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author | Paul Mundt <lethal@linux-sh.org> | 2011-03-17 07:44:08 (GMT) |
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committer | Paul Mundt <lethal@linux-sh.org> | 2011-03-17 07:44:08 (GMT) |
commit | 1d2a1959fe534279cf37aba20b08c24c20840e52 (patch) | |
tree | 67c0b9aa7fe22a44bf0b4af88947799203eb8f67 /drivers/base/power/wakeup.c | |
parent | 5a79ce76e9bb8f4b2cd8106ee36d15ee05013bcf (diff) | |
parent | 054cfaacf88865bff1dd58d305443d5d6c068a08 (diff) | |
download | linux-1d2a1959fe534279cf37aba20b08c24c20840e52.tar.xz |
Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 into sh-latest
Diffstat (limited to 'drivers/base/power/wakeup.c')
-rw-r--r-- | drivers/base/power/wakeup.c | 109 |
1 files changed, 76 insertions, 33 deletions
diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c index 8ec406d..4573c83 100644 --- a/drivers/base/power/wakeup.c +++ b/drivers/base/power/wakeup.c @@ -24,12 +24,26 @@ */ bool events_check_enabled; -/* The counter of registered wakeup events. */ -static atomic_t event_count = ATOMIC_INIT(0); -/* A preserved old value of event_count. */ +/* + * 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; -/* The counter of wakeup events being processed. */ -static atomic_t events_in_progress = ATOMIC_INIT(0); static DEFINE_SPINLOCK(events_lock); @@ -228,6 +242,35 @@ int device_wakeup_disable(struct device *dev) 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)) { + 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. @@ -307,7 +350,8 @@ static void wakeup_source_activate(struct wakeup_source *ws) ws->timer_expires = jiffies; ws->last_time = ktime_get(); - atomic_inc(&events_in_progress); + /* Increment the counter of events in progress. */ + atomic_inc(&combined_event_count); } /** @@ -394,14 +438,10 @@ static void wakeup_source_deactivate(struct wakeup_source *ws) del_timer(&ws->timer); /* - * event_count has to be incremented before events_in_progress is - * modified, so that the callers of pm_check_wakeup_events() and - * pm_save_wakeup_count() don't see the old value of event_count and - * events_in_progress equal to zero at the same time. + * Increment the counter of registered wakeup events and decrement the + * couter of wakeup events in progress simultaneously. */ - atomic_inc(&event_count); - smp_mb__before_atomic_dec(); - atomic_dec(&events_in_progress); + atomic_add(MAX_IN_PROGRESS, &combined_event_count); } /** @@ -556,8 +596,10 @@ bool pm_wakeup_pending(void) spin_lock_irqsave(&events_lock, flags); if (events_check_enabled) { - ret = ((unsigned int)atomic_read(&event_count) != saved_count) - || atomic_read(&events_in_progress); + unsigned int cnt, inpr; + + split_counters(&cnt, &inpr); + ret = (cnt != saved_count || inpr > 0); events_check_enabled = !ret; } spin_unlock_irqrestore(&events_lock, flags); @@ -573,25 +615,25 @@ bool pm_wakeup_pending(void) * 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 + * 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. + * of wakeup events being processed is still nonzero). Otherwise return 'true'. */ bool pm_get_wakeup_count(unsigned int *count) { - bool ret; - - if (capable(CAP_SYS_ADMIN)) - events_check_enabled = false; + unsigned int cnt, inpr; - while (atomic_read(&events_in_progress) && !signal_pending(current)) { + for (;;) { + split_counters(&cnt, &inpr); + if (inpr == 0 || signal_pending(current)) + break; pm_wakeup_update_hit_counts(); schedule_timeout_interruptible(msecs_to_jiffies(TIMEOUT)); } - ret = !atomic_read(&events_in_progress); - *count = atomic_read(&event_count); - return ret; + split_counters(&cnt, &inpr); + *count = cnt; + return !inpr; } /** @@ -600,24 +642,25 @@ bool pm_get_wakeup_count(unsigned int *count) * * 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 to be used by pm_check_wakeup_events() - * and return true. Otherwise return false. + * 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) { - bool ret = false; + unsigned int cnt, inpr; + events_check_enabled = false; spin_lock_irq(&events_lock); - if (count == (unsigned int)atomic_read(&event_count) - && !atomic_read(&events_in_progress)) { + split_counters(&cnt, &inpr); + if (cnt == count && inpr == 0) { saved_count = count; events_check_enabled = true; - ret = true; } spin_unlock_irq(&events_lock); - if (!ret) + if (!events_check_enabled) pm_wakeup_update_hit_counts(); - return ret; + return events_check_enabled; } static struct dentry *wakeup_sources_stats_dentry; |