diff options
Diffstat (limited to 'drivers/rtc/interface.c')
| -rw-r--r-- | drivers/rtc/interface.c | 263 |
1 files changed, 237 insertions, 26 deletions
diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c index 90384b9f6b2c..8ec6b069a7f5 100644 --- a/drivers/rtc/interface.c +++ b/drivers/rtc/interface.c @@ -16,6 +16,9 @@ #include <linux/log2.h> #include <linux/workqueue.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 int __rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm) { int err; @@ -113,6 +116,186 @@ 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 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); + } + + mutex_unlock(&rtc->ops_lock); + 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; + 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) + 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 = 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"); + } + +done: + return 0; +} + int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) { int err; @@ -120,12 +303,18 @@ int rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) err = mutex_lock_interruptible(&rtc->ops_lock); if (err) return err; - alarm->enabled = rtc->aie_timer.enabled; - if (alarm->enabled) + 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); - return 0; + return err; } EXPORT_SYMBOL_GPL(rtc_read_alarm); @@ -175,16 +364,14 @@ int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm) return err; if (rtc->aie_timer.enabled) { rtc_timer_remove(rtc, &rtc->aie_timer); - rtc->aie_timer.enabled = 0; } rtc->aie_timer.node.expires = rtc_tm_to_ktime(alarm->time); rtc->aie_timer.period = ktime_set(0, 0); if (alarm->enabled) { - rtc->aie_timer.enabled = 1; - rtc_timer_enqueue(rtc, &rtc->aie_timer); + err = rtc_timer_enqueue(rtc, &rtc->aie_timer); } mutex_unlock(&rtc->ops_lock); - return 0; + return err; } EXPORT_SYMBOL_GPL(rtc_set_alarm); @@ -195,16 +382,15 @@ int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled) return err; if (rtc->aie_timer.enabled != enabled) { - if (enabled) { - rtc->aie_timer.enabled = 1; - rtc_timer_enqueue(rtc, &rtc->aie_timer); - } else { + if (enabled) + err = rtc_timer_enqueue(rtc, &rtc->aie_timer); + else rtc_timer_remove(rtc, &rtc->aie_timer); - rtc->aie_timer.enabled = 0; - } } - if (!rtc->ops) + if (err) + /* nothing */; + else if (!rtc->ops) err = -ENODEV; else if (!rtc->ops->alarm_irq_enable) err = -EINVAL; @@ -222,6 +408,12 @@ int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled) 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; @@ -235,15 +427,22 @@ int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled) now = rtc_tm_to_ktime(tm); rtc->uie_rtctimer.node.expires = ktime_add(now, onesec); rtc->uie_rtctimer.period = ktime_set(1, 0); - rtc->uie_rtctimer.enabled = 1; - rtc_timer_enqueue(rtc, &rtc->uie_rtctimer); - } else { + err = rtc_timer_enqueue(rtc, &rtc->uie_rtctimer); + } else rtc_timer_remove(rtc, &rtc->uie_rtctimer); - rtc->uie_rtctimer.enabled = 0; - } 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; } @@ -259,7 +458,7 @@ EXPORT_SYMBOL_GPL(rtc_update_irq_enable); * * Triggers the registered irq_task function callback. */ -static void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode) +void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode) { unsigned long flags; @@ -460,6 +659,9 @@ int rtc_irq_set_freq(struct rtc_device *rtc, struct rtc_task *task, int freq) int err = 0; unsigned long flags; + if (freq <= 0) + return -EINVAL; + spin_lock_irqsave(&rtc->irq_task_lock, flags); if (rtc->irq_task != NULL && task == NULL) err = -EBUSY; @@ -488,10 +690,13 @@ EXPORT_SYMBOL_GPL(rtc_irq_set_freq); * 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 */ -void rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer) +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; @@ -501,7 +706,13 @@ void rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer) 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; } /** @@ -512,13 +723,15 @@ void rtc_timer_enqueue(struct rtc_device *rtc, struct rtc_timer *timer) * 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 */ -void rtc_timer_remove(struct rtc_device *rtc, struct rtc_timer *timer) +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; @@ -626,8 +839,7 @@ int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer* timer, timer->node.expires = expires; timer->period = period; - timer->enabled = 1; - rtc_timer_enqueue(rtc, timer); + ret = rtc_timer_enqueue(rtc, timer); mutex_unlock(&rtc->ops_lock); return ret; @@ -645,7 +857,6 @@ int rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer* timer) mutex_lock(&rtc->ops_lock); if (timer->enabled) rtc_timer_remove(rtc, timer); - timer->enabled = 0; mutex_unlock(&rtc->ops_lock); return ret; } |
