/*
* drivers/base/power/wakeup.c - System wakeup events framework
*
* Copyright (c) 2010 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
*
* This file is released under the GPLv2.
*/
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/capability.h>
#include <linux/suspend.h>
#include <linux/seq_file.h>
#include <linux/debugfs.h>
#include "power.h"
#define TIMEOUT 100
/*
* If set, the suspend/hibernate code will abort transitions to a sleep state
* if wakeup events are registered during or immediately before the transition.
*/
bool events_check_enabled;
/*
* Combined counters of registered wakeup events and wakeup events in progress.
* They need to be modified together atomically, so it's better to use one
* atomic variable to hold them both.
*/
static atomic_t combined_event_count = ATOMIC_INIT(0);
#define IN_PROGRESS_BITS (sizeof(int) * 4)
#define MAX_IN_PROGRESS ((1 << IN_PROGRESS_BITS) - 1)
static void split_counters(unsigned int *cnt, unsigned int *inpr)
{
unsigned int comb = atomic_read(&combined_event_count);
*cnt = (comb >> IN_PROGRESS_BITS);
*inpr = comb & MAX_IN_PROGRESS;
}
/* A preserved old value of the events counter. */
static unsigned int saved_count;
static DEFINE_SPINLOCK(events_lock);
static void pm_wakeup_timer_fn(unsigned long data);
static LIST_HEAD(wakeup_sources);
/**
* wakeup_source_create - Create a struct wakeup_source object.
* @name: Name of the new wakeup source.
*/
struct wakeup_source *wakeup_source_create(const char *name)
{
struct wakeup_source *ws;
ws = kzalloc(sizeof(*ws), GFP_KERNEL);
if (!ws)
return NULL;
spin_lock_init(&ws->lock);
if (name)
ws->name = kstrdup(name, GFP_KERNEL);
return ws;
}
EXPORT_SYMBOL_GPL(wakeup_source_create);
/**
* wakeup_source_destroy - Destroy a struct wakeup_source object.
* @ws: Wakeup source to destroy.
*/
void wakeup_source_destroy(struct wakeup_source *ws)
{
if (!ws)
return;
spin_lock_irq(&ws->lock);
while (ws->active) {
spin_unlock_irq(&ws->lock);
schedule_timeout_interruptible(msecs_to_jiffies(TIMEOUT));
spin_lock_irq(&ws->lock);
}
spin_unlock_irq(&ws->lock);
kfree(ws->name);
kfree(ws);
}
EXPORT_SYMBOL_GPL(wakeup_source_destroy);
/**
* wakeup_source_add - Add given object to the list of wakeup sources.
* @ws: Wakeup source object to add to the list.
*/
void wakeup_source_add(struct wakeup_source *ws)
{
if (WARN_ON(!ws))
return;
setup_timer(&ws->timer, pm_wakeup_timer_fn, (unsigned long)ws);
ws->active = false;
spin_lock_irq(&events_lock);
list_add_rcu(&ws->entry, &wakeup_sources);
spin_unlock_irq(&events_lock);
}
EXPORT_SYMBOL_GPL(wakeup_source_add);
/**
* wakeup_source_remove - Remove given object from the wakeup sources list.
* @ws: Wakeup source object to remove from the list.
*/
void wakeup_source_remove(struct wakeup_source *ws)
{
if (WARN_ON(!ws))
return;
spin_lock_irq(&events_lock);
list_del_rcu(&ws->entry);
spin_unlock_irq(&events_lock);
synchronize_rcu();
}
EXPORT_SYMBOL_GPL(wakeup_source_remove);
/**
* wakeup_source_register - Create wakeup source and add it to the list.
* @name: Name of the wakeup source to register.
*/
struct wakeup_source *wakeup_source_register(const char *name)
{
struct wakeup_source *ws;
ws = wakeup_source_create(name);
if (ws)
wakeup_source_add(ws);
return ws;
}
EXPORT_SYMBOL_GPL(wakeup_source_register);
/**
* wakeup_source_unregister - Remove wakeup source from the list and remove it.
* @ws: Wakeup source object to unregister.
*/
void wakeup_source_unregister(struct wakeup_source *ws)
{
wakeup_source_remove(ws);
wakeup_source_destroy(ws);
}
EXPORT_SYMBOL_GPL(wakeup_source_unregister);
/**
* device_wakeup_attach - Attach a wakeup source object to a device object.
* @dev: Device to handle.
* @ws: Wakeup source object to attach to @dev.
*
* This causes @dev to be treated as a wakeup device.
*/
static int device_wakeup_attach(struct device *dev, struct wakeup_source *ws)
{
spin_lock_irq(&dev->power.lock);
if (dev->power.wakeup) {
spin_unlock_irq(&dev->power.lock);
return -EEXIST;
}
dev->power.wakeup = ws;
spin_unlock_irq(&dev->power.lock);
return 0;
}
/**
* device_wakeup_enable - Enable given device to be a wakeup source.
* @dev: Device to handle.
*
* Create a wakeup source object, register it and attach it to @dev.
*/
int device_wakeup_enable(struct device *dev)
{
struct wakeup_source *ws;
int ret;
if (!dev || !dev->power.can_wakeup)
return -EINVAL;
ws = wakeup_source_register(dev_name(dev));
if (!ws)
return -ENOMEM;
ret = device_wakeup_attach(dev, ws);
if (ret)
wakeup_source_unregister(ws);
return ret;
}
EXPORT_SYMBOL_GPL(device_wakeup_enable);
/**
* device_wakeup_detach - Detach a device's wakeup source object from it.
* @dev: Device to detach the wakeup source object from.
*
* After it returns, @dev will not be treated as a wakeup device any more.
*/
static struct wakeup_source *device_wakeup_detach(struct device *dev)
{
struct wakeup_source *ws;
spin_lock_irq(&dev->power.lock);
ws = dev->power.wakeup;
dev->power.wakeup = NULL;
spin_unlock_irq(&dev->power.lock);
return ws;
}
/**
* device_wakeup_disable - Do not regard a device as a wakeup source any more.
* @dev: Device to handle.
*
* Detach the @dev's wakeup source object from it, unregister this wakeup source
* object and destroy it.
*/
int device_wakeup_disable(struct device *dev)
{
struct wakeup_source *ws;
if (!dev || !dev->power.can_wakeup)
return -EINVAL;
ws = device_wakeup_detach(dev);
if (ws)
wakeup_source_unregister(ws);
return 0;
}
EXPORT_SYMBOL_GPL(device_wakeup_disable);
/**
* device_set_wakeup_capable - Set/reset device wakeup capability flag.
* @dev: Device to handle.
* @capable: Whether or not @dev is capable of waking up the system from sleep.
*
* If @capable is set, set the @dev's power.can_wakeup flag and add its
* wakeup-related attributes to sysfs. Otherwise, unset the @dev's
* power.can_wakeup flag and remove its wakeup-related attributes from sysfs.
*
* This function may sleep and it can't be called from any context where
* sleeping is not allowed.
*/
void device_set_wakeup_capable(struct device *dev, bool capable)
{
if (!!dev->power.can_wakeup == !!capable)
return;
if (device_is_registered(dev) && !list_empty(&dev->power.entry)) {
if (capable) {
if (wakeup_sysfs_add(dev))
return;
} else {
wakeup_sysfs_remove(dev);
}
}
dev->power.can_wakeup = capable;
}
EXPORT_SYMBOL_GPL(device_set_wakeup_capable);
/**
* device_init_wakeup - Device wakeup initialization.
* @dev: Device to handle.
* @enable: Whether or not to enable @dev as a wakeup device.
*
* By default, most devices should leave wakeup disabled. The exceptions are
* devices that everyone expects to be wakeup sources: keyboards, power buttons,
* possibly network interfaces, etc. Also, devices that don't generate their
* own wakeup requests but merely forward requests from one bus to another
* (like PCI bridges) should have wakeup enabled by default.
*/
int device_init_wakeup(struct device *dev, bool enable)
{
int ret = 0;
if (enable) {
device_set_wakeup_capable(dev, true);
ret = device_wakeup_enable(dev);
} else {
device_set_wakeup_capable(dev, false);
}
return ret;
}
EXPORT_SYMBOL_GPL(device_init_wakeup);
/**
* device_set_wakeup_enable - Enable or disable a device to wake up the system.
* @dev: Device to handle.
*/
int device_set_wakeup_enable(struct device *dev, bool enable)
{
if (!dev || !dev->power.can_wakeup)
return -EINVAL;
return enable ? device_wakeup_enable(dev) : device_wakeup_disable(dev);
}
EXPORT_SYMBOL_GPL(device_set_wakeup_enable);
/*
* The functions below use the observation that each wakeup event starts a
* period in which the system should not be suspended. The moment this period
* will end depends on how the wakeup event is going to be processed after being
* detected and all of the possible cases can be divided into two distinct
* groups.
*
* First, a wakeup event may be detected by the same functional unit that will
* carry out the entire processing of it and possibly will pass it to user space
* for further processing. In that case the functional unit that has detected
* the event may later "close" the "no suspend" period associated with it
* directly as soon as it has been dealt with. The pair of pm_stay_awake() and
* pm_relax(), balanced with each other, is supposed to be used in such
* situations.
*
* Second, a wakeup event may be detected by one functional unit and processed
* by another one. In that case the unit that has detected it cannot really
* "close" the "no suspend" period associated with it, unless it knows in
* advance what's going to happen to the event during processing. This
* knowledge, however, may not be available to it, so it can simply specify time
* to wait before the system can be suspended and pass it as the second
* argument of pm_wakeup_event().
*
* It is valid to call pm_relax() after pm_wakeup_event(), in which case the
* "no suspend" period will be ended either by the pm_relax(), or by the timer
* function executed when the timer expires, whichever comes first.
*/
/**
* wakup_source_activate - Mark given wakeup source as active.
* @ws: Wakeup source to handle.
*
* Update the @ws' statistics and, if @ws has just been activated, notify the PM
* core of the event by incrementing the counter of of wakeup events being
* processed.
*/
static void wakeup_source_activate(struct wakeup_source *ws)
{
ws->active = true;
ws->active_count++;
ws->timer_expires = jiffies;
ws->last_time = ktime_get();
/* Increment the counter of events in progress. */
atomic_inc(&combined_event_count);
}
/**
* __pm_stay_awake - Notify the PM core of a wakeup event.
* @ws: Wakeup source object associated with the source of the event.
*
* It is safe to call this function from interrupt context.
*/
void __pm_stay_awake(struct wakeup_source *ws)
{
unsigned long flags;
if (!ws)
return;
spin_lock_irqsave(&ws->lock, flags);
ws->event_count++;
if (!ws->active)
wakeup_source_activate(ws);
spin_unlock_irqrestore(&ws->lock, flags);
}
EXPORT_SYMBOL_GPL(__pm_stay_awake);
/**
* pm_stay_awake - Notify the PM core that a wakeup event is being processed.
* @dev: Device the wakeup event is related to.
*
* Notify the PM core of a wakeup event (signaled by @dev) by calling
* __pm_stay_awake for the @dev's wakeup source object.
*
* Call this function after detecting of a wakeup event if pm_relax() is going
* to be called directly after processing the event (and possibly passing it to
* user space for further processing).
*/
void pm_stay_awake(struct device *dev)
{
unsigned long flags;
if (!dev)
return;
spin_lock_irqsave(&dev->power.lock, flags);
__pm_stay_awake(dev->power.wakeup);
spin_unlock_irqrestore(&dev->power.lock, flags);
}
EXPORT_SYMBOL_GPL(pm_stay_awake);
/**
* wakup_source_deactivate - Mark given wakeup source as inactive.
* @ws: Wakeup source to handle.
*
* Update the @ws' statistics and notify the PM core that the wakeup source has
* become inactive by decrementing the counter of wakeup events being processed
* and incrementing the counter of registered wakeup events.
*/
static void wakeup_source_deactivate(struct wakeup_source *ws)
{
ktime_t duration;
ktime_t now;
ws->relax_count++;
/*
* __pm_relax() may be called directly or from a timer function.
* If it is called directly right after the timer function has been
* started, but before the timer function calls __pm_relax(), it is
* possible that __pm_stay_awake() will be called in the meantime and
* will set ws->active. Then, ws->active may be cleared immediately
* by the __pm_relax() called from the timer function, but in such a
* case ws->relax_count will be different from ws->active_count.
*/
if (ws->relax_count != ws->active_count) {
ws->relax_count--;
return;
}
ws->active = false;
now = ktime_get();
duration = ktime_sub(now, ws->last_time);
ws->total_time = ktime_add(ws->total_time, duration);
if (ktime_to_ns(duration) > ktime_to_ns(ws->max_time))
ws->max_time = duration;
del_timer(&ws->timer);
/*
* Increment the counter of registered wakeup events and decrement the
* couter of wakeup events in progress simultaneously.
*/
atomic_add(MAX_IN_PROGRESS, &combined_event_count);
}
/**
* __pm_relax - Notify the PM core that processing of a wakeup event has ended.
* @ws: Wakeup source object associated with the source of the event.
*
* Call this function for wakeup events whose processing started with calling
* __pm_stay_awake().
*
* It is safe to call it from interrupt context.
*/
void __pm_relax(struct wakeup_source *ws)
{
unsigned long flags;
if (!ws)
return;
spin_lock_irqsave(&ws->lock, flags);
if (ws->active)
wakeup_source_deactivate(ws);
spin_unlock_irqrestore(&ws->lock, flags);
}
EXPORT_SYMBOL_GPL(__pm_relax);
/**
* pm_relax - Notify the PM core that processing of a wakeup event has ended.
* @dev: Device that signaled the event.
*
* Execute __pm_relax() for the @dev's wakeup source object.
*/
void pm_relax(struct device *dev)
{
unsigned long flags;
if (!dev)
return;
spin_lock_irqsave(&dev->power.lock, flags);
__pm_relax(dev->power.wakeup);
spin_unlock_irqrestore(&dev->power.lock, flags);
}
EXPORT_SYMBOL_GPL(pm_relax);
/**
* pm_wakeup_timer_fn - Delayed finalization of a wakeup event.
* @data: Address of the wakeup source object associated with the event source.
*
* Call __pm_relax() for the wakeup source whose address is stored in @data.
*/
static void pm_wakeup_timer_fn(unsigned long data)
{
__pm_relax((struct wakeup_source *)data);
}
/**
* __pm_wakeup_event - Notify the PM core of a wakeup event.
* @ws: Wakeup source object associated with the event source.
* @msec: Anticipated event processing time (in milliseconds).
*
* Notify the PM core of a wakeup event whose source is @ws that will take
* approximately @msec milliseconds to be processed by the kernel. If @ws is
* not active, activate it. If @msec is nonzero, set up the @ws' timer to
* execute pm_wakeup_timer_fn() in future.
*
* It is safe to call this function from interrupt context.
*/
void __pm_wakeup_event(struct wakeup_source *ws, unsigned int msec)
{
unsigned long flags;
unsigned long expires;
if (!ws)
return;
spin_lock_irqsave(&ws->lock, flags);
ws->event_count++;
if (!ws->active)
wakeup_source_activate(ws);
if (!msec) {
wakeup_source_deactivate(ws);
goto unlock;
}
expires = jiffies + msecs_to_jiffies(msec);
if (!expires)
expires = 1;
if (time_after(expires, ws->timer_expires)) {
mod_timer(&ws->timer, expires);
ws->timer_expires = expires;
}
unlock:
spin_unlock_irqrestore(&ws->lock, flags);
}
EXPORT_SYMBOL_GPL(__pm_wakeup_event);
/**
* pm_wakeup_event - Notify the PM core of a wakeup event.
* @dev: Device the wakeup event is related to.
* @msec: Anticipated event processing time (in milliseconds).
*
* Call __pm_wakeup_event() for the @dev's wakeup source object.
*/
void pm_wakeup_event(struct device *dev, unsigned int msec)
{
unsigned long flags;
if (!dev)
return;
spin_lock_irqsave(&dev->power.lock, flags);
__pm_wakeup_event(dev->power.wakeup, msec);
spin_unlock_irqrestore(&dev->power.lock, flags);
}
EXPORT_SYMBOL_GPL(pm_wakeup_event);
/**
* pm_wakeup_update_hit_counts - Update hit counts of all active wakeup sources.
*/
static void pm_wakeup_update_hit_counts(void)
{
unsigned long flags;
struct wakeup_source *ws;
rcu_read_lock();
list_for_each_entry_rcu(ws, &wakeup_sources, entry) {
spin_lock_irqsave(&ws->lock, flags);
if (ws->active)
ws->hit_count++;
spin_unlock_irqrestore(&ws->lock, flags);
}
rcu_read_unlock();
}
/**
* pm_wakeup_pending - Check if power transition in progress should be aborted.
*
* Compare the current number of registered wakeup events with its preserved
* value from the past and return true if new wakeup events have been registered
* since the old value was stored. Also return true if the current number of
* wakeup events being processed is different from zero.
*/
bool pm_wakeup_pending(void)
{
unsigned long flags;
bool ret = false;
spin_lock_irqsave(&events_lock, flags);
if (events_check_enabled) {
unsigned int cnt, inpr;
split_counters(&cnt, &inpr);
ret = (cnt != saved_count || inpr > 0);
events_check_enabled = !ret;
}
spin_unlock_irqrestore(&events_lock, flags);
if (ret)
pm_wakeup_update_hit_counts();
return ret;
}
/**
* pm_get_wakeup_count - Read the number of registered wakeup events.
* @count: Address to store the value at.
*
* Store the number of registered wakeup events at the address in @count. Block
* if the current number of wakeup events being processed is nonzero.
*
* Return 'false' if the wait for the number of wakeup events being processed to
* drop down to zero has been interrupted by a signal (and the current number
* of wakeup events being processed is still nonzero). Otherwise return 'true'.
*/
bool pm_get_wakeup_count(unsigned int *count)
{
unsigned int cnt, inpr;
for (;;) {
split_counters(&cnt, &inpr);
if (inpr == 0 || signal_pending(current))
break;
pm_wakeup_update_hit_counts();
schedule_timeout_interruptible(msecs_to_jiffies(TIMEOUT));
}
split_counters(&cnt, &inpr);
*count = cnt;
return !inpr;
}
/**
* pm_save_wakeup_count - Save the current number of registered wakeup events.
* @count: Value to compare with the current number of registered wakeup events.
*
* If @count is equal to the current number of registered wakeup events and the
* current number of wakeup events being processed is zero, store @count as the
* old number of registered wakeup events for pm_check_wakeup_events(), enable
* wakeup events detection and return 'true'. Otherwise disable wakeup events
* detection and return 'false'.
*/
bool pm_save_wakeup_count(unsigned int count)
{
unsigned int cnt, inpr;
events_check_enabled = false;
spin_lock_irq(&events_lock);
split_counters(&cnt, &inpr);
if (cnt == count && inpr == 0) {
saved_count = count;
events_check_enabled = true;
}
spin_unlock_irq(&events_lock);
if (!events_check_enabled)
pm_wakeup_update_hit_counts();
return events_check_enabled;
}
static struct dentry *wakeup_sources_stats_dentry;
/**
* print_wakeup_source_stats - Print wakeup source statistics information.
* @m: seq_file to print the statistics into.
* @ws: Wakeup source object to print the statistics for.
*/
static int print_wakeup_source_stats(struct seq_file *m,
struct wakeup_source *ws)
{
unsigned long flags;
ktime_t total_time;
ktime_t max_time;
unsigned long active_count;
ktime_t active_time;
int ret;
spin_lock_irqsave(&ws->lock, flags);
total_time = ws->total_time;
max_time = ws->max_time;
active_count = ws->active_count;
if (ws->active) {
active_time = ktime_sub(ktime_get(), ws->last_time);
total_time = ktime_add(total_time, active_time);
if (active_time.tv64 > max_time.tv64)
max_time = active_time;
} else {
active_time = ktime_set(0, 0);
}
ret = seq_printf(m, "%-12s\t%lu\t\t%lu\t\t%lu\t\t"
"%lld\t\t%lld\t\t%lld\t\t%lld\n",
ws->name, active_count, ws->event_count, ws->hit_count,
ktime_to_ms(active_time), ktime_to_ms(total_time),
ktime_to_ms(max_time), ktime_to_ms(ws->last_time));
spin_unlock_irqrestore(&ws->lock, flags);
return ret;
}
/**
* wakeup_sources_stats_show - Print wakeup sources statistics information.
* @m: seq_file to print the statistics into.
*/
static int wakeup_sources_stats_show(struct seq_file *m, void *unused)
{
struct wakeup_source *ws;
seq_puts(m, "name\t\tactive_count\tevent_count\thit_count\t"
"active_since\ttotal_time\tmax_time\tlast_change\n");
rcu_read_lock();
list_for_each_entry_rcu(ws, &wakeup_sources, entry)
print_wakeup_source_stats(m, ws);
rcu_read_unlock();
return 0;
}
static int wakeup_sources_stats_open(struct inode *inode, struct file *file)
{
return single_open(file, wakeup_sources_stats_show, NULL);
}
static const struct file_operations wakeup_sources_stats_fops = {
.owner = THIS_MODULE,
.open = wakeup_sources_stats_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static int __init wakeup_sources_debugfs_init(void)
{
wakeup_sources_stats_dentry = debugfs_create_file("wakeup_sources",
S_IRUGO, NULL, NULL, &wakeup_sources_stats_fops);
return 0;
}
postcore_initcall(wakeup_sources_debugfs_init);
