xref: /openbmc/linux/kernel/power/suspend.c (revision 9fdfeef4)
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 
34 #include "power.h"
35 
36 const char * const pm_labels[] = {
37 	[PM_SUSPEND_TO_IDLE] = "freeze",
38 	[PM_SUSPEND_STANDBY] = "standby",
39 	[PM_SUSPEND_MEM] = "mem",
40 };
41 const char *pm_states[PM_SUSPEND_MAX];
42 static const char * const mem_sleep_labels[] = {
43 	[PM_SUSPEND_TO_IDLE] = "s2idle",
44 	[PM_SUSPEND_STANDBY] = "shallow",
45 	[PM_SUSPEND_MEM] = "deep",
46 };
47 const char *mem_sleep_states[PM_SUSPEND_MAX];
48 
49 suspend_state_t mem_sleep_current = PM_SUSPEND_TO_IDLE;
50 suspend_state_t mem_sleep_default = PM_SUSPEND_MAX;
51 suspend_state_t pm_suspend_target_state;
52 EXPORT_SYMBOL_GPL(pm_suspend_target_state);
53 
54 unsigned int pm_suspend_global_flags;
55 EXPORT_SYMBOL_GPL(pm_suspend_global_flags);
56 
57 static const struct platform_suspend_ops *suspend_ops;
58 static const struct platform_s2idle_ops *s2idle_ops;
59 static DECLARE_SWAIT_QUEUE_HEAD(s2idle_wait_head);
60 
61 enum s2idle_states __read_mostly s2idle_state;
62 static DEFINE_RAW_SPINLOCK(s2idle_lock);
63 
64 /**
65  * pm_suspend_default_s2idle - Check if suspend-to-idle is the default suspend.
66  *
67  * Return 'true' if suspend-to-idle has been selected as the default system
68  * suspend method.
69  */
pm_suspend_default_s2idle(void)70 bool pm_suspend_default_s2idle(void)
71 {
72 	return mem_sleep_current == PM_SUSPEND_TO_IDLE;
73 }
74 EXPORT_SYMBOL_GPL(pm_suspend_default_s2idle);
75 
s2idle_set_ops(const struct platform_s2idle_ops * ops)76 void s2idle_set_ops(const struct platform_s2idle_ops *ops)
77 {
78 	unsigned int sleep_flags;
79 
80 	sleep_flags = lock_system_sleep();
81 	s2idle_ops = ops;
82 	unlock_system_sleep(sleep_flags);
83 }
84 
s2idle_begin(void)85 static void s2idle_begin(void)
86 {
87 	s2idle_state = S2IDLE_STATE_NONE;
88 }
89 
s2idle_enter(void)90 static void s2idle_enter(void)
91 {
92 	trace_suspend_resume(TPS("machine_suspend"), PM_SUSPEND_TO_IDLE, true);
93 
94 	raw_spin_lock_irq(&s2idle_lock);
95 	if (pm_wakeup_pending())
96 		goto out;
97 
98 	s2idle_state = S2IDLE_STATE_ENTER;
99 	raw_spin_unlock_irq(&s2idle_lock);
100 
101 	cpus_read_lock();
102 
103 	/* Push all the CPUs into the idle loop. */
104 	wake_up_all_idle_cpus();
105 	/* Make the current CPU wait so it can enter the idle loop too. */
106 	swait_event_exclusive(s2idle_wait_head,
107 		    s2idle_state == S2IDLE_STATE_WAKE);
108 
109 	/*
110 	 * Kick all CPUs to ensure that they resume their timers and restore
111 	 * consistent system state.
112 	 */
113 	wake_up_all_idle_cpus();
114 
115 	cpus_read_unlock();
116 
117 	raw_spin_lock_irq(&s2idle_lock);
118 
119  out:
120 	s2idle_state = S2IDLE_STATE_NONE;
121 	raw_spin_unlock_irq(&s2idle_lock);
122 
123 	trace_suspend_resume(TPS("machine_suspend"), PM_SUSPEND_TO_IDLE, false);
124 }
125 
s2idle_loop(void)126 static void s2idle_loop(void)
127 {
128 	pm_pr_dbg("suspend-to-idle\n");
129 
130 	/*
131 	 * Suspend-to-idle equals:
132 	 * frozen processes + suspended devices + idle processors.
133 	 * Thus s2idle_enter() should be called right after all devices have
134 	 * been suspended.
135 	 *
136 	 * Wakeups during the noirq suspend of devices may be spurious, so try
137 	 * to avoid them upfront.
138 	 */
139 	for (;;) {
140 		if (s2idle_ops && s2idle_ops->wake) {
141 			if (s2idle_ops->wake())
142 				break;
143 		} else if (pm_wakeup_pending()) {
144 			break;
145 		}
146 
147 		if (s2idle_ops && s2idle_ops->check)
148 			s2idle_ops->check();
149 
150 		s2idle_enter();
151 	}
152 
153 	pm_pr_dbg("resume from suspend-to-idle\n");
154 }
155 
s2idle_wake(void)156 void s2idle_wake(void)
157 {
158 	unsigned long flags;
159 
160 	raw_spin_lock_irqsave(&s2idle_lock, flags);
161 	if (s2idle_state > S2IDLE_STATE_NONE) {
162 		s2idle_state = S2IDLE_STATE_WAKE;
163 		swake_up_one(&s2idle_wait_head);
164 	}
165 	raw_spin_unlock_irqrestore(&s2idle_lock, flags);
166 }
167 EXPORT_SYMBOL_GPL(s2idle_wake);
168 
valid_state(suspend_state_t state)169 static bool valid_state(suspend_state_t state)
170 {
171 	/*
172 	 * The PM_SUSPEND_STANDBY and PM_SUSPEND_MEM states require low-level
173 	 * support and need to be valid to the low-level implementation.
174 	 *
175 	 * No ->valid() or ->enter() callback implies that none are valid.
176 	 */
177 	return suspend_ops && suspend_ops->valid && suspend_ops->valid(state) &&
178 		suspend_ops->enter;
179 }
180 
pm_states_init(void)181 void __init pm_states_init(void)
182 {
183 	/* "mem" and "freeze" are always present in /sys/power/state. */
184 	pm_states[PM_SUSPEND_MEM] = pm_labels[PM_SUSPEND_MEM];
185 	pm_states[PM_SUSPEND_TO_IDLE] = pm_labels[PM_SUSPEND_TO_IDLE];
186 	/*
187 	 * Suspend-to-idle should be supported even without any suspend_ops,
188 	 * initialize mem_sleep_states[] accordingly here.
189 	 */
190 	mem_sleep_states[PM_SUSPEND_TO_IDLE] = mem_sleep_labels[PM_SUSPEND_TO_IDLE];
191 }
192 
mem_sleep_default_setup(char * str)193 static int __init mem_sleep_default_setup(char *str)
194 {
195 	suspend_state_t state;
196 
197 	for (state = PM_SUSPEND_TO_IDLE; state <= PM_SUSPEND_MEM; state++)
198 		if (mem_sleep_labels[state] &&
199 		    !strcmp(str, mem_sleep_labels[state])) {
200 			mem_sleep_default = state;
201 			mem_sleep_current = state;
202 			break;
203 		}
204 
205 	return 1;
206 }
207 __setup("mem_sleep_default=", mem_sleep_default_setup);
208 
209 /**
210  * suspend_set_ops - Set the global suspend method table.
211  * @ops: Suspend operations to use.
212  */
suspend_set_ops(const struct platform_suspend_ops * ops)213 void suspend_set_ops(const struct platform_suspend_ops *ops)
214 {
215 	unsigned int sleep_flags;
216 
217 	sleep_flags = lock_system_sleep();
218 
219 	suspend_ops = ops;
220 
221 	if (valid_state(PM_SUSPEND_STANDBY)) {
222 		mem_sleep_states[PM_SUSPEND_STANDBY] = mem_sleep_labels[PM_SUSPEND_STANDBY];
223 		pm_states[PM_SUSPEND_STANDBY] = pm_labels[PM_SUSPEND_STANDBY];
224 		if (mem_sleep_default == PM_SUSPEND_STANDBY)
225 			mem_sleep_current = PM_SUSPEND_STANDBY;
226 	}
227 	if (valid_state(PM_SUSPEND_MEM)) {
228 		mem_sleep_states[PM_SUSPEND_MEM] = mem_sleep_labels[PM_SUSPEND_MEM];
229 		if (mem_sleep_default >= PM_SUSPEND_MEM)
230 			mem_sleep_current = PM_SUSPEND_MEM;
231 	}
232 
233 	unlock_system_sleep(sleep_flags);
234 }
235 EXPORT_SYMBOL_GPL(suspend_set_ops);
236 
237 /**
238  * suspend_valid_only_mem - Generic memory-only valid callback.
239  * @state: Target system sleep state.
240  *
241  * Platform drivers that implement mem suspend only and only need to check for
242  * that in their .valid() callback can use this instead of rolling their own
243  * .valid() callback.
244  */
suspend_valid_only_mem(suspend_state_t state)245 int suspend_valid_only_mem(suspend_state_t state)
246 {
247 	return state == PM_SUSPEND_MEM;
248 }
249 EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
250 
sleep_state_supported(suspend_state_t state)251 static bool sleep_state_supported(suspend_state_t state)
252 {
253 	return state == PM_SUSPEND_TO_IDLE ||
254 	       (valid_state(state) && !cxl_mem_active());
255 }
256 
platform_suspend_prepare(suspend_state_t state)257 static int platform_suspend_prepare(suspend_state_t state)
258 {
259 	return state != PM_SUSPEND_TO_IDLE && suspend_ops->prepare ?
260 		suspend_ops->prepare() : 0;
261 }
262 
platform_suspend_prepare_late(suspend_state_t state)263 static int platform_suspend_prepare_late(suspend_state_t state)
264 {
265 	return state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->prepare ?
266 		s2idle_ops->prepare() : 0;
267 }
268 
platform_suspend_prepare_noirq(suspend_state_t state)269 static int platform_suspend_prepare_noirq(suspend_state_t state)
270 {
271 	if (state == PM_SUSPEND_TO_IDLE)
272 		return s2idle_ops && s2idle_ops->prepare_late ?
273 			s2idle_ops->prepare_late() : 0;
274 
275 	return suspend_ops->prepare_late ? suspend_ops->prepare_late() : 0;
276 }
277 
platform_resume_noirq(suspend_state_t state)278 static void platform_resume_noirq(suspend_state_t state)
279 {
280 	if (state == PM_SUSPEND_TO_IDLE) {
281 		if (s2idle_ops && s2idle_ops->restore_early)
282 			s2idle_ops->restore_early();
283 	} else if (suspend_ops->wake) {
284 		suspend_ops->wake();
285 	}
286 }
287 
platform_resume_early(suspend_state_t state)288 static void platform_resume_early(suspend_state_t state)
289 {
290 	if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->restore)
291 		s2idle_ops->restore();
292 }
293 
platform_resume_finish(suspend_state_t state)294 static void platform_resume_finish(suspend_state_t state)
295 {
296 	if (state != PM_SUSPEND_TO_IDLE && suspend_ops->finish)
297 		suspend_ops->finish();
298 }
299 
platform_suspend_begin(suspend_state_t state)300 static int platform_suspend_begin(suspend_state_t state)
301 {
302 	if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->begin)
303 		return s2idle_ops->begin();
304 	else if (suspend_ops && suspend_ops->begin)
305 		return suspend_ops->begin(state);
306 	else
307 		return 0;
308 }
309 
platform_resume_end(suspend_state_t state)310 static void platform_resume_end(suspend_state_t state)
311 {
312 	if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->end)
313 		s2idle_ops->end();
314 	else if (suspend_ops && suspend_ops->end)
315 		suspend_ops->end();
316 }
317 
platform_recover(suspend_state_t state)318 static void platform_recover(suspend_state_t state)
319 {
320 	if (state != PM_SUSPEND_TO_IDLE && suspend_ops->recover)
321 		suspend_ops->recover();
322 }
323 
platform_suspend_again(suspend_state_t state)324 static bool platform_suspend_again(suspend_state_t state)
325 {
326 	return state != PM_SUSPEND_TO_IDLE && suspend_ops->suspend_again ?
327 		suspend_ops->suspend_again() : false;
328 }
329 
330 #ifdef CONFIG_PM_DEBUG
331 static unsigned int pm_test_delay = 5;
332 module_param(pm_test_delay, uint, 0644);
333 MODULE_PARM_DESC(pm_test_delay,
334 		 "Number of seconds to wait before resuming from suspend test");
335 #endif
336 
suspend_test(int level)337 static int suspend_test(int level)
338 {
339 #ifdef CONFIG_PM_DEBUG
340 	if (pm_test_level == level) {
341 		pr_info("suspend debug: Waiting for %d second(s).\n",
342 				pm_test_delay);
343 		mdelay(pm_test_delay * 1000);
344 		return 1;
345 	}
346 #endif /* !CONFIG_PM_DEBUG */
347 	return 0;
348 }
349 
350 /**
351  * suspend_prepare - Prepare for entering system sleep state.
352  * @state: Target system sleep state.
353  *
354  * Common code run for every system sleep state that can be entered (except for
355  * hibernation).  Run suspend notifiers, allocate the "suspend" console and
356  * freeze processes.
357  */
suspend_prepare(suspend_state_t state)358 static int suspend_prepare(suspend_state_t state)
359 {
360 	int error;
361 
362 	if (!sleep_state_supported(state))
363 		return -EPERM;
364 
365 	pm_prepare_console();
366 
367 	error = pm_notifier_call_chain_robust(PM_SUSPEND_PREPARE, PM_POST_SUSPEND);
368 	if (error)
369 		goto Restore;
370 
371 	trace_suspend_resume(TPS("freeze_processes"), 0, true);
372 	error = suspend_freeze_processes();
373 	trace_suspend_resume(TPS("freeze_processes"), 0, false);
374 	if (!error)
375 		return 0;
376 
377 	suspend_stats.failed_freeze++;
378 	dpm_save_failed_step(SUSPEND_FREEZE);
379 	pm_notifier_call_chain(PM_POST_SUSPEND);
380  Restore:
381 	pm_restore_console();
382 	return error;
383 }
384 
385 /* default implementation */
arch_suspend_disable_irqs(void)386 void __weak arch_suspend_disable_irqs(void)
387 {
388 	local_irq_disable();
389 }
390 
391 /* default implementation */
arch_suspend_enable_irqs(void)392 void __weak arch_suspend_enable_irqs(void)
393 {
394 	local_irq_enable();
395 }
396 
397 /**
398  * suspend_enter - Make the system enter the given sleep state.
399  * @state: System sleep state to enter.
400  * @wakeup: Returns information that the sleep state should not be re-entered.
401  *
402  * This function should be called after devices have been suspended.
403  */
suspend_enter(suspend_state_t state,bool * wakeup)404 static int suspend_enter(suspend_state_t state, bool *wakeup)
405 {
406 	int error;
407 
408 	error = platform_suspend_prepare(state);
409 	if (error)
410 		goto Platform_finish;
411 
412 	error = dpm_suspend_late(PMSG_SUSPEND);
413 	if (error) {
414 		pr_err("late suspend of devices failed\n");
415 		goto Platform_finish;
416 	}
417 	error = platform_suspend_prepare_late(state);
418 	if (error)
419 		goto Devices_early_resume;
420 
421 	error = dpm_suspend_noirq(PMSG_SUSPEND);
422 	if (error) {
423 		pr_err("noirq suspend of devices failed\n");
424 		goto Platform_early_resume;
425 	}
426 	error = platform_suspend_prepare_noirq(state);
427 	if (error)
428 		goto Platform_wake;
429 
430 	if (suspend_test(TEST_PLATFORM))
431 		goto Platform_wake;
432 
433 	if (state == PM_SUSPEND_TO_IDLE) {
434 		s2idle_loop();
435 		goto Platform_wake;
436 	}
437 
438 	error = pm_sleep_disable_secondary_cpus();
439 	if (error || suspend_test(TEST_CPUS))
440 		goto Enable_cpus;
441 
442 	arch_suspend_disable_irqs();
443 	BUG_ON(!irqs_disabled());
444 
445 	system_state = SYSTEM_SUSPEND;
446 
447 	error = syscore_suspend();
448 	if (!error) {
449 		*wakeup = pm_wakeup_pending();
450 		if (!(suspend_test(TEST_CORE) || *wakeup)) {
451 			trace_suspend_resume(TPS("machine_suspend"),
452 				state, true);
453 			error = suspend_ops->enter(state);
454 			trace_suspend_resume(TPS("machine_suspend"),
455 				state, false);
456 		} else if (*wakeup) {
457 			error = -EBUSY;
458 		}
459 		syscore_resume();
460 	}
461 
462 	system_state = SYSTEM_RUNNING;
463 
464 	arch_suspend_enable_irqs();
465 	BUG_ON(irqs_disabled());
466 
467  Enable_cpus:
468 	pm_sleep_enable_secondary_cpus();
469 
470  Platform_wake:
471 	platform_resume_noirq(state);
472 	dpm_resume_noirq(PMSG_RESUME);
473 
474  Platform_early_resume:
475 	platform_resume_early(state);
476 
477  Devices_early_resume:
478 	dpm_resume_early(PMSG_RESUME);
479 
480  Platform_finish:
481 	platform_resume_finish(state);
482 	return error;
483 }
484 
485 /**
486  * suspend_devices_and_enter - Suspend devices and enter system sleep state.
487  * @state: System sleep state to enter.
488  */
suspend_devices_and_enter(suspend_state_t state)489 int suspend_devices_and_enter(suspend_state_t state)
490 {
491 	int error;
492 	bool wakeup = false;
493 
494 	if (!sleep_state_supported(state))
495 		return -ENOSYS;
496 
497 	pm_suspend_target_state = state;
498 
499 	if (state == PM_SUSPEND_TO_IDLE)
500 		pm_set_suspend_no_platform();
501 
502 	error = platform_suspend_begin(state);
503 	if (error)
504 		goto Close;
505 
506 	suspend_console();
507 	suspend_test_start();
508 	error = dpm_suspend_start(PMSG_SUSPEND);
509 	if (error) {
510 		pr_err("Some devices failed to suspend, or early wake event detected\n");
511 		goto Recover_platform;
512 	}
513 	suspend_test_finish("suspend devices");
514 	if (suspend_test(TEST_DEVICES))
515 		goto Recover_platform;
516 
517 	do {
518 		error = suspend_enter(state, &wakeup);
519 	} while (!error && !wakeup && platform_suspend_again(state));
520 
521  Resume_devices:
522 	suspend_test_start();
523 	dpm_resume_end(PMSG_RESUME);
524 	suspend_test_finish("resume devices");
525 	trace_suspend_resume(TPS("resume_console"), state, true);
526 	resume_console();
527 	trace_suspend_resume(TPS("resume_console"), state, false);
528 
529  Close:
530 	platform_resume_end(state);
531 	pm_suspend_target_state = PM_SUSPEND_ON;
532 	return error;
533 
534  Recover_platform:
535 	platform_recover(state);
536 	goto Resume_devices;
537 }
538 
539 /**
540  * suspend_finish - Clean up before finishing the suspend sequence.
541  *
542  * Call platform code to clean up, restart processes, and free the console that
543  * we've allocated. This routine is not called for hibernation.
544  */
suspend_finish(void)545 static void suspend_finish(void)
546 {
547 	suspend_thaw_processes();
548 	pm_notifier_call_chain(PM_POST_SUSPEND);
549 	pm_restore_console();
550 }
551 
552 /**
553  * enter_state - Do common work needed to enter system sleep state.
554  * @state: System sleep state to enter.
555  *
556  * Make sure that no one else is trying to put the system into a sleep state.
557  * Fail if that's not the case.  Otherwise, prepare for system suspend, make the
558  * system enter the given sleep state and clean up after wakeup.
559  */
enter_state(suspend_state_t state)560 static int enter_state(suspend_state_t state)
561 {
562 	int error;
563 
564 	trace_suspend_resume(TPS("suspend_enter"), state, true);
565 	if (state == PM_SUSPEND_TO_IDLE) {
566 #ifdef CONFIG_PM_DEBUG
567 		if (pm_test_level != TEST_NONE && pm_test_level <= TEST_CPUS) {
568 			pr_warn("Unsupported test mode for suspend to idle, please choose none/freezer/devices/platform.\n");
569 			return -EAGAIN;
570 		}
571 #endif
572 	} else if (!valid_state(state)) {
573 		return -EINVAL;
574 	}
575 	if (!mutex_trylock(&system_transition_mutex))
576 		return -EBUSY;
577 
578 	if (state == PM_SUSPEND_TO_IDLE)
579 		s2idle_begin();
580 
581 	if (sync_on_suspend_enabled) {
582 		trace_suspend_resume(TPS("sync_filesystems"), 0, true);
583 		ksys_sync_helper();
584 		trace_suspend_resume(TPS("sync_filesystems"), 0, false);
585 	}
586 
587 	pm_pr_dbg("Preparing system for sleep (%s)\n", mem_sleep_labels[state]);
588 	pm_suspend_clear_flags();
589 	error = suspend_prepare(state);
590 	if (error)
591 		goto Unlock;
592 
593 	if (suspend_test(TEST_FREEZER))
594 		goto Finish;
595 
596 	trace_suspend_resume(TPS("suspend_enter"), state, false);
597 	pm_pr_dbg("Suspending system (%s)\n", mem_sleep_labels[state]);
598 	pm_restrict_gfp_mask();
599 	error = suspend_devices_and_enter(state);
600 	pm_restore_gfp_mask();
601 
602  Finish:
603 	events_check_enabled = false;
604 	pm_pr_dbg("Finishing wakeup.\n");
605 	suspend_finish();
606  Unlock:
607 	mutex_unlock(&system_transition_mutex);
608 	return error;
609 }
610 
611 /**
612  * pm_suspend - Externally visible function for suspending the system.
613  * @state: System sleep state to enter.
614  *
615  * Check if the value of @state represents one of the supported states,
616  * execute enter_state() and update system suspend statistics.
617  */
pm_suspend(suspend_state_t state)618 int pm_suspend(suspend_state_t state)
619 {
620 	int error;
621 
622 	if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
623 		return -EINVAL;
624 
625 	pr_info("suspend entry (%s)\n", mem_sleep_labels[state]);
626 	error = enter_state(state);
627 	if (error) {
628 		suspend_stats.fail++;
629 		dpm_save_failed_errno(error);
630 	} else {
631 		suspend_stats.success++;
632 	}
633 	pr_info("suspend exit\n");
634 	return error;
635 }
636 EXPORT_SYMBOL(pm_suspend);
637