v4.19.13 snapshot.
diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
new file mode 100644
index 0000000..3d577e2
--- /dev/null
+++ b/drivers/rtc/interface.c
@@ -0,0 +1,1078 @@
+/*
+ * 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) {
+ 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)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;
+
+ 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 (!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);
+
+ 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);
+
+ 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);
+
+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.
+ */
+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
+ * @task: currently registered with rtc_irq_register()
+ * @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;
+
+ 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->func)
+ timer->func(timer->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->func = f;
+ timer->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;
+}