diff options
Diffstat (limited to 'drivers/rtc/interface.c')
| -rw-r--r-- | drivers/rtc/interface.c | 557 |
1 files changed, 356 insertions, 201 deletions
diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c index a0c816238aa..cb2f0728fd7 100644 --- a/drivers/rtc/interface.c +++ b/drivers/rtc/interface.c @@ -14,15 +14,14 @@ #include <linux/rtc.h> #include <linux/sched.h> #include <linux/log2.h> +#include <linux/workqueue.h> -int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm) +static int rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer); +static void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer); + +static int __rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm) { int err; - - err = mutex_lock_interruptible(&rtc->ops_lock); - if (err) - return err; - if (!rtc->ops) err = -ENODEV; else if (!rtc->ops->read_time) @@ -31,7 +30,18 @@ int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm) memset(tm, 0, sizeof(struct rtc_time)); err = rtc->ops->read_time(rtc->dev.parent, tm); } + return err; +} +int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm) +{ + int err; + + err = mutex_lock_interruptible(&rtc->ops_lock); + if (err) + return err; + + err = __rtc_read_time(rtc, tm); mutex_unlock(&rtc->ops_lock); return err; } @@ -106,188 +116,60 @@ int rtc_set_mmss(struct rtc_device *rtc, unsigned long secs) } EXPORT_SYMBOL_GPL(rtc_set_mmss); -static int rtc_read_alarm_internal(struct rtc_device *rtc, struct rtc_wkalrm *alarm) +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)); - err = rtc->ops->read_alarm(rtc->dev.parent, alarm); + alarm->enabled = rtc->aie_timer.enabled; + alarm->time = rtc_ktime_to_tm(rtc->aie_timer.node.expires); } - mutex_unlock(&rtc->ops_lock); + return err; } +EXPORT_SYMBOL_GPL(rtc_read_alarm); -int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) +int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) { + struct rtc_time tm; + long now, scheduled; int err; - struct rtc_time before, now; - int first_time = 1; - unsigned long t_now, t_alm; - enum { none, day, month, year } missing = none; - unsigned days; - - /* The lower level RTC driver may return -1 in some fields, - * creating invalid alarm->time values, for reasons like: - * - * - The hardware may not be capable of filling them in; - * many alarms match only on time-of-day fields, not - * day/month/year calendar data. - * - * - Some hardware uses illegal values as "wildcard" match - * values, which non-Linux firmware (like a BIOS) may try - * to set up as e.g. "alarm 15 minutes after each hour". - * Linux uses only oneshot alarms. - * - * When we see that here, we deal with it by using values from - * a current RTC timestamp for any missing (-1) values. The - * RTC driver prevents "periodic alarm" modes. - * - * But this can be racey, because some fields of the RTC timestamp - * may have wrapped in the interval since we read the RTC alarm, - * which would lead to us inserting inconsistent values in place - * of the -1 fields. - * - * Reading the alarm and timestamp in the reverse sequence - * would have the same race condition, and not solve the issue. - * - * So, we must first read the RTC timestamp, - * then read the RTC alarm value, - * and then read a second RTC timestamp. - * - * If any fields of the second timestamp have changed - * when compared with the first timestamp, then we know - * our timestamp may be inconsistent with that used by - * the low-level rtc_read_alarm_internal() function. - * - * So, when the two timestamps disagree, we just loop and do - * the process again to get a fully consistent set of values. - * - * This could all instead be done in the lower level driver, - * but since more than one lower level RTC implementation needs it, - * then it's probably best best to do it here instead of there.. - */ - /* Get the "before" timestamp */ - err = rtc_read_time(rtc, &before); - if (err < 0) + err = rtc_valid_tm(&alarm->time); + if (err) 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; - if (!alarm->enabled) - return 0; - - /* 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); + rtc_tm_to_time(&alarm->time, &scheduled); - /* Fill in the missing alarm fields using the timestamp; we - * know there's at least one since alarm->time is invalid. + /* Make sure we're not setting alarms in the past */ + err = __rtc_read_time(rtc, &tm); + rtc_tm_to_time(&tm, &now); + if (scheduled <= now) + return -ETIME; + /* + * XXX - We just checked to make sure the alarm time is not + * in the past, but there is still a race window where if + * the is alarm set for the next second and the second ticks + * over right here, before we set the alarm. */ - if (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 = now.tm_mday; - missing = day; - } - if (alarm->time.tm_mon == -1) { - alarm->time.tm_mon = now.tm_mon; - if (missing == none) - missing = month; - } - if (alarm->time.tm_year == -1) { - alarm->time.tm_year = now.tm_year; - if (missing == none) - missing = year; - } - /* with luck, no rollover is needed */ - rtc_tm_to_time(&now, &t_now); - rtc_tm_to_time(&alarm->time, &t_alm); - if (t_now < t_alm) - goto done; - - switch (missing) { - - /* 24 hour rollover ... if it's now 10am Monday, an alarm that - * that will trigger at 5am will do so at 5am Tuesday, which - * could also be in the next month or year. This is a common - * case, especially for PCs. - */ - case day: - dev_dbg(&rtc->dev, "alarm rollover: %s\n", "day"); - t_alm += 24 * 60 * 60; - rtc_time_to_tm(t_alm, &alarm->time); - break; - - /* Month rollover ... if it's the 31th, an alarm on the 3rd will - * be next month. An alarm matching on the 30th, 29th, or 28th - * may end up in the month after that! Many newer PCs support - * this type of alarm. - */ - case month: - dev_dbg(&rtc->dev, "alarm rollover: %s\n", "month"); - do { - if (alarm->time.tm_mon < 11) - alarm->time.tm_mon++; - else { - alarm->time.tm_mon = 0; - alarm->time.tm_year++; - } - days = rtc_month_days(alarm->time.tm_mon, - alarm->time.tm_year); - } while (days < alarm->time.tm_mday); - break; - - /* Year rollover ... easy except for leap years! */ - case year: - dev_dbg(&rtc->dev, "alarm rollover: %s\n", "year"); - do { - alarm->time.tm_year++; - } while (rtc_valid_tm(&alarm->time) != 0); - break; - - default: - dev_warn(&rtc->dev, "alarm rollover not handled\n"); - } + if (!rtc->ops) + err = -ENODEV; + else if (!rtc->ops->set_alarm) + err = -EINVAL; + else + err = rtc->ops->set_alarm(rtc->dev.parent, alarm); -done: - return 0; + return err; } -EXPORT_SYMBOL_GPL(rtc_read_alarm); int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) { @@ -300,14 +182,14 @@ int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) err = mutex_lock_interruptible(&rtc->ops_lock); if (err) return err; - - if (!rtc->ops) - err = -ENODEV; - else if (!rtc->ops->set_alarm) - err = -EINVAL; - else - err = rtc->ops->set_alarm(rtc->dev.parent, alarm); - + if (rtc->aie_timer.enabled) { + rtc_timer_remove(rtc, &rtc->aie_timer); + } + rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time); + rtc->aie_timer.period = ktime_set(0, 0); + if (alarm->enabled) { + err = rtc_timer_enqueue(rtc, &rtc->aie_timer); + } mutex_unlock(&rtc->ops_lock); return err; } @@ -319,7 +201,16 @@ int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled) if (err) return err; - if (!rtc->ops) + 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; @@ -340,19 +231,28 @@ int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled) #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, enabled); + 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 (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); - if (!rtc->ops) - err = -ENODEV; - else if (!rtc->ops->update_irq_enable) - err = -EINVAL; - else - err = rtc->ops->update_irq_enable(rtc->dev.parent, enabled); - +out: mutex_unlock(&rtc->ops_lock); - #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL /* * Enable emulation if the driver did not provide @@ -364,25 +264,30 @@ int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled) err = rtc_dev_update_irq_enable_emul(rtc, enabled); #endif return err; + } EXPORT_SYMBOL_GPL(rtc_update_irq_enable); + /** - * rtc_update_irq - report RTC periodic, alarm, and/or update irqs - * @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 + * 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 occured (or been emulated). + * + * Triggers the registered irq_task function callback. */ -void rtc_update_irq(struct rtc_device *rtc, - unsigned long num, unsigned long events) +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)) | events; + 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); @@ -391,6 +296,69 @@ void rtc_update_irq(struct rtc_device *rtc, 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 = ktime_set(0, 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) +{ + schedule_work(&rtc->irqwork); +} EXPORT_SYMBOL_GPL(rtc_update_irq); static int __rtc_match(struct device *dev, void *data) @@ -477,18 +445,20 @@ int rtc_irq_set_state(struct rtc_device *rtc, struct rtc_task *task, int enabled int err = 0; unsigned long flags; - if (rtc->ops->irq_set_state == NULL) - return -ENXIO; - spin_lock_irqsave(&rtc->irq_task_lock, flags); if (rtc->irq_task != NULL && task == NULL) err = -EBUSY; if (rtc->irq_task != task) err = -EACCES; - spin_unlock_irqrestore(&rtc->irq_task_lock, flags); - if (err == 0) - err = rtc->ops->irq_set_state(rtc->dev.parent, enabled); + if (enabled) { + ktime_t period = ktime_set(0, NSEC_PER_SEC/rtc->irq_freq); + hrtimer_start(&rtc->pie_timer, period, HRTIMER_MODE_REL); + } else { + hrtimer_cancel(&rtc->pie_timer); + } + rtc->pie_enabled = enabled; + spin_unlock_irqrestore(&rtc->irq_task_lock, flags); return err; } @@ -509,21 +479,206 @@ int rtc_irq_set_freq(struct rtc_device *rtc, struct rtc_task *task, int freq) int err = 0; unsigned long flags; - if (rtc->ops->irq_set_freq == NULL) - return -ENXIO; + if (freq <= 0) + return -EINVAL; spin_lock_irqsave(&rtc->irq_task_lock, flags); if (rtc->irq_task != NULL && task == NULL) err = -EBUSY; if (rtc->irq_task != task) err = -EACCES; - spin_unlock_irqrestore(&rtc->irq_task_lock, flags); - if (err == 0) { - err = rtc->ops->irq_set_freq(rtc->dev.parent, freq); - if (err == 0) - rtc->irq_freq = freq; + rtc->irq_freq = freq; + if (rtc->pie_enabled) { + ktime_t period; + hrtimer_cancel(&rtc->pie_timer); + period = ktime_set(0, NSEC_PER_SEC/rtc->irq_freq); + hrtimer_start(&rtc->pie_timer, period, + HRTIMER_MODE_REL); + } } + spin_unlock_irqrestore(&rtc->irq_task_lock, flags); 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) +{ + timer->enabled = 1; + timerqueue_add(&rtc->timerqueue, &timer->node); + if (&timer->node == timerqueue_getnext(&rtc->timerqueue)) { + 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) + schedule_work(&rtc->irqwork); + else if (err) { + timerqueue_del(&rtc->timerqueue, &timer->node); + timer->enabled = 0; + return err; + } + } + return 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); + timer->enabled = 0; + if (next == &timer->node) { + struct rtc_wkalrm alarm; + int err; + next = timerqueue_getnext(&rtc->timerqueue); + if (!next) + return; + alarm.time = rtc_ktime_to_tm(next->expires); + alarm.enabled = 1; + err = __rtc_set_alarm(rtc, &alarm); + if (err == -ETIME) + 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.tv64 > now.tv64) + break; + + /* expire timer */ + timer = container_of(next, struct rtc_timer, node); + timerqueue_del(&rtc->timerqueue, &timer->node); + timer->enabled = 0; + if (timer->task.func) + timer->task.func(timer->task.private_data); + + /* 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); + } + } + + /* Set next alarm */ + if (next) { + struct rtc_wkalrm alarm; + int err; + alarm.time = rtc_ktime_to_tm(next->expires); + alarm.enabled = 1; + err = __rtc_set_alarm(rtc, &alarm); + if (err == -ETIME) + goto again; + } + + 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 + */ +int rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer* timer) +{ + int ret = 0; + mutex_lock(&rtc->ops_lock); + if (timer->enabled) + rtc_timer_remove(rtc, timer); + mutex_unlock(&rtc->ops_lock); + return ret; +} + + |