/* * Since the reading time values from RTC device are always in the RTC * original valid range, but we need to skip the overlapped region * between expanded range and original range, which is no need to add * the offset.
*/ if ((rtc->start_secs > rtc->range_min && secs >= rtc->start_secs) ||
(rtc->start_secs < rtc->range_min &&
secs <= (rtc->start_secs + rtc->range_max - rtc->range_min))) return;
/* * If the setting time values are in the valid range of RTC hardware * device, then no need to subtract the offset when setting time to RTC * device. Otherwise we need to subtract the offset to make the time * values are valid for RTC hardware device.
*/ if (secs >= rtc->range_min && secs <= rtc->range_max) return;
int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
{ int err; struct rtc_time before, now; int first_time = 1;
time64_t t_now, t_alm; enum { none, day, month, year } missing = none; unsignedint 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 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 */
err = rtc_valid_tm(&alarm->time); if (!err) goto done;
/* 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 ((unsignedint)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;
}
/* Can't proceed if alarm is still invalid after replacing * missing fields.
*/
err = rtc_valid_tm(&alarm->time); if (err) goto done;
/* with luck, no rollover is needed */
t_now = rtc_tm_to_time64(&now);
t_alm = rtc_tm_to_time64(&alarm->time); 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_time64_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 (!is_leap_year(alarm->time.tm_year + 1900) &&
rtc_valid_tm(&alarm->time) != 0); break;
default:
dev_warn(&rtc->dev, "alarm rollover not handled\n");
}
err = rtc_valid_tm(&alarm->time); if (err) return err;
scheduled = rtc_tm_to_time64(&alarm->time);
/* Make sure we're not setting alarms in the past */
err = __rtc_read_time(rtc, &tm); if (err) return err;
now = rtc_tm_to_time64(&tm);
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.
*/
/* * Check for potential race described above. If the waiting for next * second, and the second just ticked since the check above, either * * 1) It ticked after the alarm was set, and an alarm irq should be * generated. * * 2) It ticked before the alarm was set, and alarm irq most likely will * not be generated. * * While we cannot easily check for which of these two scenarios we * are in, we can return -ETIME to signal that the timer has already * expired, which is true in both cases.
*/ if ((scheduled - now) <= 1) {
err = __rtc_read_time(rtc, &tm); if (err) return err;
now = rtc_tm_to_time64(&tm); if (scheduled <= now) return -ETIME;
}
int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
{
ktime_t alarm_time; int err;
if (!rtc->ops) return -ENODEV; elseif (!test_bit(RTC_FEATURE_ALARM, rtc->features)) return -EINVAL;
err = rtc_valid_tm(&alarm->time); if (err != 0) return err;
err = rtc_valid_range(rtc, &alarm->time); if (err) 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);
alarm_time = rtc_tm_to_ktime(alarm->time); /* * Round down so we never miss a deadline, checking for past deadline is * done in __rtc_set_alarm
*/ if (test_bit(RTC_FEATURE_ALARM_RES_MINUTE, rtc->features))
alarm_time = ktime_sub_ns(alarm_time, (u64)alarm->time.tm_sec * NSEC_PER_SEC);
/* 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;
/* Alarm has to be enabled & in the future for us to enqueue it */ if (alarm->enabled && (rtc_tm_to_ktime(now) <
rtc->aie_timer.node.expires)) {
rtc->aie_timer.enabled = 1;
timerqueue_add(&rtc->timerqueue, &rtc->aie_timer.node);
trace_rtc_timer_enqueue(&rtc->aie_timer);
}
mutex_unlock(&rtc->ops_lock); return err;
}
EXPORT_SYMBOL_GPL(rtc_initialize_alarm);
int rtc_alarm_irq_enable(struct rtc_device *rtc, unsignedint enabled)
{ int err;
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);
}
/** * rtc_handle_legacy_irq - AIE, UIE and PIE event hook * @rtc: pointer to the rtc device * @num: number of occurence of the event * @mode: type of the event, RTC_AF, RTC_UF of RTC_PF * * This function is called when an AIE, UIE or PIE mode interrupt * has occurred (or been emulated). *
*/ void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode)
{ unsignedlong flags;
/* mark one irq of the appropriate mode */
spin_lock_irqsave(&rtc->irq_lock, flags);
rtc->irq_data = (rtc->irq_data + (num << 8)) | (RTC_IRQF | mode);
spin_unlock_irqrestore(&rtc->irq_lock, flags);
/** * rtc_aie_update_irq - AIE mode rtctimer hook * @rtc: pointer to the rtc_device * * This functions is called when the aie_timer expires.
*/ void rtc_aie_update_irq(struct rtc_device *rtc)
{
rtc_handle_legacy_irq(rtc, 1, RTC_AF);
}
/** * rtc_uie_update_irq - UIE mode rtctimer hook * @rtc: pointer to the rtc_device * * This functions is called when the uie_timer expires.
*/ void rtc_uie_update_irq(struct rtc_device *rtc)
{
rtc_handle_legacy_irq(rtc, 1, RTC_UF);
}
/** * rtc_pie_update_irq - PIE mode hrtimer hook * @timer: pointer to the pie mode hrtimer * * This function is used to emulate PIE mode interrupts * using an hrtimer. This function is called when the periodic * hrtimer expires.
*/ enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer)
{ struct rtc_device *rtc;
ktime_t period;
u64 count;
period = NSEC_PER_SEC / rtc->irq_freq;
count = hrtimer_forward_now(timer, period);
rtc_handle_legacy_irq(rtc, count, RTC_PF);
return HRTIMER_RESTART;
}
/** * rtc_update_irq - Triggered when a RTC interrupt occurs. * @rtc: the rtc device * @num: how many irqs are being reported (usually one) * @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF * Context: any
*/ void rtc_update_irq(struct rtc_device *rtc, unsignedlong num, unsignedlong events)
{ if (IS_ERR_OR_NULL(rtc)) return;
staticint rtc_update_hrtimer(struct rtc_device *rtc, int enabled)
{ /* * We always cancel the timer here first, because otherwise * we could run into BUG_ON(timer->state != HRTIMER_STATE_CALLBACK); * when we manage to start the timer before the callback * returns HRTIMER_RESTART. * * We cannot use hrtimer_cancel() here as a running callback * could be blocked on rtc->irq_task_lock and hrtimer_cancel() * would spin forever.
*/ if (hrtimer_try_to_cancel(&rtc->pie_timer) < 0) return -1;
if (enabled) {
ktime_t period = NSEC_PER_SEC / rtc->irq_freq;
/** * rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs * @rtc: the rtc device * @enabled: true to enable periodic IRQs * Context: any * * Note that rtc_irq_set_freq() should previously have been used to * specify the desired frequency of periodic IRQ.
*/ int rtc_irq_set_state(struct rtc_device *rtc, int enabled)
{ int err = 0;
while (rtc_update_hrtimer(rtc, enabled) < 0)
cpu_relax();
/** * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ * @rtc: the rtc device * @freq: positive frequency * Context: any * * Note that rtc_irq_set_state() is used to enable or disable the * periodic IRQs.
*/ int rtc_irq_set_freq(struct rtc_device *rtc, int freq)
{ int err = 0;
if (freq <= 0 || freq > RTC_MAX_FREQ) return -EINVAL;
/** * rtc_timer_enqueue - Adds a rtc_timer to the rtc_device timerqueue * @rtc: rtc device * @timer: timer being added. * * Enqueues a timer onto the rtc devices timerqueue and sets * the next alarm event appropriately. * * Sets the enabled bit on the added timer. * * Must hold ops_lock for proper serialization of timerqueue
*/ staticint rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer)
{ struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue); struct rtc_time tm;
ktime_t now; int err;
err = __rtc_read_time(rtc, &tm); if (err) return err;
timer->enabled = 1;
now = rtc_tm_to_ktime(tm);
/* Skip over expired timers */ while (next) { if (next->expires >= now) break;
next = timerqueue_iterate_next(next);
}
/** * rtc_timer_remove - Removes a rtc_timer from the rtc_device timerqueue * @rtc: rtc device * @timer: timer being removed. * * Removes a timer onto the rtc devices timerqueue and sets * the next alarm event appropriately. * * Clears the enabled bit on the removed timer. * * Must hold ops_lock for proper serialization of timerqueue
*/ staticvoid rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer)
{ struct timerqueue_node *next = timerqueue_getnext(&rtc->timerqueue);
timerqueue_del(&rtc->timerqueue, &timer->node);
trace_rtc_timer_dequeue(timer);
timer->enabled = 0; if (next == &timer->node) { struct rtc_wkalrm alarm; int err;
next = timerqueue_getnext(&rtc->timerqueue); if (!next) {
rtc_alarm_disable(rtc); return;
}
alarm.time = rtc_ktime_to_tm(next->expires);
alarm.enabled = 1;
err = __rtc_set_alarm(rtc, &alarm); if (err == -ETIME) {
pm_stay_awake(rtc->dev.parent);
schedule_work(&rtc->irqwork);
}
}
}
/** * rtc_timer_do_work - Expires rtc timers * @work: work item * * Expires rtc timers. Reprograms next alarm event if needed. * Called via worktask. * * Serializes access to timerqueue via ops_lock mutex
*/ void rtc_timer_do_work(struct work_struct *work)
{ struct rtc_timer *timer; struct timerqueue_node *next;
ktime_t now; struct rtc_time tm; int err;
/* rtc_timer_init - Initializes an rtc_timer * @timer: timer to be intiialized * @f: function pointer to be called when timer fires * @rtc: pointer to the rtc_device * * Kernel interface to initializing an rtc_timer.
*/ void rtc_timer_init(struct rtc_timer *timer, void (*f)(struct rtc_device *r), struct rtc_device *rtc)
{
timerqueue_init(&timer->node);
timer->enabled = 0;
timer->func = f;
timer->rtc = rtc;
}
/* rtc_timer_start - Sets an rtc_timer to fire in the future * @ rtc: rtc device to be used * @ timer: timer being set * @ expires: time at which to expire the timer * @ period: period that the timer will recur * * Kernel interface to set an rtc_timer
*/ int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
ktime_t expires, ktime_t period)
{ int ret = 0;
mutex_lock(&rtc->ops_lock); if (timer->enabled)
rtc_timer_remove(rtc, timer);
/* rtc_timer_cancel - Stops an rtc_timer * @ rtc: rtc device to be used * @ timer: timer being set * * Kernel interface to cancel an rtc_timer
*/ void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer)
{
mutex_lock(&rtc->ops_lock); if (timer->enabled)
rtc_timer_remove(rtc, timer);
mutex_unlock(&rtc->ops_lock);
}
/** * rtc_read_offset - Read the amount of rtc offset in parts per billion * @rtc: rtc device to be used * @offset: the offset in parts per billion * * see below for details. * * Kernel interface to read rtc clock offset * Returns 0 on success, or a negative number on error. * If read_offset() is not implemented for the rtc, return -EINVAL
*/ int rtc_read_offset(struct rtc_device *rtc, long *offset)
{ int ret;
if (!rtc->ops) return -ENODEV;
if (!rtc->ops->read_offset) return -EINVAL;
mutex_lock(&rtc->ops_lock);
ret = rtc->ops->read_offset(rtc->dev.parent, offset);
mutex_unlock(&rtc->ops_lock);
/** * rtc_set_offset - Adjusts the duration of the average second * @rtc: rtc device to be used * @offset: the offset in parts per billion * * Some rtc's allow an adjustment to the average duration of a second * to compensate for differences in the actual clock rate due to temperature, * the crystal, capacitor, etc. * * The adjustment applied is as follows: * t = t0 * (1 + offset * 1e-9) * where t0 is the measured length of 1 RTC second with offset = 0 * * Kernel interface to adjust an rtc clock offset. * Return 0 on success, or a negative number on error. * If the rtc offset is not setable (or not implemented), return -EINVAL
*/ int rtc_set_offset(struct rtc_device *rtc, long offset)
{ int ret;
if (!rtc->ops) return -ENODEV;
if (!rtc->ops->set_offset) return -EINVAL;
mutex_lock(&rtc->ops_lock);
ret = rtc->ops->set_offset(rtc->dev.parent, offset);
mutex_unlock(&rtc->ops_lock);
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