1 // SPDX-License-Identifier: GPL-2.0
3 * drivers/base/power/main.c - Where the driver meets power management.
5 * Copyright (c) 2003 Patrick Mochel
6 * Copyright (c) 2003 Open Source Development Lab
8 * The driver model core calls device_pm_add() when a device is registered.
9 * This will initialize the embedded device_pm_info object in the device
10 * and add it to the list of power-controlled devices. sysfs entries for
11 * controlling device power management will also be added.
13 * A separate list is used for keeping track of power info, because the power
14 * domain dependencies may differ from the ancestral dependencies that the
15 * subsystem list maintains.
18 #define pr_fmt(fmt) "PM: " fmt
20 #include <linux/device.h>
21 #include <linux/export.h>
22 #include <linux/mutex.h>
24 #include <linux/pm_runtime.h>
25 #include <linux/pm-trace.h>
26 #include <linux/pm_wakeirq.h>
27 #include <linux/interrupt.h>
28 #include <linux/sched.h>
29 #include <linux/sched/debug.h>
30 #include <linux/async.h>
31 #include <linux/suspend.h>
32 #include <trace/events/power.h>
33 #include <linux/cpufreq.h>
34 #include <linux/cpuidle.h>
35 #include <linux/devfreq.h>
36 #include <linux/timer.h>
41 typedef int (*pm_callback_t)(struct device *);
44 * The entries in the dpm_list list are in a depth first order, simply
45 * because children are guaranteed to be discovered after parents, and
46 * are inserted at the back of the list on discovery.
48 * Since device_pm_add() may be called with a device lock held,
49 * we must never try to acquire a device lock while holding
54 static LIST_HEAD(dpm_prepared_list);
55 static LIST_HEAD(dpm_suspended_list);
56 static LIST_HEAD(dpm_late_early_list);
57 static LIST_HEAD(dpm_noirq_list);
59 struct suspend_stats suspend_stats;
60 static DEFINE_MUTEX(dpm_list_mtx);
61 static pm_message_t pm_transition;
63 static int async_error;
65 static const char *pm_verb(int event)
68 case PM_EVENT_SUSPEND:
74 case PM_EVENT_QUIESCE:
76 case PM_EVENT_HIBERNATE:
80 case PM_EVENT_RESTORE:
82 case PM_EVENT_RECOVER:
85 return "(unknown PM event)";
90 * device_pm_sleep_init - Initialize system suspend-related device fields.
91 * @dev: Device object being initialized.
93 void device_pm_sleep_init(struct device *dev)
95 dev->power.is_prepared = false;
96 dev->power.is_suspended = false;
97 dev->power.is_noirq_suspended = false;
98 dev->power.is_late_suspended = false;
99 init_completion(&dev->power.completion);
100 complete_all(&dev->power.completion);
101 dev->power.wakeup = NULL;
102 INIT_LIST_HEAD(&dev->power.entry);
106 * device_pm_lock - Lock the list of active devices used by the PM core.
108 void device_pm_lock(void)
110 mutex_lock(&dpm_list_mtx);
114 * device_pm_unlock - Unlock the list of active devices used by the PM core.
116 void device_pm_unlock(void)
118 mutex_unlock(&dpm_list_mtx);
122 * device_pm_add - Add a device to the PM core's list of active devices.
123 * @dev: Device to add to the list.
125 void device_pm_add(struct device *dev)
127 /* Skip PM setup/initialization. */
128 if (device_pm_not_required(dev))
131 pr_debug("Adding info for %s:%s\n",
132 dev->bus ? dev->bus->name : "No Bus", dev_name(dev));
133 device_pm_check_callbacks(dev);
134 mutex_lock(&dpm_list_mtx);
135 if (dev->parent && dev->parent->power.is_prepared)
136 dev_warn(dev, "parent %s should not be sleeping\n",
137 dev_name(dev->parent));
138 list_add_tail(&dev->power.entry, &dpm_list);
139 dev->power.in_dpm_list = true;
140 mutex_unlock(&dpm_list_mtx);
144 * device_pm_remove - Remove a device from the PM core's list of active devices.
145 * @dev: Device to be removed from the list.
147 void device_pm_remove(struct device *dev)
149 if (device_pm_not_required(dev))
152 pr_debug("Removing info for %s:%s\n",
153 dev->bus ? dev->bus->name : "No Bus", dev_name(dev));
154 complete_all(&dev->power.completion);
155 mutex_lock(&dpm_list_mtx);
156 list_del_init(&dev->power.entry);
157 dev->power.in_dpm_list = false;
158 mutex_unlock(&dpm_list_mtx);
159 device_wakeup_disable(dev);
160 pm_runtime_remove(dev);
161 device_pm_check_callbacks(dev);
165 * device_pm_move_before - Move device in the PM core's list of active devices.
166 * @deva: Device to move in dpm_list.
167 * @devb: Device @deva should come before.
169 void device_pm_move_before(struct device *deva, struct device *devb)
171 pr_debug("Moving %s:%s before %s:%s\n",
172 deva->bus ? deva->bus->name : "No Bus", dev_name(deva),
173 devb->bus ? devb->bus->name : "No Bus", dev_name(devb));
174 /* Delete deva from dpm_list and reinsert before devb. */
175 list_move_tail(&deva->power.entry, &devb->power.entry);
179 * device_pm_move_after - Move device in the PM core's list of active devices.
180 * @deva: Device to move in dpm_list.
181 * @devb: Device @deva should come after.
183 void device_pm_move_after(struct device *deva, struct device *devb)
185 pr_debug("Moving %s:%s after %s:%s\n",
186 deva->bus ? deva->bus->name : "No Bus", dev_name(deva),
187 devb->bus ? devb->bus->name : "No Bus", dev_name(devb));
188 /* Delete deva from dpm_list and reinsert after devb. */
189 list_move(&deva->power.entry, &devb->power.entry);
193 * device_pm_move_last - Move device to end of the PM core's list of devices.
194 * @dev: Device to move in dpm_list.
196 void device_pm_move_last(struct device *dev)
198 pr_debug("Moving %s:%s to end of list\n",
199 dev->bus ? dev->bus->name : "No Bus", dev_name(dev));
200 list_move_tail(&dev->power.entry, &dpm_list);
203 static ktime_t initcall_debug_start(struct device *dev, void *cb)
205 if (!pm_print_times_enabled)
208 dev_info(dev, "calling %pS @ %i, parent: %s\n", cb,
209 task_pid_nr(current),
210 dev->parent ? dev_name(dev->parent) : "none");
214 static void initcall_debug_report(struct device *dev, ktime_t calltime,
220 if (!pm_print_times_enabled)
223 rettime = ktime_get();
224 nsecs = (s64) ktime_to_ns(ktime_sub(rettime, calltime));
226 dev_info(dev, "%pS returned %d after %Ld usecs\n", cb, error,
227 (unsigned long long)nsecs >> 10);
231 * dpm_wait - Wait for a PM operation to complete.
232 * @dev: Device to wait for.
233 * @async: If unset, wait only if the device's power.async_suspend flag is set.
235 static void dpm_wait(struct device *dev, bool async)
240 if (async || (pm_async_enabled && dev->power.async_suspend))
241 wait_for_completion(&dev->power.completion);
244 static int dpm_wait_fn(struct device *dev, void *async_ptr)
246 dpm_wait(dev, *((bool *)async_ptr));
250 static void dpm_wait_for_children(struct device *dev, bool async)
252 device_for_each_child(dev, &async, dpm_wait_fn);
255 static void dpm_wait_for_suppliers(struct device *dev, bool async)
257 struct device_link *link;
260 idx = device_links_read_lock();
263 * If the supplier goes away right after we've checked the link to it,
264 * we'll wait for its completion to change the state, but that's fine,
265 * because the only things that will block as a result are the SRCU
266 * callbacks freeing the link objects for the links in the list we're
269 list_for_each_entry_rcu(link, &dev->links.suppliers, c_node)
270 if (READ_ONCE(link->status) != DL_STATE_DORMANT)
271 dpm_wait(link->supplier, async);
273 device_links_read_unlock(idx);
276 static void dpm_wait_for_superior(struct device *dev, bool async)
278 dpm_wait(dev->parent, async);
279 dpm_wait_for_suppliers(dev, async);
282 static void dpm_wait_for_consumers(struct device *dev, bool async)
284 struct device_link *link;
287 idx = device_links_read_lock();
290 * The status of a device link can only be changed from "dormant" by a
291 * probe, but that cannot happen during system suspend/resume. In
292 * theory it can change to "dormant" at that time, but then it is
293 * reasonable to wait for the target device anyway (eg. if it goes
294 * away, it's better to wait for it to go away completely and then
295 * continue instead of trying to continue in parallel with its
298 list_for_each_entry_rcu(link, &dev->links.consumers, s_node)
299 if (READ_ONCE(link->status) != DL_STATE_DORMANT)
300 dpm_wait(link->consumer, async);
302 device_links_read_unlock(idx);
305 static void dpm_wait_for_subordinate(struct device *dev, bool async)
307 dpm_wait_for_children(dev, async);
308 dpm_wait_for_consumers(dev, async);
312 * pm_op - Return the PM operation appropriate for given PM event.
313 * @ops: PM operations to choose from.
314 * @state: PM transition of the system being carried out.
316 static pm_callback_t pm_op(const struct dev_pm_ops *ops, pm_message_t state)
318 switch (state.event) {
319 #ifdef CONFIG_SUSPEND
320 case PM_EVENT_SUSPEND:
322 case PM_EVENT_RESUME:
324 #endif /* CONFIG_SUSPEND */
325 #ifdef CONFIG_HIBERNATE_CALLBACKS
326 case PM_EVENT_FREEZE:
327 case PM_EVENT_QUIESCE:
329 case PM_EVENT_HIBERNATE:
330 return ops->poweroff;
332 case PM_EVENT_RECOVER:
335 case PM_EVENT_RESTORE:
337 #endif /* CONFIG_HIBERNATE_CALLBACKS */
344 * pm_late_early_op - Return the PM operation appropriate for given PM event.
345 * @ops: PM operations to choose from.
346 * @state: PM transition of the system being carried out.
348 * Runtime PM is disabled for @dev while this function is being executed.
350 static pm_callback_t pm_late_early_op(const struct dev_pm_ops *ops,
353 switch (state.event) {
354 #ifdef CONFIG_SUSPEND
355 case PM_EVENT_SUSPEND:
356 return ops->suspend_late;
357 case PM_EVENT_RESUME:
358 return ops->resume_early;
359 #endif /* CONFIG_SUSPEND */
360 #ifdef CONFIG_HIBERNATE_CALLBACKS
361 case PM_EVENT_FREEZE:
362 case PM_EVENT_QUIESCE:
363 return ops->freeze_late;
364 case PM_EVENT_HIBERNATE:
365 return ops->poweroff_late;
367 case PM_EVENT_RECOVER:
368 return ops->thaw_early;
369 case PM_EVENT_RESTORE:
370 return ops->restore_early;
371 #endif /* CONFIG_HIBERNATE_CALLBACKS */
378 * pm_noirq_op - Return the PM operation appropriate for given PM event.
379 * @ops: PM operations to choose from.
380 * @state: PM transition of the system being carried out.
382 * The driver of @dev will not receive interrupts while this function is being
385 static pm_callback_t pm_noirq_op(const struct dev_pm_ops *ops, pm_message_t state)
387 switch (state.event) {
388 #ifdef CONFIG_SUSPEND
389 case PM_EVENT_SUSPEND:
390 return ops->suspend_noirq;
391 case PM_EVENT_RESUME:
392 return ops->resume_noirq;
393 #endif /* CONFIG_SUSPEND */
394 #ifdef CONFIG_HIBERNATE_CALLBACKS
395 case PM_EVENT_FREEZE:
396 case PM_EVENT_QUIESCE:
397 return ops->freeze_noirq;
398 case PM_EVENT_HIBERNATE:
399 return ops->poweroff_noirq;
401 case PM_EVENT_RECOVER:
402 return ops->thaw_noirq;
403 case PM_EVENT_RESTORE:
404 return ops->restore_noirq;
405 #endif /* CONFIG_HIBERNATE_CALLBACKS */
411 static void pm_dev_dbg(struct device *dev, pm_message_t state, const char *info)
413 dev_dbg(dev, "%s%s%s\n", info, pm_verb(state.event),
414 ((state.event & PM_EVENT_SLEEP) && device_may_wakeup(dev)) ?
415 ", may wakeup" : "");
418 static void pm_dev_err(struct device *dev, pm_message_t state, const char *info,
421 pr_err("Device %s failed to %s%s: error %d\n",
422 dev_name(dev), pm_verb(state.event), info, error);
425 static void dpm_show_time(ktime_t starttime, pm_message_t state, int error,
432 calltime = ktime_get();
433 usecs64 = ktime_to_ns(ktime_sub(calltime, starttime));
434 do_div(usecs64, NSEC_PER_USEC);
439 pm_pr_dbg("%s%s%s of devices %s after %ld.%03ld msecs\n",
440 info ?: "", info ? " " : "", pm_verb(state.event),
441 error ? "aborted" : "complete",
442 usecs / USEC_PER_MSEC, usecs % USEC_PER_MSEC);
445 static int dpm_run_callback(pm_callback_t cb, struct device *dev,
446 pm_message_t state, const char *info)
454 calltime = initcall_debug_start(dev, cb);
456 pm_dev_dbg(dev, state, info);
457 trace_device_pm_callback_start(dev, info, state.event);
459 trace_device_pm_callback_end(dev, error);
460 suspend_report_result(cb, error);
462 initcall_debug_report(dev, calltime, cb, error);
467 #ifdef CONFIG_DPM_WATCHDOG
468 struct dpm_watchdog {
470 struct task_struct *tsk;
471 struct timer_list timer;
474 #define DECLARE_DPM_WATCHDOG_ON_STACK(wd) \
475 struct dpm_watchdog wd
478 * dpm_watchdog_handler - Driver suspend / resume watchdog handler.
479 * @t: The timer that PM watchdog depends on.
481 * Called when a driver has timed out suspending or resuming.
482 * There's not much we can do here to recover so panic() to
483 * capture a crash-dump in pstore.
485 static void dpm_watchdog_handler(struct timer_list *t)
487 struct dpm_watchdog *wd = from_timer(wd, t, timer);
489 dev_emerg(wd->dev, "**** DPM device timeout ****\n");
490 show_stack(wd->tsk, NULL);
491 panic("%s %s: unrecoverable failure\n",
492 dev_driver_string(wd->dev), dev_name(wd->dev));
496 * dpm_watchdog_set - Enable pm watchdog for given device.
497 * @wd: Watchdog. Must be allocated on the stack.
498 * @dev: Device to handle.
500 static void dpm_watchdog_set(struct dpm_watchdog *wd, struct device *dev)
502 struct timer_list *timer = &wd->timer;
507 timer_setup_on_stack(timer, dpm_watchdog_handler, 0);
508 /* use same timeout value for both suspend and resume */
509 timer->expires = jiffies + HZ * CONFIG_DPM_WATCHDOG_TIMEOUT;
514 * dpm_watchdog_clear - Disable suspend/resume watchdog.
515 * @wd: Watchdog to disable.
517 static void dpm_watchdog_clear(struct dpm_watchdog *wd)
519 struct timer_list *timer = &wd->timer;
521 del_timer_sync(timer);
522 destroy_timer_on_stack(timer);
525 #define DECLARE_DPM_WATCHDOG_ON_STACK(wd)
526 #define dpm_watchdog_set(x, y)
527 #define dpm_watchdog_clear(x)
530 /*------------------------- Resume routines -------------------------*/
533 * suspend_event - Return a "suspend" message for given "resume" one.
534 * @resume_msg: PM message representing a system-wide resume transition.
536 static pm_message_t suspend_event(pm_message_t resume_msg)
538 switch (resume_msg.event) {
539 case PM_EVENT_RESUME:
542 case PM_EVENT_RESTORE:
544 case PM_EVENT_RECOVER:
545 return PMSG_HIBERNATE;
551 * dev_pm_may_skip_resume - System-wide device resume optimization check.
552 * @dev: Target device.
554 * Checks whether or not the device may be left in suspend after a system-wide
555 * transition to the working state.
557 bool dev_pm_may_skip_resume(struct device *dev)
559 return !dev->power.must_resume && pm_transition.event != PM_EVENT_RESTORE;
562 static pm_callback_t dpm_subsys_resume_noirq_cb(struct device *dev,
566 pm_callback_t callback;
569 if (dev->pm_domain) {
570 info = "noirq power domain ";
571 callback = pm_noirq_op(&dev->pm_domain->ops, state);
572 } else if (dev->type && dev->type->pm) {
573 info = "noirq type ";
574 callback = pm_noirq_op(dev->type->pm, state);
575 } else if (dev->class && dev->class->pm) {
576 info = "noirq class ";
577 callback = pm_noirq_op(dev->class->pm, state);
578 } else if (dev->bus && dev->bus->pm) {
580 callback = pm_noirq_op(dev->bus->pm, state);
591 static pm_callback_t dpm_subsys_suspend_noirq_cb(struct device *dev,
593 const char **info_p);
595 static pm_callback_t dpm_subsys_suspend_late_cb(struct device *dev,
597 const char **info_p);
600 * device_resume_noirq - Execute a "noirq resume" callback for given device.
601 * @dev: Device to handle.
602 * @state: PM transition of the system being carried out.
603 * @async: If true, the device is being resumed asynchronously.
605 * The driver of @dev will not receive interrupts while this function is being
608 static int device_resume_noirq(struct device *dev, pm_message_t state, bool async)
610 pm_callback_t callback;
618 if (dev->power.syscore || dev->power.direct_complete)
621 if (!dev->power.is_noirq_suspended)
624 dpm_wait_for_superior(dev, async);
626 skip_resume = dev_pm_may_skip_resume(dev);
628 callback = dpm_subsys_resume_noirq_cb(dev, state, &info);
635 if (dev_pm_smart_suspend_and_suspended(dev)) {
636 pm_message_t suspend_msg = suspend_event(state);
639 * If "freeze" callbacks have been skipped during a transition
640 * related to hibernation, the subsequent "thaw" callbacks must
641 * be skipped too or bad things may happen. Otherwise, resume
642 * callbacks are going to be run for the device, so its runtime
643 * PM status must be changed to reflect the new state after the
644 * transition under way.
646 if (!dpm_subsys_suspend_late_cb(dev, suspend_msg, NULL) &&
647 !dpm_subsys_suspend_noirq_cb(dev, suspend_msg, NULL)) {
648 if (state.event == PM_EVENT_THAW) {
652 pm_runtime_set_active(dev);
657 if (dev->driver && dev->driver->pm) {
658 info = "noirq driver ";
659 callback = pm_noirq_op(dev->driver->pm, state);
663 error = dpm_run_callback(callback, dev, state, info);
666 dev->power.is_noirq_suspended = false;
669 /* Make the next phases of resume skip the device. */
670 dev->power.is_late_suspended = false;
671 dev->power.is_suspended = false;
673 * The device is going to be left in suspend, but it might not
674 * have been in runtime suspend before the system suspended, so
675 * its runtime PM status needs to be updated to avoid confusing
676 * the runtime PM framework when runtime PM is enabled for the
679 pm_runtime_set_suspended(dev);
683 complete_all(&dev->power.completion);
688 static bool is_async(struct device *dev)
690 return dev->power.async_suspend && pm_async_enabled
691 && !pm_trace_is_enabled();
694 static bool dpm_async_fn(struct device *dev, async_func_t func)
696 reinit_completion(&dev->power.completion);
700 async_schedule(func, dev);
707 static void async_resume_noirq(void *data, async_cookie_t cookie)
709 struct device *dev = (struct device *)data;
712 error = device_resume_noirq(dev, pm_transition, true);
714 pm_dev_err(dev, pm_transition, " async", error);
719 static void dpm_noirq_resume_devices(pm_message_t state)
722 ktime_t starttime = ktime_get();
724 trace_suspend_resume(TPS("dpm_resume_noirq"), state.event, true);
725 mutex_lock(&dpm_list_mtx);
726 pm_transition = state;
729 * Advanced the async threads upfront,
730 * in case the starting of async threads is
731 * delayed by non-async resuming devices.
733 list_for_each_entry(dev, &dpm_noirq_list, power.entry)
734 dpm_async_fn(dev, async_resume_noirq);
736 while (!list_empty(&dpm_noirq_list)) {
737 dev = to_device(dpm_noirq_list.next);
739 list_move_tail(&dev->power.entry, &dpm_late_early_list);
740 mutex_unlock(&dpm_list_mtx);
742 if (!is_async(dev)) {
745 error = device_resume_noirq(dev, state, false);
747 suspend_stats.failed_resume_noirq++;
748 dpm_save_failed_step(SUSPEND_RESUME_NOIRQ);
749 dpm_save_failed_dev(dev_name(dev));
750 pm_dev_err(dev, state, " noirq", error);
754 mutex_lock(&dpm_list_mtx);
757 mutex_unlock(&dpm_list_mtx);
758 async_synchronize_full();
759 dpm_show_time(starttime, state, 0, "noirq");
760 trace_suspend_resume(TPS("dpm_resume_noirq"), state.event, false);
764 * dpm_resume_noirq - Execute "noirq resume" callbacks for all devices.
765 * @state: PM transition of the system being carried out.
767 * Invoke the "noirq" resume callbacks for all devices in dpm_noirq_list and
768 * allow device drivers' interrupt handlers to be called.
770 void dpm_resume_noirq(pm_message_t state)
772 dpm_noirq_resume_devices(state);
774 resume_device_irqs();
775 device_wakeup_disarm_wake_irqs();
780 static pm_callback_t dpm_subsys_resume_early_cb(struct device *dev,
784 pm_callback_t callback;
787 if (dev->pm_domain) {
788 info = "early power domain ";
789 callback = pm_late_early_op(&dev->pm_domain->ops, state);
790 } else if (dev->type && dev->type->pm) {
791 info = "early type ";
792 callback = pm_late_early_op(dev->type->pm, state);
793 } else if (dev->class && dev->class->pm) {
794 info = "early class ";
795 callback = pm_late_early_op(dev->class->pm, state);
796 } else if (dev->bus && dev->bus->pm) {
798 callback = pm_late_early_op(dev->bus->pm, state);
810 * device_resume_early - Execute an "early resume" callback for given device.
811 * @dev: Device to handle.
812 * @state: PM transition of the system being carried out.
813 * @async: If true, the device is being resumed asynchronously.
815 * Runtime PM is disabled for @dev while this function is being executed.
817 static int device_resume_early(struct device *dev, pm_message_t state, bool async)
819 pm_callback_t callback;
826 if (dev->power.syscore || dev->power.direct_complete)
829 if (!dev->power.is_late_suspended)
832 dpm_wait_for_superior(dev, async);
834 callback = dpm_subsys_resume_early_cb(dev, state, &info);
836 if (!callback && dev->driver && dev->driver->pm) {
837 info = "early driver ";
838 callback = pm_late_early_op(dev->driver->pm, state);
841 error = dpm_run_callback(callback, dev, state, info);
842 dev->power.is_late_suspended = false;
847 pm_runtime_enable(dev);
848 complete_all(&dev->power.completion);
852 static void async_resume_early(void *data, async_cookie_t cookie)
854 struct device *dev = (struct device *)data;
857 error = device_resume_early(dev, pm_transition, true);
859 pm_dev_err(dev, pm_transition, " async", error);
865 * dpm_resume_early - Execute "early resume" callbacks for all devices.
866 * @state: PM transition of the system being carried out.
868 void dpm_resume_early(pm_message_t state)
871 ktime_t starttime = ktime_get();
873 trace_suspend_resume(TPS("dpm_resume_early"), state.event, true);
874 mutex_lock(&dpm_list_mtx);
875 pm_transition = state;
878 * Advanced the async threads upfront,
879 * in case the starting of async threads is
880 * delayed by non-async resuming devices.
882 list_for_each_entry(dev, &dpm_late_early_list, power.entry)
883 dpm_async_fn(dev, async_resume_early);
885 while (!list_empty(&dpm_late_early_list)) {
886 dev = to_device(dpm_late_early_list.next);
888 list_move_tail(&dev->power.entry, &dpm_suspended_list);
889 mutex_unlock(&dpm_list_mtx);
891 if (!is_async(dev)) {
894 error = device_resume_early(dev, state, false);
896 suspend_stats.failed_resume_early++;
897 dpm_save_failed_step(SUSPEND_RESUME_EARLY);
898 dpm_save_failed_dev(dev_name(dev));
899 pm_dev_err(dev, state, " early", error);
902 mutex_lock(&dpm_list_mtx);
905 mutex_unlock(&dpm_list_mtx);
906 async_synchronize_full();
907 dpm_show_time(starttime, state, 0, "early");
908 trace_suspend_resume(TPS("dpm_resume_early"), state.event, false);
912 * dpm_resume_start - Execute "noirq" and "early" device callbacks.
913 * @state: PM transition of the system being carried out.
915 void dpm_resume_start(pm_message_t state)
917 dpm_resume_noirq(state);
918 dpm_resume_early(state);
920 EXPORT_SYMBOL_GPL(dpm_resume_start);
923 * device_resume - Execute "resume" callbacks for given device.
924 * @dev: Device to handle.
925 * @state: PM transition of the system being carried out.
926 * @async: If true, the device is being resumed asynchronously.
928 static int device_resume(struct device *dev, pm_message_t state, bool async)
930 pm_callback_t callback = NULL;
931 const char *info = NULL;
933 DECLARE_DPM_WATCHDOG_ON_STACK(wd);
938 if (dev->power.syscore)
941 if (dev->power.direct_complete) {
942 /* Match the pm_runtime_disable() in __device_suspend(). */
943 pm_runtime_enable(dev);
947 dpm_wait_for_superior(dev, async);
948 dpm_watchdog_set(&wd, dev);
952 * This is a fib. But we'll allow new children to be added below
953 * a resumed device, even if the device hasn't been completed yet.
955 dev->power.is_prepared = false;
957 if (!dev->power.is_suspended)
960 if (dev->pm_domain) {
961 info = "power domain ";
962 callback = pm_op(&dev->pm_domain->ops, state);
966 if (dev->type && dev->type->pm) {
968 callback = pm_op(dev->type->pm, state);
972 if (dev->class && dev->class->pm) {
974 callback = pm_op(dev->class->pm, state);
981 callback = pm_op(dev->bus->pm, state);
982 } else if (dev->bus->resume) {
983 info = "legacy bus ";
984 callback = dev->bus->resume;
990 if (!callback && dev->driver && dev->driver->pm) {
992 callback = pm_op(dev->driver->pm, state);
996 error = dpm_run_callback(callback, dev, state, info);
997 dev->power.is_suspended = false;
1001 dpm_watchdog_clear(&wd);
1004 complete_all(&dev->power.completion);
1006 TRACE_RESUME(error);
1011 static void async_resume(void *data, async_cookie_t cookie)
1013 struct device *dev = (struct device *)data;
1016 error = device_resume(dev, pm_transition, true);
1018 pm_dev_err(dev, pm_transition, " async", error);
1023 * dpm_resume - Execute "resume" callbacks for non-sysdev devices.
1024 * @state: PM transition of the system being carried out.
1026 * Execute the appropriate "resume" callback for all devices whose status
1027 * indicates that they are suspended.
1029 void dpm_resume(pm_message_t state)
1032 ktime_t starttime = ktime_get();
1034 trace_suspend_resume(TPS("dpm_resume"), state.event, true);
1037 mutex_lock(&dpm_list_mtx);
1038 pm_transition = state;
1041 list_for_each_entry(dev, &dpm_suspended_list, power.entry)
1042 dpm_async_fn(dev, async_resume);
1044 while (!list_empty(&dpm_suspended_list)) {
1045 dev = to_device(dpm_suspended_list.next);
1047 if (!is_async(dev)) {
1050 mutex_unlock(&dpm_list_mtx);
1052 error = device_resume(dev, state, false);
1054 suspend_stats.failed_resume++;
1055 dpm_save_failed_step(SUSPEND_RESUME);
1056 dpm_save_failed_dev(dev_name(dev));
1057 pm_dev_err(dev, state, "", error);
1060 mutex_lock(&dpm_list_mtx);
1062 if (!list_empty(&dev->power.entry))
1063 list_move_tail(&dev->power.entry, &dpm_prepared_list);
1066 mutex_unlock(&dpm_list_mtx);
1067 async_synchronize_full();
1068 dpm_show_time(starttime, state, 0, NULL);
1072 trace_suspend_resume(TPS("dpm_resume"), state.event, false);
1076 * device_complete - Complete a PM transition for given device.
1077 * @dev: Device to handle.
1078 * @state: PM transition of the system being carried out.
1080 static void device_complete(struct device *dev, pm_message_t state)
1082 void (*callback)(struct device *) = NULL;
1083 const char *info = NULL;
1085 if (dev->power.syscore)
1090 if (dev->pm_domain) {
1091 info = "completing power domain ";
1092 callback = dev->pm_domain->ops.complete;
1093 } else if (dev->type && dev->type->pm) {
1094 info = "completing type ";
1095 callback = dev->type->pm->complete;
1096 } else if (dev->class && dev->class->pm) {
1097 info = "completing class ";
1098 callback = dev->class->pm->complete;
1099 } else if (dev->bus && dev->bus->pm) {
1100 info = "completing bus ";
1101 callback = dev->bus->pm->complete;
1104 if (!callback && dev->driver && dev->driver->pm) {
1105 info = "completing driver ";
1106 callback = dev->driver->pm->complete;
1110 pm_dev_dbg(dev, state, info);
1116 pm_runtime_put(dev);
1120 * dpm_complete - Complete a PM transition for all non-sysdev devices.
1121 * @state: PM transition of the system being carried out.
1123 * Execute the ->complete() callbacks for all devices whose PM status is not
1124 * DPM_ON (this allows new devices to be registered).
1126 void dpm_complete(pm_message_t state)
1128 struct list_head list;
1130 trace_suspend_resume(TPS("dpm_complete"), state.event, true);
1133 INIT_LIST_HEAD(&list);
1134 mutex_lock(&dpm_list_mtx);
1135 while (!list_empty(&dpm_prepared_list)) {
1136 struct device *dev = to_device(dpm_prepared_list.prev);
1139 dev->power.is_prepared = false;
1140 list_move(&dev->power.entry, &list);
1141 mutex_unlock(&dpm_list_mtx);
1143 trace_device_pm_callback_start(dev, "", state.event);
1144 device_complete(dev, state);
1145 trace_device_pm_callback_end(dev, 0);
1147 mutex_lock(&dpm_list_mtx);
1150 list_splice(&list, &dpm_list);
1151 mutex_unlock(&dpm_list_mtx);
1153 /* Allow device probing and trigger re-probing of deferred devices */
1154 device_unblock_probing();
1155 trace_suspend_resume(TPS("dpm_complete"), state.event, false);
1159 * dpm_resume_end - Execute "resume" callbacks and complete system transition.
1160 * @state: PM transition of the system being carried out.
1162 * Execute "resume" callbacks for all devices and complete the PM transition of
1165 void dpm_resume_end(pm_message_t state)
1168 dpm_complete(state);
1170 EXPORT_SYMBOL_GPL(dpm_resume_end);
1173 /*------------------------- Suspend routines -------------------------*/
1176 * resume_event - Return a "resume" message for given "suspend" sleep state.
1177 * @sleep_state: PM message representing a sleep state.
1179 * Return a PM message representing the resume event corresponding to given
1182 static pm_message_t resume_event(pm_message_t sleep_state)
1184 switch (sleep_state.event) {
1185 case PM_EVENT_SUSPEND:
1187 case PM_EVENT_FREEZE:
1188 case PM_EVENT_QUIESCE:
1189 return PMSG_RECOVER;
1190 case PM_EVENT_HIBERNATE:
1191 return PMSG_RESTORE;
1196 static void dpm_superior_set_must_resume(struct device *dev)
1198 struct device_link *link;
1202 dev->parent->power.must_resume = true;
1204 idx = device_links_read_lock();
1206 list_for_each_entry_rcu(link, &dev->links.suppliers, c_node)
1207 link->supplier->power.must_resume = true;
1209 device_links_read_unlock(idx);
1212 static pm_callback_t dpm_subsys_suspend_noirq_cb(struct device *dev,
1214 const char **info_p)
1216 pm_callback_t callback;
1219 if (dev->pm_domain) {
1220 info = "noirq power domain ";
1221 callback = pm_noirq_op(&dev->pm_domain->ops, state);
1222 } else if (dev->type && dev->type->pm) {
1223 info = "noirq type ";
1224 callback = pm_noirq_op(dev->type->pm, state);
1225 } else if (dev->class && dev->class->pm) {
1226 info = "noirq class ";
1227 callback = pm_noirq_op(dev->class->pm, state);
1228 } else if (dev->bus && dev->bus->pm) {
1229 info = "noirq bus ";
1230 callback = pm_noirq_op(dev->bus->pm, state);
1241 static bool device_must_resume(struct device *dev, pm_message_t state,
1242 bool no_subsys_suspend_noirq)
1244 pm_message_t resume_msg = resume_event(state);
1247 * If all of the device driver's "noirq", "late" and "early" callbacks
1248 * are invoked directly by the core, the decision to allow the device to
1249 * stay in suspend can be based on its current runtime PM status and its
1252 if (no_subsys_suspend_noirq &&
1253 !dpm_subsys_suspend_late_cb(dev, state, NULL) &&
1254 !dpm_subsys_resume_early_cb(dev, resume_msg, NULL) &&
1255 !dpm_subsys_resume_noirq_cb(dev, resume_msg, NULL))
1256 return !pm_runtime_status_suspended(dev) &&
1257 (resume_msg.event != PM_EVENT_RESUME ||
1258 (device_can_wakeup(dev) && !device_may_wakeup(dev)));
1261 * The only safe strategy here is to require that if the device may not
1262 * be left in suspend, resume callbacks must be invoked for it.
1264 return !dev->power.may_skip_resume;
1268 * __device_suspend_noirq - Execute a "noirq suspend" callback for given device.
1269 * @dev: Device to handle.
1270 * @state: PM transition of the system being carried out.
1271 * @async: If true, the device is being suspended asynchronously.
1273 * The driver of @dev will not receive interrupts while this function is being
1276 static int __device_suspend_noirq(struct device *dev, pm_message_t state, bool async)
1278 pm_callback_t callback;
1280 bool no_subsys_cb = false;
1286 dpm_wait_for_subordinate(dev, async);
1291 if (dev->power.syscore || dev->power.direct_complete)
1294 callback = dpm_subsys_suspend_noirq_cb(dev, state, &info);
1298 no_subsys_cb = !dpm_subsys_suspend_late_cb(dev, state, NULL);
1300 if (dev_pm_smart_suspend_and_suspended(dev) && no_subsys_cb)
1303 if (dev->driver && dev->driver->pm) {
1304 info = "noirq driver ";
1305 callback = pm_noirq_op(dev->driver->pm, state);
1309 error = dpm_run_callback(callback, dev, state, info);
1311 async_error = error;
1316 dev->power.is_noirq_suspended = true;
1318 if (dev_pm_test_driver_flags(dev, DPM_FLAG_LEAVE_SUSPENDED)) {
1319 dev->power.must_resume = dev->power.must_resume ||
1320 atomic_read(&dev->power.usage_count) > 1 ||
1321 device_must_resume(dev, state, no_subsys_cb);
1323 dev->power.must_resume = true;
1326 if (dev->power.must_resume)
1327 dpm_superior_set_must_resume(dev);
1330 complete_all(&dev->power.completion);
1331 TRACE_SUSPEND(error);
1335 static void async_suspend_noirq(void *data, async_cookie_t cookie)
1337 struct device *dev = (struct device *)data;
1340 error = __device_suspend_noirq(dev, pm_transition, true);
1342 dpm_save_failed_dev(dev_name(dev));
1343 pm_dev_err(dev, pm_transition, " async", error);
1349 static int device_suspend_noirq(struct device *dev)
1351 if (dpm_async_fn(dev, async_suspend_noirq))
1354 return __device_suspend_noirq(dev, pm_transition, false);
1357 static int dpm_noirq_suspend_devices(pm_message_t state)
1359 ktime_t starttime = ktime_get();
1362 trace_suspend_resume(TPS("dpm_suspend_noirq"), state.event, true);
1363 mutex_lock(&dpm_list_mtx);
1364 pm_transition = state;
1367 while (!list_empty(&dpm_late_early_list)) {
1368 struct device *dev = to_device(dpm_late_early_list.prev);
1371 mutex_unlock(&dpm_list_mtx);
1373 error = device_suspend_noirq(dev);
1375 mutex_lock(&dpm_list_mtx);
1377 pm_dev_err(dev, state, " noirq", error);
1378 dpm_save_failed_dev(dev_name(dev));
1382 if (!list_empty(&dev->power.entry))
1383 list_move(&dev->power.entry, &dpm_noirq_list);
1389 mutex_unlock(&dpm_list_mtx);
1390 async_synchronize_full();
1392 error = async_error;
1395 suspend_stats.failed_suspend_noirq++;
1396 dpm_save_failed_step(SUSPEND_SUSPEND_NOIRQ);
1398 dpm_show_time(starttime, state, error, "noirq");
1399 trace_suspend_resume(TPS("dpm_suspend_noirq"), state.event, false);
1404 * dpm_suspend_noirq - Execute "noirq suspend" callbacks for all devices.
1405 * @state: PM transition of the system being carried out.
1407 * Prevent device drivers' interrupt handlers from being called and invoke
1408 * "noirq" suspend callbacks for all non-sysdev devices.
1410 int dpm_suspend_noirq(pm_message_t state)
1416 device_wakeup_arm_wake_irqs();
1417 suspend_device_irqs();
1419 ret = dpm_noirq_suspend_devices(state);
1421 dpm_resume_noirq(resume_event(state));
1426 static void dpm_propagate_wakeup_to_parent(struct device *dev)
1428 struct device *parent = dev->parent;
1433 spin_lock_irq(&parent->power.lock);
1435 if (dev->power.wakeup_path && !parent->power.ignore_children)
1436 parent->power.wakeup_path = true;
1438 spin_unlock_irq(&parent->power.lock);
1441 static pm_callback_t dpm_subsys_suspend_late_cb(struct device *dev,
1443 const char **info_p)
1445 pm_callback_t callback;
1448 if (dev->pm_domain) {
1449 info = "late power domain ";
1450 callback = pm_late_early_op(&dev->pm_domain->ops, state);
1451 } else if (dev->type && dev->type->pm) {
1452 info = "late type ";
1453 callback = pm_late_early_op(dev->type->pm, state);
1454 } else if (dev->class && dev->class->pm) {
1455 info = "late class ";
1456 callback = pm_late_early_op(dev->class->pm, state);
1457 } else if (dev->bus && dev->bus->pm) {
1459 callback = pm_late_early_op(dev->bus->pm, state);
1471 * __device_suspend_late - Execute a "late suspend" callback for given device.
1472 * @dev: Device to handle.
1473 * @state: PM transition of the system being carried out.
1474 * @async: If true, the device is being suspended asynchronously.
1476 * Runtime PM is disabled for @dev while this function is being executed.
1478 static int __device_suspend_late(struct device *dev, pm_message_t state, bool async)
1480 pm_callback_t callback;
1487 __pm_runtime_disable(dev, false);
1489 dpm_wait_for_subordinate(dev, async);
1494 if (pm_wakeup_pending()) {
1495 async_error = -EBUSY;
1499 if (dev->power.syscore || dev->power.direct_complete)
1502 callback = dpm_subsys_suspend_late_cb(dev, state, &info);
1506 if (dev_pm_smart_suspend_and_suspended(dev) &&
1507 !dpm_subsys_suspend_noirq_cb(dev, state, NULL))
1510 if (dev->driver && dev->driver->pm) {
1511 info = "late driver ";
1512 callback = pm_late_early_op(dev->driver->pm, state);
1516 error = dpm_run_callback(callback, dev, state, info);
1518 async_error = error;
1521 dpm_propagate_wakeup_to_parent(dev);
1524 dev->power.is_late_suspended = true;
1527 TRACE_SUSPEND(error);
1528 complete_all(&dev->power.completion);
1532 static void async_suspend_late(void *data, async_cookie_t cookie)
1534 struct device *dev = (struct device *)data;
1537 error = __device_suspend_late(dev, pm_transition, true);
1539 dpm_save_failed_dev(dev_name(dev));
1540 pm_dev_err(dev, pm_transition, " async", error);
1545 static int device_suspend_late(struct device *dev)
1547 if (dpm_async_fn(dev, async_suspend_late))
1550 return __device_suspend_late(dev, pm_transition, false);
1554 * dpm_suspend_late - Execute "late suspend" callbacks for all devices.
1555 * @state: PM transition of the system being carried out.
1557 int dpm_suspend_late(pm_message_t state)
1559 ktime_t starttime = ktime_get();
1562 trace_suspend_resume(TPS("dpm_suspend_late"), state.event, true);
1563 mutex_lock(&dpm_list_mtx);
1564 pm_transition = state;
1567 while (!list_empty(&dpm_suspended_list)) {
1568 struct device *dev = to_device(dpm_suspended_list.prev);
1571 mutex_unlock(&dpm_list_mtx);
1573 error = device_suspend_late(dev);
1575 mutex_lock(&dpm_list_mtx);
1576 if (!list_empty(&dev->power.entry))
1577 list_move(&dev->power.entry, &dpm_late_early_list);
1580 pm_dev_err(dev, state, " late", error);
1581 dpm_save_failed_dev(dev_name(dev));
1590 mutex_unlock(&dpm_list_mtx);
1591 async_synchronize_full();
1593 error = async_error;
1595 suspend_stats.failed_suspend_late++;
1596 dpm_save_failed_step(SUSPEND_SUSPEND_LATE);
1597 dpm_resume_early(resume_event(state));
1599 dpm_show_time(starttime, state, error, "late");
1600 trace_suspend_resume(TPS("dpm_suspend_late"), state.event, false);
1605 * dpm_suspend_end - Execute "late" and "noirq" device suspend callbacks.
1606 * @state: PM transition of the system being carried out.
1608 int dpm_suspend_end(pm_message_t state)
1610 ktime_t starttime = ktime_get();
1613 error = dpm_suspend_late(state);
1617 error = dpm_suspend_noirq(state);
1619 dpm_resume_early(resume_event(state));
1622 dpm_show_time(starttime, state, error, "end");
1625 EXPORT_SYMBOL_GPL(dpm_suspend_end);
1628 * legacy_suspend - Execute a legacy (bus or class) suspend callback for device.
1629 * @dev: Device to suspend.
1630 * @state: PM transition of the system being carried out.
1631 * @cb: Suspend callback to execute.
1632 * @info: string description of caller.
1634 static int legacy_suspend(struct device *dev, pm_message_t state,
1635 int (*cb)(struct device *dev, pm_message_t state),
1641 calltime = initcall_debug_start(dev, cb);
1643 trace_device_pm_callback_start(dev, info, state.event);
1644 error = cb(dev, state);
1645 trace_device_pm_callback_end(dev, error);
1646 suspend_report_result(cb, error);
1648 initcall_debug_report(dev, calltime, cb, error);
1653 static void dpm_clear_superiors_direct_complete(struct device *dev)
1655 struct device_link *link;
1659 spin_lock_irq(&dev->parent->power.lock);
1660 dev->parent->power.direct_complete = false;
1661 spin_unlock_irq(&dev->parent->power.lock);
1664 idx = device_links_read_lock();
1666 list_for_each_entry_rcu(link, &dev->links.suppliers, c_node) {
1667 spin_lock_irq(&link->supplier->power.lock);
1668 link->supplier->power.direct_complete = false;
1669 spin_unlock_irq(&link->supplier->power.lock);
1672 device_links_read_unlock(idx);
1676 * __device_suspend - Execute "suspend" callbacks for given device.
1677 * @dev: Device to handle.
1678 * @state: PM transition of the system being carried out.
1679 * @async: If true, the device is being suspended asynchronously.
1681 static int __device_suspend(struct device *dev, pm_message_t state, bool async)
1683 pm_callback_t callback = NULL;
1684 const char *info = NULL;
1686 DECLARE_DPM_WATCHDOG_ON_STACK(wd);
1691 dpm_wait_for_subordinate(dev, async);
1694 dev->power.direct_complete = false;
1699 * If a device configured to wake up the system from sleep states
1700 * has been suspended at run time and there's a resume request pending
1701 * for it, this is equivalent to the device signaling wakeup, so the
1702 * system suspend operation should be aborted.
1704 if (pm_runtime_barrier(dev) && device_may_wakeup(dev))
1705 pm_wakeup_event(dev, 0);
1707 if (pm_wakeup_pending()) {
1708 dev->power.direct_complete = false;
1709 async_error = -EBUSY;
1713 if (dev->power.syscore)
1716 /* Avoid direct_complete to let wakeup_path propagate. */
1717 if (device_may_wakeup(dev) || dev->power.wakeup_path)
1718 dev->power.direct_complete = false;
1720 if (dev->power.direct_complete) {
1721 if (pm_runtime_status_suspended(dev)) {
1722 pm_runtime_disable(dev);
1723 if (pm_runtime_status_suspended(dev)) {
1724 pm_dev_dbg(dev, state, "direct-complete ");
1728 pm_runtime_enable(dev);
1730 dev->power.direct_complete = false;
1733 dev->power.may_skip_resume = false;
1734 dev->power.must_resume = false;
1736 dpm_watchdog_set(&wd, dev);
1739 if (dev->pm_domain) {
1740 info = "power domain ";
1741 callback = pm_op(&dev->pm_domain->ops, state);
1745 if (dev->type && dev->type->pm) {
1747 callback = pm_op(dev->type->pm, state);
1751 if (dev->class && dev->class->pm) {
1753 callback = pm_op(dev->class->pm, state);
1760 callback = pm_op(dev->bus->pm, state);
1761 } else if (dev->bus->suspend) {
1762 pm_dev_dbg(dev, state, "legacy bus ");
1763 error = legacy_suspend(dev, state, dev->bus->suspend,
1770 if (!callback && dev->driver && dev->driver->pm) {
1772 callback = pm_op(dev->driver->pm, state);
1775 error = dpm_run_callback(callback, dev, state, info);
1779 dev->power.is_suspended = true;
1780 if (device_may_wakeup(dev))
1781 dev->power.wakeup_path = true;
1783 dpm_propagate_wakeup_to_parent(dev);
1784 dpm_clear_superiors_direct_complete(dev);
1788 dpm_watchdog_clear(&wd);
1792 async_error = error;
1794 complete_all(&dev->power.completion);
1795 TRACE_SUSPEND(error);
1799 static void async_suspend(void *data, async_cookie_t cookie)
1801 struct device *dev = (struct device *)data;
1804 error = __device_suspend(dev, pm_transition, true);
1806 dpm_save_failed_dev(dev_name(dev));
1807 pm_dev_err(dev, pm_transition, " async", error);
1813 static int device_suspend(struct device *dev)
1815 if (dpm_async_fn(dev, async_suspend))
1818 return __device_suspend(dev, pm_transition, false);
1822 * dpm_suspend - Execute "suspend" callbacks for all non-sysdev devices.
1823 * @state: PM transition of the system being carried out.
1825 int dpm_suspend(pm_message_t state)
1827 ktime_t starttime = ktime_get();
1830 trace_suspend_resume(TPS("dpm_suspend"), state.event, true);
1836 mutex_lock(&dpm_list_mtx);
1837 pm_transition = state;
1839 while (!list_empty(&dpm_prepared_list)) {
1840 struct device *dev = to_device(dpm_prepared_list.prev);
1843 mutex_unlock(&dpm_list_mtx);
1845 error = device_suspend(dev);
1847 mutex_lock(&dpm_list_mtx);
1849 pm_dev_err(dev, state, "", error);
1850 dpm_save_failed_dev(dev_name(dev));
1854 if (!list_empty(&dev->power.entry))
1855 list_move(&dev->power.entry, &dpm_suspended_list);
1860 mutex_unlock(&dpm_list_mtx);
1861 async_synchronize_full();
1863 error = async_error;
1865 suspend_stats.failed_suspend++;
1866 dpm_save_failed_step(SUSPEND_SUSPEND);
1868 dpm_show_time(starttime, state, error, NULL);
1869 trace_suspend_resume(TPS("dpm_suspend"), state.event, false);
1874 * device_prepare - Prepare a device for system power transition.
1875 * @dev: Device to handle.
1876 * @state: PM transition of the system being carried out.
1878 * Execute the ->prepare() callback(s) for given device. No new children of the
1879 * device may be registered after this function has returned.
1881 static int device_prepare(struct device *dev, pm_message_t state)
1883 int (*callback)(struct device *) = NULL;
1886 if (dev->power.syscore)
1889 WARN_ON(!pm_runtime_enabled(dev) &&
1890 dev_pm_test_driver_flags(dev, DPM_FLAG_SMART_SUSPEND |
1891 DPM_FLAG_LEAVE_SUSPENDED));
1894 * If a device's parent goes into runtime suspend at the wrong time,
1895 * it won't be possible to resume the device. To prevent this we
1896 * block runtime suspend here, during the prepare phase, and allow
1897 * it again during the complete phase.
1899 pm_runtime_get_noresume(dev);
1903 dev->power.wakeup_path = false;
1905 if (dev->power.no_pm_callbacks)
1909 callback = dev->pm_domain->ops.prepare;
1910 else if (dev->type && dev->type->pm)
1911 callback = dev->type->pm->prepare;
1912 else if (dev->class && dev->class->pm)
1913 callback = dev->class->pm->prepare;
1914 else if (dev->bus && dev->bus->pm)
1915 callback = dev->bus->pm->prepare;
1917 if (!callback && dev->driver && dev->driver->pm)
1918 callback = dev->driver->pm->prepare;
1921 ret = callback(dev);
1927 suspend_report_result(callback, ret);
1928 pm_runtime_put(dev);
1932 * A positive return value from ->prepare() means "this device appears
1933 * to be runtime-suspended and its state is fine, so if it really is
1934 * runtime-suspended, you can leave it in that state provided that you
1935 * will do the same thing with all of its descendants". This only
1936 * applies to suspend transitions, however.
1938 spin_lock_irq(&dev->power.lock);
1939 dev->power.direct_complete = state.event == PM_EVENT_SUSPEND &&
1940 ((pm_runtime_suspended(dev) && ret > 0) ||
1941 dev->power.no_pm_callbacks) &&
1942 !dev_pm_test_driver_flags(dev, DPM_FLAG_NEVER_SKIP);
1943 spin_unlock_irq(&dev->power.lock);
1948 * dpm_prepare - Prepare all non-sysdev devices for a system PM transition.
1949 * @state: PM transition of the system being carried out.
1951 * Execute the ->prepare() callback(s) for all devices.
1953 int dpm_prepare(pm_message_t state)
1957 trace_suspend_resume(TPS("dpm_prepare"), state.event, true);
1961 * Give a chance for the known devices to complete their probes, before
1962 * disable probing of devices. This sync point is important at least
1963 * at boot time + hibernation restore.
1965 wait_for_device_probe();
1967 * It is unsafe if probing of devices will happen during suspend or
1968 * hibernation and system behavior will be unpredictable in this case.
1969 * So, let's prohibit device's probing here and defer their probes
1970 * instead. The normal behavior will be restored in dpm_complete().
1972 device_block_probing();
1974 mutex_lock(&dpm_list_mtx);
1975 while (!list_empty(&dpm_list)) {
1976 struct device *dev = to_device(dpm_list.next);
1979 mutex_unlock(&dpm_list_mtx);
1981 trace_device_pm_callback_start(dev, "", state.event);
1982 error = device_prepare(dev, state);
1983 trace_device_pm_callback_end(dev, error);
1985 mutex_lock(&dpm_list_mtx);
1987 if (error == -EAGAIN) {
1992 pr_info("Device %s not prepared for power transition: code %d\n",
1993 dev_name(dev), error);
1997 dev->power.is_prepared = true;
1998 if (!list_empty(&dev->power.entry))
1999 list_move_tail(&dev->power.entry, &dpm_prepared_list);
2002 mutex_unlock(&dpm_list_mtx);
2003 trace_suspend_resume(TPS("dpm_prepare"), state.event, false);
2008 * dpm_suspend_start - Prepare devices for PM transition and suspend them.
2009 * @state: PM transition of the system being carried out.
2011 * Prepare all non-sysdev devices for system PM transition and execute "suspend"
2012 * callbacks for them.
2014 int dpm_suspend_start(pm_message_t state)
2016 ktime_t starttime = ktime_get();
2019 error = dpm_prepare(state);
2021 suspend_stats.failed_prepare++;
2022 dpm_save_failed_step(SUSPEND_PREPARE);
2024 error = dpm_suspend(state);
2025 dpm_show_time(starttime, state, error, "start");
2028 EXPORT_SYMBOL_GPL(dpm_suspend_start);
2030 void __suspend_report_result(const char *function, void *fn, int ret)
2033 pr_err("%s(): %pS returns %d\n", function, fn, ret);
2035 EXPORT_SYMBOL_GPL(__suspend_report_result);
2038 * device_pm_wait_for_dev - Wait for suspend/resume of a device to complete.
2039 * @subordinate: Device that needs to wait for @dev.
2040 * @dev: Device to wait for.
2042 int device_pm_wait_for_dev(struct device *subordinate, struct device *dev)
2044 dpm_wait(dev, subordinate->power.async_suspend);
2047 EXPORT_SYMBOL_GPL(device_pm_wait_for_dev);
2050 * dpm_for_each_dev - device iterator.
2051 * @data: data for the callback.
2052 * @fn: function to be called for each device.
2054 * Iterate over devices in dpm_list, and call @fn for each device,
2057 void dpm_for_each_dev(void *data, void (*fn)(struct device *, void *))
2065 list_for_each_entry(dev, &dpm_list, power.entry)
2069 EXPORT_SYMBOL_GPL(dpm_for_each_dev);
2071 static bool pm_ops_is_empty(const struct dev_pm_ops *ops)
2076 return !ops->prepare &&
2078 !ops->suspend_late &&
2079 !ops->suspend_noirq &&
2080 !ops->resume_noirq &&
2081 !ops->resume_early &&
2086 void device_pm_check_callbacks(struct device *dev)
2088 spin_lock_irq(&dev->power.lock);
2089 dev->power.no_pm_callbacks =
2090 (!dev->bus || (pm_ops_is_empty(dev->bus->pm) &&
2091 !dev->bus->suspend && !dev->bus->resume)) &&
2092 (!dev->class || pm_ops_is_empty(dev->class->pm)) &&
2093 (!dev->type || pm_ops_is_empty(dev->type->pm)) &&
2094 (!dev->pm_domain || pm_ops_is_empty(&dev->pm_domain->ops)) &&
2095 (!dev->driver || (pm_ops_is_empty(dev->driver->pm) &&
2096 !dev->driver->suspend && !dev->driver->resume));
2097 spin_unlock_irq(&dev->power.lock);
2100 bool dev_pm_smart_suspend_and_suspended(struct device *dev)
2102 return dev_pm_test_driver_flags(dev, DPM_FLAG_SMART_SUSPEND) &&
2103 pm_runtime_status_suspended(dev);