/* * RTC subsystem, interface functions * * Copyright (C) 2005 Tower Technologies * Author: Alessandro Zummo <a.zummo@towertech.it> * * based on arch/arm/common/rtctime.c * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation.*/ #include <linux/rtc.h>#include <linux/sched.h>#include <linux/module.h>#include <linux/log2.h>#include <linux/workqueue.h> static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer);static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer); static int __rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm){	int err;	if (!rtc->ops)		err = -ENODEV;	else if (!rtc->ops->read_time)		err = -EINVAL;	else {		memset(tm, 0, sizeof(struct rtc_time));		err = rtc->ops->read_time(rtc->dev.parent, tm);	}	return err;} int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm){	int err; 	err = mutex_lock_interruptible(&rtc->ops_lock);	if (err)		return err; 	err = __rtc_read_time(rtc, tm);	mutex_unlock(&rtc->ops_lock);	return err;}EXPORT_SYMBOL_GPL(rtc_read_time); int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm){	int err; 	err = rtc_valid_tm(tm);	if (err != 0)		return err; 	err = mutex_lock_interruptible(&rtc->ops_lock);	if (err)		return err; 	if (!rtc->ops)		err = -ENODEV;	else if (rtc->ops->set_time)		err = rtc->ops->set_time(rtc->dev.parent, tm);	else if (rtc->ops->set_mmss) {		unsigned long secs;		err = rtc_tm_to_time(tm, &secs);		if (err == 0)			err = rtc->ops->set_mmss(rtc->dev.parent, secs);	} else		err = -EINVAL; 	mutex_unlock(&rtc->ops_lock);	/* A timer might have just expired */	schedule_work(&rtc->irqwork);	return err;}EXPORT_SYMBOL_GPL(rtc_set_time); int rtc_set_mmss(struct rtc_device *rtc, unsigned long secs){	int err; 	err = mutex_lock_interruptible(&rtc->ops_lock);	if (err)		return err; 	if (!rtc->ops)		err = -ENODEV;	else if (rtc->ops->set_mmss)		err = rtc->ops->set_mmss(rtc->dev.parent, secs);	else if (rtc->ops->read_time && rtc->ops->set_time) {		struct rtc_time new, old; 		err = rtc->ops->read_time(rtc->dev.parent, &old);		if (err == 0) {			rtc_time_to_tm(secs, &new); 			/*			 * avoid writing when we're going to change the day of			 * the month. We will retry in the next minute. This			 * basically means that if the RTC must not drift			 * by more than 1 minute in 11 minutes.			 */			if (!((old.tm_hour == 23 && old.tm_min == 59) ||				(new.tm_hour == 23 && new.tm_min == 59)))				err = rtc->ops->set_time(rtc->dev.parent,						&new);		}	}	else		err = -EINVAL; 	mutex_unlock(&rtc->ops_lock);	/* A timer might have just expired */	schedule_work(&rtc->irqwork); 	return err;}EXPORT_SYMBOL_GPL(rtc_set_mmss); static int rtc_read_alarm_internal(struct rtc_device *rtc, struct rtc_wkalrm *alarm){	int err; 	err = mutex_lock_interruptible(&rtc->ops_lock);	if (err)		return err; 	if (rtc->ops == NULL)		err = -ENODEV;	else if (!rtc->ops->read_alarm)		err = -EINVAL;	else {		memset(alarm, 0, sizeof(struct rtc_wkalrm));		err = rtc->ops->read_alarm(rtc->dev.parent, alarm);	} 	mutex_unlock(&rtc->ops_lock);	return err;} int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm){	int err;	struct rtc_time before, now;	int first_time = 1;	unsigned long t_now, t_alm;	enum { none, day, month, year } missing = none;	unsigned days; 	/* The lower level RTC driver may return -1 in some fields,	 * creating invalid alarm->time values, for reasons like:	 *	 *   - The hardware may not be capable of filling them in;	 *     many alarms match only on time-of-day fields, not	 *     day/month/year calendar data.	 *	 *   - Some hardware uses illegal values as "wildcard" match	 *     values, which non-Linux firmware (like a BIOS) may try	 *     to set up as e.g. "alarm 15 minutes after each hour".	 *     Linux uses only oneshot alarms.	 *	 * When we see that here, we deal with it by using values from	 * a current RTC timestamp for any missing (-1) values.  The	 * RTC driver prevents "periodic alarm" modes.	 *	 * But this can be racey, because some fields of the RTC timestamp	 * may have wrapped in the interval since we read the RTC alarm,	 * which would lead to us inserting inconsistent values in place	 * of the -1 fields.	 *	 * Reading the alarm and timestamp in the reverse sequence	 * would have the same race condition, and not solve the issue.	 *	 * So, we must first read the RTC timestamp,	 * then read the RTC alarm value,	 * and then read a second RTC timestamp.	 *	 * If any fields of the second timestamp have changed	 * when compared with the first timestamp, then we know	 * our timestamp may be inconsistent with that used by	 * the low-level rtc_read_alarm_internal() function.	 *	 * So, when the two timestamps disagree, we just loop and do	 * the process again to get a fully consistent set of values.	 *	 * This could all instead be done in the lower level driver,	 * but since more than one lower level RTC implementation needs it,	 * then it's probably best best to do it here instead of there..	 */ 	/* Get the "before" timestamp */	err = rtc_read_time(rtc, &before);	if (err < 0)		return err;	do {		if (!first_time)			memcpy(&before, &now, sizeof(struct rtc_time));		first_time = 0; 		/* get the RTC alarm values, which may be incomplete */		err = rtc_read_alarm_internal(rtc, alarm);		if (err)			return err; 		/* full-function RTCs won't have such missing fields */		if (rtc_valid_tm(&alarm->time) == 0)			return 0; 		/* get the "after" timestamp, to detect wrapped fields */		err = rtc_read_time(rtc, &now);		if (err < 0)			return err; 		/* note that tm_sec is a "don't care" value here: */	} while (   before.tm_min   != now.tm_min		 || before.tm_hour  != now.tm_hour		 || before.tm_mon   != now.tm_mon		 || before.tm_year  != now.tm_year); 	/* Fill in the missing alarm fields using the timestamp; we	 * know there's at least one since alarm->time is invalid.	 */	if (alarm->time.tm_sec == -1)		alarm->time.tm_sec = now.tm_sec;	if (alarm->time.tm_min == -1)		alarm->time.tm_min = now.tm_min;	if (alarm->time.tm_hour == -1)		alarm->time.tm_hour = now.tm_hour; 	/* For simplicity, only support date rollover for now */	if (alarm->time.tm_mday < 1 || alarm->time.tm_mday > 31) {		alarm->time.tm_mday = now.tm_mday;		missing = day;	}	if ((unsigned)alarm->time.tm_mon >= 12) {		alarm->time.tm_mon = now.tm_mon;		if (missing == none)			missing = month;	}	if (alarm->time.tm_year == -1) {		alarm->time.tm_year = now.tm_year;		if (missing == none)			missing = year;	} 	/* with luck, no rollover is needed */	rtc_tm_to_time(&now, &t_now);	rtc_tm_to_time(&alarm->time, &t_alm);	if (t_now < t_alm)		goto done; 	switch (missing) { 	/* 24 hour rollover ... if it's now 10am Monday, an alarm that	 * that will trigger at 5am will do so at 5am Tuesday, which	 * could also be in the next month or year.  This is a common	 * case, especially for PCs.	 */	case day:		dev_dbg(&rtc->dev, "alarm rollover: %s\n", "day");		t_alm += 24 * 60 * 60;		rtc_time_to_tm(t_alm, &alarm->time);		break; 	/* Month rollover ... if it's the 31th, an alarm on the 3rd will	 * be next month.  An alarm matching on the 30th, 29th, or 28th	 * may end up in the month after that!  Many newer PCs support	 * this type of alarm.	 */	case month:		dev_dbg(&rtc->dev, "alarm rollover: %s\n", "month");		do {			if (alarm->time.tm_mon < 11)				alarm->time.tm_mon++;			else {				alarm->time.tm_mon = 0;				alarm->time.tm_year++;			}			days = rtc_month_days(alarm->time.tm_mon,					alarm->time.tm_year);		} while (days < alarm->time.tm_mday);		break; 	/* Year rollover ... easy except for leap years! */	case year:		dev_dbg(&rtc->dev, "alarm rollover: %s\n", "year");		do {			alarm->time.tm_year++;		} while (rtc_valid_tm(&alarm->time) != 0);		break; 	default:		dev_warn(&rtc->dev, "alarm rollover not handled\n");	} done:	return 0;} int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm){	int err; 	err = mutex_lock_interruptible(&rtc->ops_lock);	if (err)		return err;	if (rtc->ops == NULL)		err = -ENODEV;	else if (!rtc->ops->read_alarm)		err = -EINVAL;	else {		memset(alarm, 0, sizeof(struct rtc_wkalrm));		alarm->enabled = rtc->aie_timer.enabled;		alarm->time = rtc_ktime_to_tm(rtc->aie_timer.node.expires);	}	mutex_unlock(&rtc->ops_lock); 	return err;}EXPORT_SYMBOL_GPL(rtc_read_alarm); static int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm){	struct rtc_time tm;	long now, scheduled;	int err; 	err = rtc_valid_tm(&alarm->time);	if (err)		return err;	rtc_tm_to_time(&alarm->time, &scheduled); 	/* Make sure we're not setting alarms in the past */	err = __rtc_read_time(rtc, &tm);	rtc_tm_to_time(&tm, &now);	if (scheduled <= now)		return -ETIME;	/*	 * XXX - We just checked to make sure the alarm time is not	 * in the past, but there is still a race window where if	 * the is alarm set for the next second and the second ticks	 * over right here, before we set the alarm.	 */ 	if (!rtc->ops)		err = -ENODEV;	else if (!rtc->ops->set_alarm)		err = -EINVAL;	else		err = rtc->ops->set_alarm(rtc->dev.parent, alarm); 	return err;} int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm){	int err; 	err = rtc_valid_tm(&alarm->time);	if (err != 0)		return err; 	err = mutex_lock_interruptible(&rtc->ops_lock);	if (err)		return err;	if (rtc->aie_timer.enabled) {		rtc_timer_remove(rtc, &rtc->aie_timer);	}	rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);	rtc->aie_timer.period = ktime_set(0, 0);	if (alarm->enabled) {		err = rtc_timer_enqueue(rtc, &rtc->aie_timer);	}	mutex_unlock(&rtc->ops_lock);	return err;}EXPORT_SYMBOL_GPL(rtc_set_alarm); /* Called once per device from rtc_device_register */int rtc_initialize_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm){	int err;	struct rtc_time now; 	err = rtc_valid_tm(&alarm->time);	if (err != 0)		return err; 	err = rtc_read_time(rtc, &now);	if (err)		return err; 	err = mutex_lock_interruptible(&rtc->ops_lock);	if (err)		return err; 	rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time);	rtc->aie_timer.period = ktime_set(0, 0); 	/* Alarm has to be enabled & in the futrure for us to enqueue it */	if (alarm->enabled && (rtc_tm_to_ktime(now).tv64 <			 rtc->aie_timer.node.expires.tv64)) { 		rtc->aie_timer.enabled = 1;		timerqueue_add(&rtc->timerqueue, &rtc->aie_timer.node);	}	mutex_unlock(&rtc->ops_lock);	return err;}EXPORT_SYMBOL_GPL(rtc_initialize_alarm);   int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled){	int err = mutex_lock_interruptible(&rtc->ops_lock);	if (err)		return err; 	if (rtc->aie_timer.enabled != enabled) {		if (enabled)			err = rtc_timer_enqueue(rtc, &rtc->aie_timer);		else			rtc_timer_remove(rtc, &rtc->aie_timer);	} 	if (err)		/* nothing */;	else if (!rtc->ops)		err = -ENODEV;	else if (!rtc->ops->alarm_irq_enable)		err = -EINVAL;	else		err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled); 	mutex_unlock(&rtc->ops_lock);	return err;}EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable); int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled){	int err = mutex_lock_interruptible(&rtc->ops_lock);	if (err)		return err; #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL	if (enabled == 0 && rtc->uie_irq_active) {		mutex_unlock(&rtc->ops_lock);		return rtc_dev_update_irq_enable_emul(rtc, 0);	}#endif	/* make sure we're changing state */	if (rtc->uie_rtctimer.enabled == enabled)		goto out; 	if (rtc->uie_unsupported) {		err = -EINVAL;		goto out;	} 	if (enabled) {		struct rtc_time tm;		ktime_t now, onesec; 		__rtc_read_time(rtc, &tm);		onesec = ktime_set(1, 0);		now = rtc_tm_to_ktime(tm);		rtc->uie_rtctimer.node.expires = ktime_add(now, onesec);		rtc->uie_rtctimer.period = ktime_set(1, 0);		err = rtc_timer_enqueue(rtc, &rtc->uie_rtctimer);	} else		rtc_timer_remove(rtc, &rtc->uie_rtctimer); out:	mutex_unlock(&rtc->ops_lock);#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL	/*	 * Enable emulation if the driver did not provide	 * the update_irq_enable function pointer or if returned	 * -EINVAL to signal that it has been configured without	 * interrupts or that are not available at the moment.	 */	if (err == -EINVAL)		err = rtc_dev_update_irq_enable_emul(rtc, enabled);#endif	return err; }EXPORT_SYMBOL_GPL(rtc_update_irq_enable);  /** * rtc_handle_legacy_irq - AIE, UIE and PIE event hook * @rtc: pointer to the rtc device *

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