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 unsigned int sleep_flags;
79
80 sleep_flags = lock_system_sleep();
81 s2idle_ops = ops;
82 unlock_system_sleep(sleep_flags);
83 }
84
85 static void s2idle_begin(void)
86 {
87 s2idle_state = S2IDLE_STATE_NONE;
88 }
89
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
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
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
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
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
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 */
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 */
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
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
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
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
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
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
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
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
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
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
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
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
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 */
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 dpm_save_failed_step(SUSPEND_FREEZE);
378 pm_notifier_call_chain(PM_POST_SUSPEND);
379 Restore:
380 pm_restore_console();
381 return error;
382 }
383
384 /* default implementation */
385 void __weak arch_suspend_disable_irqs(void)
386 {
387 local_irq_disable();
388 }
389
390 /* default implementation */
391 void __weak arch_suspend_enable_irqs(void)
392 {
393 local_irq_enable();
394 }
395
396 /**
397 * suspend_enter - Make the system enter the given sleep state.
398 * @state: System sleep state to enter.
399 * @wakeup: Returns information that the sleep state should not be re-entered.
400 *
401 * This function should be called after devices have been suspended.
402 */
403 static int suspend_enter(suspend_state_t state, bool *wakeup)
404 {
405 int error;
406
407 error = platform_suspend_prepare(state);
408 if (error)
409 goto Platform_finish;
410
411 error = dpm_suspend_late(PMSG_SUSPEND);
412 if (error) {
413 pr_err("late suspend of devices failed\n");
414 goto Platform_finish;
415 }
416 error = platform_suspend_prepare_late(state);
417 if (error)
418 goto Devices_early_resume;
419
420 error = dpm_suspend_noirq(PMSG_SUSPEND);
421 if (error) {
422 pr_err("noirq suspend of devices failed\n");
423 goto Platform_early_resume;
424 }
425 error = platform_suspend_prepare_noirq(state);
426 if (error)
427 goto Platform_wake;
428
429 if (suspend_test(TEST_PLATFORM))
430 goto Platform_wake;
431
432 if (state == PM_SUSPEND_TO_IDLE) {
433 s2idle_loop();
434 goto Platform_wake;
435 }
436
437 error = pm_sleep_disable_secondary_cpus();
438 if (error || suspend_test(TEST_CPUS))
439 goto Enable_cpus;
440
441 arch_suspend_disable_irqs();
442 BUG_ON(!irqs_disabled());
443
444 system_state = SYSTEM_SUSPEND;
445
446 error = syscore_suspend();
447 if (!error) {
448 *wakeup = pm_wakeup_pending();
449 if (!(suspend_test(TEST_CORE) || *wakeup)) {
450 trace_suspend_resume(TPS("machine_suspend"),
451 state, true);
452 error = suspend_ops->enter(state);
453 trace_suspend_resume(TPS("machine_suspend"),
454 state, false);
455 } else if (*wakeup) {
456 error = -EBUSY;
457 }
458 syscore_resume();
459 }
460
461 system_state = SYSTEM_RUNNING;
462
463 arch_suspend_enable_irqs();
464 BUG_ON(irqs_disabled());
465
466 Enable_cpus:
467 pm_sleep_enable_secondary_cpus();
468
469 Platform_wake:
470 platform_resume_noirq(state);
471 dpm_resume_noirq(PMSG_RESUME);
472
473 Platform_early_resume:
474 platform_resume_early(state);
475
476 Devices_early_resume:
477 dpm_resume_early(PMSG_RESUME);
478
479 Platform_finish:
480 platform_resume_finish(state);
481 return error;
482 }
483
484 /**
485 * suspend_devices_and_enter - Suspend devices and enter system sleep state.
486 * @state: System sleep state to enter.
487 */
488 int suspend_devices_and_enter(suspend_state_t state)
489 {
490 int error;
491 bool wakeup = false;
492
493 if (!sleep_state_supported(state))
494 return -ENOSYS;
495
496 pm_suspend_target_state = state;
497
498 if (state == PM_SUSPEND_TO_IDLE)
499 pm_set_suspend_no_platform();
500
501 error = platform_suspend_begin(state);
502 if (error)
503 goto Close;
504
505 suspend_console();
506 suspend_test_start();
507 error = dpm_suspend_start(PMSG_SUSPEND);
508 if (error) {
509 pr_err("Some devices failed to suspend, or early wake event detected\n");
510 goto Recover_platform;
511 }
512 suspend_test_finish("suspend devices");
513 if (suspend_test(TEST_DEVICES))
514 goto Recover_platform;
515
516 do {
517 error = suspend_enter(state, &wakeup);
518 } while (!error && !wakeup && platform_suspend_again(state));
519
520 Resume_devices:
521 suspend_test_start();
522 dpm_resume_end(PMSG_RESUME);
523 suspend_test_finish("resume devices");
524 trace_suspend_resume(TPS("resume_console"), state, true);
525 resume_console();
526 trace_suspend_resume(TPS("resume_console"), state, false);
527
528 Close:
529 platform_resume_end(state);
530 pm_suspend_target_state = PM_SUSPEND_ON;
531 return error;
532
533 Recover_platform:
534 platform_recover(state);
535 goto Resume_devices;
536 }
537
538 /**
539 * suspend_finish - Clean up before finishing the suspend sequence.
540 *
541 * Call platform code to clean up, restart processes, and free the console that
542 * we've allocated. This routine is not called for hibernation.
543 */
544 static void suspend_finish(void)
545 {
546 suspend_thaw_processes();
547 pm_notifier_call_chain(PM_POST_SUSPEND);
548 pm_restore_console();
549 }
550
551 /**
552 * enter_state - Do common work needed to enter system sleep state.
553 * @state: System sleep state to enter.
554 *
555 * Make sure that no one else is trying to put the system into a sleep state.
556 * Fail if that's not the case. Otherwise, prepare for system suspend, make the
557 * system enter the given sleep state and clean up after wakeup.
558 */
559 static int enter_state(suspend_state_t state)
560 {
561 int error;
562
563 trace_suspend_resume(TPS("suspend_enter"), state, true);
564 if (state == PM_SUSPEND_TO_IDLE) {
565 #ifdef CONFIG_PM_DEBUG
566 if (pm_test_level != TEST_NONE && pm_test_level <= TEST_CPUS) {
567 pr_warn("Unsupported test mode for suspend to idle, please choose none/freezer/devices/platform.\n");
568 return -EAGAIN;
569 }
570 #endif
571 } else if (!valid_state(state)) {
572 return -EINVAL;
573 }
574 if (!mutex_trylock(&system_transition_mutex))
575 return -EBUSY;
576
577 if (state == PM_SUSPEND_TO_IDLE)
578 s2idle_begin();
579
580 if (sync_on_suspend_enabled) {
581 trace_suspend_resume(TPS("sync_filesystems"), 0, true);
582 ksys_sync_helper();
583 trace_suspend_resume(TPS("sync_filesystems"), 0, false);
584 }
585
586 pm_pr_dbg("Preparing system for sleep (%s)\n", mem_sleep_labels[state]);
587 pm_suspend_clear_flags();
588 error = suspend_prepare(state);
589 if (error)
590 goto Unlock;
591
592 if (suspend_test(TEST_FREEZER))
593 goto Finish;
594
595 trace_suspend_resume(TPS("suspend_enter"), state, false);
596 pm_pr_dbg("Suspending system (%s)\n", mem_sleep_labels[state]);
597 pm_restrict_gfp_mask();
598 error = suspend_devices_and_enter(state);
599 pm_restore_gfp_mask();
600
601 Finish:
602 events_check_enabled = false;
603 pm_pr_dbg("Finishing wakeup.\n");
604 suspend_finish();
605 Unlock:
606 mutex_unlock(&system_transition_mutex);
607 return error;
608 }
609
610 /**
611 * pm_suspend - Externally visible function for suspending the system.
612 * @state: System sleep state to enter.
613 *
614 * Check if the value of @state represents one of the supported states,
615 * execute enter_state() and update system suspend statistics.
616 */
617 int pm_suspend(suspend_state_t state)
618 {
619 int error;
620
621 if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
622 return -EINVAL;
623
624 pr_info("suspend entry (%s)\n", mem_sleep_labels[state]);
625 error = enter_state(state);
626 dpm_save_errno(error);
627 pr_info("suspend exit\n");
628 return error;
629 }
630 EXPORT_SYMBOL(pm_suspend);
631
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