xref: /linux/kernel/power/suspend.c (revision bcb63314e2c23f1ed622418b65f9409512659c73)
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 
35 const char * const pm_labels[] = {
36 	[PM_SUSPEND_FREEZE] = "freeze",
37 	[PM_SUSPEND_STANDBY] = "standby",
38 	[PM_SUSPEND_MEM] = "mem",
39 };
40 const char *pm_states[PM_SUSPEND_MAX];
41 static const char * const mem_sleep_labels[] = {
42 	[PM_SUSPEND_FREEZE] = "s2idle",
43 	[PM_SUSPEND_STANDBY] = "shallow",
44 	[PM_SUSPEND_MEM] = "deep",
45 };
46 const char *mem_sleep_states[PM_SUSPEND_MAX];
47 
48 suspend_state_t mem_sleep_current = PM_SUSPEND_FREEZE;
49 suspend_state_t mem_sleep_default = PM_SUSPEND_MAX;
50 
51 unsigned int pm_suspend_global_flags;
52 EXPORT_SYMBOL_GPL(pm_suspend_global_flags);
53 
54 static const struct platform_suspend_ops *suspend_ops;
55 static const struct platform_freeze_ops *freeze_ops;
56 static DECLARE_WAIT_QUEUE_HEAD(suspend_freeze_wait_head);
57 
58 enum freeze_state __read_mostly suspend_freeze_state;
59 static DEFINE_SPINLOCK(suspend_freeze_lock);
60 
61 void freeze_set_ops(const struct platform_freeze_ops *ops)
62 {
63 	lock_system_sleep();
64 	freeze_ops = ops;
65 	unlock_system_sleep();
66 }
67 
68 static void freeze_begin(void)
69 {
70 	suspend_freeze_state = FREEZE_STATE_NONE;
71 }
72 
73 static void freeze_enter(void)
74 {
75 	spin_lock_irq(&suspend_freeze_lock);
76 	if (pm_wakeup_pending())
77 		goto out;
78 
79 	suspend_freeze_state = FREEZE_STATE_ENTER;
80 	spin_unlock_irq(&suspend_freeze_lock);
81 
82 	get_online_cpus();
83 	cpuidle_resume();
84 
85 	/* Push all the CPUs into the idle loop. */
86 	wake_up_all_idle_cpus();
87 	pr_debug("PM: suspend-to-idle\n");
88 	/* Make the current CPU wait so it can enter the idle loop too. */
89 	wait_event(suspend_freeze_wait_head,
90 		   suspend_freeze_state == FREEZE_STATE_WAKE);
91 	pr_debug("PM: resume from suspend-to-idle\n");
92 
93 	cpuidle_pause();
94 	put_online_cpus();
95 
96 	spin_lock_irq(&suspend_freeze_lock);
97 
98  out:
99 	suspend_freeze_state = FREEZE_STATE_NONE;
100 	spin_unlock_irq(&suspend_freeze_lock);
101 }
102 
103 void freeze_wake(void)
104 {
105 	unsigned long flags;
106 
107 	spin_lock_irqsave(&suspend_freeze_lock, flags);
108 	if (suspend_freeze_state > FREEZE_STATE_NONE) {
109 		suspend_freeze_state = FREEZE_STATE_WAKE;
110 		wake_up(&suspend_freeze_wait_head);
111 	}
112 	spin_unlock_irqrestore(&suspend_freeze_lock, flags);
113 }
114 EXPORT_SYMBOL_GPL(freeze_wake);
115 
116 static bool valid_state(suspend_state_t state)
117 {
118 	/*
119 	 * PM_SUSPEND_STANDBY and PM_SUSPEND_MEM states need low level
120 	 * support and need to be valid to the low level
121 	 * implementation, no valid callback implies that none are valid.
122 	 */
123 	return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
124 }
125 
126 void __init pm_states_init(void)
127 {
128 	/* "mem" and "freeze" are always present in /sys/power/state. */
129 	pm_states[PM_SUSPEND_MEM] = pm_labels[PM_SUSPEND_MEM];
130 	pm_states[PM_SUSPEND_FREEZE] = pm_labels[PM_SUSPEND_FREEZE];
131 	/*
132 	 * Suspend-to-idle should be supported even without any suspend_ops,
133 	 * initialize mem_sleep_states[] accordingly here.
134 	 */
135 	mem_sleep_states[PM_SUSPEND_FREEZE] = mem_sleep_labels[PM_SUSPEND_FREEZE];
136 }
137 
138 static int __init mem_sleep_default_setup(char *str)
139 {
140 	suspend_state_t state;
141 
142 	for (state = PM_SUSPEND_FREEZE; state <= PM_SUSPEND_MEM; state++)
143 		if (mem_sleep_labels[state] &&
144 		    !strcmp(str, mem_sleep_labels[state])) {
145 			mem_sleep_default = state;
146 			break;
147 		}
148 
149 	return 1;
150 }
151 __setup("mem_sleep_default=", mem_sleep_default_setup);
152 
153 /**
154  * suspend_set_ops - Set the global suspend method table.
155  * @ops: Suspend operations to use.
156  */
157 void suspend_set_ops(const struct platform_suspend_ops *ops)
158 {
159 	lock_system_sleep();
160 
161 	suspend_ops = ops;
162 
163 	if (valid_state(PM_SUSPEND_STANDBY)) {
164 		mem_sleep_states[PM_SUSPEND_STANDBY] = mem_sleep_labels[PM_SUSPEND_STANDBY];
165 		pm_states[PM_SUSPEND_STANDBY] = pm_labels[PM_SUSPEND_STANDBY];
166 		if (mem_sleep_default == PM_SUSPEND_STANDBY)
167 			mem_sleep_current = PM_SUSPEND_STANDBY;
168 	}
169 	if (valid_state(PM_SUSPEND_MEM)) {
170 		mem_sleep_states[PM_SUSPEND_MEM] = mem_sleep_labels[PM_SUSPEND_MEM];
171 		if (mem_sleep_default >= PM_SUSPEND_MEM)
172 			mem_sleep_current = PM_SUSPEND_MEM;
173 	}
174 
175 	unlock_system_sleep();
176 }
177 EXPORT_SYMBOL_GPL(suspend_set_ops);
178 
179 /**
180  * suspend_valid_only_mem - Generic memory-only valid callback.
181  *
182  * Platform drivers that implement mem suspend only and only need to check for
183  * that in their .valid() callback can use this instead of rolling their own
184  * .valid() callback.
185  */
186 int suspend_valid_only_mem(suspend_state_t state)
187 {
188 	return state == PM_SUSPEND_MEM;
189 }
190 EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
191 
192 static bool sleep_state_supported(suspend_state_t state)
193 {
194 	return state == PM_SUSPEND_FREEZE || (suspend_ops && suspend_ops->enter);
195 }
196 
197 static int platform_suspend_prepare(suspend_state_t state)
198 {
199 	return state != PM_SUSPEND_FREEZE && suspend_ops->prepare ?
200 		suspend_ops->prepare() : 0;
201 }
202 
203 static int platform_suspend_prepare_late(suspend_state_t state)
204 {
205 	return state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->prepare ?
206 		freeze_ops->prepare() : 0;
207 }
208 
209 static int platform_suspend_prepare_noirq(suspend_state_t state)
210 {
211 	return state != PM_SUSPEND_FREEZE && suspend_ops->prepare_late ?
212 		suspend_ops->prepare_late() : 0;
213 }
214 
215 static void platform_resume_noirq(suspend_state_t state)
216 {
217 	if (state != PM_SUSPEND_FREEZE && suspend_ops->wake)
218 		suspend_ops->wake();
219 }
220 
221 static void platform_resume_early(suspend_state_t state)
222 {
223 	if (state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->restore)
224 		freeze_ops->restore();
225 }
226 
227 static void platform_resume_finish(suspend_state_t state)
228 {
229 	if (state != PM_SUSPEND_FREEZE && suspend_ops->finish)
230 		suspend_ops->finish();
231 }
232 
233 static int platform_suspend_begin(suspend_state_t state)
234 {
235 	if (state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->begin)
236 		return freeze_ops->begin();
237 	else if (suspend_ops && suspend_ops->begin)
238 		return suspend_ops->begin(state);
239 	else
240 		return 0;
241 }
242 
243 static void platform_resume_end(suspend_state_t state)
244 {
245 	if (state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->end)
246 		freeze_ops->end();
247 	else if (suspend_ops && suspend_ops->end)
248 		suspend_ops->end();
249 }
250 
251 static void platform_recover(suspend_state_t state)
252 {
253 	if (state != PM_SUSPEND_FREEZE && suspend_ops->recover)
254 		suspend_ops->recover();
255 }
256 
257 static bool platform_suspend_again(suspend_state_t state)
258 {
259 	return state != PM_SUSPEND_FREEZE && suspend_ops->suspend_again ?
260 		suspend_ops->suspend_again() : false;
261 }
262 
263 #ifdef CONFIG_PM_DEBUG
264 static unsigned int pm_test_delay = 5;
265 module_param(pm_test_delay, uint, 0644);
266 MODULE_PARM_DESC(pm_test_delay,
267 		 "Number of seconds to wait before resuming from suspend test");
268 #endif
269 
270 static int suspend_test(int level)
271 {
272 #ifdef CONFIG_PM_DEBUG
273 	if (pm_test_level == level) {
274 		pr_info("suspend debug: Waiting for %d second(s).\n",
275 				pm_test_delay);
276 		mdelay(pm_test_delay * 1000);
277 		return 1;
278 	}
279 #endif /* !CONFIG_PM_DEBUG */
280 	return 0;
281 }
282 
283 /**
284  * suspend_prepare - Prepare for entering system sleep state.
285  *
286  * Common code run for every system sleep state that can be entered (except for
287  * hibernation).  Run suspend notifiers, allocate the "suspend" console and
288  * freeze processes.
289  */
290 static int suspend_prepare(suspend_state_t state)
291 {
292 	int error, nr_calls = 0;
293 
294 	if (!sleep_state_supported(state))
295 		return -EPERM;
296 
297 	pm_prepare_console();
298 
299 	error = __pm_notifier_call_chain(PM_SUSPEND_PREPARE, -1, &nr_calls);
300 	if (error) {
301 		nr_calls--;
302 		goto Finish;
303 	}
304 
305 	trace_suspend_resume(TPS("freeze_processes"), 0, true);
306 	error = suspend_freeze_processes();
307 	trace_suspend_resume(TPS("freeze_processes"), 0, false);
308 	if (!error)
309 		return 0;
310 
311 	suspend_stats.failed_freeze++;
312 	dpm_save_failed_step(SUSPEND_FREEZE);
313  Finish:
314 	__pm_notifier_call_chain(PM_POST_SUSPEND, nr_calls, NULL);
315 	pm_restore_console();
316 	return error;
317 }
318 
319 /* default implementation */
320 void __weak arch_suspend_disable_irqs(void)
321 {
322 	local_irq_disable();
323 }
324 
325 /* default implementation */
326 void __weak arch_suspend_enable_irqs(void)
327 {
328 	local_irq_enable();
329 }
330 
331 /**
332  * suspend_enter - Make the system enter the given sleep state.
333  * @state: System sleep state to enter.
334  * @wakeup: Returns information that the sleep state should not be re-entered.
335  *
336  * This function should be called after devices have been suspended.
337  */
338 static int suspend_enter(suspend_state_t state, bool *wakeup)
339 {
340 	int error;
341 
342 	error = platform_suspend_prepare(state);
343 	if (error)
344 		goto Platform_finish;
345 
346 	error = dpm_suspend_late(PMSG_SUSPEND);
347 	if (error) {
348 		pr_err("PM: late suspend of devices failed\n");
349 		goto Platform_finish;
350 	}
351 	error = platform_suspend_prepare_late(state);
352 	if (error)
353 		goto Devices_early_resume;
354 
355 	error = dpm_suspend_noirq(PMSG_SUSPEND);
356 	if (error) {
357 		pr_err("PM: noirq suspend of devices failed\n");
358 		goto Platform_early_resume;
359 	}
360 	error = platform_suspend_prepare_noirq(state);
361 	if (error)
362 		goto Platform_wake;
363 
364 	if (suspend_test(TEST_PLATFORM))
365 		goto Platform_wake;
366 
367 	/*
368 	 * PM_SUSPEND_FREEZE equals
369 	 * frozen processes + suspended devices + idle processors.
370 	 * Thus we should invoke freeze_enter() soon after
371 	 * all the devices are suspended.
372 	 */
373 	if (state == PM_SUSPEND_FREEZE) {
374 		trace_suspend_resume(TPS("machine_suspend"), state, true);
375 		freeze_enter();
376 		trace_suspend_resume(TPS("machine_suspend"), state, false);
377 		goto Platform_wake;
378 	}
379 
380 	error = disable_nonboot_cpus();
381 	if (error || suspend_test(TEST_CPUS))
382 		goto Enable_cpus;
383 
384 	arch_suspend_disable_irqs();
385 	BUG_ON(!irqs_disabled());
386 
387 	error = syscore_suspend();
388 	if (!error) {
389 		*wakeup = pm_wakeup_pending();
390 		if (!(suspend_test(TEST_CORE) || *wakeup)) {
391 			trace_suspend_resume(TPS("machine_suspend"),
392 				state, true);
393 			error = suspend_ops->enter(state);
394 			trace_suspend_resume(TPS("machine_suspend"),
395 				state, false);
396 			events_check_enabled = false;
397 		} else if (*wakeup) {
398 			error = -EBUSY;
399 		}
400 		syscore_resume();
401 	}
402 
403 	arch_suspend_enable_irqs();
404 	BUG_ON(irqs_disabled());
405 
406  Enable_cpus:
407 	enable_nonboot_cpus();
408 
409  Platform_wake:
410 	platform_resume_noirq(state);
411 	dpm_resume_noirq(PMSG_RESUME);
412 
413  Platform_early_resume:
414 	platform_resume_early(state);
415 
416  Devices_early_resume:
417 	dpm_resume_early(PMSG_RESUME);
418 
419  Platform_finish:
420 	platform_resume_finish(state);
421 	return error;
422 }
423 
424 /**
425  * suspend_devices_and_enter - Suspend devices and enter system sleep state.
426  * @state: System sleep state to enter.
427  */
428 int suspend_devices_and_enter(suspend_state_t state)
429 {
430 	int error;
431 	bool wakeup = false;
432 
433 	if (!sleep_state_supported(state))
434 		return -ENOSYS;
435 
436 	error = platform_suspend_begin(state);
437 	if (error)
438 		goto Close;
439 
440 	suspend_console();
441 	suspend_test_start();
442 	error = dpm_suspend_start(PMSG_SUSPEND);
443 	if (error) {
444 		pr_err("PM: Some devices failed to suspend, or early wake event detected\n");
445 		goto Recover_platform;
446 	}
447 	suspend_test_finish("suspend devices");
448 	if (suspend_test(TEST_DEVICES))
449 		goto Recover_platform;
450 
451 	do {
452 		error = suspend_enter(state, &wakeup);
453 	} while (!error && !wakeup && platform_suspend_again(state));
454 
455  Resume_devices:
456 	suspend_test_start();
457 	dpm_resume_end(PMSG_RESUME);
458 	suspend_test_finish("resume devices");
459 	trace_suspend_resume(TPS("resume_console"), state, true);
460 	resume_console();
461 	trace_suspend_resume(TPS("resume_console"), state, false);
462 
463  Close:
464 	platform_resume_end(state);
465 	return error;
466 
467  Recover_platform:
468 	platform_recover(state);
469 	goto Resume_devices;
470 }
471 
472 /**
473  * suspend_finish - Clean up before finishing the suspend sequence.
474  *
475  * Call platform code to clean up, restart processes, and free the console that
476  * we've allocated. This routine is not called for hibernation.
477  */
478 static void suspend_finish(void)
479 {
480 	suspend_thaw_processes();
481 	pm_notifier_call_chain(PM_POST_SUSPEND);
482 	pm_restore_console();
483 }
484 
485 /**
486  * enter_state - Do common work needed to enter system sleep state.
487  * @state: System sleep state to enter.
488  *
489  * Make sure that no one else is trying to put the system into a sleep state.
490  * Fail if that's not the case.  Otherwise, prepare for system suspend, make the
491  * system enter the given sleep state and clean up after wakeup.
492  */
493 static int enter_state(suspend_state_t state)
494 {
495 	int error;
496 
497 	trace_suspend_resume(TPS("suspend_enter"), state, true);
498 	if (state == PM_SUSPEND_FREEZE) {
499 #ifdef CONFIG_PM_DEBUG
500 		if (pm_test_level != TEST_NONE && pm_test_level <= TEST_CPUS) {
501 			pr_warn("PM: Unsupported test mode for suspend to idle, please choose none/freezer/devices/platform.\n");
502 			return -EAGAIN;
503 		}
504 #endif
505 	} else if (!valid_state(state)) {
506 		return -EINVAL;
507 	}
508 	if (!mutex_trylock(&pm_mutex))
509 		return -EBUSY;
510 
511 	if (state == PM_SUSPEND_FREEZE)
512 		freeze_begin();
513 
514 #ifndef CONFIG_SUSPEND_SKIP_SYNC
515 	trace_suspend_resume(TPS("sync_filesystems"), 0, true);
516 	pr_info("PM: Syncing filesystems ... ");
517 	sys_sync();
518 	pr_cont("done.\n");
519 	trace_suspend_resume(TPS("sync_filesystems"), 0, false);
520 #endif
521 
522 	pr_debug("PM: Preparing system for sleep (%s)\n", pm_states[state]);
523 	pm_suspend_clear_flags();
524 	error = suspend_prepare(state);
525 	if (error)
526 		goto Unlock;
527 
528 	if (suspend_test(TEST_FREEZER))
529 		goto Finish;
530 
531 	trace_suspend_resume(TPS("suspend_enter"), state, false);
532 	pr_debug("PM: Suspending system (%s)\n", pm_states[state]);
533 	pm_restrict_gfp_mask();
534 	error = suspend_devices_and_enter(state);
535 	pm_restore_gfp_mask();
536 
537  Finish:
538 	pr_debug("PM: Finishing wakeup.\n");
539 	suspend_finish();
540  Unlock:
541 	mutex_unlock(&pm_mutex);
542 	return error;
543 }
544 
545 /**
546  * pm_suspend - Externally visible function for suspending the system.
547  * @state: System sleep state to enter.
548  *
549  * Check if the value of @state represents one of the supported states,
550  * execute enter_state() and update system suspend statistics.
551  */
552 int pm_suspend(suspend_state_t state)
553 {
554 	int error;
555 
556 	if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
557 		return -EINVAL;
558 
559 	error = enter_state(state);
560 	if (error) {
561 		suspend_stats.fail++;
562 		dpm_save_failed_errno(error);
563 	} else {
564 		suspend_stats.success++;
565 	}
566 	return error;
567 }
568 EXPORT_SYMBOL(pm_suspend);
569