xref: /openbmc/linux/kernel/power/suspend.c (revision 5d0e4d78) 
1 /*
2  * kernel/power/suspend.c - Suspend to RAM and standby functionality.
3  *
4  * Copyright (c) 2003 Patrick Mochel
5  * Copyright (c) 2003 Open Source Development Lab
6  * Copyright (c) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
7  *
8  * This file is released under the GPLv2.
9  */
10 
11 #include <linux/string.h>
12 #include <linux/delay.h>
13 #include <linux/errno.h>
14 #include <linux/init.h>
15 #include <linux/console.h>
16 #include <linux/cpu.h>
17 #include <linux/cpuidle.h>
18 #include <linux/syscalls.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/ftrace.h>
29 #include <trace/events/power.h>
30 #include <linux/compiler.h>
31 #include <linux/moduleparam.h>
32 
33 #include "power.h"
34 
35 const char * const pm_labels[] = {
36 	[PM_SUSPEND_FREEZE] = "freeze",
37 	[PM_SUSPEND_STANDBY] = "standby",
38 	[PM_SUSPEND_MEM] = "mem",
39 };
40 const char *pm_states[PM_SUSPEND_MAX];
41 static const char * const mem_sleep_labels[] = {
42 	[PM_SUSPEND_FREEZE] = "s2idle",
43 	[PM_SUSPEND_STANDBY] = "shallow",
44 	[PM_SUSPEND_MEM] = "deep",
45 };
46 const char *mem_sleep_states[PM_SUSPEND_MAX];
47 
48 suspend_state_t mem_sleep_current = PM_SUSPEND_FREEZE;
49 static suspend_state_t mem_sleep_default = PM_SUSPEND_MEM;
50 
51 unsigned int pm_suspend_global_flags;
52 EXPORT_SYMBOL_GPL(pm_suspend_global_flags);
53 
54 static const struct platform_suspend_ops *suspend_ops;
55 static const struct platform_freeze_ops *freeze_ops;
56 static DECLARE_WAIT_QUEUE_HEAD(suspend_freeze_wait_head);
57 
58 enum freeze_state __read_mostly suspend_freeze_state;
59 static DEFINE_SPINLOCK(suspend_freeze_lock);
60 
61 void freeze_set_ops(const struct platform_freeze_ops *ops)
62 {
63 	lock_system_sleep();
64 	freeze_ops = ops;
65 	unlock_system_sleep();
66 }
67 
68 static void freeze_begin(void)
69 {
70 	suspend_freeze_state = FREEZE_STATE_NONE;
71 }
72 
73 static void freeze_enter(void)
74 {
75 	trace_suspend_resume(TPS("machine_suspend"), PM_SUSPEND_FREEZE, true);
76 
77 	spin_lock_irq(&suspend_freeze_lock);
78 	if (pm_wakeup_pending())
79 		goto out;
80 
81 	suspend_freeze_state = FREEZE_STATE_ENTER;
82 	spin_unlock_irq(&suspend_freeze_lock);
83 
84 	get_online_cpus();
85 	cpuidle_resume();
86 
87 	/* Push all the CPUs into the idle loop. */
88 	wake_up_all_idle_cpus();
89 	/* Make the current CPU wait so it can enter the idle loop too. */
90 	wait_event(suspend_freeze_wait_head,
91 		   suspend_freeze_state == FREEZE_STATE_WAKE);
92 
93 	cpuidle_pause();
94 	put_online_cpus();
95 
96 	spin_lock_irq(&suspend_freeze_lock);
97 
98  out:
99 	suspend_freeze_state = FREEZE_STATE_NONE;
100 	spin_unlock_irq(&suspend_freeze_lock);
101 
102 	trace_suspend_resume(TPS("machine_suspend"), PM_SUSPEND_FREEZE, false);
103 }
104 
105 static void s2idle_loop(void)
106 {
107 	pr_debug("PM: suspend-to-idle\n");
108 
109 	do {
110 		freeze_enter();
111 
112 		if (freeze_ops && freeze_ops->wake)
113 			freeze_ops->wake();
114 
115 		dpm_resume_noirq(PMSG_RESUME);
116 		if (freeze_ops && freeze_ops->sync)
117 			freeze_ops->sync();
118 
119 		if (pm_wakeup_pending())
120 			break;
121 
122 		pm_wakeup_clear(false);
123 	} while (!dpm_suspend_noirq(PMSG_SUSPEND));
124 
125 	pr_debug("PM: resume from suspend-to-idle\n");
126 }
127 
128 void freeze_wake(void)
129 {
130 	unsigned long flags;
131 
132 	spin_lock_irqsave(&suspend_freeze_lock, flags);
133 	if (suspend_freeze_state > FREEZE_STATE_NONE) {
134 		suspend_freeze_state = FREEZE_STATE_WAKE;
135 		wake_up(&suspend_freeze_wait_head);
136 	}
137 	spin_unlock_irqrestore(&suspend_freeze_lock, flags);
138 }
139 EXPORT_SYMBOL_GPL(freeze_wake);
140 
141 static bool valid_state(suspend_state_t state)
142 {
143 	/*
144 	 * PM_SUSPEND_STANDBY and PM_SUSPEND_MEM states need low level
145 	 * support and need to be valid to the low level
146 	 * implementation, no valid callback implies that none are valid.
147 	 */
148 	return suspend_ops && suspend_ops->valid && suspend_ops->valid(state);
149 }
150 
151 void __init pm_states_init(void)
152 {
153 	/* "mem" and "freeze" are always present in /sys/power/state. */
154 	pm_states[PM_SUSPEND_MEM] = pm_labels[PM_SUSPEND_MEM];
155 	pm_states[PM_SUSPEND_FREEZE] = pm_labels[PM_SUSPEND_FREEZE];
156 	/*
157 	 * Suspend-to-idle should be supported even without any suspend_ops,
158 	 * initialize mem_sleep_states[] accordingly here.
159 	 */
160 	mem_sleep_states[PM_SUSPEND_FREEZE] = mem_sleep_labels[PM_SUSPEND_FREEZE];
161 }
162 
163 static int __init mem_sleep_default_setup(char *str)
164 {
165 	suspend_state_t state;
166 
167 	for (state = PM_SUSPEND_FREEZE; state <= PM_SUSPEND_MEM; state++)
168 		if (mem_sleep_labels[state] &&
169 		    !strcmp(str, mem_sleep_labels[state])) {
170 			mem_sleep_default = state;
171 			break;
172 		}
173 
174 	return 1;
175 }
176 __setup("mem_sleep_default=", mem_sleep_default_setup);
177 
178 /**
179  * suspend_set_ops - Set the global suspend method table.
180  * @ops: Suspend operations to use.
181  */
182 void suspend_set_ops(const struct platform_suspend_ops *ops)
183 {
184 	lock_system_sleep();
185 
186 	suspend_ops = ops;
187 
188 	if (valid_state(PM_SUSPEND_STANDBY)) {
189 		mem_sleep_states[PM_SUSPEND_STANDBY] = mem_sleep_labels[PM_SUSPEND_STANDBY];
190 		pm_states[PM_SUSPEND_STANDBY] = pm_labels[PM_SUSPEND_STANDBY];
191 		if (mem_sleep_default == PM_SUSPEND_STANDBY)
192 			mem_sleep_current = PM_SUSPEND_STANDBY;
193 	}
194 	if (valid_state(PM_SUSPEND_MEM)) {
195 		mem_sleep_states[PM_SUSPEND_MEM] = mem_sleep_labels[PM_SUSPEND_MEM];
196 		if (mem_sleep_default == PM_SUSPEND_MEM)
197 			mem_sleep_current = PM_SUSPEND_MEM;
198 	}
199 
200 	unlock_system_sleep();
201 }
202 EXPORT_SYMBOL_GPL(suspend_set_ops);
203 
204 /**
205  * suspend_valid_only_mem - Generic memory-only valid callback.
206  *
207  * Platform drivers that implement mem suspend only and only need to check for
208  * that in their .valid() callback can use this instead of rolling their own
209  * .valid() callback.
210  */
211 int suspend_valid_only_mem(suspend_state_t state)
212 {
213 	return state == PM_SUSPEND_MEM;
214 }
215 EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
216 
217 static bool sleep_state_supported(suspend_state_t state)
218 {
219 	return state == PM_SUSPEND_FREEZE || (suspend_ops && suspend_ops->enter);
220 }
221 
222 static int platform_suspend_prepare(suspend_state_t state)
223 {
224 	return state != PM_SUSPEND_FREEZE && suspend_ops->prepare ?
225 		suspend_ops->prepare() : 0;
226 }
227 
228 static int platform_suspend_prepare_late(suspend_state_t state)
229 {
230 	return state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->prepare ?
231 		freeze_ops->prepare() : 0;
232 }
233 
234 static int platform_suspend_prepare_noirq(suspend_state_t state)
235 {
236 	return state != PM_SUSPEND_FREEZE && suspend_ops->prepare_late ?
237 		suspend_ops->prepare_late() : 0;
238 }
239 
240 static void platform_resume_noirq(suspend_state_t state)
241 {
242 	if (state != PM_SUSPEND_FREEZE && suspend_ops->wake)
243 		suspend_ops->wake();
244 }
245 
246 static void platform_resume_early(suspend_state_t state)
247 {
248 	if (state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->restore)
249 		freeze_ops->restore();
250 }
251 
252 static void platform_resume_finish(suspend_state_t state)
253 {
254 	if (state != PM_SUSPEND_FREEZE && suspend_ops->finish)
255 		suspend_ops->finish();
256 }
257 
258 static int platform_suspend_begin(suspend_state_t state)
259 {
260 	if (state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->begin)
261 		return freeze_ops->begin();
262 	else if (suspend_ops && suspend_ops->begin)
263 		return suspend_ops->begin(state);
264 	else
265 		return 0;
266 }
267 
268 static void platform_resume_end(suspend_state_t state)
269 {
270 	if (state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->end)
271 		freeze_ops->end();
272 	else if (suspend_ops && suspend_ops->end)
273 		suspend_ops->end();
274 }
275 
276 static void platform_recover(suspend_state_t state)
277 {
278 	if (state != PM_SUSPEND_FREEZE && suspend_ops->recover)
279 		suspend_ops->recover();
280 }
281 
282 static bool platform_suspend_again(suspend_state_t state)
283 {
284 	return state != PM_SUSPEND_FREEZE && suspend_ops->suspend_again ?
285 		suspend_ops->suspend_again() : false;
286 }
287 
288 #ifdef CONFIG_PM_DEBUG
289 static unsigned int pm_test_delay = 5;
290 module_param(pm_test_delay, uint, 0644);
291 MODULE_PARM_DESC(pm_test_delay,
292 		 "Number of seconds to wait before resuming from suspend test");
293 #endif
294 
295 static int suspend_test(int level)
296 {
297 #ifdef CONFIG_PM_DEBUG
298 	if (pm_test_level == level) {
299 		pr_info("suspend debug: Waiting for %d second(s).\n",
300 				pm_test_delay);
301 		mdelay(pm_test_delay * 1000);
302 		return 1;
303 	}
304 #endif /* !CONFIG_PM_DEBUG */
305 	return 0;
306 }
307 
308 /**
309  * suspend_prepare - Prepare for entering system sleep state.
310  *
311  * Common code run for every system sleep state that can be entered (except for
312  * hibernation).  Run suspend notifiers, allocate the "suspend" console and
313  * freeze processes.
314  */
315 static int suspend_prepare(suspend_state_t state)
316 {
317 	int error, nr_calls = 0;
318 
319 	if (!sleep_state_supported(state))
320 		return -EPERM;
321 
322 	pm_prepare_console();
323 
324 	error = __pm_notifier_call_chain(PM_SUSPEND_PREPARE, -1, &nr_calls);
325 	if (error) {
326 		nr_calls--;
327 		goto Finish;
328 	}
329 
330 	trace_suspend_resume(TPS("freeze_processes"), 0, true);
331 	error = suspend_freeze_processes();
332 	trace_suspend_resume(TPS("freeze_processes"), 0, false);
333 	if (!error)
334 		return 0;
335 
336 	suspend_stats.failed_freeze++;
337 	dpm_save_failed_step(SUSPEND_FREEZE);
338  Finish:
339 	__pm_notifier_call_chain(PM_POST_SUSPEND, nr_calls, NULL);
340 	pm_restore_console();
341 	return error;
342 }
343 
344 /* default implementation */
345 void __weak arch_suspend_disable_irqs(void)
346 {
347 	local_irq_disable();
348 }
349 
350 /* default implementation */
351 void __weak arch_suspend_enable_irqs(void)
352 {
353 	local_irq_enable();
354 }
355 
356 /**
357  * suspend_enter - Make the system enter the given sleep state.
358  * @state: System sleep state to enter.
359  * @wakeup: Returns information that the sleep state should not be re-entered.
360  *
361  * This function should be called after devices have been suspended.
362  */
363 static int suspend_enter(suspend_state_t state, bool *wakeup)
364 {
365 	int error;
366 
367 	error = platform_suspend_prepare(state);
368 	if (error)
369 		goto Platform_finish;
370 
371 	error = dpm_suspend_late(PMSG_SUSPEND);
372 	if (error) {
373 		pr_err("PM: late suspend of devices failed\n");
374 		goto Platform_finish;
375 	}
376 	error = platform_suspend_prepare_late(state);
377 	if (error)
378 		goto Devices_early_resume;
379 
380 	error = dpm_suspend_noirq(PMSG_SUSPEND);
381 	if (error) {
382 		pr_err("PM: noirq suspend of devices failed\n");
383 		goto Platform_early_resume;
384 	}
385 	error = platform_suspend_prepare_noirq(state);
386 	if (error)
387 		goto Platform_wake;
388 
389 	if (suspend_test(TEST_PLATFORM))
390 		goto Platform_wake;
391 
392 	/*
393 	 * PM_SUSPEND_FREEZE equals
394 	 * frozen processes + suspended devices + idle processors.
395 	 * Thus we should invoke freeze_enter() soon after
396 	 * all the devices are suspended.
397 	 */
398 	if (state == PM_SUSPEND_FREEZE) {
399 		s2idle_loop();
400 		goto Platform_early_resume;
401 	}
402 
403 	error = disable_nonboot_cpus();
404 	if (error || suspend_test(TEST_CPUS))
405 		goto Enable_cpus;
406 
407 	arch_suspend_disable_irqs();
408 	BUG_ON(!irqs_disabled());
409 
410 	error = syscore_suspend();
411 	if (!error) {
412 		*wakeup = pm_wakeup_pending();
413 		if (!(suspend_test(TEST_CORE) || *wakeup)) {
414 			trace_suspend_resume(TPS("machine_suspend"),
415 				state, true);
416 			error = suspend_ops->enter(state);
417 			trace_suspend_resume(TPS("machine_suspend"),
418 				state, false);
419 			events_check_enabled = false;
420 		} else if (*wakeup) {
421 			error = -EBUSY;
422 		}
423 		syscore_resume();
424 	}
425 
426 	arch_suspend_enable_irqs();
427 	BUG_ON(irqs_disabled());
428 
429  Enable_cpus:
430 	enable_nonboot_cpus();
431 
432  Platform_wake:
433 	platform_resume_noirq(state);
434 	dpm_resume_noirq(PMSG_RESUME);
435 
436  Platform_early_resume:
437 	platform_resume_early(state);
438 
439  Devices_early_resume:
440 	dpm_resume_early(PMSG_RESUME);
441 
442  Platform_finish:
443 	platform_resume_finish(state);
444 	return error;
445 }
446 
447 /**
448  * suspend_devices_and_enter - Suspend devices and enter system sleep state.
449  * @state: System sleep state to enter.
450  */
451 int suspend_devices_and_enter(suspend_state_t state)
452 {
453 	int error;
454 	bool wakeup = false;
455 
456 	if (!sleep_state_supported(state))
457 		return -ENOSYS;
458 
459 	error = platform_suspend_begin(state);
460 	if (error)
461 		goto Close;
462 
463 	suspend_console();
464 	suspend_test_start();
465 	error = dpm_suspend_start(PMSG_SUSPEND);
466 	if (error) {
467 		pr_err("PM: Some devices failed to suspend, or early wake event detected\n");
468 		goto Recover_platform;
469 	}
470 	suspend_test_finish("suspend devices");
471 	if (suspend_test(TEST_DEVICES))
472 		goto Recover_platform;
473 
474 	do {
475 		error = suspend_enter(state, &wakeup);
476 	} while (!error && !wakeup && platform_suspend_again(state));
477 
478  Resume_devices:
479 	suspend_test_start();
480 	dpm_resume_end(PMSG_RESUME);
481 	suspend_test_finish("resume devices");
482 	trace_suspend_resume(TPS("resume_console"), state, true);
483 	resume_console();
484 	trace_suspend_resume(TPS("resume_console"), state, false);
485 
486  Close:
487 	platform_resume_end(state);
488 	return error;
489 
490  Recover_platform:
491 	platform_recover(state);
492 	goto Resume_devices;
493 }
494 
495 /**
496  * suspend_finish - Clean up before finishing the suspend sequence.
497  *
498  * Call platform code to clean up, restart processes, and free the console that
499  * we've allocated. This routine is not called for hibernation.
500  */
501 static void suspend_finish(void)
502 {
503 	suspend_thaw_processes();
504 	pm_notifier_call_chain(PM_POST_SUSPEND);
505 	pm_restore_console();
506 }
507 
508 /**
509  * enter_state - Do common work needed to enter system sleep state.
510  * @state: System sleep state to enter.
511  *
512  * Make sure that no one else is trying to put the system into a sleep state.
513  * Fail if that's not the case.  Otherwise, prepare for system suspend, make the
514  * system enter the given sleep state and clean up after wakeup.
515  */
516 static int enter_state(suspend_state_t state)
517 {
518 	int error;
519 
520 	trace_suspend_resume(TPS("suspend_enter"), state, true);
521 	if (state == PM_SUSPEND_FREEZE) {
522 #ifdef CONFIG_PM_DEBUG
523 		if (pm_test_level != TEST_NONE && pm_test_level <= TEST_CPUS) {
524 			pr_warn("PM: Unsupported test mode for suspend to idle, please choose none/freezer/devices/platform.\n");
525 			return -EAGAIN;
526 		}
527 #endif
528 	} else if (!valid_state(state)) {
529 		return -EINVAL;
530 	}
531 	if (!mutex_trylock(&pm_mutex))
532 		return -EBUSY;
533 
534 	if (state == PM_SUSPEND_FREEZE)
535 		freeze_begin();
536 
537 #ifndef CONFIG_SUSPEND_SKIP_SYNC
538 	trace_suspend_resume(TPS("sync_filesystems"), 0, true);
539 	pr_info("PM: Syncing filesystems ... ");
540 	sys_sync();
541 	pr_cont("done.\n");
542 	trace_suspend_resume(TPS("sync_filesystems"), 0, false);
543 #endif
544 
545 	pr_debug("PM: Preparing system for sleep (%s)\n", pm_states[state]);
546 	pm_suspend_clear_flags();
547 	error = suspend_prepare(state);
548 	if (error)
549 		goto Unlock;
550 
551 	if (suspend_test(TEST_FREEZER))
552 		goto Finish;
553 
554 	trace_suspend_resume(TPS("suspend_enter"), state, false);
555 	pr_debug("PM: Suspending system (%s)\n", pm_states[state]);
556 	pm_restrict_gfp_mask();
557 	error = suspend_devices_and_enter(state);
558 	pm_restore_gfp_mask();
559 
560  Finish:
561 	pr_debug("PM: Finishing wakeup.\n");
562 	suspend_finish();
563  Unlock:
564 	mutex_unlock(&pm_mutex);
565 	return error;
566 }
567 
568 /**
569  * pm_suspend - Externally visible function for suspending the system.
570  * @state: System sleep state to enter.
571  *
572  * Check if the value of @state represents one of the supported states,
573  * execute enter_state() and update system suspend statistics.
574  */
575 int pm_suspend(suspend_state_t state)
576 {
577 	int error;
578 
579 	if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
580 		return -EINVAL;
581 
582 	error = enter_state(state);
583 	if (error) {
584 		suspend_stats.fail++;
585 		dpm_save_failed_errno(error);
586 	} else {
587 		suspend_stats.success++;
588 	}
589 	return error;
590 }
591 EXPORT_SYMBOL(pm_suspend);
592