a newline */
268 static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
269 const char *buf, size_t n)
271 #ifdef CONFIG_SUSPEND
272 suspend_state_t state = PM_SUSPEND_STANDBY;
273 const char * const *s;
279 p = memchr(buf, '\n', n);
280 len = p ? p - buf : n;
282 /* First, check if we are requested to hibernate */
283 if (len == 4 && !strncmp(buf, "disk", len)) {
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))
293 if (state < PM_SUSPEND_MAX && *s) {
294 error = enter_state(state);
296 suspend_stats.fail++;
297 dpm_save_failed_errno(error);
299 suspend_stats.success++;
304 return error ? error : n;
309 #ifdef CONFIG_PM_SLEEP
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.
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.
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.
338 static ssize_t wakeup_count_show(struct kobject *kobj,
339 struct kobj_attribute *attr,
344 return pm_get_wakeup_count(&val) ? sprintf(buf, "%u\n", val) : -EINTR;
347 static ssize_t wakeup_count_store(struct kobject *kobj,
348 struct kobj_attribute *attr,
349 const char *buf, size_t n)
353 if (sscanf(buf, "%u", &val) == 1) {
354 if (pm_save_wakeup_count(val))
360 power_attr(wakeup_count);
361 #endif /* CONFIG_PM_SLEEP */
363 #ifdef CONFIG_PM_TRACE
364 int pm_trace_enabled;
366 static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr,
369 return sprintf(buf, "%d\n", pm_trace_enabled);
373 pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr,
374 const char *buf, size_t n)
378 if (sscanf(buf, "%d", &val) == 1) {
379 pm_trace_enabled = !!val;
385 power_attr(pm_trace);
387 static ssize_t pm_trace_dev_match_show(struct kobject *kobj,
388 struct kobj_attribute *attr,
391 return show_trace_dev_match(buf, PAGE_SIZE);
395 pm_trace_dev_match_store(struct kobject *kobj, struct kobj_attribute *attr,
396 const char *buf, size_t n)
401 power_attr(pm_trace_dev_match);
403 #endif /* CONFIG_PM_TRACE */
405 static struct attribute * g[] = {
407 #ifdef CONFIG_PM_TRACE
409 &pm_trace_dev_match_attr.attr,
411 #ifdef CONFIG_PM_SLEEP
413 &wakeup_count_attr.attr,
414 #ifdef CONFIG_PM_DEBUG
421 static struct attribute_group attr_group = {
425 #ifdef CONFIG_PM_RUNTIME
426 struct workqueue_struct *pm_wq;
427 EXPORT_SYMBOL_GPL(pm_wq);
429 static int __init pm_start_workqueue(void)
431 pm_wq = alloc_workqueue("pm", WQ_FREEZABLE, 0);
433 return pm_wq ? 0 : -ENOMEM;
436 static inline int pm_start_workqueue(void) { return 0; }
439 static int __init pm_init(void)
441 int error = pm_start_workqueue();
444 hibernate_image_size_init();
445 hibernate_reserved_size_init();
446 power_kobj = kobject_create_and_add("power", NULL);
449 return sysfs_create_group(power_kobj, &attr_group);
452 core_initcall(pm_init);