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);