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/cpuidle.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 <linux/ftrace.h>
29 #include <trace/events/power.h>
30 #include <linux/compiler.h>
34 const char *pm_labels[] = { "mem", "standby", "freeze", NULL };
35 const char *pm_states[PM_SUSPEND_MAX];
37 static const struct platform_suspend_ops *suspend_ops;
38 static const struct platform_freeze_ops *freeze_ops;
39 static DECLARE_WAIT_QUEUE_HEAD(suspend_freeze_wait_head);
40 static bool suspend_freeze_wake;
42 void freeze_set_ops(const struct platform_freeze_ops *ops)
46 unlock_system_sleep();
49 static void freeze_begin(void)
51 suspend_freeze_wake = false;
54 static void freeze_enter(void)
56 cpuidle_use_deepest_state(true);
58 wait_event(suspend_freeze_wait_head, suspend_freeze_wake);
60 cpuidle_use_deepest_state(false);
63 void freeze_wake(void)
65 suspend_freeze_wake = true;
66 wake_up(&suspend_freeze_wait_head);
68 EXPORT_SYMBOL_GPL(freeze_wake);
70 static bool valid_state(suspend_state_t state)
73 * PM_SUSPEND_STANDBY and PM_SUSPEND_MEM states need low level
74 * support and need to be valid to the low level
75 * implementation, no valid callback implies that none are valid.
77 return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
81 * If this is set, the "mem" label always corresponds to the deepest sleep state
82 * available, the "standby" label corresponds to the second deepest sleep state
83 * available (if any), and the "freeze" label corresponds to the remaining
84 * available sleep state (if there is one).
86 static bool relative_states;
88 static int __init sleep_states_setup(char *str)
90 relative_states = !strncmp(str, "1", 1);
91 pm_states[PM_SUSPEND_FREEZE] = pm_labels[relative_states ? 0 : 2];
95 __setup("relative_sleep_states=", sleep_states_setup);
98 * suspend_set_ops - Set the global suspend method table.
99 * @ops: Suspend operations to use.
101 void suspend_set_ops(const struct platform_suspend_ops *ops)
109 for (i = PM_SUSPEND_MEM; i >= PM_SUSPEND_STANDBY; i--)
110 if (valid_state(i)) {
111 pm_states[i] = pm_labels[j++];
112 } else if (!relative_states) {
117 pm_states[PM_SUSPEND_FREEZE] = pm_labels[j];
119 unlock_system_sleep();
121 EXPORT_SYMBOL_GPL(suspend_set_ops);
124 * suspend_valid_only_mem - Generic memory-only valid callback.
126 * Platform drivers that implement mem suspend only and only need to check for
127 * that in their .valid() callback can use this instead of rolling their own
130 int suspend_valid_only_mem(suspend_state_t state)
132 return state == PM_SUSPEND_MEM;
134 EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
136 static bool sleep_state_supported(suspend_state_t state)
138 return state == PM_SUSPEND_FREEZE || (suspend_ops && suspend_ops->enter);
141 static int platform_suspend_prepare(suspend_state_t state)
143 return state != PM_SUSPEND_FREEZE && suspend_ops->prepare ?
144 suspend_ops->prepare() : 0;
147 static int platform_suspend_prepare_late(suspend_state_t state)
149 return state != PM_SUSPEND_FREEZE && suspend_ops->prepare_late ?
150 suspend_ops->prepare_late() : 0;
153 static void platform_suspend_wake(suspend_state_t state)
155 if (state != PM_SUSPEND_FREEZE && suspend_ops->wake)
159 static void platform_suspend_finish(suspend_state_t state)
161 if (state != PM_SUSPEND_FREEZE && suspend_ops->finish)
162 suspend_ops->finish();
165 static int platform_suspend_begin(suspend_state_t state)
167 if (state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->begin)
168 return freeze_ops->begin();
169 else if (suspend_ops->begin)
170 return suspend_ops->begin(state);
175 static void platform_suspend_end(suspend_state_t state)
177 if (state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->end)
179 else if (suspend_ops->end)
183 static void platform_suspend_recover(suspend_state_t state)
185 if (state != PM_SUSPEND_FREEZE && suspend_ops->recover)
186 suspend_ops->recover();
189 static bool platform_suspend_again(suspend_state_t state)
191 return state != PM_SUSPEND_FREEZE && suspend_ops->suspend_again ?
192 suspend_ops->suspend_again() : false;
195 static int suspend_test(int level)
197 #ifdef CONFIG_PM_DEBUG
198 if (pm_test_level == level) {
199 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
203 #endif /* !CONFIG_PM_DEBUG */
208 * suspend_prepare - Prepare for entering system sleep state.
210 * Common code run for every system sleep state that can be entered (except for
211 * hibernation). Run suspend notifiers, allocate the "suspend" console and
214 static int suspend_prepare(suspend_state_t state)
218 if (!sleep_state_supported(state))
221 pm_prepare_console();
223 error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
227 trace_suspend_resume(TPS("freeze_processes"), 0, true);
228 error = suspend_freeze_processes();
229 trace_suspend_resume(TPS("freeze_processes"), 0, false);
233 suspend_stats.failed_freeze++;
234 dpm_save_failed_step(SUSPEND_FREEZE);
236 pm_notifier_call_chain(PM_POST_SUSPEND);
237 pm_restore_console();
241 /* default implementation */
242 void __weak arch_suspend_disable_irqs(void)
247 /* default implementation */
248 void __weak arch_suspend_enable_irqs(void)
254 * suspend_enter - Make the system enter the given sleep state.
255 * @state: System sleep state to enter.
256 * @wakeup: Returns information that the sleep state should not be re-entered.
258 * This function should be called after devices have been suspended.
260 static int suspend_enter(suspend_state_t state, bool *wakeup)
264 error = platform_suspend_prepare(state);
266 goto Platform_finish;
268 error = dpm_suspend_end(PMSG_SUSPEND);
270 printk(KERN_ERR "PM: Some devices failed to power down\n");
271 goto Platform_finish;
273 error = platform_suspend_prepare_late(state);
277 if (suspend_test(TEST_PLATFORM))
281 * PM_SUSPEND_FREEZE equals
282 * frozen processes + suspended devices + idle processors.
283 * Thus we should invoke freeze_enter() soon after
284 * all the devices are suspended.
286 if (state == PM_SUSPEND_FREEZE) {
287 trace_suspend_resume(TPS("machine_suspend"), state, true);
289 trace_suspend_resume(TPS("machine_suspend"), state, false);
293 error = disable_nonboot_cpus();
294 if (error || suspend_test(TEST_CPUS))
297 arch_suspend_disable_irqs();
298 BUG_ON(!irqs_disabled());
300 error = syscore_suspend();
302 *wakeup = pm_wakeup_pending();
303 if (!(suspend_test(TEST_CORE) || *wakeup)) {
304 trace_suspend_resume(TPS("machine_suspend"),
306 error = suspend_ops->enter(state);
307 trace_suspend_resume(TPS("machine_suspend"),
309 events_check_enabled = false;
314 arch_suspend_enable_irqs();
315 BUG_ON(irqs_disabled());
318 enable_nonboot_cpus();
321 platform_suspend_wake(state);
322 dpm_resume_start(PMSG_RESUME);
325 platform_suspend_finish(state);
330 * suspend_devices_and_enter - Suspend devices and enter system sleep state.
331 * @state: System sleep state to enter.
333 int suspend_devices_and_enter(suspend_state_t state)
338 if (!sleep_state_supported(state))
341 error = platform_suspend_begin(state);
346 suspend_test_start();
347 error = dpm_suspend_start(PMSG_SUSPEND);
349 pr_err("PM: Some devices failed to suspend, or early wake event detected\n");
350 goto Recover_platform;
352 suspend_test_finish("suspend devices");
353 if (suspend_test(TEST_DEVICES))
354 goto Recover_platform;
357 error = suspend_enter(state, &wakeup);
358 } while (!error && !wakeup && platform_suspend_again(state));
361 suspend_test_start();
362 dpm_resume_end(PMSG_RESUME);
363 suspend_test_finish("resume devices");
367 platform_suspend_end(state);
371 platform_suspend_recover(state);
376 * suspend_finish - Clean up before finishing the suspend sequence.
378 * Call platform code to clean up, restart processes, and free the console that
379 * we've allocated. This routine is not called for hibernation.
381 static void suspend_finish(void)
383 suspend_thaw_processes();
384 pm_notifier_call_chain(PM_POST_SUSPEND);
385 pm_restore_console();
389 * enter_state - Do common work needed to enter system sleep state.
390 * @state: System sleep state to enter.
392 * Make sure that no one else is trying to put the system into a sleep state.
393 * Fail if that's not the case. Otherwise, prepare for system suspend, make the
394 * system enter the given sleep state and clean up after wakeup.
396 static int enter_state(suspend_state_t state)
400 trace_suspend_resume(TPS("suspend_enter"), state, true);
401 if (state == PM_SUSPEND_FREEZE) {
402 #ifdef CONFIG_PM_DEBUG
403 if (pm_test_level != TEST_NONE && pm_test_level <= TEST_CPUS) {
404 pr_warning("PM: Unsupported test mode for freeze state,"
405 "please choose none/freezer/devices/platform.\n");
409 } else if (!valid_state(state)) {
412 if (!mutex_trylock(&pm_mutex))
415 if (state == PM_SUSPEND_FREEZE)
418 trace_suspend_resume(TPS("sync_filesystems"), 0, true);
419 printk(KERN_INFO "PM: Syncing filesystems ... ");
422 trace_suspend_resume(TPS("sync_filesystems"), 0, false);
424 pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
425 error = suspend_prepare(state);
429 if (suspend_test(TEST_FREEZER))
432 trace_suspend_resume(TPS("suspend_enter"), state, false);
433 pr_debug("PM: Entering %s sleep\n", pm_states[state]);
434 pm_restrict_gfp_mask();
435 error = suspend_devices_and_enter(state);
436 pm_restore_gfp_mask();
439 pr_debug("PM: Finishing wakeup.\n");
442 mutex_unlock(&pm_mutex);
447 * pm_suspend - Externally visible function for suspending the system.
448 * @state: System sleep state to enter.
450 * Check if the value of @state represents one of the supported states,
451 * execute enter_state() and update system suspend statistics.
453 int pm_suspend(suspend_state_t state)
457 if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
460 error = enter_state(state);
462 suspend_stats.fail++;
463 dpm_save_failed_errno(error);
465 suspend_stats.success++;
469 EXPORT_SYMBOL(pm_suspend);