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/module.h>
12 #include <linux/suspend.h>
13 #include <linux/kobject.h>
14 #include <linux/string.h>
15 #include <linux/delay.h>
16 #include <linux/errno.h>
17 #include <linux/init.h>
18 #include <linux/console.h>
19 #include <linux/cpu.h>
20 #include <linux/resume-trace.h>
21 #include <linux/freezer.h>
22 #include <linux/vmstat.h>
23 #include <linux/syscalls.h>
27 DEFINE_MUTEX(pm_mutex);
29 unsigned int pm_flags;
30 EXPORT_SYMBOL(pm_flags);
32 #ifdef CONFIG_PM_SLEEP
34 /* Routines for PM-transition notifications */
36 static BLOCKING_NOTIFIER_HEAD(pm_chain_head);
38 int register_pm_notifier(struct notifier_block *nb)
40 return blocking_notifier_chain_register(&pm_chain_head, nb);
42 EXPORT_SYMBOL_GPL(register_pm_notifier);
44 int unregister_pm_notifier(struct notifier_block *nb)
46 return blocking_notifier_chain_unregister(&pm_chain_head, nb);
48 EXPORT_SYMBOL_GPL(unregister_pm_notifier);
50 int pm_notifier_call_chain(unsigned long val)
52 return (blocking_notifier_call_chain(&pm_chain_head, val, NULL)
53 == NOTIFY_BAD) ? -EINVAL : 0;
56 #endif /* CONFIG_PM_SLEEP */
58 #ifdef CONFIG_PM_DEBUG
59 int pm_test_level = TEST_NONE;
61 static int suspend_test(int level)
63 if (pm_test_level == level) {
64 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
71 static const char * const pm_tests[__TEST_AFTER_LAST] = {
74 [TEST_CPUS] = "processors",
75 [TEST_PLATFORM] = "platform",
76 [TEST_DEVICES] = "devices",
77 [TEST_FREEZER] = "freezer",
80 static ssize_t pm_test_show(struct kobject *kobj, struct kobj_attribute *attr,
86 for (level = TEST_FIRST; level <= TEST_MAX; level++)
87 if (pm_tests[level]) {
88 if (level == pm_test_level)
89 s += sprintf(s, "[%s] ", pm_tests[level]);
91 s += sprintf(s, "%s ", pm_tests[level]);
95 /* convert the last space to a newline */
101 static ssize_t pm_test_store(struct kobject *kobj, struct kobj_attribute *attr,
102 const char *buf, size_t n)
104 const char * const *s;
110 p = memchr(buf, '\n', n);
111 len = p ? p - buf : n;
113 mutex_lock(&pm_mutex);
116 for (s = &pm_tests[level]; level <= TEST_MAX; s++, level++)
117 if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) {
118 pm_test_level = level;
123 mutex_unlock(&pm_mutex);
125 return error ? error : n;
129 #else /* !CONFIG_PM_DEBUG */
130 static inline int suspend_test(int level) { return 0; }
131 #endif /* !CONFIG_PM_DEBUG */
134 #ifdef CONFIG_SUSPEND
136 /* This is just an arbitrary number */
137 #define FREE_PAGE_NUMBER (100)
139 static struct platform_suspend_ops *suspend_ops;
142 * suspend_set_ops - Set the global suspend method table.
143 * @ops: Pointer to ops structure.
146 void suspend_set_ops(struct platform_suspend_ops *ops)
148 mutex_lock(&pm_mutex);
150 mutex_unlock(&pm_mutex);
154 * suspend_valid_only_mem - generic memory-only valid callback
156 * Platform drivers that implement mem suspend only and only need
157 * to check for that in their .valid callback can use this instead
158 * of rolling their own .valid callback.
160 int suspend_valid_only_mem(suspend_state_t state)
162 return state == PM_SUSPEND_MEM;
166 * suspend_prepare - Do prep work before entering low-power state.
168 * This is common code that is called for each state that we're entering.
169 * Run suspend notifiers, allocate a console and stop all processes.
171 static int suspend_prepare(void)
174 unsigned int free_pages;
176 if (!suspend_ops || !suspend_ops->enter)
179 error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
183 pm_prepare_console();
185 if (freeze_processes()) {
190 free_pages = global_page_state(NR_FREE_PAGES);
191 if (free_pages < FREE_PAGE_NUMBER) {
192 pr_debug("PM: free some memory\n");
193 shrink_all_memory(FREE_PAGE_NUMBER - free_pages);
194 if (nr_free_pages() < FREE_PAGE_NUMBER) {
196 printk(KERN_ERR "PM: No enough memory\n");
204 pm_restore_console();
206 pm_notifier_call_chain(PM_POST_SUSPEND);
210 /* default implementation */
211 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
216 /* default implementation */
217 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
223 * suspend_enter - enter the desired system sleep state.
224 * @state: state to enter
226 * This function should be called after devices have been suspended.
228 static int suspend_enter(suspend_state_t state)
232 arch_suspend_disable_irqs();
233 BUG_ON(!irqs_disabled());
235 if ((error = device_power_down(PMSG_SUSPEND))) {
236 printk(KERN_ERR "Some devices failed to power down\n");
240 if (!suspend_test(TEST_CORE))
241 error = suspend_ops->enter(state);
245 arch_suspend_enable_irqs();
246 BUG_ON(irqs_disabled());
251 * suspend_devices_and_enter - suspend devices and enter the desired system sleep
253 * @state: state to enter
255 int suspend_devices_and_enter(suspend_state_t state)
262 if (suspend_ops->set_target) {
263 error = suspend_ops->set_target(state);
268 error = device_suspend(PMSG_SUSPEND);
270 printk(KERN_ERR "Some devices failed to suspend\n");
274 if (suspend_test(TEST_DEVICES))
277 if (suspend_ops->prepare) {
278 error = suspend_ops->prepare();
283 if (suspend_test(TEST_PLATFORM))
286 error = disable_nonboot_cpus();
287 if (!error && !suspend_test(TEST_CPUS))
288 suspend_enter(state);
290 enable_nonboot_cpus();
292 if (suspend_ops->finish)
293 suspend_ops->finish();
302 * suspend_finish - Do final work before exiting suspend sequence.
304 * Call platform code to clean up, restart processes, and free the
305 * console that we've allocated. This is not called for suspend-to-disk.
307 static void suspend_finish(void)
310 pm_restore_console();
311 pm_notifier_call_chain(PM_POST_SUSPEND);
317 static const char * const pm_states[PM_SUSPEND_MAX] = {
318 [PM_SUSPEND_STANDBY] = "standby",
319 [PM_SUSPEND_MEM] = "mem",
322 static inline int valid_state(suspend_state_t state)
324 /* All states need lowlevel support and need to be valid
325 * to the lowlevel implementation, no valid callback
326 * implies that none are valid. */
327 if (!suspend_ops || !suspend_ops->valid || !suspend_ops->valid(state))
334 * enter_state - Do common work of entering low-power state.
335 * @state: pm_state structure for state we're entering.
337 * Make sure we're the only ones trying to enter a sleep state. Fail
338 * if someone has beat us to it, since we don't want anything weird to
339 * happen when we wake up.
340 * Then, do the setup for suspend, enter the state, and cleaup (after
343 static int enter_state(suspend_state_t state)
347 if (!valid_state(state))
350 if (!mutex_trylock(&pm_mutex))
353 printk("Syncing filesystems ... ");
357 pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
358 error = suspend_prepare();
362 if (suspend_test(TEST_FREEZER))
365 pr_debug("PM: Entering %s sleep\n", pm_states[state]);
366 error = suspend_devices_and_enter(state);
369 pr_debug("PM: Finishing wakeup.\n");
372 mutex_unlock(&pm_mutex);
378 * pm_suspend - Externally visible function for suspending system.
379 * @state: Enumerated value of state to enter.
381 * Determine whether or not value is within range, get state
382 * structure, and enter (above).
385 int pm_suspend(suspend_state_t state)
387 if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
388 return enter_state(state);
392 EXPORT_SYMBOL(pm_suspend);
394 #endif /* CONFIG_SUSPEND */
396 struct kobject *power_kobj;
399 * state - control system power state.
401 * show() returns what states are supported, which is hard-coded to
402 * 'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
403 * 'disk' (Suspend-to-Disk).
405 * store() accepts one of those strings, translates it into the
406 * proper enumerated value, and initiates a suspend transition.
409 static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
413 #ifdef CONFIG_SUSPEND
416 for (i = 0; i < PM_SUSPEND_MAX; i++) {
417 if (pm_states[i] && valid_state(i))
418 s += sprintf(s,"%s ", pm_states[i]);
421 #ifdef CONFIG_HIBERNATION
422 s += sprintf(s, "%s\n", "disk");
425 /* convert the last space to a newline */
431 static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
432 const char *buf, size_t n)
434 #ifdef CONFIG_SUSPEND
435 suspend_state_t state = PM_SUSPEND_STANDBY;
436 const char * const *s;
442 p = memchr(buf, '\n', n);
443 len = p ? p - buf : n;
445 /* First, check if we are requested to hibernate */
446 if (len == 4 && !strncmp(buf, "disk", len)) {
451 #ifdef CONFIG_SUSPEND
452 for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
453 if (*s && len == strlen(*s) && !strncmp(buf, *s, len))
456 if (state < PM_SUSPEND_MAX && *s)
457 error = enter_state(state);
461 return error ? error : n;
466 #ifdef CONFIG_PM_TRACE
467 int pm_trace_enabled;
469 static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr,
472 return sprintf(buf, "%d\n", pm_trace_enabled);
476 pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr,
477 const char *buf, size_t n)
481 if (sscanf(buf, "%d", &val) == 1) {
482 pm_trace_enabled = !!val;
488 power_attr(pm_trace);
489 #endif /* CONFIG_PM_TRACE */
491 static struct attribute * g[] = {
493 #ifdef CONFIG_PM_TRACE
496 #ifdef CONFIG_PM_DEBUG
502 static struct attribute_group attr_group = {
507 static int __init pm_init(void)
509 power_kobj = kobject_create_and_add("power", NULL);
512 return sysfs_create_group(power_kobj, &attr_group);
515 core_initcall(pm_init);