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/kmod.h>
16 #include <linux/console.h>
17 #include <linux/cpu.h>
18 #include <linux/syscalls.h>
19 #include <linux/gfp.h>
21 #include <linux/kernel.h>
22 #include <linux/list.h>
24 #include <linux/slab.h>
25 #include <linux/export.h>
26 #include <linux/suspend.h>
27 #include <linux/syscore_ops.h>
28 #include <trace/events/power.h>
32 const char *const pm_states[PM_SUSPEND_MAX] = {
33 [PM_SUSPEND_STANDBY] = "standby",
34 [PM_SUSPEND_MEM] = "mem",
37 static const struct platform_suspend_ops *suspend_ops;
40 * suspend_set_ops - Set the global suspend method table.
41 * @ops: Suspend operations to use.
43 void suspend_set_ops(const struct platform_suspend_ops *ops)
47 unlock_system_sleep();
49 EXPORT_SYMBOL_GPL(suspend_set_ops);
51 bool valid_state(suspend_state_t state)
54 * All states need lowlevel support and need to be valid to the lowlevel
55 * implementation, no valid callback implies that none are valid.
57 return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
61 * suspend_valid_only_mem - Generic memory-only valid callback.
63 * Platform drivers that implement mem suspend only and only need to check for
64 * that in their .valid() callback can use this instead of rolling their own
67 int suspend_valid_only_mem(suspend_state_t state)
69 return state == PM_SUSPEND_MEM;
71 EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
73 static int suspend_test(int level)
75 #ifdef CONFIG_PM_DEBUG
76 if (pm_test_level == level) {
77 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
81 #endif /* !CONFIG_PM_DEBUG */
86 * suspend_prepare - Prepare for entering system sleep state.
88 * Common code run for every system sleep state that can be entered (except for
89 * hibernation). Run suspend notifiers, allocate the "suspend" console and
92 static int suspend_prepare(void)
96 if (!suspend_ops || !suspend_ops->enter)
101 error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
105 error = usermodehelper_disable();
109 error = suspend_freeze_processes();
113 suspend_stats.failed_freeze++;
114 dpm_save_failed_step(SUSPEND_FREEZE);
115 usermodehelper_enable();
117 pm_notifier_call_chain(PM_POST_SUSPEND);
118 pm_restore_console();
122 /* default implementation */
123 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
128 /* default implementation */
129 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
135 * suspend_enter - Make the system enter the given sleep state.
136 * @state: System sleep state to enter.
137 * @wakeup: Returns information that the sleep state should not be re-entered.
139 * This function should be called after devices have been suspended.
141 static int suspend_enter(suspend_state_t state, bool *wakeup)
145 if (suspend_ops->prepare) {
146 error = suspend_ops->prepare();
148 goto Platform_finish;
151 error = dpm_suspend_end(PMSG_SUSPEND);
153 printk(KERN_ERR "PM: Some devices failed to power down\n");
154 goto Platform_finish;
157 if (suspend_ops->prepare_late) {
158 error = suspend_ops->prepare_late();
163 if (suspend_test(TEST_PLATFORM))
166 error = disable_nonboot_cpus();
167 if (error || suspend_test(TEST_CPUS))
170 arch_suspend_disable_irqs();
171 BUG_ON(!irqs_disabled());
173 error = syscore_suspend();
175 *wakeup = pm_wakeup_pending();
176 if (!(suspend_test(TEST_CORE) || *wakeup)) {
177 error = suspend_ops->enter(state);
178 events_check_enabled = false;
183 arch_suspend_enable_irqs();
184 BUG_ON(irqs_disabled());
187 enable_nonboot_cpus();
190 if (suspend_ops->wake)
193 dpm_resume_start(PMSG_RESUME);
196 if (suspend_ops->finish)
197 suspend_ops->finish();
203 * suspend_devices_and_enter - Suspend devices and enter system sleep state.
204 * @state: System sleep state to enter.
206 int suspend_devices_and_enter(suspend_state_t state)
214 trace_machine_suspend(state);
215 if (suspend_ops->begin) {
216 error = suspend_ops->begin(state);
221 suspend_test_start();
222 error = dpm_suspend_start(PMSG_SUSPEND);
224 printk(KERN_ERR "PM: Some devices failed to suspend\n");
225 goto Recover_platform;
227 suspend_test_finish("suspend devices");
228 if (suspend_test(TEST_DEVICES))
229 goto Recover_platform;
232 error = suspend_enter(state, &wakeup);
233 } while (!error && !wakeup
234 && suspend_ops->suspend_again && suspend_ops->suspend_again());
237 suspend_test_start();
238 dpm_resume_end(PMSG_RESUME);
239 suspend_test_finish("resume devices");
242 if (suspend_ops->end)
244 trace_machine_suspend(PWR_EVENT_EXIT);
248 if (suspend_ops->recover)
249 suspend_ops->recover();
254 * suspend_finish - Clean up before finishing the suspend sequence.
256 * Call platform code to clean up, restart processes, and free the console that
257 * we've allocated. This routine is not called for hibernation.
259 static void suspend_finish(void)
261 suspend_thaw_processes();
262 usermodehelper_enable();
263 pm_notifier_call_chain(PM_POST_SUSPEND);
264 pm_restore_console();
268 * enter_state - Do common work needed to enter system sleep state.
269 * @state: System sleep state to enter.
271 * Make sure that no one else is trying to put the system into a sleep state.
272 * Fail if that's not the case. Otherwise, prepare for system suspend, make the
273 * system enter the given sleep state and clean up after wakeup.
275 static int enter_state(suspend_state_t state)
279 if (!valid_state(state))
282 if (!mutex_trylock(&pm_mutex))
285 printk(KERN_INFO "PM: Syncing filesystems ... ");
289 pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
290 error = suspend_prepare();
294 if (suspend_test(TEST_FREEZER))
297 pr_debug("PM: Entering %s sleep\n", pm_states[state]);
298 pm_restrict_gfp_mask();
299 error = suspend_devices_and_enter(state);
300 pm_restore_gfp_mask();
303 pr_debug("PM: Finishing wakeup.\n");
306 mutex_unlock(&pm_mutex);
311 * pm_suspend - Externally visible function for suspending the system.
312 * @state: System sleep state to enter.
314 * Check if the value of @state represents one of the supported states,
315 * execute enter_state() and update system suspend statistics.
317 int pm_suspend(suspend_state_t state)
321 if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
324 error = enter_state(state);
326 suspend_stats.fail++;
327 dpm_save_failed_errno(error);
329 suspend_stats.success++;
333 EXPORT_SYMBOL(pm_suspend);