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 
37 const char * const pm_labels[] = {
38 	[PM_SUSPEND_TO_IDLE] = "freeze",
39 	[PM_SUSPEND_STANDBY] = "standby",
40 	[PM_SUSPEND_MEM] = "mem",
41 };
42 const char *pm_states[PM_SUSPEND_MAX];
43 static const char * const mem_sleep_labels[] = {
44 	[PM_SUSPEND_TO_IDLE] = "s2idle",
45 	[PM_SUSPEND_STANDBY] = "shallow",
46 	[PM_SUSPEND_MEM] = "deep",
47 };
48 const char *mem_sleep_states[PM_SUSPEND_MAX];
49 
50 suspend_state_t mem_sleep_current = PM_SUSPEND_TO_IDLE;
51 suspend_state_t mem_sleep_default = PM_SUSPEND_MAX;
52 suspend_state_t pm_suspend_target_state;
53 EXPORT_SYMBOL_GPL(pm_suspend_target_state);
54 
55 unsigned int pm_suspend_global_flags;
56 EXPORT_SYMBOL_GPL(pm_suspend_global_flags);
57 
58 static const struct platform_suspend_ops *suspend_ops;
59 static const struct platform_s2idle_ops *s2idle_ops;
60 static DECLARE_SWAIT_QUEUE_HEAD(s2idle_wait_head);
61 
62 enum s2idle_states __read_mostly s2idle_state;
63 static 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  */
71 bool pm_suspend_default_s2idle(void)
72 {
73 	return mem_sleep_current == PM_SUSPEND_TO_IDLE;
74 }
75 EXPORT_SYMBOL_GPL(pm_suspend_default_s2idle);
76 
77 void 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 
86 static void s2idle_begin(void)
87 {
88 	s2idle_state = S2IDLE_STATE_NONE;
89 }
90 
91 static 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 
133 static 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 
163 void 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 }
174 EXPORT_SYMBOL_GPL(s2idle_wake);
175 
176 static 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 
188 void __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 
200 static 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  */
220 void 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 }
242 EXPORT_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  */
252 int suspend_valid_only_mem(suspend_state_t state)
253 {
254 	return state == PM_SUSPEND_MEM;
255 }
256 EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
257 
258 static 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 
264 static 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 
270 static 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 
276 static 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 
285 static 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 
295 static 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 
301 static 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 
307 static 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 
317 static 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 
325 static void platform_recover(suspend_state_t state)
326 {
327 	if (state != PM_SUSPEND_TO_IDLE && suspend_ops->recover)
328 		suspend_ops->recover();
329 }
330 
331 static 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
338 static unsigned int pm_test_delay = 5;
339 module_param(pm_test_delay, uint, 0644);
340 MODULE_PARM_DESC(pm_test_delay,
341 		 "Number of seconds to wait before resuming from suspend test");
342 #endif
343 
344 static int suspend_test(int level)
345 {
346 #ifdef CONFIG_PM_DEBUG
347 	if (pm_test_level == level) {
348 		pr_info("suspend debug: Waiting for %d second(s).\n",
349 				pm_test_delay);
350 		mdelay(pm_test_delay * 1000);
351 		return 1;
352 	}
353 #endif /* !CONFIG_PM_DEBUG */
354 	return 0;
355 }
356 
357 /**
358  * suspend_prepare - Prepare for entering system sleep state.
359  * @state: Target system sleep state.
360  *
361  * Common code run for every system sleep state that can be entered (except for
362  * hibernation).  Run suspend notifiers, allocate the "suspend" console and
363  * freeze processes.
364  */
365 static int suspend_prepare(suspend_state_t state)
366 {
367 	int error;
368 
369 	if (!sleep_state_supported(state))
370 		return -EPERM;
371 
372 	pm_prepare_console();
373 
374 	error = pm_notifier_call_chain_robust(PM_SUSPEND_PREPARE, PM_POST_SUSPEND);
375 	if (error)
376 		goto Restore;
377 
378 	if (filesystem_freeze_enabled)
379 		filesystems_freeze();
380 	trace_suspend_resume(TPS("freeze_processes"), 0, true);
381 	error = suspend_freeze_processes();
382 	trace_suspend_resume(TPS("freeze_processes"), 0, false);
383 	if (!error)
384 		return 0;
385 
386 	dpm_save_failed_step(SUSPEND_FREEZE);
387 	pm_notifier_call_chain(PM_POST_SUSPEND);
388  Restore:
389 	pm_restore_console();
390 	return error;
391 }
392 
393 /* default implementation */
394 void __weak arch_suspend_disable_irqs(void)
395 {
396 	local_irq_disable();
397 }
398 
399 /* default implementation */
400 void __weak arch_suspend_enable_irqs(void)
401 {
402 	local_irq_enable();
403 }
404 
405 /**
406  * suspend_enter - Make the system enter the given sleep state.
407  * @state: System sleep state to enter.
408  * @wakeup: Returns information that the sleep state should not be re-entered.
409  *
410  * This function should be called after devices have been suspended.
411  */
412 static int suspend_enter(suspend_state_t state, bool *wakeup)
413 {
414 	int error;
415 
416 	error = platform_suspend_prepare(state);
417 	if (error)
418 		goto Platform_finish;
419 
420 	error = dpm_suspend_late(PMSG_SUSPEND);
421 	if (error) {
422 		pr_err("late suspend of devices failed\n");
423 		goto Platform_finish;
424 	}
425 	error = platform_suspend_prepare_late(state);
426 	if (error)
427 		goto Devices_early_resume;
428 
429 	error = dpm_suspend_noirq(PMSG_SUSPEND);
430 	if (error) {
431 		pr_err("noirq suspend of devices failed\n");
432 		goto Platform_early_resume;
433 	}
434 	error = platform_suspend_prepare_noirq(state);
435 	if (error)
436 		goto Platform_wake;
437 
438 	if (suspend_test(TEST_PLATFORM))
439 		goto Platform_wake;
440 
441 	if (state == PM_SUSPEND_TO_IDLE) {
442 		s2idle_loop();
443 		goto Platform_wake;
444 	}
445 
446 	error = pm_sleep_disable_secondary_cpus();
447 	if (error || suspend_test(TEST_CPUS))
448 		goto Enable_cpus;
449 
450 	arch_suspend_disable_irqs();
451 	BUG_ON(!irqs_disabled());
452 
453 	system_state = SYSTEM_SUSPEND;
454 
455 	error = syscore_suspend();
456 	if (!error) {
457 		*wakeup = pm_wakeup_pending();
458 		if (!(suspend_test(TEST_CORE) || *wakeup)) {
459 			trace_suspend_resume(TPS("machine_suspend"),
460 				state, true);
461 			error = suspend_ops->enter(state);
462 			trace_suspend_resume(TPS("machine_suspend"),
463 				state, false);
464 		} else if (*wakeup) {
465 			error = -EBUSY;
466 		}
467 		syscore_resume();
468 	}
469 
470 	system_state = SYSTEM_RUNNING;
471 
472 	arch_suspend_enable_irqs();
473 	BUG_ON(irqs_disabled());
474 
475  Enable_cpus:
476 	pm_sleep_enable_secondary_cpus();
477 
478  Platform_wake:
479 	platform_resume_noirq(state);
480 	dpm_resume_noirq(PMSG_RESUME);
481 
482  Platform_early_resume:
483 	platform_resume_early(state);
484 
485  Devices_early_resume:
486 	dpm_resume_early(PMSG_RESUME);
487 
488  Platform_finish:
489 	platform_resume_finish(state);
490 	return error;
491 }
492 
493 /**
494  * suspend_devices_and_enter - Suspend devices and enter system sleep state.
495  * @state: System sleep state to enter.
496  */
497 int suspend_devices_and_enter(suspend_state_t state)
498 {
499 	int error;
500 	bool wakeup = false;
501 
502 	if (!sleep_state_supported(state))
503 		return -ENOSYS;
504 
505 	pm_suspend_target_state = state;
506 
507 	if (state == PM_SUSPEND_TO_IDLE)
508 		pm_set_suspend_no_platform();
509 
510 	error = platform_suspend_begin(state);
511 	if (error)
512 		goto Close;
513 
514 	console_suspend_all();
515 	suspend_test_start();
516 	error = dpm_suspend_start(PMSG_SUSPEND);
517 	if (error) {
518 		pr_err("Some devices failed to suspend, or early wake event detected\n");
519 		goto Recover_platform;
520 	}
521 	suspend_test_finish("suspend devices");
522 	if (suspend_test(TEST_DEVICES))
523 		goto Recover_platform;
524 
525 	do {
526 		error = suspend_enter(state, &wakeup);
527 	} while (!error && !wakeup && platform_suspend_again(state));
528 
529  Resume_devices:
530 	suspend_test_start();
531 	dpm_resume_end(PMSG_RESUME);
532 	suspend_test_finish("resume devices");
533 	trace_suspend_resume(TPS("console_resume_all"), state, true);
534 	console_resume_all();
535 	trace_suspend_resume(TPS("console_resume_all"), state, false);
536 
537  Close:
538 	platform_resume_end(state);
539 	pm_suspend_target_state = PM_SUSPEND_ON;
540 	return error;
541 
542  Recover_platform:
543 	platform_recover(state);
544 	goto Resume_devices;
545 }
546 
547 /**
548  * suspend_finish - Clean up before finishing the suspend sequence.
549  *
550  * Call platform code to clean up, restart processes, and free the console that
551  * we've allocated. This routine is not called for hibernation.
552  */
553 static void suspend_finish(void)
554 {
555 	suspend_thaw_processes();
556 	filesystems_thaw();
557 	pm_notifier_call_chain(PM_POST_SUSPEND);
558 	pm_restore_console();
559 }
560 
561 /**
562  * enter_state - Do common work needed to enter system sleep state.
563  * @state: System sleep state to enter.
564  *
565  * Make sure that no one else is trying to put the system into a sleep state.
566  * Fail if that's not the case.  Otherwise, prepare for system suspend, make the
567  * system enter the given sleep state and clean up after wakeup.
568  */
569 static int enter_state(suspend_state_t state)
570 {
571 	int error;
572 
573 	trace_suspend_resume(TPS("suspend_enter"), state, true);
574 	if (state == PM_SUSPEND_TO_IDLE) {
575 #ifdef CONFIG_PM_DEBUG
576 		if (pm_test_level != TEST_NONE && pm_test_level <= TEST_CPUS) {
577 			pr_warn("Unsupported test mode for suspend to idle, please choose none/freezer/devices/platform.\n");
578 			return -EAGAIN;
579 		}
580 #endif
581 	} else if (!valid_state(state)) {
582 		return -EINVAL;
583 	}
584 	if (!mutex_trylock(&system_transition_mutex))
585 		return -EBUSY;
586 
587 	if (state == PM_SUSPEND_TO_IDLE)
588 		s2idle_begin();
589 
590 	if (sync_on_suspend_enabled) {
591 		trace_suspend_resume(TPS("sync_filesystems"), 0, true);
592 		ksys_sync_helper();
593 		trace_suspend_resume(TPS("sync_filesystems"), 0, false);
594 	}
595 	if (filesystem_freeze_enabled)
596 		filesystems_freeze();
597 
598 	pm_pr_dbg("Preparing system for sleep (%s)\n", mem_sleep_labels[state]);
599 	pm_suspend_clear_flags();
600 	error = suspend_prepare(state);
601 	if (error)
602 		goto Unlock;
603 
604 	if (suspend_test(TEST_FREEZER))
605 		goto Finish;
606 
607 	trace_suspend_resume(TPS("suspend_enter"), state, false);
608 	pm_pr_dbg("Suspending system (%s)\n", mem_sleep_labels[state]);
609 	pm_restrict_gfp_mask();
610 	error = suspend_devices_and_enter(state);
611 	pm_restore_gfp_mask();
612 
613  Finish:
614 	events_check_enabled = false;
615 	pm_pr_dbg("Finishing wakeup.\n");
616 	suspend_finish();
617  Unlock:
618 	filesystems_thaw();
619 	mutex_unlock(&system_transition_mutex);
620 	return error;
621 }
622 
623 /**
624  * pm_suspend - Externally visible function for suspending the system.
625  * @state: System sleep state to enter.
626  *
627  * Check if the value of @state represents one of the supported states,
628  * execute enter_state() and update system suspend statistics.
629  */
630 int pm_suspend(suspend_state_t state)
631 {
632 	int error;
633 
634 	if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
635 		return -EINVAL;
636 
637 	pr_info("suspend entry (%s)\n", mem_sleep_labels[state]);
638 	error = enter_state(state);
639 	dpm_save_errno(error);
640 	pr_info("suspend exit\n");
641 	return error;
642 }
643 EXPORT_SYMBOL(pm_suspend);
644