From 516373b8b60fa4152334b6b6f2ece0f178c540ce Mon Sep 17 00:00:00 2001 From: Uwe Kleine-König Date: Mon, 14 Feb 2011 11:33:17 +0100 Subject: RTC: Release mutex in error path of rtc_alarm_irq_enable On hardware that doesn't support alarm interrupts, rtc_alarm_irq_enable could return without releasing the ops_lock mutex. This was introduced in aa0be0f (RTC: Propagate error handling via rtc_timer_enqueue properly) This patch corrects the issue by only returning once the mutex is released. [john.stultz: Reworded the commit log] Signed-off-by: Uwe Kleine-König Signed-off-by: John Stultz --- drivers/rtc/interface.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'drivers') diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c index a0c01967244d..413ae0537915 100644 --- a/drivers/rtc/interface.c +++ b/drivers/rtc/interface.c @@ -209,9 +209,8 @@ int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled) } if (err) - return err; - - if (!rtc->ops) + /* nothing */; + else if (!rtc->ops) err = -ENODEV; else if (!rtc->ops->alarm_irq_enable) err = -EINVAL; -- cgit v1.2.3 From 6e57b1d6a8d8ed1998229b71c102be1997e397c6 Mon Sep 17 00:00:00 2001 From: John Stultz Date: Fri, 11 Feb 2011 17:45:40 -0800 Subject: RTC: Revert UIE emulation removal Uwe pointed out that my alarm based UIE emulation is not sufficient to replace the older timer/polling based UIE emulation on devices where there is no alarm irq. This causes rtc devices without alarms to return -EINVAL to UIE ioctls. The fix is to re-instate the old timer/polling method for devices without alarm irqs. This patch reverts the following commits: 042620a018afcfba1d678062b62e46 - Remove UIE emulation 1daeddd5962acad1bea55e524fc0fa - Cleanup removed UIE emulation declaration b5cc8ca1c9c3a37eaddf709b2fd3e1 - Remove Kconfig symbol for UIE emulation The emulation mode will still need to be wired-in with a following patch before it will work. CC: Uwe Kleine-König CC: Thomas Gleixner Reported-by: Uwe Kleine-König Signed-off-by: John Stultz --- drivers/rtc/Kconfig | 12 ++++++ drivers/rtc/rtc-dev.c | 104 ++++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/rtc.h | 14 +++++++ 3 files changed, 130 insertions(+) (limited to 'drivers') diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig index cdd97192dc69..4941cade319f 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 37c3cc1b3dd5..dfa72c9c2687 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 a0b639f8e805..80408e711bed 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); -- cgit v1.2.3 From 456d66ecd09e3bc326b93174745faafb6ac378d6 Mon Sep 17 00:00:00 2001 From: John Stultz Date: Fri, 11 Feb 2011 18:15:23 -0800 Subject: RTC: Re-enable UIE timer/polling emulation This patch re-enables UIE timer/polling emulation for rtc devices that do not support alarm irqs. CC: Uwe Kleine-König CC: Thomas Gleixner Reported-by: Uwe Kleine-König Tested-by: Uwe Kleine-König Signed-off-by: John Stultz --- drivers/rtc/interface.c | 18 +++++++++++++++++- drivers/rtc/rtc-dev.c | 2 +- include/linux/rtc.h | 1 + 3 files changed, 19 insertions(+), 2 deletions(-) (limited to 'drivers') diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c index 413ae0537915..cb2f0728fd70 100644 --- a/drivers/rtc/interface.c +++ b/drivers/rtc/interface.c @@ -228,6 +228,12 @@ 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; @@ -247,6 +253,16 @@ int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled) 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; } @@ -262,7 +278,7 @@ 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; diff --git a/drivers/rtc/rtc-dev.c b/drivers/rtc/rtc-dev.c index dfa72c9c2687..d0e06edb14c5 100644 --- a/drivers/rtc/rtc-dev.c +++ b/drivers/rtc/rtc-dev.c @@ -76,7 +76,7 @@ static void rtc_uie_task(struct work_struct *work) } spin_unlock_irq(&rtc->irq_lock); if (num) - rtc_update_irq(rtc, num, RTC_UF | RTC_IRQF); + rtc_handle_legacy_irq(rtc, num, RTC_UF); } static void rtc_uie_timer(unsigned long data) { diff --git a/include/linux/rtc.h b/include/linux/rtc.h index 80408e711bed..89c3e5182991 100644 --- a/include/linux/rtc.h +++ b/include/linux/rtc.h @@ -250,6 +250,7 @@ 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_handle_legacy_irq(struct rtc_device *rtc, int num, int mode); void rtc_aie_update_irq(void *private); void rtc_uie_update_irq(void *private); enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer); -- cgit v1.2.3