diff options
| -rw-r--r-- | drivers/rtc/Kconfig | 12 | ||||
| -rw-r--r-- | drivers/rtc/rtc-dev.c | 104 | ||||
| -rw-r--r-- | include/linux/rtc.h | 14 |
3 files changed, 130 insertions, 0 deletions
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig index cdd97192dc6..4941cade319 100644 --- a/drivers/rtc/Kconfig +++ b/drivers/rtc/Kconfig @@ -97,6 +97,18 @@ config RTC_INTF_DEV If unsure, say Y. +config RTC_INTF_DEV_UIE_EMUL + bool "RTC UIE emulation on dev interface" + depends on RTC_INTF_DEV + help + Provides an emulation for RTC_UIE if the underlying rtc chip + driver does not expose RTC_UIE ioctls. Those requests generate + once-per-second update interrupts, used for synchronization. + + The emulation code will read the time from the hardware + clock several times per second, please enable this option + only if you know that you really need it. + config RTC_DRV_TEST tristate "Test driver/device" help diff --git a/drivers/rtc/rtc-dev.c b/drivers/rtc/rtc-dev.c index 37c3cc1b3dd..dfa72c9c268 100644 --- a/drivers/rtc/rtc-dev.c +++ b/drivers/rtc/rtc-dev.c @@ -46,6 +46,105 @@ static int rtc_dev_open(struct inode *inode, struct file *file) return err; } +#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL +/* + * Routine to poll RTC seconds field for change as often as possible, + * after first RTC_UIE use timer to reduce polling + */ +static void rtc_uie_task(struct work_struct *work) +{ + struct rtc_device *rtc = + container_of(work, struct rtc_device, uie_task); + struct rtc_time tm; + int num = 0; + int err; + + err = rtc_read_time(rtc, &tm); + + spin_lock_irq(&rtc->irq_lock); + if (rtc->stop_uie_polling || err) { + rtc->uie_task_active = 0; + } else if (rtc->oldsecs != tm.tm_sec) { + num = (tm.tm_sec + 60 - rtc->oldsecs) % 60; + rtc->oldsecs = tm.tm_sec; + rtc->uie_timer.expires = jiffies + HZ - (HZ/10); + rtc->uie_timer_active = 1; + rtc->uie_task_active = 0; + add_timer(&rtc->uie_timer); + } else if (schedule_work(&rtc->uie_task) == 0) { + rtc->uie_task_active = 0; + } + spin_unlock_irq(&rtc->irq_lock); + if (num) + rtc_update_irq(rtc, num, RTC_UF | RTC_IRQF); +} +static void rtc_uie_timer(unsigned long data) +{ + struct rtc_device *rtc = (struct rtc_device *)data; + unsigned long flags; + + spin_lock_irqsave(&rtc->irq_lock, flags); + rtc->uie_timer_active = 0; + rtc->uie_task_active = 1; + if ((schedule_work(&rtc->uie_task) == 0)) + rtc->uie_task_active = 0; + spin_unlock_irqrestore(&rtc->irq_lock, flags); +} + +static int clear_uie(struct rtc_device *rtc) +{ + spin_lock_irq(&rtc->irq_lock); + if (rtc->uie_irq_active) { + rtc->stop_uie_polling = 1; + if (rtc->uie_timer_active) { + spin_unlock_irq(&rtc->irq_lock); + del_timer_sync(&rtc->uie_timer); + spin_lock_irq(&rtc->irq_lock); + rtc->uie_timer_active = 0; + } + if (rtc->uie_task_active) { + spin_unlock_irq(&rtc->irq_lock); + flush_scheduled_work(); + spin_lock_irq(&rtc->irq_lock); + } + rtc->uie_irq_active = 0; + } + spin_unlock_irq(&rtc->irq_lock); + return 0; +} + +static int set_uie(struct rtc_device *rtc) +{ + struct rtc_time tm; + int err; + + err = rtc_read_time(rtc, &tm); + if (err) + return err; + spin_lock_irq(&rtc->irq_lock); + if (!rtc->uie_irq_active) { + rtc->uie_irq_active = 1; + rtc->stop_uie_polling = 0; + rtc->oldsecs = tm.tm_sec; + rtc->uie_task_active = 1; + if (schedule_work(&rtc->uie_task) == 0) + rtc->uie_task_active = 0; + } + rtc->irq_data = 0; + spin_unlock_irq(&rtc->irq_lock); + return 0; +} + +int rtc_dev_update_irq_enable_emul(struct rtc_device *rtc, unsigned int enabled) +{ + if (enabled) + return set_uie(rtc); + else + return clear_uie(rtc); +} +EXPORT_SYMBOL(rtc_dev_update_irq_enable_emul); + +#endif /* CONFIG_RTC_INTF_DEV_UIE_EMUL */ static ssize_t rtc_dev_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) @@ -387,6 +486,11 @@ void rtc_dev_prepare(struct rtc_device *rtc) rtc->dev.devt = MKDEV(MAJOR(rtc_devt), rtc->id); +#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL + INIT_WORK(&rtc->uie_task, rtc_uie_task); + setup_timer(&rtc->uie_timer, rtc_uie_timer, (unsigned long)rtc); +#endif + cdev_init(&rtc->char_dev, &rtc_dev_fops); rtc->char_dev.owner = rtc->owner; } diff --git a/include/linux/rtc.h b/include/linux/rtc.h index a0b639f8e80..80408e711be 100644 --- a/include/linux/rtc.h +++ b/include/linux/rtc.h @@ -203,6 +203,18 @@ struct rtc_device struct hrtimer pie_timer; /* sub second exp, so needs hrtimer */ int pie_enabled; struct work_struct irqwork; + + +#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL + struct work_struct uie_task; + struct timer_list uie_timer; + /* Those fields are protected by rtc->irq_lock */ + unsigned int oldsecs; + unsigned int uie_irq_active:1; + unsigned int stop_uie_polling:1; + unsigned int uie_task_active:1; + unsigned int uie_timer_active:1; +#endif }; #define to_rtc_device(d) container_of(d, struct rtc_device, dev) @@ -235,6 +247,8 @@ extern int rtc_irq_set_freq(struct rtc_device *rtc, struct rtc_task *task, int freq); extern int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled); extern int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled); +extern int rtc_dev_update_irq_enable_emul(struct rtc_device *rtc, + unsigned int enabled); void rtc_aie_update_irq(void *private); void rtc_uie_update_irq(void *private); |