summaryrefslogtreecommitdiff
path: root/kernel/power/suspend.c
blob: e3ae93bbcb9b50d487727bee16f63f67d66442ac (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
// SPDX-License-Identifier: GPL-2.0-only
/*
 * kernel/power/suspend.c - Suspend to RAM and standby functionality.
 *
 * Copyright (c) 2003 Patrick Mochel
 * Copyright (c) 2003 Open Source Development Lab
 * Copyright (c) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
 */

#define pr_fmt(fmt) "PM: " fmt

#include <linux/string.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/console.h>
#include <linux/cpu.h>
#include <linux/cpuidle.h>
#include <linux/gfp.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/export.h>
#include <linux/suspend.h>
#include <linux/syscore_ops.h>
#include <linux/swait.h>
#include <linux/ftrace.h>
#include <trace/events/power.h>
#include <linux/compiler.h>
#include <linux/moduleparam.h>

#include "power.h"

const char * const pm_labels[] = {
	[PM_SUSPEND_TO_IDLE] = "freeze",
	[PM_SUSPEND_STANDBY] = "standby",
	[PM_SUSPEND_MEM] = "mem",
};
const char *pm_states[PM_SUSPEND_MAX];
static const char * const mem_sleep_labels[] = {
	[PM_SUSPEND_TO_IDLE] = "s2idle",
	[PM_SUSPEND_STANDBY] = "shallow",
	[PM_SUSPEND_MEM] = "deep",
};
const char *mem_sleep_states[PM_SUSPEND_MAX];

suspend_state_t mem_sleep_current = PM_SUSPEND_TO_IDLE;
suspend_state_t mem_sleep_default = PM_SUSPEND_MAX;
suspend_state_t pm_suspend_target_state;
EXPORT_SYMBOL_GPL(pm_suspend_target_state);

unsigned int pm_suspend_global_flags;
EXPORT_SYMBOL_GPL(pm_suspend_global_flags);

static const struct platform_suspend_ops *suspend_ops;
static const struct platform_s2idle_ops *s2idle_ops;
static DECLARE_SWAIT_QUEUE_HEAD(s2idle_wait_head);

enum s2idle_states __read_mostly s2idle_state;
static DEFINE_RAW_SPINLOCK(s2idle_lock);

/**
 * pm_suspend_default_s2idle - Check if suspend-to-idle is the default suspend.
 *
 * Return 'true' if suspend-to-idle has been selected as the default system
 * suspend method.
 */
bool pm_suspend_default_s2idle(void)
{
	return mem_sleep_current == PM_SUSPEND_TO_IDLE;
}
EXPORT_SYMBOL_GPL(pm_suspend_default_s2idle);

void s2idle_set_ops(const struct platform_s2idle_ops *ops)
{
	unsigned int sleep_flags;

	sleep_flags = lock_system_sleep();
	s2idle_ops = ops;
	unlock_system_sleep(sleep_flags);
}

static void s2idle_begin(void)
{
	s2idle_state = S2IDLE_STATE_NONE;
}

static void s2idle_enter(void)
{
	trace_suspend_resume(TPS("machine_suspend"), PM_SUSPEND_TO_IDLE, true);

	raw_spin_lock_irq(&s2idle_lock);
	if (pm_wakeup_pending())
		goto out;

	s2idle_state = S2IDLE_STATE_ENTER;
	raw_spin_unlock_irq(&s2idle_lock);

	cpus_read_lock();

	/* Push all the CPUs into the idle loop. */
	wake_up_all_idle_cpus();
	/* Make the current CPU wait so it can enter the idle loop too. */
	swait_event_exclusive(s2idle_wait_head,
		    s2idle_state == S2IDLE_STATE_WAKE);

	cpus_read_unlock();

	raw_spin_lock_irq(&s2idle_lock);

 out:
	s2idle_state = S2IDLE_STATE_NONE;
	raw_spin_unlock_irq(&s2idle_lock);

	trace_suspend_resume(TPS("machine_suspend"), PM_SUSPEND_TO_IDLE, false);
}

static void s2idle_loop(void)
{
	pm_pr_dbg("suspend-to-idle\n");

	/*
	 * Suspend-to-idle equals:
	 * frozen processes + suspended devices + idle processors.
	 * Thus s2idle_enter() should be called right after all devices have
	 * been suspended.
	 *
	 * Wakeups during the noirq suspend of devices may be spurious, so try
	 * to avoid them upfront.
	 */
	for (;;) {
		if (s2idle_ops && s2idle_ops->wake) {
			if (s2idle_ops->wake())
				break;
		} else if (pm_wakeup_pending()) {
			break;
		}

		if (s2idle_ops && s2idle_ops->check)
			s2idle_ops->check();

		s2idle_enter();
	}

	pm_pr_dbg("resume from suspend-to-idle\n");
}

void s2idle_wake(void)
{
	unsigned long flags;

	raw_spin_lock_irqsave(&s2idle_lock, flags);
	if (s2idle_state > S2IDLE_STATE_NONE) {
		s2idle_state = S2IDLE_STATE_WAKE;
		swake_up_one(&s2idle_wait_head);
	}
	raw_spin_unlock_irqrestore(&s2idle_lock, flags);
}
EXPORT_SYMBOL_GPL(s2idle_wake);

static bool valid_state(suspend_state_t state)
{
	/*
	 * The PM_SUSPEND_STANDBY and PM_SUSPEND_MEM states require low-level
	 * support and need to be valid to the low-level implementation.
	 *
	 * No ->valid() or ->enter() callback implies that none are valid.
	 */
	return suspend_ops && suspend_ops->valid && suspend_ops->valid(state) &&
		suspend_ops->enter;
}

void __init pm_states_init(void)
{
	/* "mem" and "freeze" are always present in /sys/power/state. */
	pm_states[PM_SUSPEND_MEM] = pm_labels[PM_SUSPEND_MEM];
	pm_states[PM_SUSPEND_TO_IDLE] = pm_labels[PM_SUSPEND_TO_IDLE];
	/*
	 * Suspend-to-idle should be supported even without any suspend_ops,
	 * initialize mem_sleep_states[] accordingly here.
	 */
	mem_sleep_states[PM_SUSPEND_TO_IDLE] = mem_sleep_labels[PM_SUSPEND_TO_IDLE];
}

static int __init mem_sleep_default_setup(char *str)
{
	suspend_state_t state;

	for (state = PM_SUSPEND_TO_IDLE; state <= PM_SUSPEND_MEM; state++)
		if (mem_sleep_labels[state] &&
		    !strcmp(str, mem_sleep_labels[state])) {
			mem_sleep_default = state;
			mem_sleep_current = state;
			break;
		}

	return 1;
}
__setup("mem_sleep_default=", mem_sleep_default_setup);

/**
 * suspend_set_ops - Set the global suspend method table.
 * @ops: Suspend operations to use.
 */
void suspend_set_ops(const struct platform_suspend_ops *ops)
{
	unsigned int sleep_flags;

	sleep_flags = lock_system_sleep();

	suspend_ops = ops;

	if (valid_state(PM_SUSPEND_STANDBY)) {
		mem_sleep_states[PM_SUSPEND_STANDBY] = mem_sleep_labels[PM_SUSPEND_STANDBY];
		pm_states[PM_SUSPEND_STANDBY] = pm_labels[PM_SUSPEND_STANDBY];
		if (mem_sleep_default == PM_SUSPEND_STANDBY)
			mem_sleep_current = PM_SUSPEND_STANDBY;
	}
	if (valid_state(PM_SUSPEND_MEM)) {
		mem_sleep_states[PM_SUSPEND_MEM] = mem_sleep_labels[PM_SUSPEND_MEM];
		if (mem_sleep_default >= PM_SUSPEND_MEM)
			mem_sleep_current = PM_SUSPEND_MEM;
	}

	unlock_system_sleep(sleep_flags);
}
EXPORT_SYMBOL_GPL(suspend_set_ops);

/**
 * suspend_valid_only_mem - Generic memory-only valid callback.
 * @state: Target system sleep state.
 *
 * Platform drivers that implement mem suspend only and only need to check for
 * that in their .valid() callback can use this instead of rolling their own
 * .valid() callback.
 */
int suspend_valid_only_mem(suspend_state_t state)
{
	return state == PM_SUSPEND_MEM;
}
EXPORT_SYMBOL_GPL(suspend_valid_only_mem);

static bool sleep_state_supported(suspend_state_t state)
{
	return state == PM_SUSPEND_TO_IDLE ||
	       (valid_state(state) && !cxl_mem_active());
}

static int platform_suspend_prepare(suspend_state_t state)
{
	return state != PM_SUSPEND_TO_IDLE && suspend_ops->prepare ?
		suspend_ops->prepare() : 0;
}

static int platform_suspend_prepare_late(suspend_state_t state)
{
	return state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->prepare ?
		s2idle_ops->prepare() : 0;
}

static int platform_suspend_prepare_noirq(suspend_state_t state)
{
	if (state == PM_SUSPEND_TO_IDLE)
		return s2idle_ops && s2idle_ops->prepare_late ?
			s2idle_ops->prepare_late() : 0;

	return suspend_ops->prepare_late ? suspend_ops->prepare_late() : 0;
}

static void platform_resume_noirq(suspend_state_t state)
{
	if (state == PM_SUSPEND_TO_IDLE) {
		if (s2idle_ops && s2idle_ops->restore_early)
			s2idle_ops->restore_early();
	} else if (suspend_ops->wake) {
		suspend_ops->wake();
	}
}

static void platform_resume_early(suspend_state_t state)
{
	if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->restore)
		s2idle_ops->restore();
}

static void platform_resume_finish(suspend_state_t state)
{
	if (state != PM_SUSPEND_TO_IDLE && suspend_ops->finish)
		suspend_ops->finish();
}

static int platform_suspend_begin(suspend_state_t state)
{
	if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->begin)
		return s2idle_ops->begin();
	else if (suspend_ops && suspend_ops->begin)
		return suspend_ops->begin(state);
	else
		return 0;
}

static void platform_resume_end(suspend_state_t state)
{
	if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->end)
		s2idle_ops->end();
	else if (suspend_ops && suspend_ops->end)
		suspend_ops->end();
}

static void platform_recover(suspend_state_t state)
{
	if (state != PM_SUSPEND_TO_IDLE && suspend_ops->recover)
		suspend_ops->recover();
}

static bool platform_suspend_again(suspend_state_t state)
{
	return state != PM_SUSPEND_TO_IDLE && suspend_ops->suspend_again ?
		suspend_ops->suspend_again() : false;
}

#ifdef CONFIG_PM_DEBUG
static unsigned int pm_test_delay = 5;
module_param(pm_test_delay, uint, 0644);
MODULE_PARM_DESC(pm_test_delay,
		 "Number of seconds to wait before resuming from suspend test");
#endif

static int suspend_test(int level)
{
#ifdef CONFIG_PM_DEBUG
	if (pm_test_level == level) {
		pr_info("suspend debug: Waiting for %d second(s).\n",
				pm_test_delay);
		mdelay(pm_test_delay * 1000);
		return 1;
	}
#endif /* !CONFIG_PM_DEBUG */
	return 0;
}

/**
 * suspend_prepare - Prepare for entering system sleep state.
 * @state: Target system sleep state.
 *
 * Common code run for every system sleep state that can be entered (except for
 * hibernation).  Run suspend notifiers, allocate the "suspend" console and
 * freeze processes.
 */
static int suspend_prepare(suspend_state_t state)
{
	int error;

	if (!sleep_state_supported(state))
		return -EPERM;

	pm_prepare_console();

	error = pm_notifier_call_chain_robust(PM_SUSPEND_PREPARE, PM_POST_SUSPEND);
	if (error)
		goto Restore;

	trace_suspend_resume(TPS("freeze_processes"), 0, true);
	error = suspend_freeze_processes();
	trace_suspend_resume(TPS("freeze_processes"), 0, false);
	if (!error)
		return 0;

	dpm_save_failed_step(SUSPEND_FREEZE);
	pm_notifier_call_chain(PM_POST_SUSPEND);
 Restore:
	pm_restore_console();
	return error;
}

/* default implementation */
void __weak arch_suspend_disable_irqs(void)
{
	local_irq_disable();
}

/* default implementation */
void __weak arch_suspend_enable_irqs(void)
{
	local_irq_enable();
}

/**
 * suspend_enter - Make the system enter the given sleep state.
 * @state: System sleep state to enter.
 * @wakeup: Returns information that the sleep state should not be re-entered.
 *
 * This function should be called after devices have been suspended.
 */
static int suspend_enter(suspend_state_t state, bool *wakeup)
{
	int error;

	error = platform_suspend_prepare(state);
	if (error)
		goto Platform_finish;

	error = dpm_suspend_late(PMSG_SUSPEND);
	if (error) {
		pr_err("late suspend of devices failed\n");
		goto Platform_finish;
	}
	error = platform_suspend_prepare_late(state);
	if (error)
		goto Devices_early_resume;

	error = dpm_suspend_noirq(PMSG_SUSPEND);
	if (error) {
		pr_err("noirq suspend of devices failed\n");
		goto Platform_early_resume;
	}
	error = platform_suspend_prepare_noirq(state);
	if (error)
		goto Platform_wake;

	if (suspend_test(TEST_PLATFORM))
		goto Platform_wake;

	if (state == PM_SUSPEND_TO_IDLE) {
		s2idle_loop();
		goto Platform_wake;
	}

	error = pm_sleep_disable_secondary_cpus();
	if (error || suspend_test(TEST_CPUS))
		goto Enable_cpus;

	arch_suspend_disable_irqs();
	BUG_ON(!irqs_disabled());

	system_state = SYSTEM_SUSPEND;

	error = syscore_suspend();
	if (!error) {
		*wakeup = pm_wakeup_pending();
		if (!(suspend_test(TEST_CORE) || *wakeup)) {
			trace_suspend_resume(TPS("machine_suspend"),
				state, true);
			error = suspend_ops->enter(state);
			trace_suspend_resume(TPS("machine_suspend"),
				state, false);
		} else if (*wakeup) {
			error = -EBUSY;
		}
		syscore_resume();
	}

	system_state = SYSTEM_RUNNING;

	arch_suspend_enable_irqs();
	BUG_ON(irqs_disabled());

 Enable_cpus:
	pm_sleep_enable_secondary_cpus();

 Platform_wake:
	platform_resume_noirq(state);
	dpm_resume_noirq(PMSG_RESUME);

 Platform_early_resume:
	platform_resume_early(state);

 Devices_early_resume:
	dpm_resume_early(PMSG_RESUME);

 Platform_finish:
	platform_resume_finish(state);
	return error;
}

/**
 * suspend_devices_and_enter - Suspend devices and enter system sleep state.
 * @state: System sleep state to enter.
 */
int suspend_devices_and_enter(suspend_state_t state)
{
	int error;
	bool wakeup = false;

	if (!sleep_state_supported(state))
		return -ENOSYS;

	pm_suspend_target_state = state;

	if (state == PM_SUSPEND_TO_IDLE)
		pm_set_suspend_no_platform();

	error = platform_suspend_begin(state);
	if (error)
		goto Close;

	suspend_console();
	suspend_test_start();
	error = dpm_suspend_start(PMSG_SUSPEND);
	if (error) {
		pr_err("Some devices failed to suspend, or early wake event detected\n");
		goto Recover_platform;
	}
	suspend_test_finish("suspend devices");
	if (suspend_test(TEST_DEVICES))
		goto Recover_platform;

	do {
		error = suspend_enter(state, &wakeup);
	} while (!error && !wakeup && platform_suspend_again(state));

 Resume_devices:
	suspend_test_start();
	dpm_resume_end(PMSG_RESUME);
	suspend_test_finish("resume devices");
	trace_suspend_resume(TPS("resume_console"), state, true);
	resume_console();
	trace_suspend_resume(TPS("resume_console"), state, false);

 Close:
	platform_resume_end(state);
	pm_suspend_target_state = PM_SUSPEND_ON;
	return error;

 Recover_platform:
	platform_recover(state);
	goto Resume_devices;
}

/**
 * suspend_finish - Clean up before finishing the suspend sequence.
 *
 * Call platform code to clean up, restart processes, and free the console that
 * we've allocated. This routine is not called for hibernation.
 */
static void suspend_finish(void)
{
	suspend_thaw_processes();
	pm_notifier_call_chain(PM_POST_SUSPEND);
	pm_restore_console();
}

/**
 * enter_state - Do common work needed to enter system sleep state.
 * @state: System sleep state to enter.
 *
 * Make sure that no one else is trying to put the system into a sleep state.
 * Fail if that's not the case.  Otherwise, prepare for system suspend, make the
 * system enter the given sleep state and clean up after wakeup.
 */
static int enter_state(suspend_state_t state)
{
	int error;

	trace_suspend_resume(TPS("suspend_enter"), state, true);
	if (state == PM_SUSPEND_TO_IDLE) {
#ifdef CONFIG_PM_DEBUG
		if (pm_test_level != TEST_NONE && pm_test_level <= TEST_CPUS) {
			pr_warn("Unsupported test mode for suspend to idle, please choose none/freezer/devices/platform.\n");
			return -EAGAIN;
		}
#endif
	} else if (!valid_state(state)) {
		return -EINVAL;
	}
	if (!mutex_trylock(&system_transition_mutex))
		return -EBUSY;

	if (state == PM_SUSPEND_TO_IDLE)
		s2idle_begin();

	if (sync_on_suspend_enabled) {
		trace_suspend_resume(TPS("sync_filesystems"), 0, true);
		ksys_sync_helper();
		trace_suspend_resume(TPS("sync_filesystems"), 0, false);
	}

	pm_pr_dbg("Preparing system for sleep (%s)\n", mem_sleep_labels[state]);
	pm_suspend_clear_flags();
	error = suspend_prepare(state);
	if (error)
		goto Unlock;

	if (suspend_test(TEST_FREEZER))
		goto Finish;

	trace_suspend_resume(TPS("suspend_enter"), state, false);
	pm_pr_dbg("Suspending system (%s)\n", mem_sleep_labels[state]);
	pm_restrict_gfp_mask();
	error = suspend_devices_and_enter(state);
	pm_restore_gfp_mask();

 Finish:
	events_check_enabled = false;
	pm_pr_dbg("Finishing wakeup.\n");
	suspend_finish();
 Unlock:
	mutex_unlock(&system_transition_mutex);
	return error;
}

/**
 * pm_suspend - Externally visible function for suspending the system.
 * @state: System sleep state to enter.
 *
 * Check if the value of @state represents one of the supported states,
 * execute enter_state() and update system suspend statistics.
 */
int pm_suspend(suspend_state_t state)
{
	int error;

	if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
		return -EINVAL;

	pr_info("suspend entry (%s)\n", mem_sleep_labels[state]);
	error = enter_state(state);
	dpm_save_errno(error);
	pr_info("suspend exit\n");
	return error;
}
EXPORT_SYMBOL(pm_suspend);