suspend.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * kernel/power/suspend.c - Suspend to RAM and standby functionality.
  4 *
  5 * Copyright (c) 2003 Patrick Mochel
  6 * Copyright (c) 2003 Open Source Development Lab
  7 * Copyright (c) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
  8 */
  9
 10#define pr_fmt(fmt) "PM: " fmt
 11
 12#include <linux/string.h>
 13#include <linux/delay.h>
 14#include <linux/errno.h>
 15#include <linux/init.h>
 16#include <linux/console.h>
 17#include <linux/cpu.h>
 18#include <linux/cpuidle.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/swait.h>
 29#include <linux/ftrace.h>
 30#include <trace/events/power.h>
 31#include <linux/compiler.h>
 32#include <linux/moduleparam.h>
 33#include <linux/fs.h>
 34
 35#include "power.h"
 36
 37const char * const pm_labels[] = {
 38	[PM_SUSPEND_TO_IDLE] = "freeze",
 39	[PM_SUSPEND_STANDBY] = "standby",
 40	[PM_SUSPEND_MEM] = "mem",
 41};
 42const char *pm_states[PM_SUSPEND_MAX];
 43static const char * const mem_sleep_labels[] = {
 44	[PM_SUSPEND_TO_IDLE] = "s2idle",
 45	[PM_SUSPEND_STANDBY] = "shallow",
 46	[PM_SUSPEND_MEM] = "deep",
 47};
 48const char *mem_sleep_states[PM_SUSPEND_MAX];
 49
 50suspend_state_t mem_sleep_current = PM_SUSPEND_TO_IDLE;
 51suspend_state_t mem_sleep_default = PM_SUSPEND_MAX;
 52suspend_state_t pm_suspend_target_state;
 53EXPORT_SYMBOL_GPL(pm_suspend_target_state);
 54
 55unsigned int pm_suspend_global_flags;
 56EXPORT_SYMBOL_GPL(pm_suspend_global_flags);
 57
 58static const struct platform_suspend_ops *suspend_ops;
 59static const struct platform_s2idle_ops *s2idle_ops;
 60static DECLARE_SWAIT_QUEUE_HEAD(s2idle_wait_head);
 61
 62enum s2idle_states __read_mostly s2idle_state;
 63static DEFINE_RAW_SPINLOCK(s2idle_lock);
 64
 65/**
 66 * pm_suspend_default_s2idle - Check if suspend-to-idle is the default suspend.
 67 *
 68 * Return 'true' if suspend-to-idle has been selected as the default system
 69 * suspend method.
 70 */
 71bool pm_suspend_default_s2idle(void)
 72{
 73	return mem_sleep_current == PM_SUSPEND_TO_IDLE;
 74}
 75EXPORT_SYMBOL_GPL(pm_suspend_default_s2idle);
 76
 77void s2idle_set_ops(const struct platform_s2idle_ops *ops)
 78{
 79	unsigned int sleep_flags;
 80
 81	sleep_flags = lock_system_sleep();
 82	s2idle_ops = ops;
 83	unlock_system_sleep(sleep_flags);
 84}
 85
 86static void s2idle_begin(void)
 87{
 88	s2idle_state = S2IDLE_STATE_NONE;
 89}
 90
 91static void s2idle_enter(void)
 92{
 93	trace_suspend_resume(TPS("machine_suspend"), PM_SUSPEND_TO_IDLE, true);
 94
 95	/*
 96	 * The correctness of the code below depends on the number of online
 97	 * CPUs being stable, but CPUs cannot be taken offline or put online
 98	 * while it is running.
 99	 *
100	 * The s2idle_lock must be acquired before the pending wakeup check to
101	 * prevent pm_system_wakeup() from running as a whole between that check
102	 * and the subsequent s2idle_state update in which case a wakeup event
103	 * would get lost.
104	 */
105	raw_spin_lock_irq(&s2idle_lock);
106	if (pm_wakeup_pending())
107		goto out;
108
109	s2idle_state = S2IDLE_STATE_ENTER;
110	raw_spin_unlock_irq(&s2idle_lock);
111
112	/* Push all the CPUs into the idle loop. */
113	wake_up_all_idle_cpus();
114	/* Make the current CPU wait so it can enter the idle loop too. */
115	swait_event_exclusive(s2idle_wait_head,
116		    s2idle_state == S2IDLE_STATE_WAKE);
117
118	/*
119	 * Kick all CPUs to ensure that they resume their timers and restore
120	 * consistent system state.
121	 */
122	wake_up_all_idle_cpus();
123
124	raw_spin_lock_irq(&s2idle_lock);
125
126 out:
127	s2idle_state = S2IDLE_STATE_NONE;
128	raw_spin_unlock_irq(&s2idle_lock);
129
130	trace_suspend_resume(TPS("machine_suspend"), PM_SUSPEND_TO_IDLE, false);
131}
132
133static void s2idle_loop(void)
134{
135	pm_pr_dbg("suspend-to-idle\n");
136
137	/*
138	 * Suspend-to-idle equals:
139	 * frozen processes + suspended devices + idle processors.
140	 * Thus s2idle_enter() should be called right after all devices have
141	 * been suspended.
142	 *
143	 * Wakeups during the noirq suspend of devices may be spurious, so try
144	 * to avoid them upfront.
145	 */
146	for (;;) {
147		if (s2idle_ops && s2idle_ops->wake) {
148			if (s2idle_ops->wake())
149				break;
150		} else if (pm_wakeup_pending()) {
151			break;
152		}
153
154		if (s2idle_ops && s2idle_ops->check)
155			s2idle_ops->check();
156
157		s2idle_enter();
158	}
159
160	pm_pr_dbg("resume from suspend-to-idle\n");
161}
162
163void s2idle_wake(void)
164{
165	unsigned long flags;
166
167	raw_spin_lock_irqsave(&s2idle_lock, flags);
168	if (s2idle_state > S2IDLE_STATE_NONE) {
169		s2idle_state = S2IDLE_STATE_WAKE;
170		swake_up_one(&s2idle_wait_head);
171	}
172	raw_spin_unlock_irqrestore(&s2idle_lock, flags);
173}
174EXPORT_SYMBOL_GPL(s2idle_wake);
175
176static bool valid_state(suspend_state_t state)
177{
178	/*
179	 * The PM_SUSPEND_STANDBY and PM_SUSPEND_MEM states require low-level
180	 * support and need to be valid to the low-level implementation.
181	 *
182	 * No ->valid() or ->enter() callback implies that none are valid.
183	 */
184	return suspend_ops && suspend_ops->valid && suspend_ops->valid(state) &&
185		suspend_ops->enter;
186}
187
188void __init pm_states_init(void)
189{
190	/* "mem" and "freeze" are always present in /sys/power/state. */
191	pm_states[PM_SUSPEND_MEM] = pm_labels[PM_SUSPEND_MEM];
192	pm_states[PM_SUSPEND_TO_IDLE] = pm_labels[PM_SUSPEND_TO_IDLE];
193	/*
194	 * Suspend-to-idle should be supported even without any suspend_ops,
195	 * initialize mem_sleep_states[] accordingly here.
196	 */
197	mem_sleep_states[PM_SUSPEND_TO_IDLE] = mem_sleep_labels[PM_SUSPEND_TO_IDLE];
198}
199
200static int __init mem_sleep_default_setup(char *str)
201{
202	suspend_state_t state;
203
204	for (state = PM_SUSPEND_TO_IDLE; state <= PM_SUSPEND_MEM; state++)
205		if (mem_sleep_labels[state] &&
206		    !strcmp(str, mem_sleep_labels[state])) {
207			mem_sleep_default = state;
208			mem_sleep_current = state;
209			break;
210		}
211
212	return 1;
213}
214__setup("mem_sleep_default=", mem_sleep_default_setup);
215
216/**
217 * suspend_set_ops - Set the global suspend method table.
218 * @ops: Suspend operations to use.
219 */
220void suspend_set_ops(const struct platform_suspend_ops *ops)
221{
222	unsigned int sleep_flags;
223
224	sleep_flags = lock_system_sleep();
225
226	suspend_ops = ops;
227
228	if (valid_state(PM_SUSPEND_STANDBY)) {
229		mem_sleep_states[PM_SUSPEND_STANDBY] = mem_sleep_labels[PM_SUSPEND_STANDBY];
230		pm_states[PM_SUSPEND_STANDBY] = pm_labels[PM_SUSPEND_STANDBY];
231		if (mem_sleep_default == PM_SUSPEND_STANDBY)
232			mem_sleep_current = PM_SUSPEND_STANDBY;
233	}
234	if (valid_state(PM_SUSPEND_MEM)) {
235		mem_sleep_states[PM_SUSPEND_MEM] = mem_sleep_labels[PM_SUSPEND_MEM];
236		if (mem_sleep_default >= PM_SUSPEND_MEM)
237			mem_sleep_current = PM_SUSPEND_MEM;
238	}
239
240	unlock_system_sleep(sleep_flags);
241}
242EXPORT_SYMBOL_GPL(suspend_set_ops);
243
244/**
245 * suspend_valid_only_mem - Generic memory-only valid callback.
246 * @state: Target system sleep state.
247 *
248 * Platform drivers that implement mem suspend only and only need to check for
249 * that in their .valid() callback can use this instead of rolling their own
250 * .valid() callback.
251 */
252int suspend_valid_only_mem(suspend_state_t state)
253{
254	return state == PM_SUSPEND_MEM;
255}
256EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
257
258static bool sleep_state_supported(suspend_state_t state)
259{
260	return state == PM_SUSPEND_TO_IDLE ||
261	       (valid_state(state) && !cxl_mem_active());
262}
263
264static int platform_suspend_prepare(suspend_state_t state)
265{
266	return state != PM_SUSPEND_TO_IDLE && suspend_ops->prepare ?
267		suspend_ops->prepare() : 0;
268}
269
270static int platform_suspend_prepare_late(suspend_state_t state)
271{
272	return state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->prepare ?
273		s2idle_ops->prepare() : 0;
274}
275
276static int platform_suspend_prepare_noirq(suspend_state_t state)
277{
278	if (state == PM_SUSPEND_TO_IDLE)
279		return s2idle_ops && s2idle_ops->prepare_late ?
280			s2idle_ops->prepare_late() : 0;
281
282	return suspend_ops->prepare_late ? suspend_ops->prepare_late() : 0;
283}
284
285static void platform_resume_noirq(suspend_state_t state)
286{
287	if (state == PM_SUSPEND_TO_IDLE) {
288		if (s2idle_ops && s2idle_ops->restore_early)
289			s2idle_ops->restore_early();
290	} else if (suspend_ops->wake) {
291		suspend_ops->wake();
292	}
293}
294
295static void platform_resume_early(suspend_state_t state)
296{
297	if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->restore)
298		s2idle_ops->restore();
299}
300
301static void platform_resume_finish(suspend_state_t state)
302{
303	if (state != PM_SUSPEND_TO_IDLE && suspend_ops->finish)
304		suspend_ops->finish();
305}
306
307static int platform_suspend_begin(suspend_state_t state)
308{
309	if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->begin)
310		return s2idle_ops->begin();
311	else if (suspend_ops && suspend_ops->begin)
312		return suspend_ops->begin(state);
313	else
314		return 0;
315}
316
317static void platform_resume_end(suspend_state_t state)
318{
319	if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->end)
320		s2idle_ops->end();
321	else if (suspend_ops && suspend_ops->end)
322		suspend_ops->end();
323}
324
325static void platform_recover(suspend_state_t state)
326{
327	if (state != PM_SUSPEND_TO_IDLE && suspend_ops->recover)
328		suspend_ops->recover();
329}
330
331static bool platform_suspend_again(suspend_state_t state)
332{
333	return state != PM_SUSPEND_TO_IDLE && suspend_ops->suspend_again ?
334		suspend_ops->suspend_again() : false;
335}
336
337#ifdef CONFIG_PM_DEBUG
338static unsigned int pm_test_delay = 5;
339module_param(pm_test_delay, uint, 0644);
340MODULE_PARM_DESC(pm_test_delay,
341		 "Number of seconds to wait before resuming from suspend test");
342#endif
343
344static int suspend_test(int level)
345{
346#ifdef CONFIG_PM_DEBUG
347	int i;
348
349	if (pm_test_level == level) {
350		pr_info("suspend debug: Waiting for %d second(s).\n",
351				pm_test_delay);
352		for (i = 0; i < pm_test_delay && !pm_wakeup_pending(); i++) {
353			if (level > TEST_CORE)
354				msleep(1000);
355			else
356				mdelay(1000);
357		}
358		return 1;
359	}
360#endif /* !CONFIG_PM_DEBUG */
361	return 0;
362}
363
364/**
365 * suspend_prepare - Prepare for entering system sleep state.
366 * @state: Target system sleep state.
367 *
368 * Common code run for every system sleep state that can be entered (except for
369 * hibernation).  Run suspend notifiers, allocate the "suspend" console and
370 * freeze processes.
371 */
372static int suspend_prepare(suspend_state_t state)
373{
374	int error;
375
376	if (!sleep_state_supported(state))
377		return -EPERM;
378
379	pm_prepare_console();
380
381	error = pm_notifier_call_chain_robust(PM_SUSPEND_PREPARE, PM_POST_SUSPEND);
382	if (error)
383		goto Restore;
384
385	filesystems_freeze(filesystem_freeze_enabled);
386	trace_suspend_resume(TPS("freeze_processes"), 0, true);
387	error = suspend_freeze_processes();
388	trace_suspend_resume(TPS("freeze_processes"), 0, false);
389	if (!error)
390		return 0;
391
392	dpm_save_failed_step(SUSPEND_FREEZE);
393	filesystems_thaw();
394	pm_notifier_call_chain(PM_POST_SUSPEND);
395 Restore:
396	pm_restore_console();
397	return error;
398}
399
400/* default implementation */
401void __weak arch_suspend_disable_irqs(void)
402{
403	local_irq_disable();
404}
405
406/* default implementation */
407void __weak arch_suspend_enable_irqs(void)
408{
409	local_irq_enable();
410}
411
412/**
413 * suspend_enter - Make the system enter the given sleep state.
414 * @state: System sleep state to enter.
415 * @wakeup: Returns information that the sleep state should not be re-entered.
416 *
417 * This function should be called after devices have been suspended.
418 */
419static int suspend_enter(suspend_state_t state, bool *wakeup)
420{
421	int error;
422
423	error = platform_suspend_prepare(state);
424	if (error)
425		goto Platform_finish;
426
427	error = dpm_suspend_late(PMSG_SUSPEND);
428	if (error) {
429		pr_err("late suspend of devices failed\n");
430		goto Platform_finish;
431	}
432	error = platform_suspend_prepare_late(state);
433	if (error)
434		goto Devices_early_resume;
435
436	error = dpm_suspend_noirq(PMSG_SUSPEND);
437	if (error) {
438		pr_err("noirq suspend of devices failed\n");
439		goto Platform_early_resume;
440	}
441	error = platform_suspend_prepare_noirq(state);
442	if (error)
443		goto Platform_wake;
444
445	if (suspend_test(TEST_PLATFORM))
446		goto Platform_wake;
447
448	if (state == PM_SUSPEND_TO_IDLE) {
449		s2idle_loop();
450		goto Platform_wake;
451	}
452
453	error = pm_sleep_disable_secondary_cpus();
454	if (error || suspend_test(TEST_CPUS))
455		goto Enable_cpus;
456
457	arch_suspend_disable_irqs();
458	BUG_ON(!irqs_disabled());
459
460	system_state = SYSTEM_SUSPEND;
461
462	error = syscore_suspend();
463	if (!error) {
464		*wakeup = pm_wakeup_pending();
465		if (!(suspend_test(TEST_CORE) || *wakeup)) {
466			trace_suspend_resume(TPS("machine_suspend"),
467				state, true);
468			error = suspend_ops->enter(state);
469			trace_suspend_resume(TPS("machine_suspend"),
470				state, false);
471		} else if (*wakeup) {
472			error = -EBUSY;
473		}
474		syscore_resume();
475	}
476
477	system_state = SYSTEM_RUNNING;
478
479	arch_suspend_enable_irqs();
480	BUG_ON(irqs_disabled());
481
482 Enable_cpus:
483	pm_sleep_enable_secondary_cpus();
484
485 Platform_wake:
486	platform_resume_noirq(state);
487	dpm_resume_noirq(PMSG_RESUME);
488
489 Platform_early_resume:
490	platform_resume_early(state);
491
492 Devices_early_resume:
493	dpm_resume_early(PMSG_RESUME);
494
495 Platform_finish:
496	platform_resume_finish(state);
497	return error;
498}
499
500/**
501 * suspend_devices_and_enter - Suspend devices and enter system sleep state.
502 * @state: System sleep state to enter.
503 */
504int suspend_devices_and_enter(suspend_state_t state)
505{
506	int error;
507	bool wakeup = false;
508
509	if (!sleep_state_supported(state))
510		return -ENOSYS;
511
512	pm_suspend_target_state = state;
513
514	if (state == PM_SUSPEND_TO_IDLE)
515		pm_set_suspend_no_platform();
516
517	error = platform_suspend_begin(state);
518	if (error)
519		goto Close;
520
521	console_suspend_all();
522	suspend_test_start();
523	error = dpm_suspend_start(PMSG_SUSPEND);
524	if (error) {
525		pr_err("Some devices failed to suspend, or early wake event detected\n");
526		goto Recover_platform;
527	}
528	suspend_test_finish("suspend devices");
529	if (suspend_test(TEST_DEVICES))
530		goto Recover_platform;
531
532	do {
533		error = suspend_enter(state, &wakeup);
534	} while (!error && !wakeup && platform_suspend_again(state));
535
536 Resume_devices:
537	suspend_test_start();
538	dpm_resume_end(PMSG_RESUME);
539	suspend_test_finish("resume devices");
540	trace_suspend_resume(TPS("console_resume_all"), state, true);
541	console_resume_all();
542	trace_suspend_resume(TPS("console_resume_all"), state, false);
543
544 Close:
545	platform_resume_end(state);
546	pm_suspend_target_state = PM_SUSPEND_ON;
547	return error;
548
549 Recover_platform:
550	platform_recover(state);
551	goto Resume_devices;
552}
553
554/**
555 * suspend_finish - Clean up before finishing the suspend sequence.
556 *
557 * Call platform code to clean up, restart processes, and free the console that
558 * we've allocated. This routine is not called for hibernation.
559 */
560static void suspend_finish(void)
561{
562	suspend_thaw_processes();
563	filesystems_thaw();
564	pm_notifier_call_chain(PM_POST_SUSPEND);
565	pm_restore_console();
566}
567
568/**
569 * enter_state - Do common work needed to enter system sleep state.
570 * @state: System sleep state to enter.
571 *
572 * Make sure that no one else is trying to put the system into a sleep state.
573 * Fail if that's not the case.  Otherwise, prepare for system suspend, make the
574 * system enter the given sleep state and clean up after wakeup.
575 */
576static int enter_state(suspend_state_t state)
577{
578	int error;
579
580	trace_suspend_resume(TPS("suspend_enter"), state, true);
581	if (state == PM_SUSPEND_TO_IDLE) {
582#ifdef CONFIG_PM_DEBUG
583		if (pm_test_level != TEST_NONE && pm_test_level <= TEST_CPUS) {
584			pr_warn("Unsupported test mode for suspend to idle, please choose none/freezer/devices/platform.\n");
585			return -EAGAIN;
586		}
587#endif
588	} else if (!valid_state(state)) {
589		return -EINVAL;
590	}
591	if (!mutex_trylock(&system_transition_mutex))
592		return -EBUSY;
593
594	if (state == PM_SUSPEND_TO_IDLE)
595		s2idle_begin();
596
597	if (sync_on_suspend_enabled) {
598		trace_suspend_resume(TPS("sync_filesystems"), 0, true);
599
600		error = pm_sleep_fs_sync();
601		if (error)
602			goto Unlock;
603
604		trace_suspend_resume(TPS("sync_filesystems"), 0, false);
605	}
606
607	pm_pr_dbg("Preparing system for sleep (%s)\n", mem_sleep_labels[state]);
608	pm_suspend_clear_flags();
609	error = suspend_prepare(state);
610	if (error)
611		goto Unlock;
612
613	if (suspend_test(TEST_FREEZER))
614		goto Finish;
615
616	trace_suspend_resume(TPS("suspend_enter"), state, false);
617	pm_pr_dbg("Suspending system (%s)\n", mem_sleep_labels[state]);
618	error = suspend_devices_and_enter(state);
619
620 Finish:
621	events_check_enabled = false;
622	pm_pr_dbg("Finishing wakeup.\n");
623	suspend_finish();
624 Unlock:
625	mutex_unlock(&system_transition_mutex);
626	return error;
627}
628
629/**
630 * pm_suspend - Externally visible function for suspending the system.
631 * @state: System sleep state to enter.
632 *
633 * Check if the value of @state represents one of the supported states,
634 * execute enter_state() and update system suspend statistics.
635 */
636int pm_suspend(suspend_state_t state)
637{
638	int error;
639
640	if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
641		return -EINVAL;
642
643	pr_info("suspend entry (%s)\n", mem_sleep_labels[state]);
644	error = enter_state(state);
645	dpm_save_errno(error);
646	pr_info("suspend exit\n");
647	return error;
648}
649EXPORT_SYMBOL(pm_suspend);