linux/drivers/base/power/wakeup.c
Rafael J. Wysocki 8671bbc1bd PM / Sleep: Add more wakeup source initialization routines
The existing wakeup source initialization routines are not
particularly useful for wakeup sources that aren't created by
wakeup_source_create(), because their users have to open code
filling the objects with zeros and setting their names.  For this
reason, introduce routines that can be used for initializing, for
example, static wakeup source objects.

Requested-by: Arve Hjønnevåg <arve@android.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2012-03-04 23:08:46 +01:00

793 lines
21 KiB
C

/*
* 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/export.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_prepare - Prepare a new wakeup source for initialization.
* @ws: Wakeup source to prepare.
* @name: Pointer to the name of the new wakeup source.
*
* Callers must ensure that the @name string won't be freed when @ws is still in
* use.
*/
void wakeup_source_prepare(struct wakeup_source *ws, const char *name)
{
if (ws) {
memset(ws, 0, sizeof(*ws));
ws->name = name;
}
}
EXPORT_SYMBOL_GPL(wakeup_source_prepare);
/**
* 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 = kmalloc(sizeof(*ws), GFP_KERNEL);
if (!ws)
return NULL;
wakeup_source_prepare(ws, name ? kstrdup(name, GFP_KERNEL) : NULL);
return ws;
}
EXPORT_SYMBOL_GPL(wakeup_source_create);
/**
* wakeup_source_drop - Prepare a struct wakeup_source object for destruction.
* @ws: Wakeup source to prepare for destruction.
*
* Callers must ensure that __pm_stay_awake() or __pm_wakeup_event() will never
* be run in parallel with this function for the same wakeup source object.
*/
void wakeup_source_drop(struct wakeup_source *ws)
{
if (!ws)
return;
del_timer_sync(&ws->timer);
__pm_relax(ws);
}
EXPORT_SYMBOL_GPL(wakeup_source_drop);
/**
* wakeup_source_destroy - Destroy a struct wakeup_source object.
* @ws: Wakeup source to destroy.
*
* Use only for wakeup source objects created with wakeup_source_create().
*/
void wakeup_source_destroy(struct wakeup_source *ws)
{
if (!ws)
return;
wakeup_source_drop(ws);
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;
spin_lock_init(&ws->lock);
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)
{
if (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->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);
del_timer(&ws->timer);
ws->timer_expires = 0;
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);
ws->timer_expires = 0;
/*
* 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 wakeup_source_deactivate() for the wakeup source whose address is stored
* in @data if it is currently active and its timer has not been canceled and
* the expiration time of the timer is not in future.
*/
static void pm_wakeup_timer_fn(unsigned long data)
{
struct wakeup_source *ws = (struct wakeup_source *)data;
unsigned long flags;
spin_lock_irqsave(&ws->lock, flags);
if (ws->active && ws->timer_expires
&& time_after_eq(jiffies, ws->timer_expires))
wakeup_source_deactivate(ws);
spin_unlock_irqrestore(&ws->lock, flags);
}
/**
* __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 (!ws->timer_expires || 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);