I got a lockdep warning when running "rtctest" so I though it'd be good to see what was up. - The warning was for rtc->irq_task_lock, gotten from rtc_update_irq() by irq handlerss ... but in a handful of other cases, grabbed without blocking IRQs. - Some callers to rtc_update_irq() were not ensuring IRQs were blocked, yet the routine expects that; make sure all callers block IRQs. It would appear that RTC API tests haven't been part of anyone's kernel regression test suite recently, at least not with lockdep running. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Acked-by: Alessandro Zummo <a.zummo@towertech.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
275 lines
6.4 KiB
C
275 lines
6.4 KiB
C
/*
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* RTC subsystem, interface functions
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*
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* Copyright (C) 2005 Tower Technologies
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* Author: Alessandro Zummo <a.zummo@towertech.it>
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*
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* based on arch/arm/common/rtctime.c
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/rtc.h>
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int rtc_read_time(struct class_device *class_dev, struct rtc_time *tm)
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{
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int err;
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struct rtc_device *rtc = to_rtc_device(class_dev);
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err = mutex_lock_interruptible(&rtc->ops_lock);
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if (err)
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return -EBUSY;
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if (!rtc->ops)
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err = -ENODEV;
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else if (!rtc->ops->read_time)
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err = -EINVAL;
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else {
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memset(tm, 0, sizeof(struct rtc_time));
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err = rtc->ops->read_time(class_dev->dev, tm);
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}
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mutex_unlock(&rtc->ops_lock);
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return err;
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}
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EXPORT_SYMBOL_GPL(rtc_read_time);
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int rtc_set_time(struct class_device *class_dev, struct rtc_time *tm)
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{
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int err;
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struct rtc_device *rtc = to_rtc_device(class_dev);
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err = rtc_valid_tm(tm);
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if (err != 0)
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return err;
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err = mutex_lock_interruptible(&rtc->ops_lock);
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if (err)
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return -EBUSY;
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if (!rtc->ops)
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err = -ENODEV;
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else if (!rtc->ops->set_time)
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err = -EINVAL;
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else
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err = rtc->ops->set_time(class_dev->dev, tm);
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mutex_unlock(&rtc->ops_lock);
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return err;
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}
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EXPORT_SYMBOL_GPL(rtc_set_time);
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int rtc_set_mmss(struct class_device *class_dev, unsigned long secs)
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{
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int err;
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struct rtc_device *rtc = to_rtc_device(class_dev);
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err = mutex_lock_interruptible(&rtc->ops_lock);
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if (err)
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return -EBUSY;
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if (!rtc->ops)
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err = -ENODEV;
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else if (rtc->ops->set_mmss)
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err = rtc->ops->set_mmss(class_dev->dev, secs);
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else if (rtc->ops->read_time && rtc->ops->set_time) {
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struct rtc_time new, old;
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err = rtc->ops->read_time(class_dev->dev, &old);
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if (err == 0) {
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rtc_time_to_tm(secs, &new);
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/*
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* avoid writing when we're going to change the day of
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* the month. We will retry in the next minute. This
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* basically means that if the RTC must not drift
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* by more than 1 minute in 11 minutes.
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*/
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if (!((old.tm_hour == 23 && old.tm_min == 59) ||
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(new.tm_hour == 23 && new.tm_min == 59)))
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err = rtc->ops->set_time(class_dev->dev, &new);
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}
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}
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else
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err = -EINVAL;
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mutex_unlock(&rtc->ops_lock);
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return err;
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}
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EXPORT_SYMBOL_GPL(rtc_set_mmss);
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int rtc_read_alarm(struct class_device *class_dev, struct rtc_wkalrm *alarm)
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{
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int err;
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struct rtc_device *rtc = to_rtc_device(class_dev);
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err = mutex_lock_interruptible(&rtc->ops_lock);
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if (err)
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return -EBUSY;
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if (rtc->ops == NULL)
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err = -ENODEV;
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else if (!rtc->ops->read_alarm)
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err = -EINVAL;
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else {
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memset(alarm, 0, sizeof(struct rtc_wkalrm));
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err = rtc->ops->read_alarm(class_dev->dev, alarm);
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}
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mutex_unlock(&rtc->ops_lock);
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return err;
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}
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EXPORT_SYMBOL_GPL(rtc_read_alarm);
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int rtc_set_alarm(struct class_device *class_dev, struct rtc_wkalrm *alarm)
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{
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int err;
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struct rtc_device *rtc = to_rtc_device(class_dev);
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err = mutex_lock_interruptible(&rtc->ops_lock);
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if (err)
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return -EBUSY;
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if (!rtc->ops)
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err = -ENODEV;
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else if (!rtc->ops->set_alarm)
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err = -EINVAL;
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else
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err = rtc->ops->set_alarm(class_dev->dev, alarm);
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mutex_unlock(&rtc->ops_lock);
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return err;
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}
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EXPORT_SYMBOL_GPL(rtc_set_alarm);
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/**
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* rtc_update_irq - report RTC periodic, alarm, and/or update irqs
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* @class_dev: the rtc's class device
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* @num: how many irqs are being reported (usually one)
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* @events: mask of RTC_IRQF with one or more of RTC_PF, RTC_AF, RTC_UF
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* Context: in_interrupt(), irqs blocked
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*/
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void rtc_update_irq(struct class_device *class_dev,
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unsigned long num, unsigned long events)
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{
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struct rtc_device *rtc = to_rtc_device(class_dev);
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spin_lock(&rtc->irq_lock);
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rtc->irq_data = (rtc->irq_data + (num << 8)) | events;
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spin_unlock(&rtc->irq_lock);
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spin_lock(&rtc->irq_task_lock);
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if (rtc->irq_task)
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rtc->irq_task->func(rtc->irq_task->private_data);
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spin_unlock(&rtc->irq_task_lock);
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wake_up_interruptible(&rtc->irq_queue);
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kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
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}
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EXPORT_SYMBOL_GPL(rtc_update_irq);
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struct class_device *rtc_class_open(char *name)
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{
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struct class_device *class_dev = NULL,
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*class_dev_tmp;
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down(&rtc_class->sem);
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list_for_each_entry(class_dev_tmp, &rtc_class->children, node) {
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if (strncmp(class_dev_tmp->class_id, name, BUS_ID_SIZE) == 0) {
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class_dev = class_dev_tmp;
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break;
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}
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}
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if (class_dev) {
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if (!try_module_get(to_rtc_device(class_dev)->owner))
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class_dev = NULL;
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}
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up(&rtc_class->sem);
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return class_dev;
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}
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EXPORT_SYMBOL_GPL(rtc_class_open);
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void rtc_class_close(struct class_device *class_dev)
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{
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module_put(to_rtc_device(class_dev)->owner);
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}
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EXPORT_SYMBOL_GPL(rtc_class_close);
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int rtc_irq_register(struct class_device *class_dev, struct rtc_task *task)
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{
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int retval = -EBUSY;
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struct rtc_device *rtc = to_rtc_device(class_dev);
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if (task == NULL || task->func == NULL)
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return -EINVAL;
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spin_lock_irq(&rtc->irq_task_lock);
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if (rtc->irq_task == NULL) {
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rtc->irq_task = task;
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retval = 0;
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}
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spin_unlock_irq(&rtc->irq_task_lock);
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return retval;
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}
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EXPORT_SYMBOL_GPL(rtc_irq_register);
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void rtc_irq_unregister(struct class_device *class_dev, struct rtc_task *task)
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{
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struct rtc_device *rtc = to_rtc_device(class_dev);
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spin_lock_irq(&rtc->irq_task_lock);
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if (rtc->irq_task == task)
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rtc->irq_task = NULL;
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spin_unlock_irq(&rtc->irq_task_lock);
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}
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EXPORT_SYMBOL_GPL(rtc_irq_unregister);
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int rtc_irq_set_state(struct class_device *class_dev, struct rtc_task *task, int enabled)
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{
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int err = 0;
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unsigned long flags;
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struct rtc_device *rtc = to_rtc_device(class_dev);
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if (rtc->ops->irq_set_state == NULL)
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return -ENXIO;
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spin_lock_irqsave(&rtc->irq_task_lock, flags);
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if (rtc->irq_task != task)
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err = -ENXIO;
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spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
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if (err == 0)
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err = rtc->ops->irq_set_state(class_dev->dev, enabled);
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return err;
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}
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EXPORT_SYMBOL_GPL(rtc_irq_set_state);
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int rtc_irq_set_freq(struct class_device *class_dev, struct rtc_task *task, int freq)
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{
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int err = 0;
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unsigned long flags;
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struct rtc_device *rtc = to_rtc_device(class_dev);
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if (rtc->ops->irq_set_freq == NULL)
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return -ENXIO;
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spin_lock_irqsave(&rtc->irq_task_lock, flags);
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if (rtc->irq_task != task)
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err = -ENXIO;
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spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
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if (err == 0) {
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err = rtc->ops->irq_set_freq(class_dev->dev, freq);
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if (err == 0)
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rtc->irq_freq = freq;
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}
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return err;
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}
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EXPORT_SYMBOL_GPL(rtc_irq_set_freq);
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