staging: android-alarm: Convert ALARM_ELAPSED_REALTIME to use CLOCK_BOOTTIME

The ALARM_ELAPSED_REALTIME clock domain in Android pointed
to the need for something similar in linux system-wide
(instead of limited to just the alarm interface).

Thus CLOCK_BOOTTIME was introduced into the upstream kernel
in 2.6.39.

This patch attempts to convert the android alarm timer to utilize
the kernel's CLOCK_BOOTTIME clockid for ALARM_ELAPSED_REALTIME,
instead of managing it itself.

CC: Colin Cross <ccross@android.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Android Kernel Team <kernel-team@android.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/android/alarm-dev.c b/drivers/staging/android/alarm-dev.c
index 1b618f32811584abcac6547706515a4eddd85893..3840ca22d835cf551703ca02f79d2b6343f3a7f0 100644 (file)
--- a/drivers/staging/android/alarm-dev.c
+++ b/drivers/staging/android/alarm-dev.c
@@ -179,8 +179,7 @@ from_old_alarm_set:
                        break;
                case ANDROID_ALARM_ELAPSED_REALTIME_WAKEUP:
                case ANDROID_ALARM_ELAPSED_REALTIME:
-                       tmp_time =
-                               ktime_to_timespec(alarm_get_elapsed_realtime());
+                       get_monotonic_boottime(&tmp_time);
                        break;
                case ANDROID_ALARM_TYPE_COUNT:
                case ANDROID_ALARM_SYSTEMTIME:

diff --git a/drivers/staging/android/alarm.c b/drivers/staging/android/alarm.c
index 0cae132fbfd7ba88da518ed4afb776500f5ee2dc..22b18d1f1fe8c3a42776e65cc7b2687f4145d2db 100644 (file)
--- a/drivers/staging/android/alarm.c
+++ b/drivers/staging/android/alarm.c
@@ -65,7 +65,6 @@ struct alarm_queue {
        struct rb_root alarms;
        struct rb_node *first;
        struct hrtimer timer;
-       ktime_t delta;
        bool stopped;
        ktime_t stopped_time;
 };
@@ -107,8 +106,8 @@ static void update_timer_locked(struct alarm_queue *base, bool head_removed)
        }
 
        hrtimer_try_to_cancel(&base->timer);
-       base->timer.node.expires = ktime_add(base->delta, alarm->expires);
-       base->timer._softexpires = ktime_add(base->delta, alarm->softexpires);
+       base->timer.node.expires = alarm->expires;
+       base->timer._softexpires = alarm->softexpires;
        hrtimer_start_expires(&base->timer, HRTIMER_MODE_ABS);
 }
 
@@ -279,10 +278,6 @@ int android_alarm_set_rtc(struct timespec new_time)
                alarms[i].stopped = true;
                alarms[i].stopped_time = timespec_to_ktime(tmp_time);
        }
-       alarms[ANDROID_ALARM_ELAPSED_REALTIME_WAKEUP].delta =
-               alarms[ANDROID_ALARM_ELAPSED_REALTIME].delta =
-               ktime_sub(alarms[ANDROID_ALARM_ELAPSED_REALTIME].delta,
-                       timespec_to_ktime(timespec_sub(tmp_time, new_time)));
        spin_unlock_irqrestore(&alarm_slock, flags);
        ret = do_settimeofday(&new_time);
        spin_lock_irqsave(&alarm_slock, flags);
@@ -310,24 +305,6 @@ err:
        return ret;
 }
 
-/**
- * alarm_get_elapsed_realtime - get the elapsed real time in ktime_t format
- *
- * returns the time in ktime_t format
- */
-ktime_t alarm_get_elapsed_realtime(void)
-{
-       ktime_t now;
-       unsigned long flags;
-       struct alarm_queue *base = &alarms[ANDROID_ALARM_ELAPSED_REALTIME];
-
-       spin_lock_irqsave(&alarm_slock, flags);
-       now = base->stopped ? base->stopped_time : ktime_get_real();
-       now = ktime_sub(now, base->delta);
-       spin_unlock_irqrestore(&alarm_slock, flags);
-       return now;
-}
-
 static enum hrtimer_restart alarm_timer_triggered(struct hrtimer *timer)
 {
        struct alarm_queue *base;
@@ -339,7 +316,6 @@ static enum hrtimer_restart alarm_timer_triggered(struct hrtimer *timer)
 
        base = container_of(timer, struct alarm_queue, timer);
        now = base->stopped ? base->stopped_time : hrtimer_cb_get_time(timer);
-       now = ktime_sub(now, base->delta);
 
        pr_alarm(INT, "alarm_timer_triggered type %td at %lld\n",
                base - alarms, ktime_to_ns(now));
@@ -536,40 +512,25 @@ static struct platform_driver alarm_driver = {
        }
 };
 
-static int __init alarm_late_init(void)
-{
-       unsigned long   flags;
-       struct timespec tmp_time, system_time;
-
-       /* this needs to run after the rtc is read at boot */
-       spin_lock_irqsave(&alarm_slock, flags);
-       /* We read the current rtc and system time so we can later calculate
-        * elasped realtime to be (boot_systemtime + rtc - boot_rtc) ==
-        * (rtc - (boot_rtc - boot_systemtime))
-        */
-       getnstimeofday(&tmp_time);
-       ktime_get_ts(&system_time);
-       alarms[ANDROID_ALARM_ELAPSED_REALTIME_WAKEUP].delta =
-               alarms[ANDROID_ALARM_ELAPSED_REALTIME].delta =
-                       timespec_to_ktime(timespec_sub(tmp_time, system_time));
-
-       spin_unlock_irqrestore(&alarm_slock, flags);
-       return 0;
-}
-
 static int __init alarm_driver_init(void)
 {
        int err;
        int i;
 
-       for (i = 0; i < ANDROID_ALARM_SYSTEMTIME; i++) {
-               hrtimer_init(&alarms[i].timer,
-                               CLOCK_REALTIME, HRTIMER_MODE_ABS);
-               alarms[i].timer.function = alarm_timer_triggered;
-       }
+       hrtimer_init(&alarms[ANDROID_ALARM_RTC_WAKEUP].timer,
+                       CLOCK_REALTIME, HRTIMER_MODE_ABS);
+       hrtimer_init(&alarms[ANDROID_ALARM_RTC].timer,
+                       CLOCK_REALTIME, HRTIMER_MODE_ABS);
+       hrtimer_init(&alarms[ANDROID_ALARM_ELAPSED_REALTIME_WAKEUP].timer,
+                       CLOCK_BOOTTIME, HRTIMER_MODE_ABS);
+       hrtimer_init(&alarms[ANDROID_ALARM_ELAPSED_REALTIME].timer,
+                       CLOCK_BOOTTIME, HRTIMER_MODE_ABS);
        hrtimer_init(&alarms[ANDROID_ALARM_SYSTEMTIME].timer,
-                    CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
-       alarms[ANDROID_ALARM_SYSTEMTIME].timer.function = alarm_timer_triggered;
+                       CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
+
+       for (i = 0; i < ANDROID_ALARM_TYPE_COUNT; i++)
+               alarms[i].timer.function = alarm_timer_triggered;
+
        err = platform_driver_register(&alarm_driver);
        if (err < 0)
                goto err1;
@@ -595,7 +556,6 @@ static void  __exit alarm_exit(void)
        platform_driver_unregister(&alarm_driver);
 }
 
-late_initcall(alarm_late_init);
 module_init(alarm_driver_init);
 module_exit(alarm_exit);
 

diff --git a/drivers/staging/android/android_alarm.h b/drivers/staging/android/android_alarm.h
index e586caef4ba8e82788b010d13272aa3c37502b67..a1121772bc2eef2640aa759eafee1181bc1a285e 100644 (file)
--- a/drivers/staging/android/android_alarm.h
+++ b/drivers/staging/android/android_alarm.h
@@ -37,6 +37,7 @@ enum android_alarm_type {
 
 #include <linux/ktime.h>
 #include <linux/rbtree.h>
+#include <linux/hrtimer.h>
 
 /*
  * The alarm interface is similar to the hrtimer interface but adds support
@@ -71,7 +72,11 @@ void android_alarm_start_range(struct android_alarm *alarm, ktime_t start,
                                                                ktime_t end);
 int android_alarm_try_to_cancel(struct android_alarm *alarm);
 int android_alarm_cancel(struct android_alarm *alarm);
-ktime_t alarm_get_elapsed_realtime(void);
+
+static inline ktime_t alarm_get_elapsed_realtime(void)
+{
+       return ktime_get_boottime();
+}
 
 /* set rtc while preserving elapsed realtime */
 int android_alarm_set_rtc(const struct timespec ts);