xref: /openbmc/linux/kernel/power/suspend.c (revision e6c81cce)
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 *pm_labels[] = { "mem", "standby", "freeze", NULL };
36 const char *pm_states[PM_SUSPEND_MAX];
37 
38 static const struct platform_suspend_ops *suspend_ops;
39 static const struct platform_freeze_ops *freeze_ops;
40 static DECLARE_WAIT_QUEUE_HEAD(suspend_freeze_wait_head);
41 
42 enum freeze_state __read_mostly suspend_freeze_state;
43 static DEFINE_SPINLOCK(suspend_freeze_lock);
44 
45 void freeze_set_ops(const struct platform_freeze_ops *ops)
46 {
47 	lock_system_sleep();
48 	freeze_ops = ops;
49 	unlock_system_sleep();
50 }
51 
52 static void freeze_begin(void)
53 {
54 	suspend_freeze_state = FREEZE_STATE_NONE;
55 }
56 
57 static 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 
87 void 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 }
98 EXPORT_SYMBOL_GPL(freeze_wake);
99 
100 static 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  */
116 static bool relative_states;
117 
118 static 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  */
131 void 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 }
151 EXPORT_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  */
160 int suspend_valid_only_mem(suspend_state_t state)
161 {
162 	return state == PM_SUSPEND_MEM;
163 }
164 EXPORT_SYMBOL_GPL(suspend_valid_only_mem);
165 
166 static bool sleep_state_supported(suspend_state_t state)
167 {
168 	return state == PM_SUSPEND_FREEZE || (suspend_ops && suspend_ops->enter);
169 }
170 
171 static 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 
177 static 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 
183 static 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 
189 static void platform_resume_noirq(suspend_state_t state)
190 {
191 	if (state != PM_SUSPEND_FREEZE && suspend_ops->wake)
192 		suspend_ops->wake();
193 }
194 
195 static 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 
201 static void platform_resume_finish(suspend_state_t state)
202 {
203 	if (state != PM_SUSPEND_FREEZE && suspend_ops->finish)
204 		suspend_ops->finish();
205 }
206 
207 static 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 
217 static 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 
225 static void platform_recover(suspend_state_t state)
226 {
227 	if (state != PM_SUSPEND_FREEZE && suspend_ops->recover)
228 		suspend_ops->recover();
229 }
230 
231 static 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
238 static unsigned int pm_test_delay = 5;
239 module_param(pm_test_delay, uint, 0644);
240 MODULE_PARM_DESC(pm_test_delay,
241 		 "Number of seconds to wait before resuming from suspend test");
242 #endif
243 
244 static 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  */
264 static 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 */
292 void __weak arch_suspend_disable_irqs(void)
293 {
294 	local_irq_disable();
295 }
296 
297 /* default implementation */
298 void __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  */
310 static 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  */
398 int 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  */
448 static 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  */
463 static 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  */
520 int 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 }
536 EXPORT_SYMBOL(pm_suspend);
537