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