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 */
pm_suspend_default_s2idle(void)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
s2idle_set_ops(const struct platform_s2idle_ops * ops)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
s2idle_begin(void)86 static void s2idle_begin(void)
87 {
88 s2idle_state = S2IDLE_STATE_NONE;
89 }
90
s2idle_enter(void)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
s2idle_loop(void)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
s2idle_wake(void)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
valid_state(suspend_state_t state)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
pm_states_init(void)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
mem_sleep_default_setup(char * str)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 */
suspend_set_ops(const struct platform_suspend_ops * ops)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 */
suspend_valid_only_mem(suspend_state_t state)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
sleep_state_supported(suspend_state_t state)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
platform_suspend_prepare(suspend_state_t state)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
platform_suspend_prepare_late(suspend_state_t state)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
platform_suspend_prepare_noirq(suspend_state_t state)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
platform_resume_noirq(suspend_state_t state)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
platform_resume_early(suspend_state_t state)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
platform_resume_finish(suspend_state_t state)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
platform_suspend_begin(suspend_state_t state)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
platform_resume_end(suspend_state_t state)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
platform_recover(suspend_state_t state)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
platform_suspend_again(suspend_state_t state)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
suspend_test(int level)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 */
suspend_prepare(suspend_state_t state)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 filesystems_thaw();
388 pm_notifier_call_chain(PM_POST_SUSPEND);
389 Restore:
390 pm_restore_console();
391 return error;
392 }
393
394 /* default implementation */
arch_suspend_disable_irqs(void)395 void __weak arch_suspend_disable_irqs(void)
396 {
397 local_irq_disable();
398 }
399
400 /* default implementation */
arch_suspend_enable_irqs(void)401 void __weak arch_suspend_enable_irqs(void)
402 {
403 local_irq_enable();
404 }
405
406 /**
407 * suspend_enter - Make the system enter the given sleep state.
408 * @state: System sleep state to enter.
409 * @wakeup: Returns information that the sleep state should not be re-entered.
410 *
411 * This function should be called after devices have been suspended.
412 */
suspend_enter(suspend_state_t state,bool * wakeup)413 static int suspend_enter(suspend_state_t state, bool *wakeup)
414 {
415 int error;
416
417 error = platform_suspend_prepare(state);
418 if (error)
419 goto Platform_finish;
420
421 error = dpm_suspend_late(PMSG_SUSPEND);
422 if (error) {
423 pr_err("late suspend of devices failed\n");
424 goto Platform_finish;
425 }
426 error = platform_suspend_prepare_late(state);
427 if (error)
428 goto Devices_early_resume;
429
430 error = dpm_suspend_noirq(PMSG_SUSPEND);
431 if (error) {
432 pr_err("noirq suspend of devices failed\n");
433 goto Platform_early_resume;
434 }
435 error = platform_suspend_prepare_noirq(state);
436 if (error)
437 goto Platform_wake;
438
439 if (suspend_test(TEST_PLATFORM))
440 goto Platform_wake;
441
442 if (state == PM_SUSPEND_TO_IDLE) {
443 s2idle_loop();
444 goto Platform_wake;
445 }
446
447 error = pm_sleep_disable_secondary_cpus();
448 if (error || suspend_test(TEST_CPUS))
449 goto Enable_cpus;
450
451 arch_suspend_disable_irqs();
452 BUG_ON(!irqs_disabled());
453
454 system_state = SYSTEM_SUSPEND;
455
456 error = syscore_suspend();
457 if (!error) {
458 *wakeup = pm_wakeup_pending();
459 if (!(suspend_test(TEST_CORE) || *wakeup)) {
460 trace_suspend_resume(TPS("machine_suspend"),
461 state, true);
462 error = suspend_ops->enter(state);
463 trace_suspend_resume(TPS("machine_suspend"),
464 state, false);
465 } else if (*wakeup) {
466 error = -EBUSY;
467 }
468 syscore_resume();
469 }
470
471 system_state = SYSTEM_RUNNING;
472
473 arch_suspend_enable_irqs();
474 BUG_ON(irqs_disabled());
475
476 Enable_cpus:
477 pm_sleep_enable_secondary_cpus();
478
479 Platform_wake:
480 platform_resume_noirq(state);
481 dpm_resume_noirq(PMSG_RESUME);
482
483 Platform_early_resume:
484 platform_resume_early(state);
485
486 Devices_early_resume:
487 dpm_resume_early(PMSG_RESUME);
488
489 Platform_finish:
490 platform_resume_finish(state);
491 return error;
492 }
493
494 /**
495 * suspend_devices_and_enter - Suspend devices and enter system sleep state.
496 * @state: System sleep state to enter.
497 */
suspend_devices_and_enter(suspend_state_t state)498 int suspend_devices_and_enter(suspend_state_t state)
499 {
500 int error;
501 bool wakeup = false;
502
503 if (!sleep_state_supported(state))
504 return -ENOSYS;
505
506 pm_suspend_target_state = state;
507
508 if (state == PM_SUSPEND_TO_IDLE)
509 pm_set_suspend_no_platform();
510
511 error = platform_suspend_begin(state);
512 if (error)
513 goto Close;
514
515 console_suspend_all();
516 suspend_test_start();
517 error = dpm_suspend_start(PMSG_SUSPEND);
518 if (error) {
519 pr_err("Some devices failed to suspend, or early wake event detected\n");
520 goto Recover_platform;
521 }
522 suspend_test_finish("suspend devices");
523 if (suspend_test(TEST_DEVICES))
524 goto Recover_platform;
525
526 do {
527 error = suspend_enter(state, &wakeup);
528 } while (!error && !wakeup && platform_suspend_again(state));
529
530 Resume_devices:
531 suspend_test_start();
532 dpm_resume_end(PMSG_RESUME);
533 suspend_test_finish("resume devices");
534 trace_suspend_resume(TPS("console_resume_all"), state, true);
535 console_resume_all();
536 trace_suspend_resume(TPS("console_resume_all"), state, false);
537
538 Close:
539 platform_resume_end(state);
540 pm_suspend_target_state = PM_SUSPEND_ON;
541 return error;
542
543 Recover_platform:
544 platform_recover(state);
545 goto Resume_devices;
546 }
547
548 /**
549 * suspend_finish - Clean up before finishing the suspend sequence.
550 *
551 * Call platform code to clean up, restart processes, and free the console that
552 * we've allocated. This routine is not called for hibernation.
553 */
suspend_finish(void)554 static void suspend_finish(void)
555 {
556 suspend_thaw_processes();
557 filesystems_thaw();
558 pm_notifier_call_chain(PM_POST_SUSPEND);
559 pm_restore_console();
560 }
561
562 /**
563 * enter_state - Do common work needed to enter system sleep state.
564 * @state: System sleep state to enter.
565 *
566 * Make sure that no one else is trying to put the system into a sleep state.
567 * Fail if that's not the case. Otherwise, prepare for system suspend, make the
568 * system enter the given sleep state and clean up after wakeup.
569 */
enter_state(suspend_state_t state)570 static int enter_state(suspend_state_t state)
571 {
572 int error;
573
574 trace_suspend_resume(TPS("suspend_enter"), state, true);
575 if (state == PM_SUSPEND_TO_IDLE) {
576 #ifdef CONFIG_PM_DEBUG
577 if (pm_test_level != TEST_NONE && pm_test_level <= TEST_CPUS) {
578 pr_warn("Unsupported test mode for suspend to idle, please choose none/freezer/devices/platform.\n");
579 return -EAGAIN;
580 }
581 #endif
582 } else if (!valid_state(state)) {
583 return -EINVAL;
584 }
585 if (!mutex_trylock(&system_transition_mutex))
586 return -EBUSY;
587
588 if (state == PM_SUSPEND_TO_IDLE)
589 s2idle_begin();
590
591 if (sync_on_suspend_enabled) {
592 trace_suspend_resume(TPS("sync_filesystems"), 0, true);
593 ksys_sync_helper();
594 trace_suspend_resume(TPS("sync_filesystems"), 0, false);
595 }
596
597 pm_pr_dbg("Preparing system for sleep (%s)\n", mem_sleep_labels[state]);
598 pm_suspend_clear_flags();
599 error = suspend_prepare(state);
600 if (error)
601 goto Unlock;
602
603 if (suspend_test(TEST_FREEZER))
604 goto Finish;
605
606 trace_suspend_resume(TPS("suspend_enter"), state, false);
607 pm_pr_dbg("Suspending system (%s)\n", mem_sleep_labels[state]);
608 error = suspend_devices_and_enter(state);
609
610 Finish:
611 events_check_enabled = false;
612 pm_pr_dbg("Finishing wakeup.\n");
613 suspend_finish();
614 Unlock:
615 mutex_unlock(&system_transition_mutex);
616 return error;
617 }
618
619 /**
620 * pm_suspend - Externally visible function for suspending the system.
621 * @state: System sleep state to enter.
622 *
623 * Check if the value of @state represents one of the supported states,
624 * execute enter_state() and update system suspend statistics.
625 */
pm_suspend(suspend_state_t state)626 int pm_suspend(suspend_state_t state)
627 {
628 int error;
629
630 if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
631 return -EINVAL;
632
633 pr_info("suspend entry (%s)\n", mem_sleep_labels[state]);
634 error = enter_state(state);
635 dpm_save_errno(error);
636 pr_info("suspend exit\n");
637 return error;
638 }
639 EXPORT_SYMBOL(pm_suspend);
640