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: Pointer to ops structure.
43 void suspend_set_ops(const struct platform_suspend_ops *ops)
45 mutex_lock(&pm_mutex);
47 mutex_unlock(&pm_mutex);
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
64 * to check for that in their .valid callback can use this instead
65 * of rolling their own .valid callback.
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 - Do prep work before entering low-power state.
88 * This is common code that is called for each state that we're entering.
89 * Run suspend notifiers, allocate a console and stop all processes.
91 static int suspend_prepare(void)
95 if (!suspend_ops || !suspend_ops->enter)
100 error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
104 error = usermodehelper_disable();
108 error = suspend_freeze_processes();
110 suspend_stats.failed_freeze++;
111 dpm_save_failed_step(SUSPEND_FREEZE);
115 suspend_thaw_processes();
116 usermodehelper_enable();
118 pm_notifier_call_chain(PM_POST_SUSPEND);
119 pm_restore_console();
123 /* default implementation */
124 void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
129 /* default implementation */
130 void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
136 * suspend_enter - enter the desired system sleep state.
137 * @state: State to enter
138 * @wakeup: Returns information that suspend should not be entered again.
140 * This function should be called after devices have been suspended.
142 static int suspend_enter(suspend_state_t state, bool *wakeup)
146 if (suspend_ops->prepare) {
147 error = suspend_ops->prepare();
149 goto Platform_finish;
152 error = dpm_suspend_noirq(PMSG_SUSPEND);
154 printk(KERN_ERR "PM: Some devices failed to power down\n");
155 goto Platform_finish;
158 if (suspend_ops->prepare_late) {
159 error = suspend_ops->prepare_late();
164 if (suspend_test(TEST_PLATFORM))
167 error = disable_nonboot_cpus();
168 if (error || suspend_test(TEST_CPUS))
171 arch_suspend_disable_irqs();
172 BUG_ON(!irqs_disabled());
174 error = syscore_suspend();
176 *wakeup = pm_wakeup_pending();
177 if (!(suspend_test(TEST_CORE) || *wakeup)) {
178 error = suspend_ops->enter(state);
179 events_check_enabled = false;
184 arch_suspend_enable_irqs();
185 BUG_ON(irqs_disabled());
188 enable_nonboot_cpus();
191 if (suspend_ops->wake)
194 dpm_resume_noirq(PMSG_RESUME);
197 if (suspend_ops->finish)
198 suspend_ops->finish();
204 * suspend_devices_and_enter - suspend devices and enter the desired system
206 * @state: state to enter
208 int suspend_devices_and_enter(suspend_state_t state)
216 trace_machine_suspend(state);
217 if (suspend_ops->begin) {
218 error = suspend_ops->begin(state);
223 suspend_test_start();
224 error = dpm_suspend_start(PMSG_SUSPEND);
226 printk(KERN_ERR "PM: Some devices failed to suspend\n");
227 goto Recover_platform;
229 suspend_test_finish("suspend devices");
230 if (suspend_test(TEST_DEVICES))
231 goto Recover_platform;
234 error = suspend_enter(state, &wakeup);
235 } while (!error && !wakeup
236 && suspend_ops->suspend_again && suspend_ops->suspend_again());
239 suspend_test_start();
240 dpm_resume_end(PMSG_RESUME);
241 suspend_test_finish("resume devices");
244 if (suspend_ops->end)
246 trace_machine_suspend(PWR_EVENT_EXIT);
250 if (suspend_ops->recover)
251 suspend_ops->recover();
256 * suspend_finish - Do final work before exiting suspend sequence.
258 * Call platform code to clean up, restart processes, and free the
259 * console that we've allocated. This is not called for suspend-to-disk.
261 static void suspend_finish(void)
263 suspend_thaw_processes();
264 usermodehelper_enable();
265 pm_notifier_call_chain(PM_POST_SUSPEND);
266 pm_restore_console();
270 * enter_state - Do common work of entering low-power state.
271 * @state: pm_state structure for state we're entering.
273 * Make sure we're the only ones trying to enter a sleep state. Fail
274 * if someone has beat us to it, since we don't want anything weird to
275 * happen when we wake up.
276 * Then, do the setup for suspend, enter the state, and cleaup (after
279 int enter_state(suspend_state_t state)
283 if (!valid_state(state))
286 if (!mutex_trylock(&pm_mutex))
289 printk(KERN_INFO "PM: Syncing filesystems ... ");
293 pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
294 error = suspend_prepare();
298 if (suspend_test(TEST_FREEZER))
301 pr_debug("PM: Entering %s sleep\n", pm_states[state]);
302 pm_restrict_gfp_mask();
303 error = suspend_devices_and_enter(state);
304 pm_restore_gfp_mask();
307 pr_debug("PM: Finishing wakeup.\n");
310 mutex_unlock(&pm_mutex);
315 * pm_suspend - Externally visible function for suspending system.
316 * @state: Enumerated value of state to enter.
318 * Determine whether or not value is within range, get state
319 * structure, and enter (above).
321 int pm_suspend(suspend_state_t state)
324 if (state > PM_SUSPEND_ON && state < PM_SUSPEND_MAX) {
325 ret = enter_state(state);
327 suspend_stats.fail++;
328 dpm_save_failed_errno(ret);
330 suspend_stats.success++;
335 EXPORT_SYMBOL(pm_suspend);