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Diffstat (limited to 'kernel/time/alarmtimer.c')
-rw-r--r--kernel/time/alarmtimer.c158
1 files changed, 88 insertions, 70 deletions
diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
index 2d966244ea60..59f369f98a04 100644
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -42,15 +42,75 @@ static struct alarm_base {
clockid_t base_clockid;
} alarm_bases[ALARM_NUMTYPE];
+/* freezer delta & lock used to handle clock_nanosleep triggered wakeups */
+static ktime_t freezer_delta;
+static DEFINE_SPINLOCK(freezer_delta_lock);
+
#ifdef CONFIG_RTC_CLASS
/* rtc timer and device for setting alarm wakeups at suspend */
static struct rtc_timer rtctimer;
static struct rtc_device *rtcdev;
-#endif
+static DEFINE_SPINLOCK(rtcdev_lock);
-/* freezer delta & lock used to handle clock_nanosleep triggered wakeups */
-static ktime_t freezer_delta;
-static DEFINE_SPINLOCK(freezer_delta_lock);
+/**
+ * has_wakealarm - check rtc device has wakealarm ability
+ * @dev: current device
+ * @name_ptr: name to be returned
+ *
+ * This helper function checks to see if the rtc device can wake
+ * from suspend.
+ */
+static int has_wakealarm(struct device *dev, void *name_ptr)
+{
+ struct rtc_device *candidate = to_rtc_device(dev);
+
+ if (!candidate->ops->set_alarm)
+ return 0;
+ if (!device_may_wakeup(candidate->dev.parent))
+ return 0;
+
+ *(const char **)name_ptr = dev_name(dev);
+ return 1;
+}
+
+/**
+ * alarmtimer_get_rtcdev - Return selected rtcdevice
+ *
+ * This function returns the rtc device to use for wakealarms.
+ * If one has not already been chosen, it checks to see if a
+ * functional rtc device is available.
+ */
+static struct rtc_device *alarmtimer_get_rtcdev(void)
+{
+ struct device *dev;
+ char *str;
+ unsigned long flags;
+ struct rtc_device *ret;
+
+ spin_lock_irqsave(&rtcdev_lock, flags);
+ if (!rtcdev) {
+ /* Find an rtc device and init the rtc_timer */
+ dev = class_find_device(rtc_class, NULL, &str, has_wakealarm);
+ /* If we have a device then str is valid. See has_wakealarm() */
+ if (dev) {
+ rtcdev = rtc_class_open(str);
+ /*
+ * Drop the reference we got in class_find_device,
+ * rtc_open takes its own.
+ */
+ put_device(dev);
+ rtc_timer_init(&rtctimer, NULL, NULL);
+ }
+ }
+ ret = rtcdev;
+ spin_unlock_irqrestore(&rtcdev_lock, flags);
+
+ return ret;
+}
+#else
+#define alarmtimer_get_rtcdev() (0)
+#define rtcdev (0)
+#endif
/**
@@ -166,6 +226,7 @@ static int alarmtimer_suspend(struct device *dev)
struct rtc_time tm;
ktime_t min, now;
unsigned long flags;
+ struct rtc_device *rtc;
int i;
spin_lock_irqsave(&freezer_delta_lock, flags);
@@ -173,8 +234,9 @@ static int alarmtimer_suspend(struct device *dev)
freezer_delta = ktime_set(0, 0);
spin_unlock_irqrestore(&freezer_delta_lock, flags);
+ rtc = rtcdev;
/* If we have no rtcdev, just return */
- if (!rtcdev)
+ if (!rtc)
return 0;
/* Find the soonest timer to expire*/
@@ -199,12 +261,12 @@ static int alarmtimer_suspend(struct device *dev)
WARN_ON(min.tv64 < NSEC_PER_SEC);
/* Setup an rtc timer to fire that far in the future */
- rtc_timer_cancel(rtcdev, &rtctimer);
- rtc_read_time(rtcdev, &tm);
+ rtc_timer_cancel(rtc, &rtctimer);
+ rtc_read_time(rtc, &tm);
now = rtc_tm_to_ktime(tm);
now = ktime_add(now, min);
- rtc_timer_start(rtcdev, &rtctimer, now, ktime_set(0, 0));
+ rtc_timer_start(rtc, &rtctimer, now, ktime_set(0, 0));
return 0;
}
@@ -322,6 +384,9 @@ static int alarm_clock_getres(const clockid_t which_clock, struct timespec *tp)
{
clockid_t baseid = alarm_bases[clock2alarm(which_clock)].base_clockid;
+ if (!alarmtimer_get_rtcdev())
+ return -ENOTSUPP;
+
return hrtimer_get_res(baseid, tp);
}
@@ -336,6 +401,9 @@ static int alarm_clock_get(clockid_t which_clock, struct timespec *tp)
{
struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)];
+ if (!alarmtimer_get_rtcdev())
+ return -ENOTSUPP;
+
*tp = ktime_to_timespec(base->gettime());
return 0;
}
@@ -351,6 +419,9 @@ static int alarm_timer_create(struct k_itimer *new_timer)
enum alarmtimer_type type;
struct alarm_base *base;
+ if (!alarmtimer_get_rtcdev())
+ return -ENOTSUPP;
+
if (!capable(CAP_WAKE_ALARM))
return -EPERM;
@@ -385,6 +456,9 @@ static void alarm_timer_get(struct k_itimer *timr,
*/
static int alarm_timer_del(struct k_itimer *timr)
{
+ if (!rtcdev)
+ return -ENOTSUPP;
+
alarm_cancel(&timr->it.alarmtimer);
return 0;
}
@@ -402,6 +476,9 @@ static int alarm_timer_set(struct k_itimer *timr, int flags,
struct itimerspec *new_setting,
struct itimerspec *old_setting)
{
+ if (!rtcdev)
+ return -ENOTSUPP;
+
/* Save old values */
old_setting->it_interval =
ktime_to_timespec(timr->it.alarmtimer.period);
@@ -541,6 +618,9 @@ static int alarm_timer_nsleep(const clockid_t which_clock, int flags,
int ret = 0;
struct restart_block *restart;
+ if (!alarmtimer_get_rtcdev())
+ return -ENOTSUPP;
+
if (!capable(CAP_WAKE_ALARM))
return -EPERM;
@@ -638,65 +718,3 @@ static int __init alarmtimer_init(void)
}
device_initcall(alarmtimer_init);
-#ifdef CONFIG_RTC_CLASS
-/**
- * has_wakealarm - check rtc device has wakealarm ability
- * @dev: current device
- * @name_ptr: name to be returned
- *
- * This helper function checks to see if the rtc device can wake
- * from suspend.
- */
-static int __init has_wakealarm(struct device *dev, void *name_ptr)
-{
- struct rtc_device *candidate = to_rtc_device(dev);
-
- if (!candidate->ops->set_alarm)
- return 0;
- if (!device_may_wakeup(candidate->dev.parent))
- return 0;
-
- *(const char **)name_ptr = dev_name(dev);
- return 1;
-}
-
-/**
- * alarmtimer_init_late - Late initializing of alarmtimer code
- *
- * This function locates a rtc device to use for wakealarms.
- * Run as late_initcall to make sure rtc devices have been
- * registered.
- */
-static int __init alarmtimer_init_late(void)
-{
- struct device *dev;
- char *str;
-
- /* Find an rtc device and init the rtc_timer */
- dev = class_find_device(rtc_class, NULL, &str, has_wakealarm);
- /* If we have a device then str is valid. See has_wakealarm() */
- if (dev) {
- rtcdev = rtc_class_open(str);
- /*
- * Drop the reference we got in class_find_device,
- * rtc_open takes its own.
- */
- put_device(dev);
- }
- if (!rtcdev) {
- printk(KERN_WARNING "No RTC device found, ALARM timers will"
- " not wake from suspend");
- }
- rtc_timer_init(&rtctimer, NULL, NULL);
-
- return 0;
-}
-#else
-static int __init alarmtimer_init_late(void)
-{
- printk(KERN_WARNING "Kernel not built with RTC support, ALARM timers"
- " will not wake from suspend");
- return 0;
-}
-#endif
-late_initcall(alarmtimer_init_late);