kernel-ark/arch/arm/common/rtctime.c
Arjan van de Ven 5dfe4c964a [PATCH] mark struct file_operations const 2
Many struct file_operations in the kernel can be "const".  Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data.  In addition it'll catch accidental writes at compile time to
these shared resources.

[akpm@osdl.org: sparc64 fix]
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 09:48:44 -08:00

437 lines
8.9 KiB
C

/*
* linux/arch/arm/common/rtctime.c
*
* Copyright (C) 2003 Deep Blue Solutions Ltd.
* Based on sa1100-rtc.c, Nils Faerber, CIH, Nicolas Pitre.
* Based on rtc.c by Paul Gortmaker
*
* 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/module.h>
#include <linux/kernel.h>
#include <linux/time.h>
#include <linux/rtc.h>
#include <linux/poll.h>
#include <linux/proc_fs.h>
#include <linux/miscdevice.h>
#include <linux/spinlock.h>
#include <linux/capability.h>
#include <linux/device.h>
#include <linux/mutex.h>
#include <linux/rtc.h>
#include <asm/rtc.h>
#include <asm/semaphore.h>
static DECLARE_WAIT_QUEUE_HEAD(rtc_wait);
static struct fasync_struct *rtc_async_queue;
/*
* rtc_lock protects rtc_irq_data
*/
static DEFINE_SPINLOCK(rtc_lock);
static unsigned long rtc_irq_data;
/*
* rtc_sem protects rtc_inuse and rtc_ops
*/
static DEFINE_MUTEX(rtc_mutex);
static unsigned long rtc_inuse;
static struct rtc_ops *rtc_ops;
#define rtc_epoch 1900UL
/*
* Calculate the next alarm time given the requested alarm time mask
* and the current time.
*/
void rtc_next_alarm_time(struct rtc_time *next, struct rtc_time *now, struct rtc_time *alrm)
{
unsigned long next_time;
unsigned long now_time;
next->tm_year = now->tm_year;
next->tm_mon = now->tm_mon;
next->tm_mday = now->tm_mday;
next->tm_hour = alrm->tm_hour;
next->tm_min = alrm->tm_min;
next->tm_sec = alrm->tm_sec;
rtc_tm_to_time(now, &now_time);
rtc_tm_to_time(next, &next_time);
if (next_time < now_time) {
/* Advance one day */
next_time += 60 * 60 * 24;
rtc_time_to_tm(next_time, next);
}
}
EXPORT_SYMBOL(rtc_next_alarm_time);
static inline int rtc_arm_read_time(struct rtc_ops *ops, struct rtc_time *tm)
{
memset(tm, 0, sizeof(struct rtc_time));
return ops->read_time(tm);
}
static inline int rtc_arm_set_time(struct rtc_ops *ops, struct rtc_time *tm)
{
int ret;
ret = rtc_valid_tm(tm);
if (ret == 0)
ret = ops->set_time(tm);
return ret;
}
static inline int rtc_arm_read_alarm(struct rtc_ops *ops, struct rtc_wkalrm *alrm)
{
int ret = -EINVAL;
if (ops->read_alarm) {
memset(alrm, 0, sizeof(struct rtc_wkalrm));
ret = ops->read_alarm(alrm);
}
return ret;
}
static inline int rtc_arm_set_alarm(struct rtc_ops *ops, struct rtc_wkalrm *alrm)
{
int ret = -EINVAL;
if (ops->set_alarm)
ret = ops->set_alarm(alrm);
return ret;
}
void rtc_update(unsigned long num, unsigned long events)
{
spin_lock(&rtc_lock);
rtc_irq_data = (rtc_irq_data + (num << 8)) | events;
spin_unlock(&rtc_lock);
wake_up_interruptible(&rtc_wait);
kill_fasync(&rtc_async_queue, SIGIO, POLL_IN);
}
EXPORT_SYMBOL(rtc_update);
static ssize_t
rtc_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
DECLARE_WAITQUEUE(wait, current);
unsigned long data;
ssize_t ret;
if (count < sizeof(unsigned long))
return -EINVAL;
add_wait_queue(&rtc_wait, &wait);
do {
__set_current_state(TASK_INTERRUPTIBLE);
spin_lock_irq(&rtc_lock);
data = rtc_irq_data;
rtc_irq_data = 0;
spin_unlock_irq(&rtc_lock);
if (data != 0) {
ret = 0;
break;
}
if (file->f_flags & O_NONBLOCK) {
ret = -EAGAIN;
break;
}
if (signal_pending(current)) {
ret = -ERESTARTSYS;
break;
}
schedule();
} while (1);
set_current_state(TASK_RUNNING);
remove_wait_queue(&rtc_wait, &wait);
if (ret == 0) {
ret = put_user(data, (unsigned long __user *)buf);
if (ret == 0)
ret = sizeof(unsigned long);
}
return ret;
}
static unsigned int rtc_poll(struct file *file, poll_table *wait)
{
unsigned long data;
poll_wait(file, &rtc_wait, wait);
spin_lock_irq(&rtc_lock);
data = rtc_irq_data;
spin_unlock_irq(&rtc_lock);
return data != 0 ? POLLIN | POLLRDNORM : 0;
}
static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
unsigned long arg)
{
struct rtc_ops *ops = file->private_data;
struct rtc_time tm;
struct rtc_wkalrm alrm;
void __user *uarg = (void __user *)arg;
int ret = -EINVAL;
switch (cmd) {
case RTC_ALM_READ:
ret = rtc_arm_read_alarm(ops, &alrm);
if (ret)
break;
ret = copy_to_user(uarg, &alrm.time, sizeof(tm));
if (ret)
ret = -EFAULT;
break;
case RTC_ALM_SET:
ret = copy_from_user(&alrm.time, uarg, sizeof(tm));
if (ret) {
ret = -EFAULT;
break;
}
alrm.enabled = 0;
alrm.pending = 0;
alrm.time.tm_mday = -1;
alrm.time.tm_mon = -1;
alrm.time.tm_year = -1;
alrm.time.tm_wday = -1;
alrm.time.tm_yday = -1;
alrm.time.tm_isdst = -1;
ret = rtc_arm_set_alarm(ops, &alrm);
break;
case RTC_RD_TIME:
ret = rtc_arm_read_time(ops, &tm);
if (ret)
break;
ret = copy_to_user(uarg, &tm, sizeof(tm));
if (ret)
ret = -EFAULT;
break;
case RTC_SET_TIME:
if (!capable(CAP_SYS_TIME)) {
ret = -EACCES;
break;
}
ret = copy_from_user(&tm, uarg, sizeof(tm));
if (ret) {
ret = -EFAULT;
break;
}
ret = rtc_arm_set_time(ops, &tm);
break;
case RTC_EPOCH_SET:
#ifndef rtc_epoch
/*
* There were no RTC clocks before 1900.
*/
if (arg < 1900) {
ret = -EINVAL;
break;
}
if (!capable(CAP_SYS_TIME)) {
ret = -EACCES;
break;
}
rtc_epoch = arg;
ret = 0;
#endif
break;
case RTC_EPOCH_READ:
ret = put_user(rtc_epoch, (unsigned long __user *)uarg);
break;
case RTC_WKALM_SET:
ret = copy_from_user(&alrm, uarg, sizeof(alrm));
if (ret) {
ret = -EFAULT;
break;
}
ret = rtc_arm_set_alarm(ops, &alrm);
break;
case RTC_WKALM_RD:
ret = rtc_arm_read_alarm(ops, &alrm);
if (ret)
break;
ret = copy_to_user(uarg, &alrm, sizeof(alrm));
if (ret)
ret = -EFAULT;
break;
default:
if (ops->ioctl)
ret = ops->ioctl(cmd, arg);
break;
}
return ret;
}
static int rtc_open(struct inode *inode, struct file *file)
{
int ret;
mutex_lock(&rtc_mutex);
if (rtc_inuse) {
ret = -EBUSY;
} else if (!rtc_ops || !try_module_get(rtc_ops->owner)) {
ret = -ENODEV;
} else {
file->private_data = rtc_ops;
ret = rtc_ops->open ? rtc_ops->open() : 0;
if (ret == 0) {
spin_lock_irq(&rtc_lock);
rtc_irq_data = 0;
spin_unlock_irq(&rtc_lock);
rtc_inuse = 1;
}
}
mutex_unlock(&rtc_mutex);
return ret;
}
static int rtc_release(struct inode *inode, struct file *file)
{
struct rtc_ops *ops = file->private_data;
if (ops->release)
ops->release();
spin_lock_irq(&rtc_lock);
rtc_irq_data = 0;
spin_unlock_irq(&rtc_lock);
module_put(rtc_ops->owner);
rtc_inuse = 0;
return 0;
}
static int rtc_fasync(int fd, struct file *file, int on)
{
return fasync_helper(fd, file, on, &rtc_async_queue);
}
static const struct file_operations rtc_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.read = rtc_read,
.poll = rtc_poll,
.ioctl = rtc_ioctl,
.open = rtc_open,
.release = rtc_release,
.fasync = rtc_fasync,
};
static struct miscdevice rtc_miscdev = {
.minor = RTC_MINOR,
.name = "rtc",
.fops = &rtc_fops,
};
static int rtc_read_proc(char *page, char **start, off_t off, int count, int *eof, void *data)
{
struct rtc_ops *ops = data;
struct rtc_wkalrm alrm;
struct rtc_time tm;
char *p = page;
if (rtc_arm_read_time(ops, &tm) == 0) {
p += sprintf(p,
"rtc_time\t: %02d:%02d:%02d\n"
"rtc_date\t: %04d-%02d-%02d\n"
"rtc_epoch\t: %04lu\n",
tm.tm_hour, tm.tm_min, tm.tm_sec,
tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
rtc_epoch);
}
if (rtc_arm_read_alarm(ops, &alrm) == 0) {
p += sprintf(p, "alrm_time\t: ");
if ((unsigned int)alrm.time.tm_hour <= 24)
p += sprintf(p, "%02d:", alrm.time.tm_hour);
else
p += sprintf(p, "**:");
if ((unsigned int)alrm.time.tm_min <= 59)
p += sprintf(p, "%02d:", alrm.time.tm_min);
else
p += sprintf(p, "**:");
if ((unsigned int)alrm.time.tm_sec <= 59)
p += sprintf(p, "%02d\n", alrm.time.tm_sec);
else
p += sprintf(p, "**\n");
p += sprintf(p, "alrm_date\t: ");
if ((unsigned int)alrm.time.tm_year <= 200)
p += sprintf(p, "%04d-", alrm.time.tm_year + 1900);
else
p += sprintf(p, "****-");
if ((unsigned int)alrm.time.tm_mon <= 11)
p += sprintf(p, "%02d-", alrm.time.tm_mon + 1);
else
p += sprintf(p, "**-");
if ((unsigned int)alrm.time.tm_mday <= 31)
p += sprintf(p, "%02d\n", alrm.time.tm_mday);
else
p += sprintf(p, "**\n");
p += sprintf(p, "alrm_wakeup\t: %s\n",
alrm.enabled ? "yes" : "no");
p += sprintf(p, "alrm_pending\t: %s\n",
alrm.pending ? "yes" : "no");
}
if (ops->proc)
p += ops->proc(p);
return p - page;
}
int register_rtc(struct rtc_ops *ops)
{
int ret = -EBUSY;
mutex_lock(&rtc_mutex);
if (rtc_ops == NULL) {
rtc_ops = ops;
ret = misc_register(&rtc_miscdev);
if (ret == 0)
create_proc_read_entry("driver/rtc", 0, NULL,
rtc_read_proc, ops);
}
mutex_unlock(&rtc_mutex);
return ret;
}
EXPORT_SYMBOL(register_rtc);
void unregister_rtc(struct rtc_ops *rtc)
{
mutex_lock(&rtc_mutex);
if (rtc == rtc_ops) {
remove_proc_entry("driver/rtc", NULL);
misc_deregister(&rtc_miscdev);
rtc_ops = NULL;
}
mutex_unlock(&rtc_mutex);
}
EXPORT_SYMBOL(unregister_rtc);