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 BLOCKING_NOTIFIER_HEAD(pm_chain_head);
29 DEFINE_MUTEX(pm_mutex);
31 unsigned int pm_flags;
32 EXPORT_SYMBOL(pm_flags);
34 #ifdef CONFIG_PM_DEBUG
35 int pm_test_level = TEST_NONE;
37 static int suspend_test(int level)
39 if (pm_test_level == level) {
40 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
47 static const char * const pm_tests[__TEST_AFTER_LAST] = {
50 [TEST_CPUS] = "processors",
51 [TEST_PLATFORM] = "platform",
52 [TEST_DEVICES] = "devices",
53 [TEST_FREEZER] = "freezer",
56 static ssize_t pm_test_show(struct kset *kset, char *buf)
61 for (level = TEST_FIRST; level <= TEST_MAX; level++)
62 if (pm_tests[level]) {
63 if (level == pm_test_level)
64 s += sprintf(s, "[%s] ", pm_tests[level]);
66 s += sprintf(s, "%s ", pm_tests[level]);
70 /* convert the last space to a newline */
76 static ssize_t pm_test_store(struct kset *kset, const char *buf, size_t n)
78 const char * const *s;
84 p = memchr(buf, '\n', n);
85 len = p ? p - buf : n;
87 mutex_lock(&pm_mutex);
90 for (s = &pm_tests[level]; level <= TEST_MAX; s++, level++)
91 if (*s && len == strlen(*s) && !strncmp(buf, *s, len)) {
92 pm_test_level = level;
97 mutex_unlock(&pm_mutex);
99 return error ? error : n;
103 #else /* !CONFIG_PM_DEBUG */
104 static inline int suspend_test(int level) { return 0; }
105 #endif /* !CONFIG_PM_DEBUG */
107 #ifdef CONFIG_SUSPEND
109 /* This is just an arbitrary number */
110 #define FREE_PAGE_NUMBER (100)
112 static struct platform_suspend_ops *suspend_ops;
115 * suspend_set_ops - Set the global suspend method table.
116 * @ops: Pointer to ops structure.
119 void suspend_set_ops(struct platform_suspend_ops *ops)
121 mutex_lock(&pm_mutex);
123 mutex_unlock(&pm_mutex);
127 * suspend_valid_only_mem - generic memory-only valid callback
129 * Platform drivers that implement mem suspend only and only need
130 * to check for that in their .valid callback can use this instead
131 * of rolling their own .valid callback.
133 int suspend_valid_only_mem(suspend_state_t state)
135 return state == PM_SUSPEND_MEM;
139 * suspend_prepare - Do prep work before entering low-power state.
141 * This is common code that is called for each state that we're entering.
142 * Run suspend notifiers, allocate a console and stop all processes.
144 static int suspend_prepare(void)
147 unsigned int free_pages;
149 if (!suspend_ops || !suspend_ops->enter)
152 error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
156 pm_prepare_console();
158 if (freeze_processes()) {
163 free_pages = global_page_state(NR_FREE_PAGES);
164 if (free_pages < FREE_PAGE_NUMBER) {
165 pr_debug("PM: free some memory\n");
166 shrink_all_memory(FREE_PAGE_NUMBER - free_pages);
167 if (nr_free_pages() < FREE_PAGE_NUMBER) {
169 printk(KERN_ERR "PM: No enough memory\n");
177 pm_restore_console();
179 pm_notifier_call_chain(PM_POST_SUSPEND);
183 /* default implementation */
184 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
189 /* default implementation */
190 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
196 * suspend_enter - enter the desired system sleep state.
197 * @state: state to enter
199 * This function should be called after devices have been suspended.
201 static int suspend_enter(suspend_state_t state)
205 arch_suspend_disable_irqs();
206 BUG_ON(!irqs_disabled());
208 if ((error = device_power_down(PMSG_SUSPEND))) {
209 printk(KERN_ERR "Some devices failed to power down\n");
213 if (!suspend_test(TEST_CORE))
214 error = suspend_ops->enter(state);
218 arch_suspend_enable_irqs();
219 BUG_ON(irqs_disabled());
224 * suspend_devices_and_enter - suspend devices and enter the desired system sleep
226 * @state: state to enter
228 int suspend_devices_and_enter(suspend_state_t state)
235 if (suspend_ops->set_target) {
236 error = suspend_ops->set_target(state);
241 error = device_suspend(PMSG_SUSPEND);
243 printk(KERN_ERR "Some devices failed to suspend\n");
247 if (suspend_test(TEST_DEVICES))
250 if (suspend_ops->prepare) {
251 error = suspend_ops->prepare();
256 if (suspend_test(TEST_PLATFORM))
259 error = disable_nonboot_cpus();
260 if (!error && !suspend_test(TEST_CPUS))
261 suspend_enter(state);
263 enable_nonboot_cpus();
265 if (suspend_ops->finish)
266 suspend_ops->finish();
275 * suspend_finish - Do final work before exiting suspend sequence.
277 * Call platform code to clean up, restart processes, and free the
278 * console that we've allocated. This is not called for suspend-to-disk.
280 static void suspend_finish(void)
283 pm_restore_console();
284 pm_notifier_call_chain(PM_POST_SUSPEND);
290 static const char * const pm_states[PM_SUSPEND_MAX] = {
291 [PM_SUSPEND_STANDBY] = "standby",
292 [PM_SUSPEND_MEM] = "mem",
295 static inline int valid_state(suspend_state_t state)
297 /* All states need lowlevel support and need to be valid
298 * to the lowlevel implementation, no valid callback
299 * implies that none are valid. */
300 if (!suspend_ops || !suspend_ops->valid || !suspend_ops->valid(state))
307 * enter_state - Do common work of entering low-power state.
308 * @state: pm_state structure for state we're entering.
310 * Make sure we're the only ones trying to enter a sleep state. Fail
311 * if someone has beat us to it, since we don't want anything weird to
312 * happen when we wake up.
313 * Then, do the setup for suspend, enter the state, and cleaup (after
316 static int enter_state(suspend_state_t state)
320 if (!valid_state(state))
323 if (!mutex_trylock(&pm_mutex))
326 printk("Syncing filesystems ... ");
330 pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
331 error = suspend_prepare();
335 if (suspend_test(TEST_FREEZER))
338 pr_debug("PM: Entering %s sleep\n", pm_states[state]);
339 error = suspend_devices_and_enter(state);
342 pr_debug("PM: Finishing wakeup.\n");
345 mutex_unlock(&pm_mutex);
351 * pm_suspend - Externally visible function for suspending system.
352 * @state: Enumerated value of state to enter.
354 * Determine whether or not value is within range, get state
355 * structure, and enter (above).
358 int pm_suspend(suspend_state_t state)
360 if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
361 return enter_state(state);
365 EXPORT_SYMBOL(pm_suspend);
367 #endif /* CONFIG_SUSPEND */
369 struct kobject *power_kobj;
372 * state - control system power state.
374 * show() returns what states are supported, which is hard-coded to
375 * 'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
376 * 'disk' (Suspend-to-Disk).
378 * store() accepts one of those strings, translates it into the
379 * proper enumerated value, and initiates a suspend transition.
382 static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
386 #ifdef CONFIG_SUSPEND
389 for (i = 0; i < PM_SUSPEND_MAX; i++) {
390 if (pm_states[i] && valid_state(i))
391 s += sprintf(s,"%s ", pm_states[i]);
394 #ifdef CONFIG_HIBERNATION
395 s += sprintf(s, "%s\n", "disk");
398 /* convert the last space to a newline */
404 static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
405 const char *buf, size_t n)
407 #ifdef CONFIG_SUSPEND
408 suspend_state_t state = PM_SUSPEND_STANDBY;
409 const char * const *s;
415 p = memchr(buf, '\n', n);
416 len = p ? p - buf : n;
418 /* First, check if we are requested to hibernate */
419 if (len == 4 && !strncmp(buf, "disk", len)) {
424 #ifdef CONFIG_SUSPEND
425 for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
426 if (*s && len == strlen(*s) && !strncmp(buf, *s, len))
429 if (state < PM_SUSPEND_MAX && *s)
430 error = enter_state(state);
434 return error ? error : n;
439 #ifdef CONFIG_PM_TRACE
440 int pm_trace_enabled;
442 static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr,
445 return sprintf(buf, "%d\n", pm_trace_enabled);
449 pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr,
450 const char *buf, size_t n)
454 if (sscanf(buf, "%d", &val) == 1) {
455 pm_trace_enabled = !!val;
461 power_attr(pm_trace);
462 #endif /* CONFIG_PM_TRACE */
464 static struct attribute * g[] = {
466 #ifdef CONFIG_PM_TRACE
469 #ifdef CONFIG_PM_DEBUG
475 static struct attribute_group attr_group = {
480 static int __init pm_init(void)
482 power_kobj = kobject_create_and_add("power", NULL);
485 return sysfs_create_group(power_kobj, &attr_group);
488 core_initcall(pm_init);