/*
* Driver for the SGS-Thomson M48T35 Timekeeper RAM chip
*
* Real Time Clock interface for Linux
*
* TODO: Implement periodic interrupts.
*
* Copyright (C) 2000 Silicon Graphics, Inc.
* Written by Ulf Carlsson (ulfc@engr.sgi.com)
*
* 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.
*
* 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.
*
*/
#define RTC_VERSION "1.09b"
#include <linux/bcd.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/miscdevice.h>
#include <linux/ioport.h>
#include <linux/fcntl.h>
#include <linux/rtc.h>
#include <linux/init.h>
#include <linux/poll.h>
#include <linux/proc_fs.h>
#include <asm/m48t35.h>
#include <asm/sn/ioc3.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/sn/klconfig.h>
#include <asm/sn/sn0/ip27.h>
#include <asm/sn/sn0/hub.h>
#include <asm/sn/sn_private.h>
static int rtc_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg);
static int rtc_read_proc(char *page, char **start, off_t off,
int count, int *eof, void *data);
static void get_rtc_time(struct rtc_time *rtc_tm);
/*
* Bits in rtc_status. (6 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 rtc_status; /* bitmapped status byte. */
static unsigned long rtc_freq; /* Current periodic IRQ rate */
static struct m48t35_rtc *rtc;
/*
* If this driver ever becomes modularised, it will be really nice
* to make the epoch retain its value across module reload...
*/
static unsigned long epoch = 1970; /* year corresponding to 0x00 */
static const unsigned char days_in_mo[] =
{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
static int rtc_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
unsigned long arg)
{
struct rtc_time wtime;
switch (cmd) {
case RTC_RD_TIME: /* Read the time/date from RTC */
{
get_rtc_time(&wtime);
break;
}
case RTC_SET_TIME: /* Set the RTC */
{
struct rtc_time rtc_tm;
unsigned char mon, day, hrs, min, sec, leap_yr;
unsigned int yrs;
if (!capable(CAP_SYS_TIME))
return -EACCES;
if (copy_from_user(&rtc_tm, (struct rtc_time*)arg,
sizeof(struct rtc_time)))
return -EFAULT;
yrs = rtc_tm.tm_year + 1900;
mon = rtc_tm.tm_mon + 1; /* tm_mon starts at zero */
day = rtc_tm.tm_mday;
hrs = rtc_tm.tm_hour;
min = rtc_tm.tm_min;
sec = rtc_tm.tm_sec;
if (yrs < 1970)
return -EINVAL;
leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
if ((mon > 12) || (day == 0))
return -EINVAL;
if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr)))
return -EINVAL;
if ((hrs >= 24) || (min >= 60) || (sec >= 60))
return -EINVAL;
if ((yrs -= epoch) > 255) /* They are unsigned */
return -EINVAL;
if (yrs > 169)
return -EINVAL;
if (yrs >= 100)
yrs -= 100;
sec = BIN2BCD(sec);
min = BIN2BCD(min);
hrs = BIN2BCD(hrs);
day = BIN2BCD(day);
mon = BIN2BCD(mon);
yrs = BIN2BCD(yrs);
spin_lock_irq(&rtc_lock);
rtc->control |= M48T35_RTC_SET;
rtc->year = yrs;
rtc->month = mon;
rtc->date = day;
rtc->hour = hrs;
rtc->min = min;
rtc->sec = sec;
rtc->control &= ~M48T35_RTC_SET;
spin_unlock_irq(&rtc_lock);
return 0;
}
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 rtc_open(struct inode *inode, struct file *file)
{
spin_lock_irq(&rtc_lock);
if (rtc_status & RTC_IS_OPEN) {
spin_unlock_irq(&rtc_lock);
return -EBUSY;
}
rtc_status |= RTC_IS_OPEN;
spin_unlock_irq(&rtc_lock);
return 0;
}
static int rtc_release(struct inode *inode, struct file *file)
{
/*
* Turn off all interrupts once the device is no longer
* in use, and clear the data.
*/
spin_lock_irq(&rtc_lock);
rtc_status &= ~RTC_IS_OPEN;
spin_unlock_irq(&rtc_lock);
return 0;
}
/*
* The various file operations we support.
*/
static const struct file_operations rtc_fops = {
.owner = THIS_MODULE,
.ioctl = rtc_ioctl,
.open = rtc_open,
.release = rtc_release,
};
static struct miscdevice rtc_dev=
{
RTC_MINOR,
"rtc",
&rtc_fops
};
static int __init rtc_init(void)
{
rtc = (struct m48t35_rtc *)
(KL_CONFIG_CH_CONS_INFO(master_nasid)->memory_base + IOC3_BYTEBUS_DEV0);
printk(KERN_INFO "Real Time Clock Driver v%s\n", RTC_VERSION);
if (misc_register(&rtc_dev)) {
printk(KERN_ERR "rtc: cannot register misc device.\n");
return -ENODEV;
}
if (!create_proc_read_entry("driver/rtc", 0, NULL, rtc_read_proc, NULL)) {
printk(KERN_ERR "rtc: cannot create /proc/rtc.\n");
misc_deregister(&rtc_dev);
return -ENOENT;
}
rtc_freq = 1024;
return 0;
}
static void __exit rtc_exit (void)
{
/* interrupts and timer disabled at this point by rtc_release */
remove_proc_entry ("rtc", NULL);
misc_deregister(&rtc_dev);
}
module_init(rtc_init);
module_exit(rtc_exit);
/*
* Info exported via "/proc/rtc".
*/
static int rtc_get_status(char *buf)
{
char *p;
struct rtc_time tm;
/*
* Just emulate the standard /proc/rtc
*/
p = buf;
get_rtc_time(&tm);
/*
* There is no way to tell if the luser has the RTC set for local
* time or for Universal Standard Time (GMT). Probably local though.
*/
p += sprintf(p,
"rtc_time\t: %02d:%02d:%02d\n"
"rtc_date\t: %04d-%02d-%02d\n"
"rtc_epoch\t: %04lu\n"
"24hr\t\t: yes\n",
tm.tm_hour, tm.tm_min, tm.tm_sec,
tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, epoch);
return p - buf;
}
static int rtc_read_proc(char *page, char **start, off_t off,
int count, int *eof, void *data)
{
int len = rtc_get_status(page);
if (len <= off+count) *eof = 1;
*start = page + off;
len -= off;
if (len>count) len = count;
if (len<0) len = 0;
return len;
}
static void get_rtc_time(struct rtc_time *rtc_tm)
{
/*
* Do we need to wait for the last update to finish?
*/
/*
* Only the values that we read from the RTC are set. We leave
* tm_wday, tm_yday and tm_isdst untouched. Even though the
* RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated
* by the RTC when initially set to a non-zero value.
*/
spin_lock_irq(&rtc_lock);
rtc->control |= M48T35_RTC_READ;
rtc_tm->tm_sec = rtc->sec;
rtc_tm->tm_min = rtc->min;
rtc_tm->tm_hour = rtc->hour;
rtc_tm->tm_mday = rtc->date;
rtc_tm->tm_mon = rtc->month;
rtc_tm->tm_year = rtc->year;
rtc->control &= ~M48T35_RTC_READ;
spin_unlock_irq(&rtc_lock);
rtc_tm->tm_sec = BCD2BIN(rtc_tm->tm_sec);
rtc_tm->tm_min = BCD2BIN(rtc_tm->tm_min);
rtc_tm->tm_hour = BCD2BIN(rtc_tm->tm_hour);
rtc_tm->tm_mday = BCD2BIN(rtc_tm->tm_mday);
rtc_tm->tm_mon = BCD2BIN(rtc_tm->tm_mon);
rtc_tm->tm_year = BCD2BIN(rtc_tm->tm_year);
/*
* Account for differences between how the RTC uses the values
* and how they are defined in a struct rtc_time;
*/
if ((rtc_tm->tm_year += (epoch - 1900)) <= 69)
rtc_tm->tm_year += 100;
rtc_tm->tm_mon--;
}
