diff options
Diffstat (limited to 'drivers/rtc/interface.c')
| -rw-r--r-- | drivers/rtc/interface.c | 1086 |
1 files changed, 1086 insertions, 0 deletions
diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c new file mode 100644 index 000000000..3d0fbc644 --- /dev/null +++ b/drivers/rtc/interface.c @@ -0,0 +1,1086 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * RTC subsystem, interface functions + * + * Copyright (C) 2005 Tower Technologies + * Author: Alessandro Zummo <a.zummo@towertech.it> + * + * based on arch/arm/common/rtctime.c + */ + +#include <linux/rtc.h> +#include <linux/sched.h> +#include <linux/module.h> +#include <linux/log2.h> +#include <linux/workqueue.h> + +#define CREATE_TRACE_POINTS +#include <trace/events/rtc.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 void rtc_add_offset(struct rtc_device *rtc, struct rtc_time *tm) +{ + time64_t secs; + + if (!rtc->offset_secs) + return; + + secs = rtc_tm_to_time64(tm); + + /* + * 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; + + rtc_time64_to_tm(secs + rtc->offset_secs, tm); +} + +static void rtc_subtract_offset(struct rtc_device *rtc, struct rtc_time *tm) +{ + time64_t secs; + + if (!rtc->offset_secs) + return; + + secs = rtc_tm_to_time64(tm); + + /* + * 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; + + rtc_time64_to_tm(secs - rtc->offset_secs, tm); +} + +static int rtc_valid_range(struct rtc_device *rtc, struct rtc_time *tm) +{ + if (rtc->range_min != rtc->range_max) { + time64_t time = rtc_tm_to_time64(tm); + time64_t range_min = rtc->set_start_time ? rtc->start_secs : + rtc->range_min; + timeu64_t range_max = rtc->set_start_time ? + (rtc->start_secs + rtc->range_max - rtc->range_min) : + rtc->range_max; + + if (time < range_min || time > range_max) + return -ERANGE; + } + + return 0; +} + +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); + if (err < 0) { + dev_dbg(&rtc->dev, "read_time: fail to read: %d\n", + err); + return err; + } + + rtc_add_offset(rtc, tm); + + err = rtc_valid_tm(tm); + if (err < 0) + dev_dbg(&rtc->dev, "read_time: rtc_time isn't valid\n"); + } + 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); + + trace_rtc_read_time(rtc_tm_to_time64(tm), err); + return err; +} +EXPORT_SYMBOL_GPL(rtc_read_time); + +int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm) +{ + int err, uie; + + err = rtc_valid_tm(tm); + if (err != 0) + return err; + + err = rtc_valid_range(rtc, tm); + if (err) + return err; + + rtc_subtract_offset(rtc, tm); + +#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL + uie = rtc->uie_rtctimer.enabled || rtc->uie_irq_active; +#else + uie = rtc->uie_rtctimer.enabled; +#endif + if (uie) { + err = rtc_update_irq_enable(rtc, 0); + if (err) + 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 + err = -EINVAL; + + pm_stay_awake(rtc->dev.parent); + mutex_unlock(&rtc->ops_lock); + /* A timer might have just expired */ + schedule_work(&rtc->irqwork); + + if (uie) { + err = rtc_update_irq_enable(rtc, 1); + if (err) + return err; + } + + trace_rtc_set_time(rtc_tm_to_time64(tm), err); + return err; +} +EXPORT_SYMBOL_GPL(rtc_set_time); + +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) { + err = -ENODEV; + } else if (!test_bit(RTC_FEATURE_ALARM, rtc->features) || !rtc->ops->read_alarm) { + err = -EINVAL; + } else { + alarm->enabled = 0; + alarm->pending = 0; + alarm->time.tm_sec = -1; + alarm->time.tm_min = -1; + alarm->time.tm_hour = -1; + alarm->time.tm_mday = -1; + alarm->time.tm_mon = -1; + alarm->time.tm_year = -1; + alarm->time.tm_wday = -1; + alarm->time.tm_yday = -1; + alarm->time.tm_isdst = -1; + err = rtc->ops->read_alarm(rtc->dev.parent, alarm); + } + + mutex_unlock(&rtc->ops_lock); + + trace_rtc_read_alarm(rtc_tm_to_time64(&alarm->time), err); + 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; + time64_t t_now, t_alm; + enum { none, day, month, year } missing = none; + unsigned int 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) { + rtc_add_offset(rtc, &alarm->time); + 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 int)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); + +done: + if (err) + dev_warn(&rtc->dev, "invalid alarm value: %ptR\n", + &alarm->time); + + return err; +} + +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) { + err = -ENODEV; + } else if (!test_bit(RTC_FEATURE_ALARM, rtc->features)) { + 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); + + trace_rtc_read_alarm(rtc_tm_to_time64(&alarm->time), err); + 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; + time64_t now, scheduled; + int err; + + 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. + */ + + rtc_subtract_offset(rtc, &alarm->time); + + if (!rtc->ops) + err = -ENODEV; + else if (!test_bit(RTC_FEATURE_ALARM, rtc->features)) + err = -EINVAL; + else + err = rtc->ops->set_alarm(rtc->dev.parent, alarm); + + trace_rtc_set_alarm(rtc_tm_to_time64(&alarm->time), err); + return err; +} + +int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) +{ + ktime_t alarm_time; + int err; + + if (!rtc->ops) + return -ENODEV; + else if (!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); + + rtc->aie_timer.node.expires = alarm_time; + rtc->aie_timer.period = 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 = 0; + + /* 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, unsigned int 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); + } + + if (err) + /* nothing */; + else if (!rtc->ops) + err = -ENODEV; + else if (!test_bit(RTC_FEATURE_ALARM, rtc->features) || !rtc->ops->alarm_irq_enable) + err = -EINVAL; + else + err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled); + + mutex_unlock(&rtc->ops_lock); + + trace_rtc_alarm_irq_enable(enabled, err); + return err; +} +EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable); + +int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled) +{ + int err; + + 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 (!test_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->features) || + !test_bit(RTC_FEATURE_ALARM, rtc->features)) { + mutex_unlock(&rtc->ops_lock); +#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL + return rtc_dev_update_irq_enable_emul(rtc, enabled); +#else + return -EINVAL; +#endif + } + + if (enabled) { + struct rtc_time tm; + ktime_t now, onesec; + + err = __rtc_read_time(rtc, &tm); + if (err) + goto out; + 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); + + 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 + * @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) +{ + unsigned long 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); + + wake_up_interruptible(&rtc->irq_queue); + kill_fasync(&rtc->async_queue, SIGIO, POLL_IN); +} + +/** + * 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; + + rtc = container_of(timer, struct rtc_device, pie_timer); + + 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, + unsigned long num, unsigned long events) +{ + if (IS_ERR_OR_NULL(rtc)) + return; + + pm_stay_awake(rtc->dev.parent); + schedule_work(&rtc->irqwork); +} +EXPORT_SYMBOL_GPL(rtc_update_irq); + +struct rtc_device *rtc_class_open(const char *name) +{ + struct device *dev; + struct rtc_device *rtc = NULL; + + dev = class_find_device_by_name(rtc_class, name); + if (dev) + rtc = to_rtc_device(dev); + + if (rtc) { + if (!try_module_get(rtc->owner)) { + put_device(dev); + rtc = NULL; + } + } + + return rtc; +} +EXPORT_SYMBOL_GPL(rtc_class_open); + +void rtc_class_close(struct rtc_device *rtc) +{ + module_put(rtc->owner); + put_device(&rtc->dev); +} +EXPORT_SYMBOL_GPL(rtc_class_close); + +static int 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; + + hrtimer_start(&rtc->pie_timer, period, HRTIMER_MODE_REL); + } + return 0; +} + +/** + * 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->pie_enabled = enabled; + + trace_rtc_irq_set_state(enabled, err); + return err; +} + +/** + * 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->irq_freq = freq; + while (rtc->pie_enabled && rtc_update_hrtimer(rtc, 1) < 0) + cpu_relax(); + + trace_rtc_irq_set_freq(freq, err); + return err; +} + +/** + * 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 + */ +static int 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); + } + + timerqueue_add(&rtc->timerqueue, &timer->node); + trace_rtc_timer_enqueue(timer); + if (!next || ktime_before(timer->node.expires, next->expires)) { + struct rtc_wkalrm alarm; + + alarm.time = rtc_ktime_to_tm(timer->node.expires); + alarm.enabled = 1; + err = __rtc_set_alarm(rtc, &alarm); + if (err == -ETIME) { + pm_stay_awake(rtc->dev.parent); + schedule_work(&rtc->irqwork); + } else if (err) { + timerqueue_del(&rtc->timerqueue, &timer->node); + trace_rtc_timer_dequeue(timer); + timer->enabled = 0; + return err; + } + } + return 0; +} + +static void rtc_alarm_disable(struct rtc_device *rtc) +{ + if (!rtc->ops || !test_bit(RTC_FEATURE_ALARM, rtc->features) || !rtc->ops->alarm_irq_enable) + return; + + rtc->ops->alarm_irq_enable(rtc->dev.parent, false); + trace_rtc_alarm_irq_enable(0, 0); +} + +/** + * 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 + */ +static void 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; + + struct rtc_device *rtc = + container_of(work, struct rtc_device, irqwork); + + mutex_lock(&rtc->ops_lock); +again: + __rtc_read_time(rtc, &tm); + now = rtc_tm_to_ktime(tm); + while ((next = timerqueue_getnext(&rtc->timerqueue))) { + if (next->expires > now) + break; + + /* expire timer */ + timer = container_of(next, struct rtc_timer, node); + timerqueue_del(&rtc->timerqueue, &timer->node); + trace_rtc_timer_dequeue(timer); + timer->enabled = 0; + if (timer->func) + timer->func(timer->rtc); + + trace_rtc_timer_fired(timer); + /* Re-add/fwd periodic timers */ + if (ktime_to_ns(timer->period)) { + timer->node.expires = ktime_add(timer->node.expires, + timer->period); + timer->enabled = 1; + timerqueue_add(&rtc->timerqueue, &timer->node); + trace_rtc_timer_enqueue(timer); + } + } + + /* Set next alarm */ + if (next) { + struct rtc_wkalrm alarm; + int err; + int retry = 3; + + alarm.time = rtc_ktime_to_tm(next->expires); + alarm.enabled = 1; +reprogram: + err = __rtc_set_alarm(rtc, &alarm); + if (err == -ETIME) { + goto again; + } else if (err) { + if (retry-- > 0) + goto reprogram; + + timer = container_of(next, struct rtc_timer, node); + timerqueue_del(&rtc->timerqueue, &timer->node); + trace_rtc_timer_dequeue(timer); + timer->enabled = 0; + dev_err(&rtc->dev, "__rtc_set_alarm: err=%d\n", err); + goto again; + } + } else { + rtc_alarm_disable(rtc); + } + + pm_relax(rtc->dev.parent); + mutex_unlock(&rtc->ops_lock); +} + +/* 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); + + timer->node.expires = expires; + timer->period = period; + + ret = rtc_timer_enqueue(rtc, timer); + + mutex_unlock(&rtc->ops_lock); + return ret; +} + +/* 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); + + trace_rtc_read_offset(*offset, ret); + return ret; +} + +/** + * 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); + + trace_rtc_set_offset(offset, ret); + return ret; +} |