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);
36 /* This is just an arbitrary number */
37 #define FREE_PAGE_NUMBER (100)
39 static struct platform_suspend_ops *suspend_ops;
42 * suspend_set_ops - Set the global suspend method table.
43 * @ops: Pointer to ops structure.
46 void suspend_set_ops(struct platform_suspend_ops *ops)
48 mutex_lock(&pm_mutex);
50 mutex_unlock(&pm_mutex);
54 * suspend_valid_only_mem - generic memory-only valid callback
56 * Platform drivers that implement mem suspend only and only need
57 * to check for that in their .valid callback can use this instead
58 * of rolling their own .valid callback.
60 int suspend_valid_only_mem(suspend_state_t state)
62 return state == PM_SUSPEND_MEM;
66 * suspend_prepare - Do prep work before entering low-power state.
68 * This is common code that is called for each state that we're entering.
69 * Run suspend notifiers, allocate a console and stop all processes.
71 static int suspend_prepare(void)
74 unsigned int free_pages;
76 if (!suspend_ops || !suspend_ops->enter)
79 error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
85 if (freeze_processes()) {
90 free_pages = global_page_state(NR_FREE_PAGES);
91 if (free_pages < FREE_PAGE_NUMBER) {
92 pr_debug("PM: free some memory\n");
93 shrink_all_memory(FREE_PAGE_NUMBER - free_pages);
94 if (nr_free_pages() < FREE_PAGE_NUMBER) {
96 printk(KERN_ERR "PM: No enough memory\n");
104 pm_restore_console();
106 pm_notifier_call_chain(PM_POST_SUSPEND);
110 /* default implementation */
111 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
116 /* default implementation */
117 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
123 * suspend_enter - enter the desired system sleep state.
124 * @state: state to enter
126 * This function should be called after devices have been suspended.
128 static int suspend_enter(suspend_state_t state)
132 arch_suspend_disable_irqs();
133 BUG_ON(!irqs_disabled());
135 if ((error = device_power_down(PMSG_SUSPEND))) {
136 printk(KERN_ERR "Some devices failed to power down\n");
139 error = suspend_ops->enter(state);
142 arch_suspend_enable_irqs();
143 BUG_ON(irqs_disabled());
148 * suspend_devices_and_enter - suspend devices and enter the desired system sleep
150 * @state: state to enter
152 int suspend_devices_and_enter(suspend_state_t state)
159 if (suspend_ops->set_target) {
160 error = suspend_ops->set_target(state);
165 error = device_suspend(PMSG_SUSPEND);
167 printk(KERN_ERR "Some devices failed to suspend\n");
170 if (suspend_ops->prepare) {
171 error = suspend_ops->prepare();
175 error = disable_nonboot_cpus();
177 suspend_enter(state);
179 enable_nonboot_cpus();
180 if (suspend_ops->finish)
181 suspend_ops->finish();
190 * suspend_finish - Do final work before exiting suspend sequence.
192 * Call platform code to clean up, restart processes, and free the
193 * console that we've allocated. This is not called for suspend-to-disk.
195 static void suspend_finish(void)
198 pm_restore_console();
199 pm_notifier_call_chain(PM_POST_SUSPEND);
205 static const char * const pm_states[PM_SUSPEND_MAX] = {
206 [PM_SUSPEND_STANDBY] = "standby",
207 [PM_SUSPEND_MEM] = "mem",
210 static inline int valid_state(suspend_state_t state)
212 /* All states need lowlevel support and need to be valid
213 * to the lowlevel implementation, no valid callback
214 * implies that none are valid. */
215 if (!suspend_ops || !suspend_ops->valid || !suspend_ops->valid(state))
222 * enter_state - Do common work of entering low-power state.
223 * @state: pm_state structure for state we're entering.
225 * Make sure we're the only ones trying to enter a sleep state. Fail
226 * if someone has beat us to it, since we don't want anything weird to
227 * happen when we wake up.
228 * Then, do the setup for suspend, enter the state, and cleaup (after
231 static int enter_state(suspend_state_t state)
235 if (!valid_state(state))
238 if (!mutex_trylock(&pm_mutex))
241 printk("Syncing filesystems ... ");
245 pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
246 if ((error = suspend_prepare()))
249 pr_debug("PM: Entering %s sleep\n", pm_states[state]);
250 error = suspend_devices_and_enter(state);
252 pr_debug("PM: Finishing wakeup.\n");
255 mutex_unlock(&pm_mutex);
261 * pm_suspend - Externally visible function for suspending system.
262 * @state: Enumerated value of state to enter.
264 * Determine whether or not value is within range, get state
265 * structure, and enter (above).
268 int pm_suspend(suspend_state_t state)
270 if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
271 return enter_state(state);
275 EXPORT_SYMBOL(pm_suspend);
277 #endif /* CONFIG_SUSPEND */
279 struct kobject *power_kobj;
282 * state - control system power state.
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).
288 * store() accepts one of those strings, translates it into the
289 * proper enumerated value, and initiates a suspend transition.
292 static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
296 #ifdef CONFIG_SUSPEND
299 for (i = 0; i < PM_SUSPEND_MAX; i++) {
300 if (pm_states[i] && valid_state(i))
301 s += sprintf(s,"%s ", pm_states[i]);
304 #ifdef CONFIG_HIBERNATION
305 s += sprintf(s, "%s\n", "disk");
308 /* convert the last space to a newline */
314 static ssize_t state_store(struct kobject *kobj, struct kobj_attribute *attr,
315 const char *buf, size_t n)
317 #ifdef CONFIG_SUSPEND
318 suspend_state_t state = PM_SUSPEND_STANDBY;
319 const char * const *s;
325 p = memchr(buf, '\n', n);
326 len = p ? p - buf : n;
328 /* First, check if we are requested to hibernate */
329 if (len == 4 && !strncmp(buf, "disk", len)) {
334 #ifdef CONFIG_SUSPEND
335 for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
336 if (*s && len == strlen(*s) && !strncmp(buf, *s, len))
339 if (state < PM_SUSPEND_MAX && *s)
340 error = enter_state(state);
344 return error ? error : n;
349 #ifdef CONFIG_PM_TRACE
350 int pm_trace_enabled;
352 static ssize_t pm_trace_show(struct kobject *kobj, struct kobj_attribute *attr,
355 return sprintf(buf, "%d\n", pm_trace_enabled);
359 pm_trace_store(struct kobject *kobj, struct kobj_attribute *attr,
360 const char *buf, size_t n)
364 if (sscanf(buf, "%d", &val) == 1) {
365 pm_trace_enabled = !!val;
371 power_attr(pm_trace);
373 static struct attribute * g[] = {
379 static struct attribute * g[] = {
383 #endif /* CONFIG_PM_TRACE */
385 static struct attribute_group attr_group = {
390 static int __init pm_init(void)
392 power_kobj = kobject_create_and_add("power", NULL);
395 return sysfs_create_group(power_kobj, &attr_group);
398 core_initcall(pm_init);