2 * kernel/power/suspend.c - Suspend to RAM and standby functionality.
4 * Copyright (c) 2003 Patrick Mochel
5 * Copyright (c) 2003 Open Source Development Lab
6 * Copyright (c) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
8 * This file is released under the GPLv2.
11 #include <linux/string.h>
12 #include <linux/delay.h>
13 #include <linux/errno.h>
14 #include <linux/init.h>
15 #include <linux/console.h>
16 #include <linux/cpu.h>
17 #include <linux/syscalls.h>
18 #include <linux/gfp.h>
20 #include <linux/kernel.h>
21 #include <linux/list.h>
23 #include <linux/slab.h>
24 #include <linux/suspend.h>
25 #include <linux/syscore_ops.h>
26 #include <trace/events/power.h>
30 const char *const pm_states[PM_SUSPEND_MAX] = {
31 [PM_SUSPEND_STANDBY] = "standby",
32 [PM_SUSPEND_MEM] = "mem",
35 static const struct platform_suspend_ops *suspend_ops;
38 * suspend_set_ops - Set the global suspend method table.
39 * @ops: Pointer to ops structure.
41 void suspend_set_ops(const struct platform_suspend_ops *ops)
43 mutex_lock(&pm_mutex);
45 mutex_unlock(&pm_mutex);
47 EXPORT_SYMBOL_GPL(suspend_set_ops);
49 bool valid_state(suspend_state_t state)
52 * All states need lowlevel support and need to be valid to the lowlevel
53 * implementation, no valid callback implies that none are valid.
55 return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
59 * suspend_valid_only_mem - generic memory-only valid callback
61 * Platform drivers that implement mem suspend only and only need
62 * to check for that in their .valid callback can use this instead
63 * of rolling their own .valid callback.
65 int suspend_valid_only_mem(suspend_state_t state)
67 return state == PM_SUSPEND_MEM;
69 EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
71 static int suspend_test(int level)
73 #ifdef CONFIG_PM_DEBUG
74 if (pm_test_level == level) {
75 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
79 #endif /* !CONFIG_PM_DEBUG */
84 * suspend_prepare - Do prep work before entering low-power state.
86 * This is common code that is called for each state that we're entering.
87 * Run suspend notifiers, allocate a console and stop all processes.
89 static int suspend_prepare(void)
93 if (!suspend_ops || !suspend_ops->enter)
98 error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
102 error = usermodehelper_disable();
106 error = suspend_freeze_processes();
110 suspend_thaw_processes();
111 usermodehelper_enable();
113 pm_notifier_call_chain(PM_POST_SUSPEND);
114 pm_restore_console();
118 /* default implementation */
119 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
124 /* default implementation */
125 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
131 * suspend_enter - enter the desired system sleep state.
132 * @state: State to enter
133 * @wakeup: Returns information that suspend should not be entered again.
135 * This function should be called after devices have been suspended.
137 static int suspend_enter(suspend_state_t state, bool *wakeup)
141 if (suspend_ops->prepare) {
142 error = suspend_ops->prepare();
144 goto Platform_finish;
147 error = dpm_suspend_noirq(PMSG_SUSPEND);
149 printk(KERN_ERR "PM: Some devices failed to power down\n");
150 goto Platform_finish;
153 if (suspend_ops->prepare_late) {
154 error = suspend_ops->prepare_late();
159 if (suspend_test(TEST_PLATFORM))
162 error = disable_nonboot_cpus();
163 if (error || suspend_test(TEST_CPUS))
166 arch_suspend_disable_irqs();
167 BUG_ON(!irqs_disabled());
169 error = syscore_suspend();
171 *wakeup = pm_wakeup_pending();
172 if (!(suspend_test(TEST_CORE) || *wakeup)) {
173 error = suspend_ops->enter(state);
174 events_check_enabled = false;
179 arch_suspend_enable_irqs();
180 BUG_ON(irqs_disabled());
183 enable_nonboot_cpus();
186 if (suspend_ops->wake)
189 dpm_resume_noirq(PMSG_RESUME);
192 if (suspend_ops->finish)
193 suspend_ops->finish();
199 * suspend_devices_and_enter - suspend devices and enter the desired system
201 * @state: state to enter
203 int suspend_devices_and_enter(suspend_state_t state)
211 trace_machine_suspend(state);
212 if (suspend_ops->begin) {
213 error = suspend_ops->begin(state);
218 suspend_test_start();
219 error = dpm_suspend_start(PMSG_SUSPEND);
221 printk(KERN_ERR "PM: Some devices failed to suspend\n");
222 goto Recover_platform;
224 suspend_test_finish("suspend devices");
225 if (suspend_test(TEST_DEVICES))
226 goto Recover_platform;
229 error = suspend_enter(state, &wakeup);
230 } while (!error && !wakeup
231 && suspend_ops->suspend_again && suspend_ops->suspend_again());
234 suspend_test_start();
235 dpm_resume_end(PMSG_RESUME);
236 suspend_test_finish("resume devices");
239 if (suspend_ops->end)
241 trace_machine_suspend(PWR_EVENT_EXIT);
245 if (suspend_ops->recover)
246 suspend_ops->recover();
251 * suspend_finish - Do final work before exiting suspend sequence.
253 * Call platform code to clean up, restart processes, and free the
254 * console that we've allocated. This is not called for suspend-to-disk.
256 static void suspend_finish(void)
258 suspend_thaw_processes();
259 usermodehelper_enable();
260 pm_notifier_call_chain(PM_POST_SUSPEND);
261 pm_restore_console();
265 * enter_state - Do common work of entering low-power state.
266 * @state: pm_state structure for state we're entering.
268 * Make sure we're the only ones trying to enter a sleep state. Fail
269 * if someone has beat us to it, since we don't want anything weird to
270 * happen when we wake up.
271 * Then, do the setup for suspend, enter the state, and cleaup (after
274 int enter_state(suspend_state_t state)
278 if (!valid_state(state))
281 if (!mutex_trylock(&pm_mutex))
284 printk(KERN_INFO "PM: Syncing filesystems ... ");
288 pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
289 error = suspend_prepare();
293 if (suspend_test(TEST_FREEZER))
296 pr_debug("PM: Entering %s sleep\n", pm_states[state]);
297 pm_restrict_gfp_mask();
298 error = suspend_devices_and_enter(state);
299 pm_restore_gfp_mask();
302 pr_debug("PM: Finishing wakeup.\n");
305 mutex_unlock(&pm_mutex);
310 * pm_suspend - Externally visible function for suspending system.
311 * @state: Enumerated value of state to enter.
313 * Determine whether or not value is within range, get state
314 * structure, and enter (above).
316 int pm_suspend(suspend_state_t state)
318 if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
319 return enter_state(state);
322 EXPORT_SYMBOL(pm_suspend);