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>
19 #include <linux/console.h>
20 #include <linux/cpu.h>
21 #include <linux/resume-trace.h>
22 #include <linux/freezer.h>
23 #include <linux/vmstat.h>
27 /*This is just an arbitrary number */
28 #define FREE_PAGE_NUMBER (100)
30 DEFINE_MUTEX(pm_mutex);
32 struct pm_ops *pm_ops;
33 suspend_disk_method_t pm_disk_mode = PM_DISK_PLATFORM;
36 * pm_set_ops - Set the global power method table.
37 * @ops: Pointer to ops structure.
40 void pm_set_ops(struct pm_ops * ops)
42 mutex_lock(&pm_mutex);
44 mutex_unlock(&pm_mutex);
47 static inline void pm_finish(suspend_state_t state)
50 pm_ops->finish(state);
54 * suspend_prepare - Do prep work before entering low-power state.
55 * @state: State we're entering.
57 * This is common code that is called for each state that we're
58 * entering. Allocate a console, stop all processes, then make sure
59 * the platform can enter the requested state.
62 static int suspend_prepare(suspend_state_t state)
65 unsigned int free_pages;
67 if (!pm_ops || !pm_ops->enter)
72 if (freeze_processes()) {
77 if ((free_pages = global_page_state(NR_FREE_PAGES))
79 pr_debug("PM: free some memory\n");
80 shrink_all_memory(FREE_PAGE_NUMBER - free_pages);
81 if (nr_free_pages() < FREE_PAGE_NUMBER) {
83 printk(KERN_ERR "PM: No enough memory\n");
88 if (pm_ops->prepare) {
89 if ((error = pm_ops->prepare(state)))
94 error = device_suspend(PMSG_SUSPEND);
96 printk(KERN_ERR "Some devices failed to suspend\n");
99 error = disable_nonboot_cpus();
103 enable_nonboot_cpus();
110 pm_restore_console();
115 int suspend_enter(suspend_state_t state)
120 local_irq_save(flags);
122 if ((error = device_power_down(PMSG_SUSPEND))) {
123 printk(KERN_ERR "Some devices failed to power down\n");
126 error = pm_ops->enter(state);
129 local_irq_restore(flags);
135 * suspend_finish - Do final work before exiting suspend sequence.
136 * @state: State we're coming out of.
138 * Call platform code to clean up, restart processes, and free the
139 * console that we've allocated. This is not called for suspend-to-disk.
142 static void suspend_finish(suspend_state_t state)
144 enable_nonboot_cpus();
149 pm_restore_console();
155 static const char * const pm_states[PM_SUSPEND_MAX] = {
156 [PM_SUSPEND_STANDBY] = "standby",
157 [PM_SUSPEND_MEM] = "mem",
158 #ifdef CONFIG_SOFTWARE_SUSPEND
159 [PM_SUSPEND_DISK] = "disk",
163 static inline int valid_state(suspend_state_t state)
165 /* Suspend-to-disk does not really need low-level support.
166 * It can work with reboot if needed. */
167 if (state == PM_SUSPEND_DISK)
170 if (pm_ops && pm_ops->valid && !pm_ops->valid(state))
177 * enter_state - Do common work of entering low-power state.
178 * @state: pm_state structure for state we're entering.
180 * Make sure we're the only ones trying to enter a sleep state. Fail
181 * if someone has beat us to it, since we don't want anything weird to
182 * happen when we wake up.
183 * Then, do the setup for suspend, enter the state, and cleaup (after
187 static int enter_state(suspend_state_t state)
191 if (!valid_state(state))
193 if (!mutex_trylock(&pm_mutex))
196 if (state == PM_SUSPEND_DISK) {
197 error = pm_suspend_disk();
201 pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
202 if ((error = suspend_prepare(state)))
205 pr_debug("PM: Entering %s sleep\n", pm_states[state]);
206 error = suspend_enter(state);
208 pr_debug("PM: Finishing wakeup.\n");
209 suspend_finish(state);
211 mutex_unlock(&pm_mutex);
216 * This is main interface to the outside world. It needs to be
217 * called from process context.
219 int software_suspend(void)
221 return enter_state(PM_SUSPEND_DISK);
226 * pm_suspend - Externally visible function for suspending system.
227 * @state: Enumarted value of state to enter.
229 * Determine whether or not value is within range, get state
230 * structure, and enter (above).
233 int pm_suspend(suspend_state_t state)
235 if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
236 return enter_state(state);
240 EXPORT_SYMBOL(pm_suspend);
242 decl_subsys(power,NULL,NULL);
246 * state - control system power state.
248 * show() returns what states are supported, which is hard-coded to
249 * 'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
250 * 'disk' (Suspend-to-Disk).
252 * store() accepts one of those strings, translates it into the
253 * proper enumerated value, and initiates a suspend transition.
256 static ssize_t state_show(struct subsystem * subsys, char * buf)
261 for (i = 0; i < PM_SUSPEND_MAX; i++) {
262 if (pm_states[i] && valid_state(i))
263 s += sprintf(s,"%s ", pm_states[i]);
265 s += sprintf(s,"\n");
269 static ssize_t state_store(struct subsystem * subsys, const char * buf, size_t n)
271 suspend_state_t state = PM_SUSPEND_STANDBY;
272 const char * const *s;
277 p = memchr(buf, '\n', n);
278 len = p ? p - buf : n;
280 for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
281 if (*s && !strncmp(buf, *s, len))
284 if (state < PM_SUSPEND_MAX && *s)
285 error = enter_state(state);
288 return error ? error : n;
293 #ifdef CONFIG_PM_TRACE
294 int pm_trace_enabled;
296 static ssize_t pm_trace_show(struct subsystem * subsys, char * buf)
298 return sprintf(buf, "%d\n", pm_trace_enabled);
302 pm_trace_store(struct subsystem * subsys, const char * buf, size_t n)
306 if (sscanf(buf, "%d", &val) == 1) {
307 pm_trace_enabled = !!val;
313 power_attr(pm_trace);
315 static struct attribute * g[] = {
321 static struct attribute * g[] = {
325 #endif /* CONFIG_PM_TRACE */
327 static struct attribute_group attr_group = {
332 static int __init pm_init(void)
334 int error = subsystem_register(&power_subsys);
336 error = sysfs_create_group(&power_subsys.kset.kobj,&attr_group);
340 core_initcall(pm_init);