xref: /openbmc/linux/kernel/power/suspend.c (revision dc6a81c3)
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  */
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 
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 
83 static void s2idle_begin(void)
84 {
85 	s2idle_state = S2IDLE_STATE_NONE;
86 }
87 
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 	get_online_cpus();
100 	cpuidle_resume();
101 
102 	/* Push all the CPUs into the idle loop. */
103 	wake_up_all_idle_cpus();
104 	/* Make the current CPU wait so it can enter the idle loop too. */
105 	swait_event_exclusive(s2idle_wait_head,
106 		    s2idle_state == S2IDLE_STATE_WAKE);
107 
108 	cpuidle_pause();
109 	put_online_cpus();
110 
111 	raw_spin_lock_irq(&s2idle_lock);
112 
113  out:
114 	s2idle_state = S2IDLE_STATE_NONE;
115 	raw_spin_unlock_irq(&s2idle_lock);
116 
117 	trace_suspend_resume(TPS("machine_suspend"), PM_SUSPEND_TO_IDLE, false);
118 }
119 
120 static void s2idle_loop(void)
121 {
122 	pm_pr_dbg("suspend-to-idle\n");
123 
124 	/*
125 	 * Suspend-to-idle equals:
126 	 * frozen processes + suspended devices + idle processors.
127 	 * Thus s2idle_enter() should be called right after all devices have
128 	 * been suspended.
129 	 *
130 	 * Wakeups during the noirq suspend of devices may be spurious, so try
131 	 * to avoid them upfront.
132 	 */
133 	for (;;) {
134 		if (s2idle_ops && s2idle_ops->wake)
135 			s2idle_ops->wake();
136 
137 		if (pm_wakeup_pending())
138 			break;
139 
140 		pm_wakeup_clear(false);
141 
142 		s2idle_enter();
143 	}
144 
145 	pm_pr_dbg("resume from suspend-to-idle\n");
146 }
147 
148 void s2idle_wake(void)
149 {
150 	unsigned long flags;
151 
152 	raw_spin_lock_irqsave(&s2idle_lock, flags);
153 	if (s2idle_state > S2IDLE_STATE_NONE) {
154 		s2idle_state = S2IDLE_STATE_WAKE;
155 		swake_up_one(&s2idle_wait_head);
156 	}
157 	raw_spin_unlock_irqrestore(&s2idle_lock, flags);
158 }
159 EXPORT_SYMBOL_GPL(s2idle_wake);
160 
161 static bool valid_state(suspend_state_t state)
162 {
163 	/*
164 	 * PM_SUSPEND_STANDBY and PM_SUSPEND_MEM states need low level
165 	 * support and need to be valid to the low level
166 	 * implementation, no valid callback implies that none are valid.
167 	 */
168 	return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
169 }
170 
171 void __init pm_states_init(void)
172 {
173 	/* "mem" and "freeze" are always present in /sys/power/state. */
174 	pm_states[PM_SUSPEND_MEM] = pm_labels[PM_SUSPEND_MEM];
175 	pm_states[PM_SUSPEND_TO_IDLE] = pm_labels[PM_SUSPEND_TO_IDLE];
176 	/*
177 	 * Suspend-to-idle should be supported even without any suspend_ops,
178 	 * initialize mem_sleep_states[] accordingly here.
179 	 */
180 	mem_sleep_states[PM_SUSPEND_TO_IDLE] = mem_sleep_labels[PM_SUSPEND_TO_IDLE];
181 }
182 
183 static int __init mem_sleep_default_setup(char *str)
184 {
185 	suspend_state_t state;
186 
187 	for (state = PM_SUSPEND_TO_IDLE; state <= PM_SUSPEND_MEM; state++)
188 		if (mem_sleep_labels[state] &&
189 		    !strcmp(str, mem_sleep_labels[state])) {
190 			mem_sleep_default = state;
191 			break;
192 		}
193 
194 	return 1;
195 }
196 __setup("mem_sleep_default=", mem_sleep_default_setup);
197 
198 /**
199  * suspend_set_ops - Set the global suspend method table.
200  * @ops: Suspend operations to use.
201  */
202 void suspend_set_ops(const struct platform_suspend_ops *ops)
203 {
204 	lock_system_sleep();
205 
206 	suspend_ops = ops;
207 
208 	if (valid_state(PM_SUSPEND_STANDBY)) {
209 		mem_sleep_states[PM_SUSPEND_STANDBY] = mem_sleep_labels[PM_SUSPEND_STANDBY];
210 		pm_states[PM_SUSPEND_STANDBY] = pm_labels[PM_SUSPEND_STANDBY];
211 		if (mem_sleep_default == PM_SUSPEND_STANDBY)
212 			mem_sleep_current = PM_SUSPEND_STANDBY;
213 	}
214 	if (valid_state(PM_SUSPEND_MEM)) {
215 		mem_sleep_states[PM_SUSPEND_MEM] = mem_sleep_labels[PM_SUSPEND_MEM];
216 		if (mem_sleep_default >= PM_SUSPEND_MEM)
217 			mem_sleep_current = PM_SUSPEND_MEM;
218 	}
219 
220 	unlock_system_sleep();
221 }
222 EXPORT_SYMBOL_GPL(suspend_set_ops);
223 
224 /**
225  * suspend_valid_only_mem - Generic memory-only valid callback.
226  *
227  * Platform drivers that implement mem suspend only and only need to check for
228  * that in their .valid() callback can use this instead of rolling their own
229  * .valid() callback.
230  */
231 int suspend_valid_only_mem(suspend_state_t state)
232 {
233 	return state == PM_SUSPEND_MEM;
234 }
235 EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
236 
237 static bool sleep_state_supported(suspend_state_t state)
238 {
239 	return state == PM_SUSPEND_TO_IDLE || (suspend_ops && suspend_ops->enter);
240 }
241 
242 static int platform_suspend_prepare(suspend_state_t state)
243 {
244 	return state != PM_SUSPEND_TO_IDLE && suspend_ops->prepare ?
245 		suspend_ops->prepare() : 0;
246 }
247 
248 static int platform_suspend_prepare_late(suspend_state_t state)
249 {
250 	return state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->prepare ?
251 		s2idle_ops->prepare() : 0;
252 }
253 
254 static int platform_suspend_prepare_noirq(suspend_state_t state)
255 {
256 	if (state == PM_SUSPEND_TO_IDLE)
257 		return s2idle_ops && s2idle_ops->prepare_late ?
258 			s2idle_ops->prepare_late() : 0;
259 
260 	return suspend_ops->prepare_late ? suspend_ops->prepare_late() : 0;
261 }
262 
263 static void platform_resume_noirq(suspend_state_t state)
264 {
265 	if (state == PM_SUSPEND_TO_IDLE) {
266 		if (s2idle_ops && s2idle_ops->restore_early)
267 			s2idle_ops->restore_early();
268 	} else if (suspend_ops->wake) {
269 		suspend_ops->wake();
270 	}
271 }
272 
273 static void platform_resume_early(suspend_state_t state)
274 {
275 	if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->restore)
276 		s2idle_ops->restore();
277 }
278 
279 static void platform_resume_finish(suspend_state_t state)
280 {
281 	if (state != PM_SUSPEND_TO_IDLE && suspend_ops->finish)
282 		suspend_ops->finish();
283 }
284 
285 static int platform_suspend_begin(suspend_state_t state)
286 {
287 	if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->begin)
288 		return s2idle_ops->begin();
289 	else if (suspend_ops && suspend_ops->begin)
290 		return suspend_ops->begin(state);
291 	else
292 		return 0;
293 }
294 
295 static void platform_resume_end(suspend_state_t state)
296 {
297 	if (state == PM_SUSPEND_TO_IDLE && s2idle_ops && s2idle_ops->end)
298 		s2idle_ops->end();
299 	else if (suspend_ops && suspend_ops->end)
300 		suspend_ops->end();
301 }
302 
303 static void platform_recover(suspend_state_t state)
304 {
305 	if (state != PM_SUSPEND_TO_IDLE && suspend_ops->recover)
306 		suspend_ops->recover();
307 }
308 
309 static bool platform_suspend_again(suspend_state_t state)
310 {
311 	return state != PM_SUSPEND_TO_IDLE && suspend_ops->suspend_again ?
312 		suspend_ops->suspend_again() : false;
313 }
314 
315 #ifdef CONFIG_PM_DEBUG
316 static unsigned int pm_test_delay = 5;
317 module_param(pm_test_delay, uint, 0644);
318 MODULE_PARM_DESC(pm_test_delay,
319 		 "Number of seconds to wait before resuming from suspend test");
320 #endif
321 
322 static int suspend_test(int level)
323 {
324 #ifdef CONFIG_PM_DEBUG
325 	if (pm_test_level == level) {
326 		pr_info("suspend debug: Waiting for %d second(s).\n",
327 				pm_test_delay);
328 		mdelay(pm_test_delay * 1000);
329 		return 1;
330 	}
331 #endif /* !CONFIG_PM_DEBUG */
332 	return 0;
333 }
334 
335 /**
336  * suspend_prepare - Prepare for entering system sleep state.
337  *
338  * Common code run for every system sleep state that can be entered (except for
339  * hibernation).  Run suspend notifiers, allocate the "suspend" console and
340  * freeze processes.
341  */
342 static int suspend_prepare(suspend_state_t state)
343 {
344 	int error, nr_calls = 0;
345 
346 	if (!sleep_state_supported(state))
347 		return -EPERM;
348 
349 	pm_prepare_console();
350 
351 	error = __pm_notifier_call_chain(PM_SUSPEND_PREPARE, -1, &nr_calls);
352 	if (error) {
353 		nr_calls--;
354 		goto Finish;
355 	}
356 
357 	trace_suspend_resume(TPS("freeze_processes"), 0, true);
358 	error = suspend_freeze_processes();
359 	trace_suspend_resume(TPS("freeze_processes"), 0, false);
360 	if (!error)
361 		return 0;
362 
363 	suspend_stats.failed_freeze++;
364 	dpm_save_failed_step(SUSPEND_FREEZE);
365  Finish:
366 	__pm_notifier_call_chain(PM_POST_SUSPEND, nr_calls, NULL);
367 	pm_restore_console();
368 	return error;
369 }
370 
371 /* default implementation */
372 void __weak arch_suspend_disable_irqs(void)
373 {
374 	local_irq_disable();
375 }
376 
377 /* default implementation */
378 void __weak arch_suspend_enable_irqs(void)
379 {
380 	local_irq_enable();
381 }
382 
383 /**
384  * suspend_enter - Make the system enter the given sleep state.
385  * @state: System sleep state to enter.
386  * @wakeup: Returns information that the sleep state should not be re-entered.
387  *
388  * This function should be called after devices have been suspended.
389  */
390 static int suspend_enter(suspend_state_t state, bool *wakeup)
391 {
392 	int error;
393 
394 	error = platform_suspend_prepare(state);
395 	if (error)
396 		goto Platform_finish;
397 
398 	error = dpm_suspend_late(PMSG_SUSPEND);
399 	if (error) {
400 		pr_err("late suspend of devices failed\n");
401 		goto Platform_finish;
402 	}
403 	error = platform_suspend_prepare_late(state);
404 	if (error)
405 		goto Devices_early_resume;
406 
407 	error = dpm_suspend_noirq(PMSG_SUSPEND);
408 	if (error) {
409 		pr_err("noirq suspend of devices failed\n");
410 		goto Platform_early_resume;
411 	}
412 	error = platform_suspend_prepare_noirq(state);
413 	if (error)
414 		goto Platform_wake;
415 
416 	if (suspend_test(TEST_PLATFORM))
417 		goto Platform_wake;
418 
419 	if (state == PM_SUSPEND_TO_IDLE) {
420 		s2idle_loop();
421 		goto Platform_wake;
422 	}
423 
424 	error = suspend_disable_secondary_cpus();
425 	if (error || suspend_test(TEST_CPUS))
426 		goto Enable_cpus;
427 
428 	arch_suspend_disable_irqs();
429 	BUG_ON(!irqs_disabled());
430 
431 	system_state = SYSTEM_SUSPEND;
432 
433 	error = syscore_suspend();
434 	if (!error) {
435 		*wakeup = pm_wakeup_pending();
436 		if (!(suspend_test(TEST_CORE) || *wakeup)) {
437 			trace_suspend_resume(TPS("machine_suspend"),
438 				state, true);
439 			error = suspend_ops->enter(state);
440 			trace_suspend_resume(TPS("machine_suspend"),
441 				state, false);
442 		} else if (*wakeup) {
443 			error = -EBUSY;
444 		}
445 		syscore_resume();
446 	}
447 
448 	system_state = SYSTEM_RUNNING;
449 
450 	arch_suspend_enable_irqs();
451 	BUG_ON(irqs_disabled());
452 
453  Enable_cpus:
454 	suspend_enable_secondary_cpus();
455 
456  Platform_wake:
457 	platform_resume_noirq(state);
458 	dpm_resume_noirq(PMSG_RESUME);
459 
460  Platform_early_resume:
461 	platform_resume_early(state);
462 
463  Devices_early_resume:
464 	dpm_resume_early(PMSG_RESUME);
465 
466  Platform_finish:
467 	platform_resume_finish(state);
468 	return error;
469 }
470 
471 /**
472  * suspend_devices_and_enter - Suspend devices and enter system sleep state.
473  * @state: System sleep state to enter.
474  */
475 int suspend_devices_and_enter(suspend_state_t state)
476 {
477 	int error;
478 	bool wakeup = false;
479 
480 	if (!sleep_state_supported(state))
481 		return -ENOSYS;
482 
483 	pm_suspend_target_state = state;
484 
485 	if (state == PM_SUSPEND_TO_IDLE)
486 		pm_set_suspend_no_platform();
487 
488 	error = platform_suspend_begin(state);
489 	if (error)
490 		goto Close;
491 
492 	suspend_console();
493 	suspend_test_start();
494 	error = dpm_suspend_start(PMSG_SUSPEND);
495 	if (error) {
496 		pr_err("Some devices failed to suspend, or early wake event detected\n");
497 		goto Recover_platform;
498 	}
499 	suspend_test_finish("suspend devices");
500 	if (suspend_test(TEST_DEVICES))
501 		goto Recover_platform;
502 
503 	do {
504 		error = suspend_enter(state, &wakeup);
505 	} while (!error && !wakeup && platform_suspend_again(state));
506 
507  Resume_devices:
508 	suspend_test_start();
509 	dpm_resume_end(PMSG_RESUME);
510 	suspend_test_finish("resume devices");
511 	trace_suspend_resume(TPS("resume_console"), state, true);
512 	resume_console();
513 	trace_suspend_resume(TPS("resume_console"), state, false);
514 
515  Close:
516 	platform_resume_end(state);
517 	pm_suspend_target_state = PM_SUSPEND_ON;
518 	return error;
519 
520  Recover_platform:
521 	platform_recover(state);
522 	goto Resume_devices;
523 }
524 
525 /**
526  * suspend_finish - Clean up before finishing the suspend sequence.
527  *
528  * Call platform code to clean up, restart processes, and free the console that
529  * we've allocated. This routine is not called for hibernation.
530  */
531 static void suspend_finish(void)
532 {
533 	suspend_thaw_processes();
534 	pm_notifier_call_chain(PM_POST_SUSPEND);
535 	pm_restore_console();
536 }
537 
538 /**
539  * enter_state - Do common work needed to enter system sleep state.
540  * @state: System sleep state to enter.
541  *
542  * Make sure that no one else is trying to put the system into a sleep state.
543  * Fail if that's not the case.  Otherwise, prepare for system suspend, make the
544  * system enter the given sleep state and clean up after wakeup.
545  */
546 static int enter_state(suspend_state_t state)
547 {
548 	int error;
549 
550 	trace_suspend_resume(TPS("suspend_enter"), state, true);
551 	if (state == PM_SUSPEND_TO_IDLE) {
552 #ifdef CONFIG_PM_DEBUG
553 		if (pm_test_level != TEST_NONE && pm_test_level <= TEST_CPUS) {
554 			pr_warn("Unsupported test mode for suspend to idle, please choose none/freezer/devices/platform.\n");
555 			return -EAGAIN;
556 		}
557 #endif
558 	} else if (!valid_state(state)) {
559 		return -EINVAL;
560 	}
561 	if (!mutex_trylock(&system_transition_mutex))
562 		return -EBUSY;
563 
564 	if (state == PM_SUSPEND_TO_IDLE)
565 		s2idle_begin();
566 
567 	if (sync_on_suspend_enabled) {
568 		trace_suspend_resume(TPS("sync_filesystems"), 0, true);
569 		ksys_sync_helper();
570 		trace_suspend_resume(TPS("sync_filesystems"), 0, false);
571 	}
572 
573 	pm_pr_dbg("Preparing system for sleep (%s)\n", mem_sleep_labels[state]);
574 	pm_suspend_clear_flags();
575 	error = suspend_prepare(state);
576 	if (error)
577 		goto Unlock;
578 
579 	if (suspend_test(TEST_FREEZER))
580 		goto Finish;
581 
582 	trace_suspend_resume(TPS("suspend_enter"), state, false);
583 	pm_pr_dbg("Suspending system (%s)\n", mem_sleep_labels[state]);
584 	pm_restrict_gfp_mask();
585 	error = suspend_devices_and_enter(state);
586 	pm_restore_gfp_mask();
587 
588  Finish:
589 	events_check_enabled = false;
590 	pm_pr_dbg("Finishing wakeup.\n");
591 	suspend_finish();
592  Unlock:
593 	mutex_unlock(&system_transition_mutex);
594 	return error;
595 }
596 
597 /**
598  * pm_suspend - Externally visible function for suspending the system.
599  * @state: System sleep state to enter.
600  *
601  * Check if the value of @state represents one of the supported states,
602  * execute enter_state() and update system suspend statistics.
603  */
604 int pm_suspend(suspend_state_t state)
605 {
606 	int error;
607 
608 	if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
609 		return -EINVAL;
610 
611 	pr_info("suspend entry (%s)\n", mem_sleep_labels[state]);
612 	error = enter_state(state);
613 	if (error) {
614 		suspend_stats.fail++;
615 		dpm_save_failed_errno(error);
616 	} else {
617 		suspend_stats.success++;
618 	}
619 	pr_info("suspend exit\n");
620 	return error;
621 }
622 EXPORT_SYMBOL(pm_suspend);
623