rtc: alarm: Add power-on alarm feature

Android does not support powering-up the phone through alarm.
Set rtc alarm in timerfd to power-up the phone after alarm
expiration.

Change-Id: I781389c658fb00ba7f0ce089d706c10f202a7dc6
Signed-off-by: Mao Jinlong <c_jmao@codeaurora.org>

fs/timerfd.c

@@ -49,7 +49,8 @@ static DEFINE_SPINLOCK(cancel_lock);
 static inline bool isalarm(struct timerfd_ctx *ctx)
 {
 	return ctx->clockid == CLOCK_REALTIME_ALARM ||
-		ctx->clockid == CLOCK_BOOTTIME_ALARM;
+		ctx->clockid == CLOCK_BOOTTIME_ALARM ||
+		ctx->clockid == CLOCK_POWEROFF_ALARM;
 }
 
 /*
@@ -133,7 +134,8 @@ static bool timerfd_canceled(struct timerfd_ctx *ctx)
 static void timerfd_setup_cancel(struct timerfd_ctx *ctx, int flags)
 {
 	if ((ctx->clockid == CLOCK_REALTIME ||
-	     ctx->clockid == CLOCK_REALTIME_ALARM) &&
+	     ctx->clockid == CLOCK_REALTIME_ALARM ||
+	     ctx->clockid == CLOCK_POWEROFF_ALARM) &&
 	    (flags & TFD_TIMER_ABSTIME) && (flags & TFD_TIMER_CANCEL_ON_SET)) {
 		if (!ctx->might_cancel) {
 			ctx->might_cancel = true;
@@ -164,6 +166,7 @@ static int timerfd_setup(struct timerfd_ctx *ctx, int flags,
 	enum hrtimer_mode htmode;
 	ktime_t texp;
 	int clockid = ctx->clockid;
+	enum alarmtimer_type type;
 
 	htmode = (flags & TFD_TIMER_ABSTIME) ?
 		HRTIMER_MODE_ABS: HRTIMER_MODE_REL;
@@ -174,10 +177,8 @@ static int timerfd_setup(struct timerfd_ctx *ctx, int flags,
 	ctx->tintv = timespec_to_ktime(ktmr->it_interval);
 
 	if (isalarm(ctx)) {
-		alarm_init(&ctx->t.alarm,
-			   ctx->clockid == CLOCK_REALTIME_ALARM ?
-			   ALARM_REALTIME : ALARM_BOOTTIME,
-			   timerfd_alarmproc);
+		type = clock2alarm(ctx->clockid);
+		alarm_init(&ctx->t.alarm, type, timerfd_alarmproc);
 	} else {
 		hrtimer_init(&ctx->t.tmr, clockid, htmode);
 		hrtimer_set_expires(&ctx->t.tmr, texp);
@@ -377,6 +378,7 @@ SYSCALL_DEFINE2(timerfd_create, int, clockid, int, flags)
 {
 	int ufd;
 	struct timerfd_ctx *ctx;
+	enum alarmtimer_type type;
 
 	/* Check the TFD_* constants for consistency.  */
 	BUILD_BUG_ON(TFD_CLOEXEC != O_CLOEXEC);
@@ -387,7 +389,8 @@ SYSCALL_DEFINE2(timerfd_create, int, clockid, int, flags)
 	     clockid != CLOCK_REALTIME &&
 	     clockid != CLOCK_REALTIME_ALARM &&
 	     clockid != CLOCK_BOOTTIME &&
-	     clockid != CLOCK_BOOTTIME_ALARM))
+	     clockid != CLOCK_BOOTTIME_ALARM &&
+	     clockid != CLOCK_POWEROFF_ALARM))
 		return -EINVAL;
 
 	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
@@ -397,13 +400,12 @@ SYSCALL_DEFINE2(timerfd_create, int, clockid, int, flags)
 	init_waitqueue_head(&ctx->wqh);
 	ctx->clockid = clockid;
 
-	if (isalarm(ctx))
-		alarm_init(&ctx->t.alarm,
-			   ctx->clockid == CLOCK_REALTIME_ALARM ?
-			   ALARM_REALTIME : ALARM_BOOTTIME,
-			   timerfd_alarmproc);
-	else
+	if (isalarm(ctx)) {
+		type = clock2alarm(ctx->clockid);
+		alarm_init(&ctx->t.alarm, type, timerfd_alarmproc);
+	} else {
 		hrtimer_init(&ctx->t.tmr, clockid, HRTIMER_MODE_ABS);
+	}
 
 	ctx->moffs = ktime_mono_to_real((ktime_t){ .tv64 = 0 });
 
@@ -475,6 +477,10 @@ static int do_timerfd_settime(int ufd, int flags,
 	ret = timerfd_setup(ctx, flags, new);
 
 	spin_unlock_irq(&ctx->wqh.lock);
+
+	if (ctx->clockid == CLOCK_POWEROFF_ALARM)
+		set_power_on_alarm();
+
 	fdput(f);
 	return ret;
 }

include/linux/alarmtimer.h

@@ -5,10 +5,12 @@
 #include <linux/hrtimer.h>
 #include <linux/timerqueue.h>
 #include <linux/rtc.h>
+#include <linux/types.h>
 
 enum alarmtimer_type {
 	ALARM_REALTIME,
 	ALARM_BOOTTIME,
+	ALARM_POWEROFF_REALTIME,
 
 	ALARM_NUMTYPE,
 };
@@ -48,6 +50,9 @@ void alarm_start_relative(struct alarm *alarm, ktime_t start);
 void alarm_restart(struct alarm *alarm);
 int alarm_try_to_cancel(struct alarm *alarm);
 int alarm_cancel(struct alarm *alarm);
+void set_power_on_alarm(void);
+void power_on_alarm_init(void);
+enum alarmtimer_type clock2alarm(clockid_t clockid);
 
 u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval);
 u64 alarm_forward_now(struct alarm *alarm, ktime_t interval);

include/uapi/linux/time.h

@@ -56,6 +56,7 @@ struct itimerval {
 #define CLOCK_BOOTTIME_ALARM		9
 #define CLOCK_SGI_CYCLE			10	/* Hardware specific */
 #define CLOCK_TAI			11
+#define CLOCK_POWEROFF_ALARM		12
 
 #define MAX_CLOCKS			16
 #define CLOCKS_MASK			(CLOCK_REALTIME | CLOCK_MONOTONIC)

kernel/time/alarmtimer.c

@@ -25,6 +25,7 @@
 #include <linux/posix-timers.h>
 #include <linux/workqueue.h>
 #include <linux/freezer.h>
+#include <linux/workqueue.h>
 
 /**
  * struct alarm_base - Alarm timer bases
@@ -46,12 +47,116 @@ static ktime_t freezer_delta;
 static DEFINE_SPINLOCK(freezer_delta_lock);
 
 static struct wakeup_source *ws;
+static struct delayed_work work;
+static struct workqueue_struct *power_off_alarm_workqueue;
 
 #ifdef CONFIG_RTC_CLASS
 /* rtc timer and device for setting alarm wakeups at suspend */
 static struct rtc_timer		rtctimer;
 static struct rtc_device	*rtcdev;
 static DEFINE_SPINLOCK(rtcdev_lock);
+static struct mutex power_on_alarm_lock;
+static struct alarm init_alarm;
+
+/**
+ * power_on_alarm_init - Init power on alarm value
+ *
+ * Read rtc alarm value after device booting up and add this alarm
+ * into alarm queue.
+ */
+void power_on_alarm_init(void)
+{
+	struct rtc_wkalrm rtc_alarm;
+	struct rtc_time rt;
+	unsigned long alarm_time;
+	struct rtc_device *rtc;
+	ktime_t alarm_ktime;
+
+	rtc = alarmtimer_get_rtcdev();
+
+	if (!rtc)
+		return;
+
+	rtc_read_alarm(rtc, &rtc_alarm);
+	rt = rtc_alarm.time;
+
+	rtc_tm_to_time(&rt, &alarm_time);
+
+	if (alarm_time) {
+		alarm_ktime = ktime_set(alarm_time, 0);
+		alarm_init(&init_alarm, ALARM_POWEROFF_REALTIME, NULL);
+		alarm_start(&init_alarm, alarm_ktime);
+	}
+}
+
+/**
+ * set_power_on_alarm - set power on alarm value into rtc register
+ *
+ * Get the soonest power off alarm timer and set the alarm value into rtc
+ * register.
+ */
+void set_power_on_alarm(void)
+{
+	int rc;
+	struct timespec wall_time, alarm_ts;
+	long alarm_secs = 0l;
+	long rtc_secs, alarm_time, alarm_delta;
+	struct rtc_time rtc_time;
+	struct rtc_wkalrm alarm;
+	struct rtc_device *rtc;
+	struct timerqueue_node *next;
+	unsigned long flags;
+	struct alarm_base *base = &alarm_bases[ALARM_POWEROFF_REALTIME];
+
+	rc = mutex_lock_interruptible(&power_on_alarm_lock);
+	if (rc != 0)
+		return;
+
+	spin_lock_irqsave(&base->lock, flags);
+	next = timerqueue_getnext(&base->timerqueue);
+	spin_unlock_irqrestore(&base->lock, flags);
+
+	if (next) {
+		alarm_ts = ktime_to_timespec(next->expires);
+		alarm_secs = alarm_ts.tv_sec;
+	}
+
+	if (!alarm_secs)
+		goto disable_alarm;
+
+	getnstimeofday(&wall_time);
+
+	/*
+	 * alarm_secs have to be bigger than "wall_time +1".
+	 * It is to make sure that alarm time will be always
+	 * bigger than wall time.
+	*/
+	if (alarm_secs <= wall_time.tv_sec + 1)
+		goto disable_alarm;
+
+	rtc = alarmtimer_get_rtcdev();
+	if (!rtc)
+		goto exit;
+
+	rtc_read_time(rtc, &rtc_time);
+	rtc_tm_to_time(&rtc_time, &rtc_secs);
+	alarm_delta = wall_time.tv_sec - rtc_secs;
+	alarm_time = alarm_secs - alarm_delta;
+
+	rtc_time_to_tm(alarm_time, &alarm.time);
+	alarm.enabled = 1;
+	rc = rtc_set_alarm(rtcdev, &alarm);
+	if (rc)
+		goto disable_alarm;
+
+	mutex_unlock(&power_on_alarm_lock);
+	return;
+
+disable_alarm:
+	rtc_alarm_irq_enable(rtcdev, 0);
+exit:
+	mutex_unlock(&power_on_alarm_lock);
+}
 
 static void alarmtimer_triggered_func(void *p)
 {
@@ -123,6 +228,8 @@ static void alarmtimer_rtc_remove_device(struct device *dev,
 
 static inline void alarmtimer_rtc_timer_init(void)
 {
+	mutex_init(&power_on_alarm_lock);
+
 	rtc_timer_init(&rtctimer, NULL, NULL);
 }
 
@@ -149,8 +256,14 @@ struct rtc_device *alarmtimer_get_rtcdev(void)
 static inline int alarmtimer_rtc_interface_setup(void) { return 0; }
 static inline void alarmtimer_rtc_interface_remove(void) { }
 static inline void alarmtimer_rtc_timer_init(void) { }
+void set_power_on_alarm(void) { }
 #endif
 
+static void alarm_work_func(struct work_struct *unused)
+{
+	set_power_on_alarm();
+}
+
 /**
  * alarmtimer_enqueue - Adds an alarm timer to an alarm_base timerqueue
  * @base: pointer to the base where the timer is being run
@@ -220,6 +333,10 @@ static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer)
 	}
 	spin_unlock_irqrestore(&base->lock, flags);
 
+	/* set next power off alarm */
+	if (alarm->type == ALARM_POWEROFF_REALTIME)
+		queue_delayed_work(power_off_alarm_workqueue, &work, 0);
+
 	return ret;
 
 }
@@ -251,6 +368,8 @@ static int alarmtimer_suspend(struct device *dev)
 	int i;
 	int ret;
 
+	cancel_delayed_work_sync(&work);
+
 	spin_lock_irqsave(&freezer_delta_lock, flags);
 	min = freezer_delta;
 	freezer_delta = ktime_set(0, 0);
@@ -306,8 +425,11 @@ static int alarmtimer_resume(struct device *dev)
 	if (!rtc)
 		return 0;
 	rtc_timer_cancel(rtc, &rtctimer);
+
+	queue_delayed_work(power_off_alarm_workqueue, &work, 0);
 	return 0;
 }
+
 #else
 static int alarmtimer_suspend(struct device *dev)
 {
@@ -485,12 +607,14 @@ EXPORT_SYMBOL_GPL(alarm_forward_now);
  * clock2alarm - helper that converts from clockid to alarmtypes
  * @clockid: clockid.
  */
-static enum alarmtimer_type clock2alarm(clockid_t clockid)
+enum alarmtimer_type clock2alarm(clockid_t clockid)
 {
 	if (clockid == CLOCK_REALTIME_ALARM)
 		return ALARM_REALTIME;
 	if (clockid == CLOCK_BOOTTIME_ALARM)
 		return ALARM_BOOTTIME;
+	if (clockid == CLOCK_POWEROFF_ALARM)
+		return ALARM_POWEROFF_REALTIME;
 	return -1;
 }
 
@@ -877,10 +1001,13 @@ static int __init alarmtimer_init(void)
 
 	posix_timers_register_clock(CLOCK_REALTIME_ALARM, &alarm_clock);
 	posix_timers_register_clock(CLOCK_BOOTTIME_ALARM, &alarm_clock);
+	posix_timers_register_clock(CLOCK_POWEROFF_ALARM, &alarm_clock);
 
 	/* Initialize alarm bases */
 	alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME;
 	alarm_bases[ALARM_REALTIME].gettime = &ktime_get_real;
+	alarm_bases[ALARM_POWEROFF_REALTIME].base_clockid = CLOCK_REALTIME;
+	alarm_bases[ALARM_POWEROFF_REALTIME].gettime = &ktime_get_real;
 	alarm_bases[ALARM_BOOTTIME].base_clockid = CLOCK_BOOTTIME;
 	alarm_bases[ALARM_BOOTTIME].gettime = &ktime_get_boottime;
 	for (i = 0; i < ALARM_NUMTYPE; i++) {
@@ -902,8 +1029,24 @@ static int __init alarmtimer_init(void)
 		goto out_drv;
 	}
 	ws = wakeup_source_register("alarmtimer");
-	return 0;
+	if (!ws) {
+		error = -ENOMEM;
+		goto out_ws;
+	}
 
+	INIT_DELAYED_WORK(&work, alarm_work_func);
+	power_off_alarm_workqueue =
+		create_singlethread_workqueue("power_off_alarm");
+	if (!power_off_alarm_workqueue) {
+		error = -ENOMEM;
+		goto out_wq;
+	}
+
+	return 0;
+out_wq:
+	wakeup_source_unregister(ws);
+out_ws:
+	platform_device_unregister(pdev);
 out_drv:
 	platform_driver_unregister(&alarmtimer_driver);
 out_if: