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