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