| /* |
| * 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> |
| |
| #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; |
| time64_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; |
| |
| 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); |
| |
| 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_mmss64) { |
| time64_t secs64 = rtc_tm_to_time64(tm); |
| |
| err = rtc->ops->set_mmss64(rtc->dev.parent, secs64); |
| } else if (rtc->ops->set_mmss) { |
| time64_t secs64 = rtc_tm_to_time64(tm); |
| err = rtc->ops->set_mmss(rtc->dev.parent, secs64); |
| } else |
| err = -EINVAL; |
| |
| pm_stay_awake(rtc->dev.parent); |
| mutex_unlock(&rtc->ops_lock); |
| /* A timer might have just expired */ |
| schedule_work(&rtc->irqwork); |
| |
| 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 == NULL) |
| err = -ENODEV; |
| else if (!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 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; |
| } |
| |
| /* 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: %d-%d-%d %d:%d:%d\n", |
| alarm->time.tm_year + 1900, alarm->time.tm_mon + 1, |
| alarm->time.tm_mday, alarm->time.tm_hour, alarm->time.tm_min, |
| alarm->time.tm_sec); |
| } |
| |
| 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 == 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); |
| |
| 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; |
| |
| rtc_subtract_offset(rtc, &alarm->time); |
| 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. |
| */ |
| |
| if (!rtc->ops) |
| err = -ENODEV; |
| else if (!rtc->ops->set_alarm) |
| 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) |
| { |
| int err; |
| |
| if (!rtc->ops) |
| return -ENODEV; |
| else if (!rtc->ops->set_alarm) |
| 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); |
| |
| rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time); |
| rtc->aie_timer.period = 0; |
| if (alarm->enabled) |
| err = rtc_timer_enqueue(rtc, &rtc->aie_timer); |
| |
| mutex_unlock(&rtc->ops_lock); |
| |
| rtc_add_offset(rtc, &alarm->time); |
| 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 = 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); |
| |
| 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 = 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 |
| * |
| * This function is called when an AIE, UIE or PIE mode interrupt |
| * has occurred (or been emulated). |
| * |
| * Triggers the registered irq_task function callback. |
| */ |
| 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); |
| |
| /* call the task func */ |
| spin_lock_irqsave(&rtc->irq_task_lock, flags); |
| if (rtc->irq_task) |
| rtc->irq_task->func(rtc->irq_task->private_data); |
| spin_unlock_irqrestore(&rtc->irq_task_lock, flags); |
| |
| wake_up_interruptible(&rtc->irq_queue); |
| kill_fasync(&rtc->async_queue, SIGIO, POLL_IN); |
| } |
| |
| |
| /** |
| * rtc_aie_update_irq - AIE mode rtctimer hook |
| * @private: pointer to the rtc_device |
| * |
| * This functions is called when the aie_timer expires. |
| */ |
| void rtc_aie_update_irq(void *private) |
| { |
| struct rtc_device *rtc = (struct rtc_device *)private; |
| rtc_handle_legacy_irq(rtc, 1, RTC_AF); |
| } |
| |
| |
| /** |
| * rtc_uie_update_irq - UIE mode rtctimer hook |
| * @private: pointer to the rtc_device |
| * |
| * This functions is called when the uie_timer expires. |
| */ |
| void rtc_uie_update_irq(void *private) |
| { |
| struct rtc_device *rtc = (struct rtc_device *)private; |
| 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; |
| int 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); |
| |
| static int __rtc_match(struct device *dev, const void *data) |
| { |
| const char *name = data; |
| |
| if (strcmp(dev_name(dev), name) == 0) |
| return 1; |
| return 0; |
| } |
| |
| struct rtc_device *rtc_class_open(const char *name) |
| { |
| struct device *dev; |
| struct rtc_device *rtc = NULL; |
| |
| dev = class_find_device(rtc_class, NULL, name, __rtc_match); |
| 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); |
| |
| int rtc_irq_register(struct rtc_device *rtc, struct rtc_task *task) |
| { |
| int retval = -EBUSY; |
| |
| if (task == NULL || task->func == NULL) |
| return -EINVAL; |
| |
| /* Cannot register while the char dev is in use */ |
| if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags)) |
| return -EBUSY; |
| |
| spin_lock_irq(&rtc->irq_task_lock); |
| if (rtc->irq_task == NULL) { |
| rtc->irq_task = task; |
| retval = 0; |
| } |
| spin_unlock_irq(&rtc->irq_task_lock); |
| |
| clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags); |
| |
| return retval; |
| } |
| EXPORT_SYMBOL_GPL(rtc_irq_register); |
| |
| void rtc_irq_unregister(struct rtc_device *rtc, struct rtc_task *task) |
| { |
| spin_lock_irq(&rtc->irq_task_lock); |
| if (rtc->irq_task == task) |
| rtc->irq_task = NULL; |
| spin_unlock_irq(&rtc->irq_task_lock); |
| } |
| EXPORT_SYMBOL_GPL(rtc_irq_unregister); |
| |
| 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 |
| * @task: currently registered with rtc_irq_register() |
| * @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 task->func() callbacks. |
| */ |
| int rtc_irq_set_state(struct rtc_device *rtc, struct rtc_task *task, int enabled) |
| { |
| int err = 0; |
| unsigned long flags; |
| |
| retry: |
| spin_lock_irqsave(&rtc->irq_task_lock, flags); |
| if (rtc->irq_task != NULL && task == NULL) |
| err = -EBUSY; |
| else if (rtc->irq_task != task) |
| err = -EACCES; |
| else { |
| if (rtc_update_hrtimer(rtc, enabled) < 0) { |
| spin_unlock_irqrestore(&rtc->irq_task_lock, flags); |
| cpu_relax(); |
| goto retry; |
| } |
| rtc->pie_enabled = enabled; |
| } |
| spin_unlock_irqrestore(&rtc->irq_task_lock, flags); |
| |
| trace_rtc_irq_set_state(enabled, err); |
| return err; |
| } |
| EXPORT_SYMBOL_GPL(rtc_irq_set_state); |
| |
| /** |
| * rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ |
| * @rtc: the rtc device |
| * @task: currently registered with rtc_irq_register() |
| * @freq: positive frequency with which task->func() will be called |
| * 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, struct rtc_task *task, int freq) |
| { |
| int err = 0; |
| unsigned long flags; |
| |
| if (freq <= 0 || freq > RTC_MAX_FREQ) |
| return -EINVAL; |
| retry: |
| spin_lock_irqsave(&rtc->irq_task_lock, flags); |
| if (rtc->irq_task != NULL && task == NULL) |
| err = -EBUSY; |
| else if (rtc->irq_task != task) |
| err = -EACCES; |
| else { |
| rtc->irq_freq = freq; |
| if (rtc->pie_enabled && rtc_update_hrtimer(rtc, 1) < 0) { |
| spin_unlock_irqrestore(&rtc->irq_task_lock, flags); |
| cpu_relax(); |
| goto retry; |
| } |
| } |
| spin_unlock_irqrestore(&rtc->irq_task_lock, flags); |
| |
| trace_rtc_irq_set_freq(freq, err); |
| return err; |
| } |
| EXPORT_SYMBOL_GPL(rtc_irq_set_freq); |
| |
| /** |
| * 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; |
| |
| timer->enabled = 1; |
| __rtc_read_time(rtc, &tm); |
| 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; |
| int err; |
| 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 || !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 |
| * @rtc rtc device |
| * @timer timer being removed. |
| * |
| * 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->task.func) |
| timer->task.func(timer->task.private_data); |
| |
| 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 |
| * @data: private data passed to function pointer |
| * |
| * Kernel interface to initializing an rtc_timer. |
| */ |
| void rtc_timer_init(struct rtc_timer *timer, void (*f)(void *p), void *data) |
| { |
| timerqueue_init(&timer->node); |
| timer->enabled = 0; |
| timer->task.func = f; |
| timer->task.private_data = data; |
| } |
| |
| /* 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; |
| } |