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
19 #define dev_fmt pr_fmt
21 #include <linux/device.h>
22 #include <linux/export.h>
23 #include <linux/mutex.h>
25 #include <linux/pm_runtime.h>
26 #include <linux/pm-trace.h>
27 #include <linux/pm_wakeirq.h>
28 #include <linux/interrupt.h>
29 #include <linux/sched.h>
30 #include <linux/sched/debug.h>
31 #include <linux/async.h>
32 #include <linux/suspend.h>
33 #include <trace/events/power.h>
34 #include <linux/cpufreq.h>
35 #include <linux/cpuidle.h>
36 #include <linux/devfreq.h>
37 #include <linux/timer.h>
42 typedef int (*pm_callback_t)(struct device *);
44 #define list_for_each_entry_rcu_locked(pos, head, member) \
45 list_for_each_entry_rcu(pos, head, member, \
46 device_links_read_lock_held())
49 * The entries in the dpm_list list are in a depth first order, simply
50 * because children are guaranteed to be discovered after parents, and
51 * are inserted at the back of the list on discovery.
53 * Since device_pm_add() may be called with a device lock held,
54 * we must never try to acquire a device lock while holding
59 static LIST_HEAD(dpm_prepared_list);
60 static LIST_HEAD(dpm_suspended_list);
61 static LIST_HEAD(dpm_late_early_list);
62 static LIST_HEAD(dpm_noirq_list);
64 struct suspend_stats suspend_stats;
65 static DEFINE_MUTEX(dpm_list_mtx);
66 static pm_message_t pm_transition;
68 static int async_error;
70 static const char *pm_verb(int event)
73 case PM_EVENT_SUSPEND:
79 case PM_EVENT_QUIESCE:
81 case PM_EVENT_HIBERNATE:
85 case PM_EVENT_RESTORE:
87 case PM_EVENT_RECOVER:
90 return "(unknown PM event)";
95 * device_pm_sleep_init - Initialize system suspend-related device fields.
96 * @dev: Device object being initialized.
98 void device_pm_sleep_init(struct device *dev)
100 dev->power.is_prepared = false;
101 dev->power.is_suspended = false;
102 dev->power.is_noirq_suspended = false;
103 dev->power.is_late_suspended = false;
104 init_completion(&dev->power.completion);
105 complete_all(&dev->power.completion);
106 dev->power.wakeup = NULL;
107 INIT_LIST_HEAD(&dev->power.entry);
111 * device_pm_lock - Lock the list of active devices used by the PM core.
113 void device_pm_lock(void)
115 mutex_lock(&dpm_list_mtx);
119 * device_pm_unlock - Unlock the list of active devices used by the PM core.
121 void device_pm_unlock(void)
123 mutex_unlock(&dpm_list_mtx);
127 * device_pm_add - Add a device to the PM core's list of active devices.
128 * @dev: Device to add to the list.
130 void device_pm_add(struct device *dev)
132 /* Skip PM setup/initialization. */
133 if (device_pm_not_required(dev))
136 pr_debug("Adding info for %s:%s\n",
137 dev->bus ? dev->bus->name : "No Bus", dev_name(dev));
138 device_pm_check_callbacks(dev);
139 mutex_lock(&dpm_list_mtx);
140 if (dev->parent && dev->parent->power.is_prepared)
141 dev_warn(dev, "parent %s should not be sleeping\n",
142 dev_name(dev->parent));
143 list_add_tail(&dev->power.entry, &dpm_list);
144 dev->power.in_dpm_list = true;
145 mutex_unlock(&dpm_list_mtx);
149 * device_pm_remove - Remove a device from the PM core's list of active devices.
150 * @dev: Device to be removed from the list.
152 void device_pm_remove(struct device *dev)
154 if (device_pm_not_required(dev))
157 pr_debug("Removing info for %s:%s\n",
158 dev->bus ? dev->bus->name : "No Bus", dev_name(dev));
159 complete_all(&dev->power.completion);
160 mutex_lock(&dpm_list_mtx);
161 list_del_init(&dev->power.entry);
162 dev->power.in_dpm_list = false;
163 mutex_unlock(&dpm_list_mtx);
164 device_wakeup_disable(dev);
165 pm_runtime_remove(dev);
166 device_pm_check_callbacks(dev);
170 * device_pm_move_before - Move device in the PM core's list of active devices.
171 * @deva: Device to move in dpm_list.
172 * @devb: Device @deva should come before.
174 void device_pm_move_before(struct device *deva, struct device *devb)
176 pr_debug("Moving %s:%s before %s:%s\n",
177 deva->bus ? deva->bus->name : "No Bus", dev_name(deva),
178 devb->bus ? devb->bus->name : "No Bus", dev_name(devb));
179 /* Delete deva from dpm_list and reinsert before devb. */
180 list_move_tail(&deva->power.entry, &devb->power.entry);
184 * device_pm_move_after - Move device in the PM core's list of active devices.
185 * @deva: Device to move in dpm_list.
186 * @devb: Device @deva should come after.
188 void device_pm_move_after(struct device *deva, struct device *devb)
190 pr_debug("Moving %s:%s after %s:%s\n",
191 deva->bus ? deva->bus->name : "No Bus", dev_name(deva),
192 devb->bus ? devb->bus->name : "No Bus", dev_name(devb));
193 /* Delete deva from dpm_list and reinsert after devb. */
194 list_move(&deva->power.entry, &devb->power.entry);
198 * device_pm_move_last - Move device to end of the PM core's list of devices.
199 * @dev: Device to move in dpm_list.
201 void device_pm_move_last(struct device *dev)
203 pr_debug("Moving %s:%s to end of list\n",
204 dev->bus ? dev->bus->name : "No Bus", dev_name(dev));
205 list_move_tail(&dev->power.entry, &dpm_list);
208 static ktime_t initcall_debug_start(struct device *dev, void *cb)
210 if (!pm_print_times_enabled)
213 dev_info(dev, "calling %pS @ %i, parent: %s\n", cb,
214 task_pid_nr(current),
215 dev->parent ? dev_name(dev->parent) : "none");
219 static void initcall_debug_report(struct device *dev, ktime_t calltime,
225 if (!pm_print_times_enabled)
228 rettime = ktime_get();
229 nsecs = (s64) ktime_to_ns(ktime_sub(rettime, calltime));
231 dev_info(dev, "%pS returned %d after %Ld usecs\n", cb, error,
232 (unsigned long long)nsecs >> 10);
236 * dpm_wait - Wait for a PM operation to complete.
237 * @dev: Device to wait for.
238 * @async: If unset, wait only if the device's power.async_suspend flag is set.
240 static void dpm_wait(struct device *dev, bool async)
245 if (async || (pm_async_enabled && dev->power.async_suspend))
246 wait_for_completion(&dev->power.completion);
249 static int dpm_wait_fn(struct device *dev, void *async_ptr)
251 dpm_wait(dev, *((bool *)async_ptr));
255 static void dpm_wait_for_children(struct device *dev, bool async)
257 device_for_each_child(dev, &async, dpm_wait_fn);
260 static void dpm_wait_for_suppliers(struct device *dev, bool async)
262 struct device_link *link;
265 idx = device_links_read_lock();
268 * If the supplier goes away right after we've checked the link to it,
269 * we'll wait for its completion to change the state, but that's fine,
270 * because the only things that will block as a result are the SRCU
271 * callbacks freeing the link objects for the links in the list we're
274 list_for_each_entry_rcu_locked(link, &dev->links.suppliers, c_node)
275 if (READ_ONCE(link->status) != DL_STATE_DORMANT)
276 dpm_wait(link->supplier, async);
278 device_links_read_unlock(idx);
281 static bool dpm_wait_for_superior(struct device *dev, bool async)
283 struct device *parent;
286 * If the device is resumed asynchronously and the parent's callback
287 * deletes both the device and the parent itself, the parent object may
288 * be freed while this function is running, so avoid that by reference
289 * counting the parent once more unless the device has been deleted
290 * already (in which case return right away).
292 mutex_lock(&dpm_list_mtx);
294 if (!device_pm_initialized(dev)) {
295 mutex_unlock(&dpm_list_mtx);
299 parent = get_device(dev->parent);
301 mutex_unlock(&dpm_list_mtx);
303 dpm_wait(parent, async);
306 dpm_wait_for_suppliers(dev, async);
309 * If the parent's callback has deleted the device, attempting to resume
310 * it would be invalid, so avoid doing that then.
312 return device_pm_initialized(dev);
315 static void dpm_wait_for_consumers(struct device *dev, bool async)
317 struct device_link *link;
320 idx = device_links_read_lock();
323 * The status of a device link can only be changed from "dormant" by a
324 * probe, but that cannot happen during system suspend/resume. In
325 * theory it can change to "dormant" at that time, but then it is
326 * reasonable to wait for the target device anyway (eg. if it goes
327 * away, it's better to wait for it to go away completely and then
328 * continue instead of trying to continue in parallel with its
331 list_for_each_entry_rcu_locked(link, &dev->links.consumers, s_node)
332 if (READ_ONCE(link->status) != DL_STATE_DORMANT)
333 dpm_wait(link->consumer, async);
335 device_links_read_unlock(idx);
338 static void dpm_wait_for_subordinate(struct device *dev, bool async)
340 dpm_wait_for_children(dev, async);
341 dpm_wait_for_consumers(dev, async);
345 * pm_op - Return the PM operation appropriate for given PM event.
346 * @ops: PM operations to choose from.
347 * @state: PM transition of the system being carried out.
349 static pm_callback_t pm_op(const struct dev_pm_ops *ops, pm_message_t state)
351 switch (state.event) {
352 #ifdef CONFIG_SUSPEND
353 case PM_EVENT_SUSPEND:
355 case PM_EVENT_RESUME:
357 #endif /* CONFIG_SUSPEND */
358 #ifdef CONFIG_HIBERNATE_CALLBACKS
359 case PM_EVENT_FREEZE:
360 case PM_EVENT_QUIESCE:
362 case PM_EVENT_HIBERNATE:
363 return ops->poweroff;
365 case PM_EVENT_RECOVER:
367 case PM_EVENT_RESTORE:
369 #endif /* CONFIG_HIBERNATE_CALLBACKS */
376 * pm_late_early_op - Return the PM operation appropriate for given PM event.
377 * @ops: PM operations to choose from.
378 * @state: PM transition of the system being carried out.
380 * Runtime PM is disabled for @dev while this function is being executed.
382 static pm_callback_t pm_late_early_op(const struct dev_pm_ops *ops,
385 switch (state.event) {
386 #ifdef CONFIG_SUSPEND
387 case PM_EVENT_SUSPEND:
388 return ops->suspend_late;
389 case PM_EVENT_RESUME:
390 return ops->resume_early;
391 #endif /* CONFIG_SUSPEND */
392 #ifdef CONFIG_HIBERNATE_CALLBACKS
393 case PM_EVENT_FREEZE:
394 case PM_EVENT_QUIESCE:
395 return ops->freeze_late;
396 case PM_EVENT_HIBERNATE:
397 return ops->poweroff_late;
399 case PM_EVENT_RECOVER:
400 return ops->thaw_early;
401 case PM_EVENT_RESTORE:
402 return ops->restore_early;
403 #endif /* CONFIG_HIBERNATE_CALLBACKS */
410 * pm_noirq_op - Return the PM operation appropriate for given PM event.
411 * @ops: PM operations to choose from.
412 * @state: PM transition of the system being carried out.
414 * The driver of @dev will not receive interrupts while this function is being
417 static pm_callback_t pm_noirq_op(const struct dev_pm_ops *ops, pm_message_t state)
419 switch (state.event) {
420 #ifdef CONFIG_SUSPEND
421 case PM_EVENT_SUSPEND:
422 return ops->suspend_noirq;
423 case PM_EVENT_RESUME:
424 return ops->resume_noirq;
425 #endif /* CONFIG_SUSPEND */
426 #ifdef CONFIG_HIBERNATE_CALLBACKS
427 case PM_EVENT_FREEZE:
428 case PM_EVENT_QUIESCE:
429 return ops->freeze_noirq;
430 case PM_EVENT_HIBERNATE:
431 return ops->poweroff_noirq;
433 case PM_EVENT_RECOVER:
434 return ops->thaw_noirq;
435 case PM_EVENT_RESTORE:
436 return ops->restore_noirq;
437 #endif /* CONFIG_HIBERNATE_CALLBACKS */
443 static void pm_dev_dbg(struct device *dev, pm_message_t state, const char *info)
445 dev_dbg(dev, "%s%s%s\n", info, pm_verb(state.event),
446 ((state.event & PM_EVENT_SLEEP) && device_may_wakeup(dev)) ?
447 ", may wakeup" : "");
450 static void pm_dev_err(struct device *dev, pm_message_t state, const char *info,
453 dev_err(dev, "failed to %s%s: error %d\n", pm_verb(state.event), info,
457 static void dpm_show_time(ktime_t starttime, pm_message_t state, int error,
464 calltime = ktime_get();
465 usecs64 = ktime_to_ns(ktime_sub(calltime, starttime));
466 do_div(usecs64, NSEC_PER_USEC);
471 pm_pr_dbg("%s%s%s of devices %s after %ld.%03ld msecs\n",
472 info ?: "", info ? " " : "", pm_verb(state.event),
473 error ? "aborted" : "complete",
474 usecs / USEC_PER_MSEC, usecs % USEC_PER_MSEC);
477 static int dpm_run_callback(pm_callback_t cb, struct device *dev,
478 pm_message_t state, const char *info)
486 calltime = initcall_debug_start(dev, cb);
488 pm_dev_dbg(dev, state, info);
489 trace_device_pm_callback_start(dev, info, state.event);
491 trace_device_pm_callback_end(dev, error);
492 suspend_report_result(cb, error);
494 initcall_debug_report(dev, calltime, cb, error);
499 #ifdef CONFIG_DPM_WATCHDOG
500 struct dpm_watchdog {
502 struct task_struct *tsk;
503 struct timer_list timer;
506 #define DECLARE_DPM_WATCHDOG_ON_STACK(wd) \
507 struct dpm_watchdog wd
510 * dpm_watchdog_handler - Driver suspend / resume watchdog handler.
511 * @t: The timer that PM watchdog depends on.
513 * Called when a driver has timed out suspending or resuming.
514 * There's not much we can do here to recover so panic() to
515 * capture a crash-dump in pstore.
517 static void dpm_watchdog_handler(struct timer_list *t)
519 struct dpm_watchdog *wd = from_timer(wd, t, timer);
521 dev_emerg(wd->dev, "**** DPM device timeout ****\n");
522 show_stack(wd->tsk, NULL, KERN_EMERG);
523 panic("%s %s: unrecoverable failure\n",
524 dev_driver_string(wd->dev), dev_name(wd->dev));
528 * dpm_watchdog_set - Enable pm watchdog for given device.
529 * @wd: Watchdog. Must be allocated on the stack.
530 * @dev: Device to handle.
532 static void dpm_watchdog_set(struct dpm_watchdog *wd, struct device *dev)
534 struct timer_list *timer = &wd->timer;
539 timer_setup_on_stack(timer, dpm_watchdog_handler, 0);
540 /* use same timeout value for both suspend and resume */
541 timer->expires = jiffies + HZ * CONFIG_DPM_WATCHDOG_TIMEOUT;
546 * dpm_watchdog_clear - Disable suspend/resume watchdog.
547 * @wd: Watchdog to disable.
549 static void dpm_watchdog_clear(struct dpm_watchdog *wd)
551 struct timer_list *timer = &wd->timer;
553 del_timer_sync(timer);
554 destroy_timer_on_stack(timer);
557 #define DECLARE_DPM_WATCHDOG_ON_STACK(wd)
558 #define dpm_watchdog_set(x, y)
559 #define dpm_watchdog_clear(x)
562 /*------------------------- Resume routines -------------------------*/
565 * dev_pm_skip_resume - System-wide device resume optimization check.
566 * @dev: Target device.
569 * - %false if the transition under way is RESTORE.
570 * - Return value of dev_pm_skip_suspend() if the transition under way is THAW.
571 * - The logical negation of %power.must_resume otherwise (that is, when the
572 * transition under way is RESUME).
574 bool dev_pm_skip_resume(struct device *dev)
576 if (pm_transition.event == PM_EVENT_RESTORE)
579 if (pm_transition.event == PM_EVENT_THAW)
580 return dev_pm_skip_suspend(dev);
582 return !dev->power.must_resume;
586 * __device_resume_noirq - Execute a "noirq resume" callback for given device.
587 * @dev: Device to handle.
588 * @state: PM transition of the system being carried out.
589 * @async: If true, the device is being resumed asynchronously.
591 * The driver of @dev will not receive interrupts while this function is being
594 static void __device_resume_noirq(struct device *dev, pm_message_t state, bool async)
596 pm_callback_t callback = NULL;
597 const char *info = NULL;
604 if (dev->power.syscore || dev->power.direct_complete)
607 if (!dev->power.is_noirq_suspended)
610 if (!dpm_wait_for_superior(dev, async))
613 skip_resume = dev_pm_skip_resume(dev);
615 * If the driver callback is skipped below or by the middle layer
616 * callback and device_resume_early() also skips the driver callback for
617 * this device later, it needs to appear as "suspended" to PM-runtime,
618 * so change its status accordingly.
620 * Otherwise, the device is going to be resumed, so set its PM-runtime
621 * status to "active", but do that only if DPM_FLAG_SMART_SUSPEND is set
622 * to avoid confusing drivers that don't use it.
625 pm_runtime_set_suspended(dev);
626 else if (dev_pm_skip_suspend(dev))
627 pm_runtime_set_active(dev);
629 if (dev->pm_domain) {
630 info = "noirq power domain ";
631 callback = pm_noirq_op(&dev->pm_domain->ops, state);
632 } else if (dev->type && dev->type->pm) {
633 info = "noirq type ";
634 callback = pm_noirq_op(dev->type->pm, state);
635 } else if (dev->class && dev->class->pm) {
636 info = "noirq class ";
637 callback = pm_noirq_op(dev->class->pm, state);
638 } else if (dev->bus && dev->bus->pm) {
640 callback = pm_noirq_op(dev->bus->pm, state);
648 if (dev->driver && dev->driver->pm) {
649 info = "noirq driver ";
650 callback = pm_noirq_op(dev->driver->pm, state);
654 error = dpm_run_callback(callback, dev, state, info);
657 dev->power.is_noirq_suspended = false;
660 complete_all(&dev->power.completion);
664 suspend_stats.failed_resume_noirq++;
665 dpm_save_failed_step(SUSPEND_RESUME_NOIRQ);
666 dpm_save_failed_dev(dev_name(dev));
667 pm_dev_err(dev, state, async ? " async noirq" : " noirq", error);
671 static bool is_async(struct device *dev)
673 return dev->power.async_suspend && pm_async_enabled
674 && !pm_trace_is_enabled();
677 static bool dpm_async_fn(struct device *dev, async_func_t func)
679 reinit_completion(&dev->power.completion);
686 if (async_schedule_dev_nocall(func, dev))
694 static void async_resume_noirq(void *data, async_cookie_t cookie)
696 struct device *dev = data;
698 __device_resume_noirq(dev, pm_transition, true);
702 static void device_resume_noirq(struct device *dev)
704 if (dpm_async_fn(dev, async_resume_noirq))
707 __device_resume_noirq(dev, pm_transition, false);
710 static void dpm_noirq_resume_devices(pm_message_t state)
713 ktime_t starttime = ktime_get();
715 trace_suspend_resume(TPS("dpm_resume_noirq"), state.event, true);
716 mutex_lock(&dpm_list_mtx);
717 pm_transition = state;
719 while (!list_empty(&dpm_noirq_list)) {
720 dev = to_device(dpm_noirq_list.next);
722 list_move_tail(&dev->power.entry, &dpm_late_early_list);
724 mutex_unlock(&dpm_list_mtx);
726 device_resume_noirq(dev);
730 mutex_lock(&dpm_list_mtx);
732 mutex_unlock(&dpm_list_mtx);
733 async_synchronize_full();
734 dpm_show_time(starttime, state, 0, "noirq");
735 trace_suspend_resume(TPS("dpm_resume_noirq"), state.event, false);
739 * dpm_resume_noirq - Execute "noirq resume" callbacks for all devices.
740 * @state: PM transition of the system being carried out.
742 * Invoke the "noirq" resume callbacks for all devices in dpm_noirq_list and
743 * allow device drivers' interrupt handlers to be called.
745 void dpm_resume_noirq(pm_message_t state)
747 dpm_noirq_resume_devices(state);
749 resume_device_irqs();
750 device_wakeup_disarm_wake_irqs();
756 * __device_resume_early - Execute an "early resume" callback for given device.
757 * @dev: Device to handle.
758 * @state: PM transition of the system being carried out.
759 * @async: If true, the device is being resumed asynchronously.
761 * Runtime PM is disabled for @dev while this function is being executed.
763 static void __device_resume_early(struct device *dev, pm_message_t state, bool async)
765 pm_callback_t callback = NULL;
766 const char *info = NULL;
772 if (dev->power.syscore || dev->power.direct_complete)
775 if (!dev->power.is_late_suspended)
778 if (!dpm_wait_for_superior(dev, async))
781 if (dev->pm_domain) {
782 info = "early power domain ";
783 callback = pm_late_early_op(&dev->pm_domain->ops, state);
784 } else if (dev->type && dev->type->pm) {
785 info = "early type ";
786 callback = pm_late_early_op(dev->type->pm, state);
787 } else if (dev->class && dev->class->pm) {
788 info = "early class ";
789 callback = pm_late_early_op(dev->class->pm, state);
790 } else if (dev->bus && dev->bus->pm) {
792 callback = pm_late_early_op(dev->bus->pm, state);
797 if (dev_pm_skip_resume(dev))
800 if (dev->driver && dev->driver->pm) {
801 info = "early driver ";
802 callback = pm_late_early_op(dev->driver->pm, state);
806 error = dpm_run_callback(callback, dev, state, info);
809 dev->power.is_late_suspended = false;
814 pm_runtime_enable(dev);
815 complete_all(&dev->power.completion);
818 suspend_stats.failed_resume_early++;
819 dpm_save_failed_step(SUSPEND_RESUME_EARLY);
820 dpm_save_failed_dev(dev_name(dev));
821 pm_dev_err(dev, state, async ? " async early" : " early", error);
825 static void async_resume_early(void *data, async_cookie_t cookie)
827 struct device *dev = data;
829 __device_resume_early(dev, pm_transition, true);
833 static void device_resume_early(struct device *dev)
835 if (dpm_async_fn(dev, async_resume_early))
838 __device_resume_early(dev, pm_transition, false);
842 * dpm_resume_early - Execute "early resume" callbacks for all devices.
843 * @state: PM transition of the system being carried out.
845 void dpm_resume_early(pm_message_t state)
848 ktime_t starttime = ktime_get();
850 trace_suspend_resume(TPS("dpm_resume_early"), state.event, true);
851 mutex_lock(&dpm_list_mtx);
852 pm_transition = state;
854 while (!list_empty(&dpm_late_early_list)) {
855 dev = to_device(dpm_late_early_list.next);
857 list_move_tail(&dev->power.entry, &dpm_suspended_list);
859 mutex_unlock(&dpm_list_mtx);
861 device_resume_early(dev);
865 mutex_lock(&dpm_list_mtx);
867 mutex_unlock(&dpm_list_mtx);
868 async_synchronize_full();
869 dpm_show_time(starttime, state, 0, "early");
870 trace_suspend_resume(TPS("dpm_resume_early"), state.event, false);
874 * dpm_resume_start - Execute "noirq" and "early" device callbacks.
875 * @state: PM transition of the system being carried out.
877 void dpm_resume_start(pm_message_t state)
879 dpm_resume_noirq(state);
880 dpm_resume_early(state);
882 EXPORT_SYMBOL_GPL(dpm_resume_start);
885 * __device_resume - Execute "resume" callbacks for given device.
886 * @dev: Device to handle.
887 * @state: PM transition of the system being carried out.
888 * @async: If true, the device is being resumed asynchronously.
890 static void __device_resume(struct device *dev, pm_message_t state, bool async)
892 pm_callback_t callback = NULL;
893 const char *info = NULL;
895 DECLARE_DPM_WATCHDOG_ON_STACK(wd);
900 if (dev->power.syscore)
903 if (dev->power.direct_complete) {
904 /* Match the pm_runtime_disable() in __device_suspend(). */
905 pm_runtime_enable(dev);
909 if (!dpm_wait_for_superior(dev, async))
912 dpm_watchdog_set(&wd, dev);
916 * This is a fib. But we'll allow new children to be added below
917 * a resumed device, even if the device hasn't been completed yet.
919 dev->power.is_prepared = false;
921 if (!dev->power.is_suspended)
924 if (dev->pm_domain) {
925 info = "power domain ";
926 callback = pm_op(&dev->pm_domain->ops, state);
930 if (dev->type && dev->type->pm) {
932 callback = pm_op(dev->type->pm, state);
936 if (dev->class && dev->class->pm) {
938 callback = pm_op(dev->class->pm, state);
945 callback = pm_op(dev->bus->pm, state);
946 } else if (dev->bus->resume) {
947 info = "legacy bus ";
948 callback = dev->bus->resume;
954 if (!callback && dev->driver && dev->driver->pm) {
956 callback = pm_op(dev->driver->pm, state);
960 error = dpm_run_callback(callback, dev, state, info);
961 dev->power.is_suspended = false;
965 dpm_watchdog_clear(&wd);
968 complete_all(&dev->power.completion);
973 suspend_stats.failed_resume++;
974 dpm_save_failed_step(SUSPEND_RESUME);
975 dpm_save_failed_dev(dev_name(dev));
976 pm_dev_err(dev, state, async ? " async" : "", error);
980 static void async_resume(void *data, async_cookie_t cookie)
982 struct device *dev = data;
984 __device_resume(dev, pm_transition, true);
988 static void device_resume(struct device *dev)
990 if (dpm_async_fn(dev, async_resume))
993 __device_resume(dev, pm_transition, false);
997 * dpm_resume - Execute "resume" callbacks for non-sysdev devices.
998 * @state: PM transition of the system being carried out.
1000 * Execute the appropriate "resume" callback for all devices whose status
1001 * indicates that they are suspended.
1003 void dpm_resume(pm_message_t state)
1006 ktime_t starttime = ktime_get();
1008 trace_suspend_resume(TPS("dpm_resume"), state.event, true);
1011 mutex_lock(&dpm_list_mtx);
1012 pm_transition = state;
1015 while (!list_empty(&dpm_suspended_list)) {
1016 dev = to_device(dpm_suspended_list.next);
1020 mutex_unlock(&dpm_list_mtx);
1024 mutex_lock(&dpm_list_mtx);
1026 if (!list_empty(&dev->power.entry))
1027 list_move_tail(&dev->power.entry, &dpm_prepared_list);
1029 mutex_unlock(&dpm_list_mtx);
1033 mutex_lock(&dpm_list_mtx);
1035 mutex_unlock(&dpm_list_mtx);
1036 async_synchronize_full();
1037 dpm_show_time(starttime, state, 0, NULL);
1041 trace_suspend_resume(TPS("dpm_resume"), state.event, false);
1045 * device_complete - Complete a PM transition for given device.
1046 * @dev: Device to handle.
1047 * @state: PM transition of the system being carried out.
1049 static void device_complete(struct device *dev, pm_message_t state)
1051 void (*callback)(struct device *) = NULL;
1052 const char *info = NULL;
1054 if (dev->power.syscore)
1059 if (dev->pm_domain) {
1060 info = "completing power domain ";
1061 callback = dev->pm_domain->ops.complete;
1062 } else if (dev->type && dev->type->pm) {
1063 info = "completing type ";
1064 callback = dev->type->pm->complete;
1065 } else if (dev->class && dev->class->pm) {
1066 info = "completing class ";
1067 callback = dev->class->pm->complete;
1068 } else if (dev->bus && dev->bus->pm) {
1069 info = "completing bus ";
1070 callback = dev->bus->pm->complete;
1073 if (!callback && dev->driver && dev->driver->pm) {
1074 info = "completing driver ";
1075 callback = dev->driver->pm->complete;
1079 pm_dev_dbg(dev, state, info);
1086 pm_runtime_put(dev);
1090 * dpm_complete - Complete a PM transition for all non-sysdev devices.
1091 * @state: PM transition of the system being carried out.
1093 * Execute the ->complete() callbacks for all devices whose PM status is not
1094 * DPM_ON (this allows new devices to be registered).
1096 void dpm_complete(pm_message_t state)
1098 struct list_head list;
1100 trace_suspend_resume(TPS("dpm_complete"), state.event, true);
1103 INIT_LIST_HEAD(&list);
1104 mutex_lock(&dpm_list_mtx);
1105 while (!list_empty(&dpm_prepared_list)) {
1106 struct device *dev = to_device(dpm_prepared_list.prev);
1109 dev->power.is_prepared = false;
1110 list_move(&dev->power.entry, &list);
1112 mutex_unlock(&dpm_list_mtx);
1114 trace_device_pm_callback_start(dev, "", state.event);
1115 device_complete(dev, state);
1116 trace_device_pm_callback_end(dev, 0);
1120 mutex_lock(&dpm_list_mtx);
1122 list_splice(&list, &dpm_list);
1123 mutex_unlock(&dpm_list_mtx);
1125 /* Allow device probing and trigger re-probing of deferred devices */
1126 device_unblock_probing();
1127 trace_suspend_resume(TPS("dpm_complete"), state.event, false);
1131 * dpm_resume_end - Execute "resume" callbacks and complete system transition.
1132 * @state: PM transition of the system being carried out.
1134 * Execute "resume" callbacks for all devices and complete the PM transition of
1137 void dpm_resume_end(pm_message_t state)
1140 dpm_complete(state);
1142 EXPORT_SYMBOL_GPL(dpm_resume_end);
1145 /*------------------------- Suspend routines -------------------------*/
1148 * resume_event - Return a "resume" message for given "suspend" sleep state.
1149 * @sleep_state: PM message representing a sleep state.
1151 * Return a PM message representing the resume event corresponding to given
1154 static pm_message_t resume_event(pm_message_t sleep_state)
1156 switch (sleep_state.event) {
1157 case PM_EVENT_SUSPEND:
1159 case PM_EVENT_FREEZE:
1160 case PM_EVENT_QUIESCE:
1161 return PMSG_RECOVER;
1162 case PM_EVENT_HIBERNATE:
1163 return PMSG_RESTORE;
1168 static void dpm_superior_set_must_resume(struct device *dev)
1170 struct device_link *link;
1174 dev->parent->power.must_resume = true;
1176 idx = device_links_read_lock();
1178 list_for_each_entry_rcu_locked(link, &dev->links.suppliers, c_node)
1179 link->supplier->power.must_resume = true;
1181 device_links_read_unlock(idx);
1185 * __device_suspend_noirq - Execute a "noirq suspend" callback for given device.
1186 * @dev: Device to handle.
1187 * @state: PM transition of the system being carried out.
1188 * @async: If true, the device is being suspended asynchronously.
1190 * The driver of @dev will not receive interrupts while this function is being
1193 static int __device_suspend_noirq(struct device *dev, pm_message_t state, bool async)
1195 pm_callback_t callback = NULL;
1196 const char *info = NULL;
1202 dpm_wait_for_subordinate(dev, async);
1207 if (dev->power.syscore || dev->power.direct_complete)
1210 if (dev->pm_domain) {
1211 info = "noirq power domain ";
1212 callback = pm_noirq_op(&dev->pm_domain->ops, state);
1213 } else if (dev->type && dev->type->pm) {
1214 info = "noirq type ";
1215 callback = pm_noirq_op(dev->type->pm, state);
1216 } else if (dev->class && dev->class->pm) {
1217 info = "noirq class ";
1218 callback = pm_noirq_op(dev->class->pm, state);
1219 } else if (dev->bus && dev->bus->pm) {
1220 info = "noirq bus ";
1221 callback = pm_noirq_op(dev->bus->pm, state);
1226 if (dev_pm_skip_suspend(dev))
1229 if (dev->driver && dev->driver->pm) {
1230 info = "noirq driver ";
1231 callback = pm_noirq_op(dev->driver->pm, state);
1235 error = dpm_run_callback(callback, dev, state, info);
1237 async_error = error;
1242 dev->power.is_noirq_suspended = true;
1245 * Skipping the resume of devices that were in use right before the
1246 * system suspend (as indicated by their PM-runtime usage counters)
1247 * would be suboptimal. Also resume them if doing that is not allowed
1250 if (atomic_read(&dev->power.usage_count) > 1 ||
1251 !(dev_pm_test_driver_flags(dev, DPM_FLAG_MAY_SKIP_RESUME) &&
1252 dev->power.may_skip_resume))
1253 dev->power.must_resume = true;
1255 if (dev->power.must_resume)
1256 dpm_superior_set_must_resume(dev);
1259 complete_all(&dev->power.completion);
1260 TRACE_SUSPEND(error);
1264 static void async_suspend_noirq(void *data, async_cookie_t cookie)
1266 struct device *dev = data;
1269 error = __device_suspend_noirq(dev, pm_transition, true);
1271 dpm_save_failed_dev(dev_name(dev));
1272 pm_dev_err(dev, pm_transition, " async", error);
1278 static int device_suspend_noirq(struct device *dev)
1280 if (dpm_async_fn(dev, async_suspend_noirq))
1283 return __device_suspend_noirq(dev, pm_transition, false);
1286 static int dpm_noirq_suspend_devices(pm_message_t state)
1288 ktime_t starttime = ktime_get();
1291 trace_suspend_resume(TPS("dpm_suspend_noirq"), state.event, true);
1292 mutex_lock(&dpm_list_mtx);
1293 pm_transition = state;
1296 while (!list_empty(&dpm_late_early_list)) {
1297 struct device *dev = to_device(dpm_late_early_list.prev);
1300 mutex_unlock(&dpm_list_mtx);
1302 error = device_suspend_noirq(dev);
1304 mutex_lock(&dpm_list_mtx);
1307 pm_dev_err(dev, state, " noirq", error);
1308 dpm_save_failed_dev(dev_name(dev));
1309 } else if (!list_empty(&dev->power.entry)) {
1310 list_move(&dev->power.entry, &dpm_noirq_list);
1313 mutex_unlock(&dpm_list_mtx);
1317 mutex_lock(&dpm_list_mtx);
1319 if (error || async_error)
1322 mutex_unlock(&dpm_list_mtx);
1323 async_synchronize_full();
1325 error = async_error;
1328 suspend_stats.failed_suspend_noirq++;
1329 dpm_save_failed_step(SUSPEND_SUSPEND_NOIRQ);
1331 dpm_show_time(starttime, state, error, "noirq");
1332 trace_suspend_resume(TPS("dpm_suspend_noirq"), state.event, false);
1337 * dpm_suspend_noirq - Execute "noirq suspend" callbacks for all devices.
1338 * @state: PM transition of the system being carried out.
1340 * Prevent device drivers' interrupt handlers from being called and invoke
1341 * "noirq" suspend callbacks for all non-sysdev devices.
1343 int dpm_suspend_noirq(pm_message_t state)
1349 device_wakeup_arm_wake_irqs();
1350 suspend_device_irqs();
1352 ret = dpm_noirq_suspend_devices(state);
1354 dpm_resume_noirq(resume_event(state));
1359 static void dpm_propagate_wakeup_to_parent(struct device *dev)
1361 struct device *parent = dev->parent;
1366 spin_lock_irq(&parent->power.lock);
1368 if (dev->power.wakeup_path && !parent->power.ignore_children)
1369 parent->power.wakeup_path = true;
1371 spin_unlock_irq(&parent->power.lock);
1375 * __device_suspend_late - Execute a "late suspend" callback for given device.
1376 * @dev: Device to handle.
1377 * @state: PM transition of the system being carried out.
1378 * @async: If true, the device is being suspended asynchronously.
1380 * Runtime PM is disabled for @dev while this function is being executed.
1382 static int __device_suspend_late(struct device *dev, pm_message_t state, bool async)
1384 pm_callback_t callback = NULL;
1385 const char *info = NULL;
1391 __pm_runtime_disable(dev, false);
1393 dpm_wait_for_subordinate(dev, async);
1398 if (pm_wakeup_pending()) {
1399 async_error = -EBUSY;
1403 if (dev->power.syscore || dev->power.direct_complete)
1406 if (dev->pm_domain) {
1407 info = "late power domain ";
1408 callback = pm_late_early_op(&dev->pm_domain->ops, state);
1409 } else if (dev->type && dev->type->pm) {
1410 info = "late type ";
1411 callback = pm_late_early_op(dev->type->pm, state);
1412 } else if (dev->class && dev->class->pm) {
1413 info = "late class ";
1414 callback = pm_late_early_op(dev->class->pm, state);
1415 } else if (dev->bus && dev->bus->pm) {
1417 callback = pm_late_early_op(dev->bus->pm, state);
1422 if (dev_pm_skip_suspend(dev))
1425 if (dev->driver && dev->driver->pm) {
1426 info = "late driver ";
1427 callback = pm_late_early_op(dev->driver->pm, state);
1431 error = dpm_run_callback(callback, dev, state, info);
1433 async_error = error;
1436 dpm_propagate_wakeup_to_parent(dev);
1439 dev->power.is_late_suspended = true;
1442 TRACE_SUSPEND(error);
1443 complete_all(&dev->power.completion);
1447 static void async_suspend_late(void *data, async_cookie_t cookie)
1449 struct device *dev = data;
1452 error = __device_suspend_late(dev, pm_transition, true);
1454 dpm_save_failed_dev(dev_name(dev));
1455 pm_dev_err(dev, pm_transition, " async", error);
1460 static int device_suspend_late(struct device *dev)
1462 if (dpm_async_fn(dev, async_suspend_late))
1465 return __device_suspend_late(dev, pm_transition, false);
1469 * dpm_suspend_late - Execute "late suspend" callbacks for all devices.
1470 * @state: PM transition of the system being carried out.
1472 int dpm_suspend_late(pm_message_t state)
1474 ktime_t starttime = ktime_get();
1477 trace_suspend_resume(TPS("dpm_suspend_late"), state.event, true);
1478 mutex_lock(&dpm_list_mtx);
1479 pm_transition = state;
1482 while (!list_empty(&dpm_suspended_list)) {
1483 struct device *dev = to_device(dpm_suspended_list.prev);
1487 mutex_unlock(&dpm_list_mtx);
1489 error = device_suspend_late(dev);
1491 mutex_lock(&dpm_list_mtx);
1493 if (!list_empty(&dev->power.entry))
1494 list_move(&dev->power.entry, &dpm_late_early_list);
1497 pm_dev_err(dev, state, " late", error);
1498 dpm_save_failed_dev(dev_name(dev));
1501 mutex_unlock(&dpm_list_mtx);
1505 mutex_lock(&dpm_list_mtx);
1507 if (error || async_error)
1510 mutex_unlock(&dpm_list_mtx);
1511 async_synchronize_full();
1513 error = async_error;
1515 suspend_stats.failed_suspend_late++;
1516 dpm_save_failed_step(SUSPEND_SUSPEND_LATE);
1517 dpm_resume_early(resume_event(state));
1519 dpm_show_time(starttime, state, error, "late");
1520 trace_suspend_resume(TPS("dpm_suspend_late"), state.event, false);
1525 * dpm_suspend_end - Execute "late" and "noirq" device suspend callbacks.
1526 * @state: PM transition of the system being carried out.
1528 int dpm_suspend_end(pm_message_t state)
1530 ktime_t starttime = ktime_get();
1533 error = dpm_suspend_late(state);
1537 error = dpm_suspend_noirq(state);
1539 dpm_resume_early(resume_event(state));
1542 dpm_show_time(starttime, state, error, "end");
1545 EXPORT_SYMBOL_GPL(dpm_suspend_end);
1548 * legacy_suspend - Execute a legacy (bus or class) suspend callback for device.
1549 * @dev: Device to suspend.
1550 * @state: PM transition of the system being carried out.
1551 * @cb: Suspend callback to execute.
1552 * @info: string description of caller.
1554 static int legacy_suspend(struct device *dev, pm_message_t state,
1555 int (*cb)(struct device *dev, pm_message_t state),
1561 calltime = initcall_debug_start(dev, cb);
1563 trace_device_pm_callback_start(dev, info, state.event);
1564 error = cb(dev, state);
1565 trace_device_pm_callback_end(dev, error);
1566 suspend_report_result(cb, error);
1568 initcall_debug_report(dev, calltime, cb, error);
1573 static void dpm_clear_superiors_direct_complete(struct device *dev)
1575 struct device_link *link;
1579 spin_lock_irq(&dev->parent->power.lock);
1580 dev->parent->power.direct_complete = false;
1581 spin_unlock_irq(&dev->parent->power.lock);
1584 idx = device_links_read_lock();
1586 list_for_each_entry_rcu_locked(link, &dev->links.suppliers, c_node) {
1587 spin_lock_irq(&link->supplier->power.lock);
1588 link->supplier->power.direct_complete = false;
1589 spin_unlock_irq(&link->supplier->power.lock);
1592 device_links_read_unlock(idx);
1596 * __device_suspend - Execute "suspend" callbacks for given device.
1597 * @dev: Device to handle.
1598 * @state: PM transition of the system being carried out.
1599 * @async: If true, the device is being suspended asynchronously.
1601 static int __device_suspend(struct device *dev, pm_message_t state, bool async)
1603 pm_callback_t callback = NULL;
1604 const char *info = NULL;
1606 DECLARE_DPM_WATCHDOG_ON_STACK(wd);
1611 dpm_wait_for_subordinate(dev, async);
1614 dev->power.direct_complete = false;
1619 * Wait for possible runtime PM transitions of the device in progress
1620 * to complete and if there's a runtime resume request pending for it,
1621 * resume it before proceeding with invoking the system-wide suspend
1624 * If the system-wide suspend callbacks below change the configuration
1625 * of the device, they must disable runtime PM for it or otherwise
1626 * ensure that its runtime-resume callbacks will not be confused by that
1627 * change in case they are invoked going forward.
1629 pm_runtime_barrier(dev);
1631 if (pm_wakeup_pending()) {
1632 dev->power.direct_complete = false;
1633 async_error = -EBUSY;
1637 if (dev->power.syscore)
1640 /* Avoid direct_complete to let wakeup_path propagate. */
1641 if (device_may_wakeup(dev) || dev->power.wakeup_path)
1642 dev->power.direct_complete = false;
1644 if (dev->power.direct_complete) {
1645 if (pm_runtime_status_suspended(dev)) {
1646 pm_runtime_disable(dev);
1647 if (pm_runtime_status_suspended(dev)) {
1648 pm_dev_dbg(dev, state, "direct-complete ");
1652 pm_runtime_enable(dev);
1654 dev->power.direct_complete = false;
1657 dev->power.may_skip_resume = true;
1658 dev->power.must_resume = !dev_pm_test_driver_flags(dev, DPM_FLAG_MAY_SKIP_RESUME);
1660 dpm_watchdog_set(&wd, dev);
1663 if (dev->pm_domain) {
1664 info = "power domain ";
1665 callback = pm_op(&dev->pm_domain->ops, state);
1669 if (dev->type && dev->type->pm) {
1671 callback = pm_op(dev->type->pm, state);
1675 if (dev->class && dev->class->pm) {
1677 callback = pm_op(dev->class->pm, state);
1684 callback = pm_op(dev->bus->pm, state);
1685 } else if (dev->bus->suspend) {
1686 pm_dev_dbg(dev, state, "legacy bus ");
1687 error = legacy_suspend(dev, state, dev->bus->suspend,
1694 if (!callback && dev->driver && dev->driver->pm) {
1696 callback = pm_op(dev->driver->pm, state);
1699 error = dpm_run_callback(callback, dev, state, info);
1703 dev->power.is_suspended = true;
1704 if (device_may_wakeup(dev))
1705 dev->power.wakeup_path = true;
1707 dpm_propagate_wakeup_to_parent(dev);
1708 dpm_clear_superiors_direct_complete(dev);
1712 dpm_watchdog_clear(&wd);
1716 async_error = error;
1718 complete_all(&dev->power.completion);
1719 TRACE_SUSPEND(error);
1723 static void async_suspend(void *data, async_cookie_t cookie)
1725 struct device *dev = data;
1728 error = __device_suspend(dev, pm_transition, true);
1730 dpm_save_failed_dev(dev_name(dev));
1731 pm_dev_err(dev, pm_transition, " async", error);
1737 static int device_suspend(struct device *dev)
1739 if (dpm_async_fn(dev, async_suspend))
1742 return __device_suspend(dev, pm_transition, false);
1746 * dpm_suspend - Execute "suspend" callbacks for all non-sysdev devices.
1747 * @state: PM transition of the system being carried out.
1749 int dpm_suspend(pm_message_t state)
1751 ktime_t starttime = ktime_get();
1754 trace_suspend_resume(TPS("dpm_suspend"), state.event, true);
1760 mutex_lock(&dpm_list_mtx);
1761 pm_transition = state;
1763 while (!list_empty(&dpm_prepared_list)) {
1764 struct device *dev = to_device(dpm_prepared_list.prev);
1768 mutex_unlock(&dpm_list_mtx);
1770 error = device_suspend(dev);
1772 mutex_lock(&dpm_list_mtx);
1775 pm_dev_err(dev, state, "", error);
1776 dpm_save_failed_dev(dev_name(dev));
1777 } else if (!list_empty(&dev->power.entry)) {
1778 list_move(&dev->power.entry, &dpm_suspended_list);
1781 mutex_unlock(&dpm_list_mtx);
1785 mutex_lock(&dpm_list_mtx);
1787 if (error || async_error)
1790 mutex_unlock(&dpm_list_mtx);
1791 async_synchronize_full();
1793 error = async_error;
1795 suspend_stats.failed_suspend++;
1796 dpm_save_failed_step(SUSPEND_SUSPEND);
1798 dpm_show_time(starttime, state, error, NULL);
1799 trace_suspend_resume(TPS("dpm_suspend"), state.event, false);
1804 * device_prepare - Prepare a device for system power transition.
1805 * @dev: Device to handle.
1806 * @state: PM transition of the system being carried out.
1808 * Execute the ->prepare() callback(s) for given device. No new children of the
1809 * device may be registered after this function has returned.
1811 static int device_prepare(struct device *dev, pm_message_t state)
1813 int (*callback)(struct device *) = NULL;
1817 * If a device's parent goes into runtime suspend at the wrong time,
1818 * it won't be possible to resume the device. To prevent this we
1819 * block runtime suspend here, during the prepare phase, and allow
1820 * it again during the complete phase.
1822 pm_runtime_get_noresume(dev);
1824 if (dev->power.syscore)
1829 dev->power.wakeup_path = false;
1831 if (dev->power.no_pm_callbacks)
1835 callback = dev->pm_domain->ops.prepare;
1836 else if (dev->type && dev->type->pm)
1837 callback = dev->type->pm->prepare;
1838 else if (dev->class && dev->class->pm)
1839 callback = dev->class->pm->prepare;
1840 else if (dev->bus && dev->bus->pm)
1841 callback = dev->bus->pm->prepare;
1843 if (!callback && dev->driver && dev->driver->pm)
1844 callback = dev->driver->pm->prepare;
1847 ret = callback(dev);
1853 suspend_report_result(callback, ret);
1854 pm_runtime_put(dev);
1858 * A positive return value from ->prepare() means "this device appears
1859 * to be runtime-suspended and its state is fine, so if it really is
1860 * runtime-suspended, you can leave it in that state provided that you
1861 * will do the same thing with all of its descendants". This only
1862 * applies to suspend transitions, however.
1864 spin_lock_irq(&dev->power.lock);
1865 dev->power.direct_complete = state.event == PM_EVENT_SUSPEND &&
1866 (ret > 0 || dev->power.no_pm_callbacks) &&
1867 !dev_pm_test_driver_flags(dev, DPM_FLAG_NO_DIRECT_COMPLETE);
1868 spin_unlock_irq(&dev->power.lock);
1873 * dpm_prepare - Prepare all non-sysdev devices for a system PM transition.
1874 * @state: PM transition of the system being carried out.
1876 * Execute the ->prepare() callback(s) for all devices.
1878 int dpm_prepare(pm_message_t state)
1882 trace_suspend_resume(TPS("dpm_prepare"), state.event, true);
1886 * Give a chance for the known devices to complete their probes, before
1887 * disable probing of devices. This sync point is important at least
1888 * at boot time + hibernation restore.
1890 wait_for_device_probe();
1892 * It is unsafe if probing of devices will happen during suspend or
1893 * hibernation and system behavior will be unpredictable in this case.
1894 * So, let's prohibit device's probing here and defer their probes
1895 * instead. The normal behavior will be restored in dpm_complete().
1897 device_block_probing();
1899 mutex_lock(&dpm_list_mtx);
1900 while (!list_empty(&dpm_list) && !error) {
1901 struct device *dev = to_device(dpm_list.next);
1905 mutex_unlock(&dpm_list_mtx);
1907 trace_device_pm_callback_start(dev, "", state.event);
1908 error = device_prepare(dev, state);
1909 trace_device_pm_callback_end(dev, error);
1911 mutex_lock(&dpm_list_mtx);
1914 dev->power.is_prepared = true;
1915 if (!list_empty(&dev->power.entry))
1916 list_move_tail(&dev->power.entry, &dpm_prepared_list);
1917 } else if (error == -EAGAIN) {
1920 dev_info(dev, "not prepared for power transition: code %d\n",
1924 mutex_unlock(&dpm_list_mtx);
1928 mutex_lock(&dpm_list_mtx);
1930 mutex_unlock(&dpm_list_mtx);
1931 trace_suspend_resume(TPS("dpm_prepare"), state.event, false);
1936 * dpm_suspend_start - Prepare devices for PM transition and suspend them.
1937 * @state: PM transition of the system being carried out.
1939 * Prepare all non-sysdev devices for system PM transition and execute "suspend"
1940 * callbacks for them.
1942 int dpm_suspend_start(pm_message_t state)
1944 ktime_t starttime = ktime_get();
1947 error = dpm_prepare(state);
1949 suspend_stats.failed_prepare++;
1950 dpm_save_failed_step(SUSPEND_PREPARE);
1952 error = dpm_suspend(state);
1953 dpm_show_time(starttime, state, error, "start");
1956 EXPORT_SYMBOL_GPL(dpm_suspend_start);
1958 void __suspend_report_result(const char *function, void *fn, int ret)
1961 pr_err("%s(): %pS returns %d\n", function, fn, ret);
1963 EXPORT_SYMBOL_GPL(__suspend_report_result);
1966 * device_pm_wait_for_dev - Wait for suspend/resume of a device to complete.
1967 * @subordinate: Device that needs to wait for @dev.
1968 * @dev: Device to wait for.
1970 int device_pm_wait_for_dev(struct device *subordinate, struct device *dev)
1972 dpm_wait(dev, subordinate->power.async_suspend);
1975 EXPORT_SYMBOL_GPL(device_pm_wait_for_dev);
1978 * dpm_for_each_dev - device iterator.
1979 * @data: data for the callback.
1980 * @fn: function to be called for each device.
1982 * Iterate over devices in dpm_list, and call @fn for each device,
1985 void dpm_for_each_dev(void *data, void (*fn)(struct device *, void *))
1993 list_for_each_entry(dev, &dpm_list, power.entry)
1997 EXPORT_SYMBOL_GPL(dpm_for_each_dev);
1999 static bool pm_ops_is_empty(const struct dev_pm_ops *ops)
2004 return !ops->prepare &&
2006 !ops->suspend_late &&
2007 !ops->suspend_noirq &&
2008 !ops->resume_noirq &&
2009 !ops->resume_early &&
2014 void device_pm_check_callbacks(struct device *dev)
2016 unsigned long flags;
2018 spin_lock_irqsave(&dev->power.lock, flags);
2019 dev->power.no_pm_callbacks =
2020 (!dev->bus || (pm_ops_is_empty(dev->bus->pm) &&
2021 !dev->bus->suspend && !dev->bus->resume)) &&
2022 (!dev->class || pm_ops_is_empty(dev->class->pm)) &&
2023 (!dev->type || pm_ops_is_empty(dev->type->pm)) &&
2024 (!dev->pm_domain || pm_ops_is_empty(&dev->pm_domain->ops)) &&
2025 (!dev->driver || (pm_ops_is_empty(dev->driver->pm) &&
2026 !dev->driver->suspend && !dev->driver->resume));
2027 spin_unlock_irqrestore(&dev->power.lock, flags);
2030 bool dev_pm_skip_suspend(struct device *dev)
2032 return dev_pm_test_driver_flags(dev, DPM_FLAG_SMART_SUSPEND) &&
2033 pm_runtime_status_suspended(dev);