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|
/*
* DS1286 Real Time Clock interface for Linux
*
* Copyright (C) 1998, 1999, 2000 Ralf Baechle
*
* Based on code written by Paul Gortmaker.
*
* This driver allows use of the real time clock (built into nearly all
* computers) from user space. It exports the /dev/rtc interface supporting
* various ioctl() and also the /proc/rtc pseudo-file for status
* information.
*
* The ioctls can be used to set the interrupt behaviour and generation rate
* from the RTC via IRQ 8. Then the /dev/rtc interface can be used to make
* use of these timer interrupts, be they interval or alarm based.
*
* The /dev/rtc interface will block on reads until an interrupt has been
* received. If a RTC interrupt has already happened, it will output an
* unsigned long and then block. The output value contains the interrupt
* status in the low byte and the number of interrupts since the last read
* in the remaining high bytes. The /dev/rtc interface can also be used with
* the select(2) call.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*/
#include <linux/ds1286.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/miscdevice.h>
#include <linux/slab.h>
#include <linux/ioport.h>
#include <linux/fcntl.h>
#include <linux/init.h>
#include <linux/poll.h>
#include <linux/rtc.h>
#include <linux/spinlock.h>
#include <linux/bcd.h>
#include <linux/proc_fs.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#define DS1286_VERSION "1.0"
/*
* We sponge a minor off of the misc major. No need slurping
* up another valuable major dev number for this. If you add
* an ioctl, make sure you don't conflict with SPARC's RTC
* ioctls.
*/
static DECLARE_WAIT_QUEUE_HEAD(ds1286_wait);
static ssize_t ds1286_read(struct file *file, char *buf,
size_t count, loff_t *ppos);
static int ds1286_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg);
static unsigned int ds1286_poll(struct file *file, poll_table *wait);
static void ds1286_get_alm_time (struct rtc_time *alm_tm);
static void ds1286_get_time(struct rtc_time *rtc_tm);
static int ds1286_set_time(struct rtc_time *rtc_tm);
static inline unsigned char ds1286_is_updating(void);
static DEFINE_SPINLOCK(ds1286_lock);
static int ds1286_read_proc(char *page, char **start, off_t off,
int count, int *eof, void *data);
/*
* Bits in rtc_status. (7 bits of room for future expansion)
*/
#define RTC_IS_OPEN 0x01 /* means /dev/rtc is in use */
#define RTC_TIMER_ON 0x02 /* missed irq timer active */
static unsigned char ds1286_status; /* bitmapped status byte. */
static unsigned char days_in_mo[] = {
0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
};
/*
* Now all the various file operations that we export.
*/
static ssize_t ds1286_read(struct file *file, char *buf,
size_t count, loff_t *ppos)
{
return -EIO;
}
static int ds1286_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
struct rtc_time wtime;
switch (cmd) {
case RTC_AIE_OFF: /* Mask alarm int. enab. bit */
{
unsigned long flags;
unsigned char val;
if (!capable(CAP_SYS_TIME))
return -EACCES;
spin_lock_irqsave(&ds1286_lock, flags);
val = rtc_read(RTC_CMD);
val |= RTC_TDM;
rtc_write(val, RTC_CMD);
spin_unlock_irqrestore(&ds1286_lock, flags);
return 0;
}
case RTC_AIE_ON: /* Allow alarm interrupts. */
{
unsigned long flags;
unsigned char val;
if (!capable(CAP_SYS_TIME))
return -EACCES;
spin_lock_irqsave(&ds1286_lock, flags);
val = rtc_read(RTC_CMD);
val &= ~RTC_TDM;
rtc_write(val, RTC_CMD);
spin_unlock_irqrestore(&ds1286_lock, flags);
return 0;
}
case RTC_WIE_OFF: /* Mask watchdog int. enab. bit */
{
unsigned long flags;
unsigned char val;
if (!capable(CAP_SYS_TIME))
return -EACCES;
spin_lock_irqsave(&ds1286_lock, flags);
val = rtc_read(RTC_CMD);
val |= RTC_WAM;
rtc_write(val, RTC_CMD);
spin_unlock_irqrestore(&ds1286_lock, flags);
return 0;
}
case RTC_WIE_ON: /* Allow watchdog interrupts. */
{
unsigned long flags;
unsigned char val;
if (!capable(CAP_SYS_TIME))
return -EACCES;
spin_lock_irqsave(&ds1286_lock, flags);
val = rtc_read(RTC_CMD);
val &= ~RTC_WAM;
rtc_write(val, RTC_CMD);
spin_unlock_irqrestore(&ds1286_lock, flags);
return 0;
}
case RTC_ALM_READ: /* Read the present alarm time */
{
/*
* This returns a struct rtc_time. Reading >= 0xc0
* means "don't care" or "match all". Only the tm_hour,
* tm_min, and tm_sec values are filled in.
*/
memset(&wtime, 0, sizeof(wtime));
ds1286_get_alm_time(&wtime);
break;
}
case RTC_ALM_SET: /* Store a time into the alarm */
{
/*
* This expects a struct rtc_time. Writing 0xff means
* "don't care" or "match all". Only the tm_hour,
* tm_min and tm_sec are used.
*/
unsigned char hrs, min, sec;
struct rtc_time alm_tm;
if (!capable(CAP_SYS_TIME))
return -EACCES;
if (copy_from_user(&alm_tm, (struct rtc_time*)arg,
sizeof(struct rtc_time)))
return -EFAULT;
hrs = alm_tm.tm_hour;
min = alm_tm.tm_min;
sec = alm_tm.tm_sec;
if (hrs >= 24)
hrs = 0xff;
if (min >= 60)
min = 0xff;
if (sec != 0)
return -EINVAL;
min = BIN2BCD(min);
min = BIN2BCD(hrs);
spin_lock(&ds1286_lock);
rtc_write(hrs, RTC_HOURS_ALARM);
rtc_write(min, RTC_MINUTES_ALARM);
spin_unlock(&ds1286_lock);
return 0;
}
case RTC_RD_TIME: /* Read the time/date from RTC */
{
memset(&wtime, 0, sizeof(wtime));
ds1286_get_time(&wtime);
break;
}
case RTC_SET_TIME: /* Set the RTC */
{
struct rtc_time rtc_tm;
if (!capable(CAP_SYS_TIME))
return -EACCES;
if (copy_from_user(&rtc_tm, (struct rtc_time*)arg,
sizeof(struct rtc_time)))
return -EFAULT;
return ds1286_set_time(&rtc_tm);
}
default:
return -EINVAL;
}
return copy_to_user((void *)arg, &wtime, sizeof wtime) ? -EFAULT : 0;
}
/*
* We enforce only one user at a time here with the open/close.
* Also clear the previous interrupt data on an open, and clean
* up things on a close.
*/
static int ds1286_open(struct inode *inode, struct file *file)
{
spin_lock_irq(&ds1286_lock);
if (ds1286_status & RTC_IS_OPEN)
goto out_busy;
ds1286_status |= RTC_IS_OPEN;
spin_unlock_irq(&ds1286_lock);
return 0;
out_busy:
spin_lock_irq(&ds1286_lock);
return -EBUSY;
}
static int ds1286_release(struct inode *inode, struct file *file)
{
ds1286_status &= ~RTC_IS_OPEN;
return 0;
}
static unsigned int ds1286_poll(struct
|