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1/*
2 * kernel/power/suspend.c - Suspend to RAM and standby functionality.
3 *
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.
7 *
8 * This file is released under the GPLv2.
9 */
10
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>
19#include <linux/io.h>
20#include <linux/kernel.h>
21#include <linux/list.h>
22#include <linux/mm.h>
23#include <linux/slab.h>
24#include <linux/suspend.h>
25#include <linux/syscore_ops.h>
26#include <trace/events/power.h>
27
28#include "power.h"
29
30const char *const pm_states[PM_SUSPEND_MAX] = {
31 [PM_SUSPEND_STANDBY] = "standby",
32 [PM_SUSPEND_MEM] = "mem",
33};
34
35static const struct platform_suspend_ops *suspend_ops;
36
37/**
38 * suspend_set_ops - Set the global suspend method table.
39 * @ops: Pointer to ops structure.
40 */
41void suspend_set_ops(const struct platform_suspend_ops *ops)
42{
43 mutex_lock(&pm_mutex);
44 suspend_ops = ops;
45 mutex_unlock(&pm_mutex);
46}
47EXPORT_SYMBOL_GPL(suspend_set_ops);
48
49bool valid_state(suspend_state_t state)
50{
51 /*
52 * All states need lowlevel support and need to be valid to the lowlevel
53 * implementation, no valid callback implies that none are valid.
54 */
55 return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
56}
57
58/**
59 * suspend_valid_only_mem - generic memory-only valid callback
60 *
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.
64 */
65int suspend_valid_only_mem(suspend_state_t state)
66{
67 return state == PM_SUSPEND_MEM;
68}
69EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
70
71static int suspend_test(int level)
72{
73#ifdef CONFIG_PM_DEBUG
74 if (pm_test_level == level) {
75 printk(KERN_INFO "suspend debug: Waiting for 5 seconds.\n");
76 mdelay(5000);
77 return 1;
78 }
79#endif /* !CONFIG_PM_DEBUG */
80 return 0;
81}
82
83/**
84 * suspend_prepare - Do prep work before entering low-power state.
85 *
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.
88 */
89static int suspend_prepare(void)
90{
91 int error;
92
93 if (!suspend_ops || !suspend_ops->enter)
94 return -EPERM;
95
96 pm_prepare_console();
97
98 error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
99 if (error)
100 goto Finish;
101
102 error = usermodehelper_disable();
103 if (error)
104 goto Finish;
105
106 error = suspend_freeze_processes();
107 if (!error)
108 return 0;
109
110 suspend_thaw_processes();
111 usermodehelper_enable();
112 Finish:
113 pm_notifier_call_chain(PM_POST_SUSPEND);
114 pm_restore_console();
115 return error;
116}
117
118/* default implementation */
119void __attribute__ ((weak)) arch_suspend_disable_irqs(void)
120{
121 local_irq_disable();
122}
123
124/* default implementation */
125void __attribute__ ((weak)) arch_suspend_enable_irqs(void)
126{
127 local_irq_enable();
128}
129
130/**
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.
134 *
135 * This function should be called after devices have been suspended.
136 */
137static int suspend_enter(suspend_state_t state, bool *wakeup)
138{
139 int error;
140
141 if (suspend_ops->prepare) {
142 error = suspend_ops->prepare();
143 if (error)
144 goto Platform_finish;
145 }
146
147 error = dpm_suspend_noirq(PMSG_SUSPEND);
148 if (error) {
149 printk(KERN_ERR "PM: Some devices failed to power down\n");
150 goto Platform_finish;
151 }
152
153 if (suspend_ops->prepare_late) {
154 error = suspend_ops->prepare_late();
155 if (error)
156 goto Platform_wake;
157 }
158
159 if (suspend_test(TEST_PLATFORM))
160 goto Platform_wake;
161
162 error = disable_nonboot_cpus();
163 if (error || suspend_test(TEST_CPUS))
164 goto Enable_cpus;
165
166 arch_suspend_disable_irqs();
167 BUG_ON(!irqs_disabled());
168
169 error = syscore_suspend();
170 if (!error) {
171 *wakeup = pm_wakeup_pending();
172 if (!(suspend_test(TEST_CORE) || *wakeup)) {
173 error = suspend_ops->enter(state);
174 events_check_enabled = false;
175 }
176 syscore_resume();
177 }
178
179 arch_suspend_enable_irqs();
180 BUG_ON(irqs_disabled());
181
182 Enable_cpus:
183 enable_nonboot_cpus();
184
185 Platform_wake:
186 if (suspend_ops->wake)
187 suspend_ops->wake();
188
189 dpm_resume_noirq(PMSG_RESUME);
190
191 Platform_finish:
192 if (suspend_ops->finish)
193 suspend_ops->finish();
194
195 return error;
196}
197
198/**
199 * suspend_devices_and_enter - suspend devices and enter the desired system
200 * sleep state.
201 * @state: state to enter
202 */
203int suspend_devices_and_enter(suspend_state_t state)
204{
205 int error;
206 bool wakeup = false;
207
208 if (!suspend_ops)
209 return -ENOSYS;
210
211 trace_machine_suspend(state);
212 if (suspend_ops->begin) {
213 error = suspend_ops->begin(state);
214 if (error)
215 goto Close;
216 }
217 suspend_console();
218 suspend_test_start();
219 error = dpm_suspend_start(PMSG_SUSPEND);
220 if (error) {
221 printk(KERN_ERR "PM: Some devices failed to suspend\n");
222 goto Recover_platform;
223 }
224 suspend_test_finish("suspend devices");
225 if (suspend_test(TEST_DEVICES))
226 goto Recover_platform;
227
228 do {
229 error = suspend_enter(state, &wakeup);
230 } while (!error && !wakeup
231 && suspend_ops->suspend_again && suspend_ops->suspend_again());
232
233 Resume_devices:
234 suspend_test_start();
235 dpm_resume_end(PMSG_RESUME);
236 suspend_test_finish("resume devices");
237 resume_console();
238 Close:
239 if (suspend_ops->end)
240 suspend_ops->end();
241 trace_machine_suspend(PWR_EVENT_EXIT);
242 return error;
243
244 Recover_platform:
245 if (suspend_ops->recover)
246 suspend_ops->recover();
247 goto Resume_devices;
248}
249
250/**
251 * suspend_finish - Do final work before exiting suspend sequence.
252 *
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.
255 */
256static void suspend_finish(void)
257{
258 suspend_thaw_processes();
259 usermodehelper_enable();
260 pm_notifier_call_chain(PM_POST_SUSPEND);
261 pm_restore_console();
262}
263
264/**
265 * enter_state - Do common work of entering low-power state.
266 * @state: pm_state structure for state we're entering.
267 *
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
272 * we've woken up).
273 */
274int enter_state(suspend_state_t state)
275{
276 int error;
277
278 if (!valid_state(state))
279 return -ENODEV;
280
281 if (!mutex_trylock(&pm_mutex))
282 return -EBUSY;
283
284 printk(KERN_INFO "PM: Syncing filesystems ... ");
285 sys_sync();
286 printk("done.\n");
287
288 pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
289 error = suspend_prepare();
290 if (error)
291 goto Unlock;
292
293 if (suspend_test(TEST_FREEZER))
294 goto Finish;
295
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();
300
301 Finish:
302 pr_debug("PM: Finishing wakeup.\n");
303 suspend_finish();
304 Unlock:
305 mutex_unlock(&pm_mutex);
306 return error;
307}
308
309/**
310 * pm_suspend - Externally visible function for suspending system.
311 * @state: Enumerated value of state to enter.
312 *
313 * Determine whether or not value is within range, get state
314 * structure, and enter (above).
315 */
316int pm_suspend(suspend_state_t state)
317{
318 if (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX)
319 return enter_state(state);
320 return -EINVAL;
321}
322EXPORT_SYMBOL(pm_suspend);
1/*
2 * kernel/power/suspend.c - Suspend to RAM and standby functionality.
3 *
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.
7 *
8 * This file is released under the GPLv2.
9 */
10
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>
20#include <linux/io.h>
21#include <linux/kernel.h>
22#include <linux/list.h>
23#include <linux/mm.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>
31#include <linux/moduleparam.h>
32
33#include "power.h"
34
35const char *pm_labels[] = { "mem", "standby", "freeze", NULL };
36const char *pm_states[PM_SUSPEND_MAX];
37
38unsigned int pm_suspend_global_flags;
39EXPORT_SYMBOL_GPL(pm_suspend_global_flags);
40
41static const struct platform_suspend_ops *suspend_ops;
42static const struct platform_freeze_ops *freeze_ops;
43static DECLARE_WAIT_QUEUE_HEAD(suspend_freeze_wait_head);
44
45enum freeze_state __read_mostly suspend_freeze_state;
46static DEFINE_SPINLOCK(suspend_freeze_lock);
47
48void freeze_set_ops(const struct platform_freeze_ops *ops)
49{
50 lock_system_sleep();
51 freeze_ops = ops;
52 unlock_system_sleep();
53}
54
55static void freeze_begin(void)
56{
57 suspend_freeze_state = FREEZE_STATE_NONE;
58}
59
60static void freeze_enter(void)
61{
62 spin_lock_irq(&suspend_freeze_lock);
63 if (pm_wakeup_pending())
64 goto out;
65
66 suspend_freeze_state = FREEZE_STATE_ENTER;
67 spin_unlock_irq(&suspend_freeze_lock);
68
69 get_online_cpus();
70 cpuidle_resume();
71
72 /* Push all the CPUs into the idle loop. */
73 wake_up_all_idle_cpus();
74 pr_debug("PM: suspend-to-idle\n");
75 /* Make the current CPU wait so it can enter the idle loop too. */
76 wait_event(suspend_freeze_wait_head,
77 suspend_freeze_state == FREEZE_STATE_WAKE);
78 pr_debug("PM: resume from suspend-to-idle\n");
79
80 cpuidle_pause();
81 put_online_cpus();
82
83 spin_lock_irq(&suspend_freeze_lock);
84
85 out:
86 suspend_freeze_state = FREEZE_STATE_NONE;
87 spin_unlock_irq(&suspend_freeze_lock);
88}
89
90void freeze_wake(void)
91{
92 unsigned long flags;
93
94 spin_lock_irqsave(&suspend_freeze_lock, flags);
95 if (suspend_freeze_state > FREEZE_STATE_NONE) {
96 suspend_freeze_state = FREEZE_STATE_WAKE;
97 wake_up(&suspend_freeze_wait_head);
98 }
99 spin_unlock_irqrestore(&suspend_freeze_lock, flags);
100}
101EXPORT_SYMBOL_GPL(freeze_wake);
102
103static bool valid_state(suspend_state_t state)
104{
105 /*
106 * PM_SUSPEND_STANDBY and PM_SUSPEND_MEM states need low level
107 * support and need to be valid to the low level
108 * implementation, no valid callback implies that none are valid.
109 */
110 return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
111}
112
113/*
114 * If this is set, the "mem" label always corresponds to the deepest sleep state
115 * available, the "standby" label corresponds to the second deepest sleep state
116 * available (if any), and the "freeze" label corresponds to the remaining
117 * available sleep state (if there is one).
118 */
119static bool relative_states;
120
121static int __init sleep_states_setup(char *str)
122{
123 relative_states = !strncmp(str, "1", 1);
124 pm_states[PM_SUSPEND_FREEZE] = pm_labels[relative_states ? 0 : 2];
125 return 1;
126}
127
128__setup("relative_sleep_states=", sleep_states_setup);
129
130/**
131 * suspend_set_ops - Set the global suspend method table.
132 * @ops: Suspend operations to use.
133 */
134void suspend_set_ops(const struct platform_suspend_ops *ops)
135{
136 suspend_state_t i;
137 int j = 0;
138
139 lock_system_sleep();
140
141 suspend_ops = ops;
142 for (i = PM_SUSPEND_MEM; i >= PM_SUSPEND_STANDBY; i--)
143 if (valid_state(i)) {
144 pm_states[i] = pm_labels[j++];
145 } else if (!relative_states) {
146 pm_states[i] = NULL;
147 j++;
148 }
149
150 pm_states[PM_SUSPEND_FREEZE] = pm_labels[j];
151
152 unlock_system_sleep();
153}
154EXPORT_SYMBOL_GPL(suspend_set_ops);
155
156/**
157 * suspend_valid_only_mem - Generic memory-only valid callback.
158 *
159 * Platform drivers that implement mem suspend only and only need to check for
160 * that in their .valid() callback can use this instead of rolling their own
161 * .valid() callback.
162 */
163int suspend_valid_only_mem(suspend_state_t state)
164{
165 return state == PM_SUSPEND_MEM;
166}
167EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
168
169static bool sleep_state_supported(suspend_state_t state)
170{
171 return state == PM_SUSPEND_FREEZE || (suspend_ops && suspend_ops->enter);
172}
173
174static int platform_suspend_prepare(suspend_state_t state)
175{
176 return state != PM_SUSPEND_FREEZE && suspend_ops->prepare ?
177 suspend_ops->prepare() : 0;
178}
179
180static int platform_suspend_prepare_late(suspend_state_t state)
181{
182 return state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->prepare ?
183 freeze_ops->prepare() : 0;
184}
185
186static int platform_suspend_prepare_noirq(suspend_state_t state)
187{
188 return state != PM_SUSPEND_FREEZE && suspend_ops->prepare_late ?
189 suspend_ops->prepare_late() : 0;
190}
191
192static void platform_resume_noirq(suspend_state_t state)
193{
194 if (state != PM_SUSPEND_FREEZE && suspend_ops->wake)
195 suspend_ops->wake();
196}
197
198static void platform_resume_early(suspend_state_t state)
199{
200 if (state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->restore)
201 freeze_ops->restore();
202}
203
204static void platform_resume_finish(suspend_state_t state)
205{
206 if (state != PM_SUSPEND_FREEZE && suspend_ops->finish)
207 suspend_ops->finish();
208}
209
210static int platform_suspend_begin(suspend_state_t state)
211{
212 if (state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->begin)
213 return freeze_ops->begin();
214 else if (suspend_ops->begin)
215 return suspend_ops->begin(state);
216 else
217 return 0;
218}
219
220static void platform_resume_end(suspend_state_t state)
221{
222 if (state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->end)
223 freeze_ops->end();
224 else if (suspend_ops->end)
225 suspend_ops->end();
226}
227
228static void platform_recover(suspend_state_t state)
229{
230 if (state != PM_SUSPEND_FREEZE && suspend_ops->recover)
231 suspend_ops->recover();
232}
233
234static bool platform_suspend_again(suspend_state_t state)
235{
236 return state != PM_SUSPEND_FREEZE && suspend_ops->suspend_again ?
237 suspend_ops->suspend_again() : false;
238}
239
240#ifdef CONFIG_PM_DEBUG
241static unsigned int pm_test_delay = 5;
242module_param(pm_test_delay, uint, 0644);
243MODULE_PARM_DESC(pm_test_delay,
244 "Number of seconds to wait before resuming from suspend test");
245#endif
246
247static int suspend_test(int level)
248{
249#ifdef CONFIG_PM_DEBUG
250 if (pm_test_level == level) {
251 pr_info("suspend debug: Waiting for %d second(s).\n",
252 pm_test_delay);
253 mdelay(pm_test_delay * 1000);
254 return 1;
255 }
256#endif /* !CONFIG_PM_DEBUG */
257 return 0;
258}
259
260/**
261 * suspend_prepare - Prepare for entering system sleep state.
262 *
263 * Common code run for every system sleep state that can be entered (except for
264 * hibernation). Run suspend notifiers, allocate the "suspend" console and
265 * freeze processes.
266 */
267static int suspend_prepare(suspend_state_t state)
268{
269 int error;
270
271 if (!sleep_state_supported(state))
272 return -EPERM;
273
274 pm_prepare_console();
275
276 error = pm_notifier_call_chain(PM_SUSPEND_PREPARE);
277 if (error)
278 goto Finish;
279
280 trace_suspend_resume(TPS("freeze_processes"), 0, true);
281 error = suspend_freeze_processes();
282 trace_suspend_resume(TPS("freeze_processes"), 0, false);
283 if (!error)
284 return 0;
285
286 suspend_stats.failed_freeze++;
287 dpm_save_failed_step(SUSPEND_FREEZE);
288 Finish:
289 pm_notifier_call_chain(PM_POST_SUSPEND);
290 pm_restore_console();
291 return error;
292}
293
294/* default implementation */
295void __weak arch_suspend_disable_irqs(void)
296{
297 local_irq_disable();
298}
299
300/* default implementation */
301void __weak arch_suspend_enable_irqs(void)
302{
303 local_irq_enable();
304}
305
306/**
307 * suspend_enter - Make the system enter the given sleep state.
308 * @state: System sleep state to enter.
309 * @wakeup: Returns information that the sleep state should not be re-entered.
310 *
311 * This function should be called after devices have been suspended.
312 */
313static int suspend_enter(suspend_state_t state, bool *wakeup)
314{
315 int error;
316
317 error = platform_suspend_prepare(state);
318 if (error)
319 goto Platform_finish;
320
321 error = dpm_suspend_late(PMSG_SUSPEND);
322 if (error) {
323 pr_err("PM: late suspend of devices failed\n");
324 goto Platform_finish;
325 }
326 error = platform_suspend_prepare_late(state);
327 if (error)
328 goto Devices_early_resume;
329
330 error = dpm_suspend_noirq(PMSG_SUSPEND);
331 if (error) {
332 pr_err("PM: noirq suspend of devices failed\n");
333 goto Platform_early_resume;
334 }
335 error = platform_suspend_prepare_noirq(state);
336 if (error)
337 goto Platform_wake;
338
339 if (suspend_test(TEST_PLATFORM))
340 goto Platform_wake;
341
342 /*
343 * PM_SUSPEND_FREEZE equals
344 * frozen processes + suspended devices + idle processors.
345 * Thus we should invoke freeze_enter() soon after
346 * all the devices are suspended.
347 */
348 if (state == PM_SUSPEND_FREEZE) {
349 trace_suspend_resume(TPS("machine_suspend"), state, true);
350 freeze_enter();
351 trace_suspend_resume(TPS("machine_suspend"), state, false);
352 goto Platform_wake;
353 }
354
355 error = disable_nonboot_cpus();
356 if (error || suspend_test(TEST_CPUS))
357 goto Enable_cpus;
358
359 arch_suspend_disable_irqs();
360 BUG_ON(!irqs_disabled());
361
362 error = syscore_suspend();
363 if (!error) {
364 *wakeup = pm_wakeup_pending();
365 if (!(suspend_test(TEST_CORE) || *wakeup)) {
366 trace_suspend_resume(TPS("machine_suspend"),
367 state, true);
368 error = suspend_ops->enter(state);
369 trace_suspend_resume(TPS("machine_suspend"),
370 state, false);
371 events_check_enabled = false;
372 } else if (*wakeup) {
373 error = -EBUSY;
374 }
375 syscore_resume();
376 }
377
378 arch_suspend_enable_irqs();
379 BUG_ON(irqs_disabled());
380
381 Enable_cpus:
382 enable_nonboot_cpus();
383
384 Platform_wake:
385 platform_resume_noirq(state);
386 dpm_resume_noirq(PMSG_RESUME);
387
388 Platform_early_resume:
389 platform_resume_early(state);
390
391 Devices_early_resume:
392 dpm_resume_early(PMSG_RESUME);
393
394 Platform_finish:
395 platform_resume_finish(state);
396 return error;
397}
398
399/**
400 * suspend_devices_and_enter - Suspend devices and enter system sleep state.
401 * @state: System sleep state to enter.
402 */
403int suspend_devices_and_enter(suspend_state_t state)
404{
405 int error;
406 bool wakeup = false;
407
408 if (!sleep_state_supported(state))
409 return -ENOSYS;
410
411 error = platform_suspend_begin(state);
412 if (error)
413 goto Close;
414
415 suspend_console();
416 suspend_test_start();
417 error = dpm_suspend_start(PMSG_SUSPEND);
418 if (error) {
419 pr_err("PM: Some devices failed to suspend, or early wake event detected\n");
420 goto Recover_platform;
421 }
422 suspend_test_finish("suspend devices");
423 if (suspend_test(TEST_DEVICES))
424 goto Recover_platform;
425
426 do {
427 error = suspend_enter(state, &wakeup);
428 } while (!error && !wakeup && platform_suspend_again(state));
429
430 Resume_devices:
431 suspend_test_start();
432 dpm_resume_end(PMSG_RESUME);
433 suspend_test_finish("resume devices");
434 trace_suspend_resume(TPS("resume_console"), state, true);
435 resume_console();
436 trace_suspend_resume(TPS("resume_console"), state, false);
437
438 Close:
439 platform_resume_end(state);
440 return error;
441
442 Recover_platform:
443 platform_recover(state);
444 goto Resume_devices;
445}
446
447/**
448 * suspend_finish - Clean up before finishing the suspend sequence.
449 *
450 * Call platform code to clean up, restart processes, and free the console that
451 * we've allocated. This routine is not called for hibernation.
452 */
453static void suspend_finish(void)
454{
455 suspend_thaw_processes();
456 pm_notifier_call_chain(PM_POST_SUSPEND);
457 pm_restore_console();
458}
459
460/**
461 * enter_state - Do common work needed to enter system sleep state.
462 * @state: System sleep state to enter.
463 *
464 * Make sure that no one else is trying to put the system into a sleep state.
465 * Fail if that's not the case. Otherwise, prepare for system suspend, make the
466 * system enter the given sleep state and clean up after wakeup.
467 */
468static int enter_state(suspend_state_t state)
469{
470 int error;
471
472 trace_suspend_resume(TPS("suspend_enter"), state, true);
473 if (state == PM_SUSPEND_FREEZE) {
474#ifdef CONFIG_PM_DEBUG
475 if (pm_test_level != TEST_NONE && pm_test_level <= TEST_CPUS) {
476 pr_warn("PM: Unsupported test mode for suspend to idle, please choose none/freezer/devices/platform.\n");
477 return -EAGAIN;
478 }
479#endif
480 } else if (!valid_state(state)) {
481 return -EINVAL;
482 }
483 if (!mutex_trylock(&pm_mutex))
484 return -EBUSY;
485
486 if (state == PM_SUSPEND_FREEZE)
487 freeze_begin();
488
489#ifndef CONFIG_SUSPEND_SKIP_SYNC
490 trace_suspend_resume(TPS("sync_filesystems"), 0, true);
491 printk(KERN_INFO "PM: Syncing filesystems ... ");
492 sys_sync();
493 printk("done.\n");
494 trace_suspend_resume(TPS("sync_filesystems"), 0, false);
495#endif
496
497 pr_debug("PM: Preparing system for sleep (%s)\n", pm_states[state]);
498 pm_suspend_clear_flags();
499 error = suspend_prepare(state);
500 if (error)
501 goto Unlock;
502
503 if (suspend_test(TEST_FREEZER))
504 goto Finish;
505
506 trace_suspend_resume(TPS("suspend_enter"), state, false);
507 pr_debug("PM: Suspending system (%s)\n", pm_states[state]);
508 pm_restrict_gfp_mask();
509 error = suspend_devices_and_enter(state);
510 pm_restore_gfp_mask();
511
512 Finish:
513 pr_debug("PM: Finishing wakeup.\n");
514 suspend_finish();
515 Unlock:
516 mutex_unlock(&pm_mutex);
517 return error;
518}
519
520/**
521 * pm_suspend - Externally visible function for suspending the system.
522 * @state: System sleep state to enter.
523 *
524 * Check if the value of @state represents one of the supported states,
525 * execute enter_state() and update system suspend statistics.
526 */
527int pm_suspend(suspend_state_t state)
528{
529 int error;
530
531 if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
532 return -EINVAL;
533
534 error = enter_state(state);
535 if (error) {
536 suspend_stats.fail++;
537 dpm_save_failed_errno(error);
538 } else {
539 suspend_stats.success++;
540 }
541 return error;
542}
543EXPORT_SYMBOL(pm_suspend);