mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-23 01:10:04 +00:00
![Atsushi Nemoto](/assets/img/avatar_default.png)
The rtc_update_irq() might be called with irqs enabled, if a interrupt handler was registered without IRQF_DISABLED. Use spin_lock_irqsave/spin_unlock_irqrestore instead of spin_lock/spin_unlock. Also update kerneldoc and drivers which do extra work to follow the current interface spec, as suggestted by David Brownell. Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp> Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: David Brownell <david-b@pacbell.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
528 lines
13 KiB
C
528 lines
13 KiB
C
/*
|
|
* RTC subsystem, interface functions
|
|
*
|
|
* Copyright (C) 2005 Tower Technologies
|
|
* Author: Alessandro Zummo <a.zummo@towertech.it>
|
|
*
|
|
* based on arch/arm/common/rtctime.c
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*/
|
|
|
|
#include <linux/rtc.h>
|
|
#include <linux/log2.h>
|
|
|
|
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)
|
|
err = -EINVAL;
|
|
else {
|
|
memset(tm, 0, sizeof(struct rtc_time));
|
|
err = rtc->ops->read_time(rtc->dev.parent, tm);
|
|
}
|
|
|
|
mutex_unlock(&rtc->ops_lock);
|
|
return err;
|
|
}
|
|
EXPORT_SYMBOL_GPL(rtc_read_time);
|
|
|
|
int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm)
|
|
{
|
|
int err;
|
|
|
|
err = rtc_valid_tm(tm);
|
|
if (err != 0)
|
|
return err;
|
|
|
|
err = mutex_lock_interruptible(&rtc->ops_lock);
|
|
if (err)
|
|
return err;
|
|
|
|
if (!rtc->ops)
|
|
err = -ENODEV;
|
|
else if (rtc->ops->set_time)
|
|
err = rtc->ops->set_time(rtc->dev.parent, tm);
|
|
else if (rtc->ops->set_mmss) {
|
|
unsigned long secs;
|
|
err = rtc_tm_to_time(tm, &secs);
|
|
if (err == 0)
|
|
err = rtc->ops->set_mmss(rtc->dev.parent, secs);
|
|
} else
|
|
err = -EINVAL;
|
|
|
|
mutex_unlock(&rtc->ops_lock);
|
|
return err;
|
|
}
|
|
EXPORT_SYMBOL_GPL(rtc_set_time);
|
|
|
|
int rtc_set_mmss(struct rtc_device *rtc, unsigned long secs)
|
|
{
|
|
int err;
|
|
|
|
err = mutex_lock_interruptible(&rtc->ops_lock);
|
|
if (err)
|
|
return err;
|
|
|
|
if (!rtc->ops)
|
|
err = -ENODEV;
|
|
else if (rtc->ops->set_mmss)
|
|
err = rtc->ops->set_mmss(rtc->dev.parent, secs);
|
|
else if (rtc->ops->read_time && rtc->ops->set_time) {
|
|
struct rtc_time new, old;
|
|
|
|
err = rtc->ops->read_time(rtc->dev.parent, &old);
|
|
if (err == 0) {
|
|
rtc_time_to_tm(secs, &new);
|
|
|
|
/*
|
|
* avoid writing when we're going to change the day of
|
|
* the month. We will retry in the next minute. This
|
|
* basically means that if the RTC must not drift
|
|
* by more than 1 minute in 11 minutes.
|
|
*/
|
|
if (!((old.tm_hour == 23 && old.tm_min == 59) ||
|
|
(new.tm_hour == 23 && new.tm_min == 59)))
|
|
err = rtc->ops->set_time(rtc->dev.parent,
|
|
&new);
|
|
}
|
|
}
|
|
else
|
|
err = -EINVAL;
|
|
|
|
mutex_unlock(&rtc->ops_lock);
|
|
|
|
return err;
|
|
}
|
|
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;
|
|
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);
|
|
|
|
/* 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;
|
|
}
|
|
EXPORT_SYMBOL_GPL(rtc_read_alarm);
|
|
|
|
int rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
|
|
{
|
|
int err;
|
|
|
|
err = rtc_valid_tm(&alarm->time);
|
|
if (err != 0)
|
|
return err;
|
|
|
|
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);
|
|
|
|
mutex_unlock(&rtc->ops_lock);
|
|
return err;
|
|
}
|
|
EXPORT_SYMBOL_GPL(rtc_set_alarm);
|
|
|
|
int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled)
|
|
{
|
|
int err = mutex_lock_interruptible(&rtc->ops_lock);
|
|
if (err)
|
|
return err;
|
|
|
|
if (!rtc->ops)
|
|
err = -ENODEV;
|
|
else if (!rtc->ops->alarm_irq_enable)
|
|
err = -EINVAL;
|
|
else
|
|
err = rtc->ops->alarm_irq_enable(rtc->dev.parent, enabled);
|
|
|
|
mutex_unlock(&rtc->ops_lock);
|
|
return err;
|
|
}
|
|
EXPORT_SYMBOL_GPL(rtc_alarm_irq_enable);
|
|
|
|
int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
|
|
{
|
|
int err = mutex_lock_interruptible(&rtc->ops_lock);
|
|
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, enabled);
|
|
}
|
|
#endif
|
|
|
|
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);
|
|
|
|
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;
|
|
}
|
|
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
|
|
*/
|
|
void rtc_update_irq(struct rtc_device *rtc,
|
|
unsigned long num, unsigned long events)
|
|
{
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&rtc->irq_lock, flags);
|
|
rtc->irq_data = (rtc->irq_data + (num << 8)) | events;
|
|
spin_unlock_irqrestore(&rtc->irq_lock, flags);
|
|
|
|
spin_lock_irqsave(&rtc->irq_task_lock, flags);
|
|
if (rtc->irq_task)
|
|
rtc->irq_task->func(rtc->irq_task->private_data);
|
|
spin_unlock_irqrestore(&rtc->irq_task_lock, flags);
|
|
|
|
wake_up_interruptible(&rtc->irq_queue);
|
|
kill_fasync(&rtc->async_queue, SIGIO, POLL_IN);
|
|
}
|
|
EXPORT_SYMBOL_GPL(rtc_update_irq);
|
|
|
|
static int __rtc_match(struct device *dev, void *data)
|
|
{
|
|
char *name = (char *)data;
|
|
|
|
if (strcmp(dev_name(dev), name) == 0)
|
|
return 1;
|
|
return 0;
|
|
}
|
|
|
|
struct rtc_device *rtc_class_open(char *name)
|
|
{
|
|
struct device *dev;
|
|
struct rtc_device *rtc = NULL;
|
|
|
|
dev = class_find_device(rtc_class, NULL, name, __rtc_match);
|
|
if (dev)
|
|
rtc = to_rtc_device(dev);
|
|
|
|
if (rtc) {
|
|
if (!try_module_get(rtc->owner)) {
|
|
put_device(dev);
|
|
rtc = NULL;
|
|
}
|
|
}
|
|
|
|
return rtc;
|
|
}
|
|
EXPORT_SYMBOL_GPL(rtc_class_open);
|
|
|
|
void rtc_class_close(struct rtc_device *rtc)
|
|
{
|
|
module_put(rtc->owner);
|
|
put_device(&rtc->dev);
|
|
}
|
|
EXPORT_SYMBOL_GPL(rtc_class_close);
|
|
|
|
int rtc_irq_register(struct rtc_device *rtc, struct rtc_task *task)
|
|
{
|
|
int retval = -EBUSY;
|
|
|
|
if (task == NULL || task->func == NULL)
|
|
return -EINVAL;
|
|
|
|
/* Cannot register while the char dev is in use */
|
|
if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags))
|
|
return -EBUSY;
|
|
|
|
spin_lock_irq(&rtc->irq_task_lock);
|
|
if (rtc->irq_task == NULL) {
|
|
rtc->irq_task = task;
|
|
retval = 0;
|
|
}
|
|
spin_unlock_irq(&rtc->irq_task_lock);
|
|
|
|
clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
|
|
|
|
return retval;
|
|
}
|
|
EXPORT_SYMBOL_GPL(rtc_irq_register);
|
|
|
|
void rtc_irq_unregister(struct rtc_device *rtc, struct rtc_task *task)
|
|
{
|
|
spin_lock_irq(&rtc->irq_task_lock);
|
|
if (rtc->irq_task == task)
|
|
rtc->irq_task = NULL;
|
|
spin_unlock_irq(&rtc->irq_task_lock);
|
|
}
|
|
EXPORT_SYMBOL_GPL(rtc_irq_unregister);
|
|
|
|
/**
|
|
* rtc_irq_set_state - enable/disable 2^N Hz periodic IRQs
|
|
* @rtc: the rtc device
|
|
* @task: currently registered with rtc_irq_register()
|
|
* @enabled: true to enable periodic IRQs
|
|
* Context: any
|
|
*
|
|
* Note that rtc_irq_set_freq() should previously have been used to
|
|
* specify the desired frequency of periodic IRQ task->func() callbacks.
|
|
*/
|
|
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);
|
|
|
|
return err;
|
|
}
|
|
EXPORT_SYMBOL_GPL(rtc_irq_set_state);
|
|
|
|
/**
|
|
* rtc_irq_set_freq - set 2^N Hz periodic IRQ frequency for IRQ
|
|
* @rtc: the rtc device
|
|
* @task: currently registered with rtc_irq_register()
|
|
* @freq: positive frequency with which task->func() will be called
|
|
* Context: any
|
|
*
|
|
* Note that rtc_irq_set_state() is used to enable or disable the
|
|
* periodic IRQs.
|
|
*/
|
|
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;
|
|
|
|
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;
|
|
}
|
|
return err;
|
|
}
|
|
EXPORT_SYMBOL_GPL(rtc_irq_set_freq);
|