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/suspend.h>
12 #include <linux/kobject.h>
13 #include <linux/string.h>
14 #include <linux/delay.h>
15 #include <linux/errno.h>
16 #include <linux/init.h>
22 /*This is just an arbitrary number */
23 #define FREE_PAGE_NUMBER (100)
25 DECLARE_MUTEX(pm_sem);
27 struct pm_ops * pm_ops = NULL;
28 suspend_disk_method_t pm_disk_mode = PM_DISK_SHUTDOWN;
31 * pm_set_ops - Set the global power method table.
32 * @ops: Pointer to ops structure.
35 void pm_set_ops(struct pm_ops * ops)
44 * suspend_prepare - Do prep work before entering low-power state.
45 * @state: State we're entering.
47 * This is common code that is called for each state that we're
48 * entering. Allocate a console, stop all processes, then make sure
49 * the platform can enter the requested state.
52 static int suspend_prepare(suspend_state_t state)
55 unsigned int free_pages;
57 if (!pm_ops || !pm_ops->enter)
62 disable_nonboot_cpus();
64 if (num_online_cpus() != 1) {
69 if (freeze_processes()) {
74 if ((free_pages = nr_free_pages()) < FREE_PAGE_NUMBER) {
75 pr_debug("PM: free some memory\n");
76 shrink_all_memory(FREE_PAGE_NUMBER - free_pages);
77 if (nr_free_pages() < FREE_PAGE_NUMBER) {
79 printk(KERN_ERR "PM: No enough memory\n");
84 if (pm_ops->prepare) {
85 if ((error = pm_ops->prepare(state)))
89 if ((error = device_suspend(PMSG_SUSPEND))) {
90 printk(KERN_ERR "Some devices failed to suspend\n");
96 pm_ops->finish(state);
100 enable_nonboot_cpus();
101 pm_restore_console();
106 static int suspend_enter(suspend_state_t state)
111 local_irq_save(flags);
113 if ((error = device_power_down(PMSG_SUSPEND))) {
114 printk(KERN_ERR "Some devices failed to power down\n");
117 error = pm_ops->enter(state);
120 local_irq_restore(flags);
126 * suspend_finish - Do final work before exiting suspend sequence.
127 * @state: State we're coming out of.
129 * Call platform code to clean up, restart processes, and free the
130 * console that we've allocated. This is not called for suspend-to-disk.
133 static void suspend_finish(suspend_state_t state)
136 if (pm_ops && pm_ops->finish)
137 pm_ops->finish(state);
139 enable_nonboot_cpus();
140 pm_restore_console();
146 static char *pm_states[PM_SUSPEND_MAX] = {
147 [PM_SUSPEND_STANDBY] = "standby",
148 [PM_SUSPEND_MEM] = "mem",
149 #ifdef CONFIG_SOFTWARE_SUSPEND
150 [PM_SUSPEND_DISK] = "disk",
156 * enter_state - Do common work of entering low-power state.
157 * @state: pm_state structure for state we're entering.
159 * Make sure we're the only ones trying to enter a sleep state. Fail
160 * if someone has beat us to it, since we don't want anything weird to
161 * happen when we wake up.
162 * Then, do the setup for suspend, enter the state, and cleaup (after
166 static int enter_state(suspend_state_t state)
170 if (pm_ops->valid && !pm_ops->valid(state))
172 if (down_trylock(&pm_sem))
175 if (state == PM_SUSPEND_DISK) {
176 error = pm_suspend_disk();
180 pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
181 if ((error = suspend_prepare(state)))
184 pr_debug("PM: Entering %s sleep\n", pm_states[state]);
185 error = suspend_enter(state);
187 pr_debug("PM: Finishing wakeup.\n");
188 suspend_finish(state);
195 * This is main interface to the outside world. It needs to be
196 * called from process context.
198 int software_suspend(void)
200 return enter_state(PM_SUSPEND_DISK);
205 * pm_suspend - Externally visible function for suspending system.
206 * @state: Enumarted value of state to enter.
208 * Determine whether or not value is within range, get state
209 * structure, and enter (above).
212 int pm_suspend(suspend_state_t state)
214 if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
215 return enter_state(state);
221 decl_subsys(power,NULL,NULL);
225 * state - control system power state.
227 * show() returns what states are supported, which is hard-coded to
228 * 'standby' (Power-On Suspend), 'mem' (Suspend-to-RAM), and
229 * 'disk' (Suspend-to-Disk).
231 * store() accepts one of those strings, translates it into the
232 * proper enumerated value, and initiates a suspend transition.
235 static ssize_t state_show(struct subsystem * subsys, char * buf)
240 for (i = 0; i < PM_SUSPEND_MAX; i++) {
241 if (pm_states[i] && pm_ops && (!pm_ops->valid
242 ||(pm_ops->valid && pm_ops->valid(i))))
243 s += sprintf(s,"%s ",pm_states[i]);
245 s += sprintf(s,"\n");
249 static ssize_t state_store(struct subsystem * subsys, const char * buf, size_t n)
251 suspend_state_t state = PM_SUSPEND_STANDBY;
257 p = memchr(buf, '\n', n);
258 len = p ? p - buf : n;
260 for (s = &pm_states[state]; state < PM_SUSPEND_MAX; s++, state++) {
261 if (*s && !strncmp(buf, *s, len))
265 error = enter_state(state);
268 return error ? error : n;
273 static struct attribute * g[] = {
278 static struct attribute_group attr_group = {
283 static int __init pm_init(void)
285 int error = subsystem_register(&power_subsys);
287 error = sysfs_create_group(&power_subsys.kset.kobj,&attr_group);
291 core_initcall(pm_init);