rtc.c
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/*
* Real Time Clock interface for Linux on the BVME6000
*
* Based on the PC driver by Paul Gortmaker.
*/
#define RTC_VERSION "1.00"
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/miscdevice.h>
#include <linux/ioport.h>
#include <linux/capability.h>
#include <linux/fcntl.h>
#include <linux/init.h>
#include <linux/poll.h>
#include <linux/module.h>
#include <linux/mc146818rtc.h> /* For struct rtc_time and ioctls, etc */
#include <linux/bcd.h>
#include <asm/bvme6000hw.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/setup.h>
/*
* 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 unsigned char days_in_mo[] =
{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
static atomic_t rtc_status = ATOMIC_INIT(1);
static long rtc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
volatile RtcPtr_t rtc = (RtcPtr_t)BVME_RTC_BASE;
unsigned char msr;
unsigned long flags;
struct rtc_time wtime;
void __user *argp = (void __user *)arg;
switch (cmd) {
case RTC_RD_TIME: /* Read the time/date from RTC */
{
local_irq_save(flags);
/* Ensure clock and real-time-mode-register are accessible */
msr = rtc->msr & 0xc0;
rtc->msr = 0x40;
memset(&wtime, 0, sizeof(struct rtc_time));
do {
wtime.tm_sec = bcd2bin(rtc->bcd_sec);
wtime.tm_min = bcd2bin(rtc->bcd_min);
wtime.tm_hour = bcd2bin(rtc->bcd_hr);
wtime.tm_mday = bcd2bin(rtc->bcd_dom);
wtime.tm_mon = bcd2bin(rtc->bcd_mth)-1;
wtime.tm_year = bcd2bin(rtc->bcd_year);
if (wtime.tm_year < 70)
wtime.tm_year += 100;
wtime.tm_wday = bcd2bin(rtc->bcd_dow)-1;
} while (wtime.tm_sec != bcd2bin(rtc->bcd_sec));
rtc->msr = msr;
local_irq_restore(flags);
return copy_to_user(argp, &wtime, sizeof wtime) ?
-EFAULT : 0;
}
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_ADMIN))
return -EACCES;
if (copy_from_user(&rtc_tm, argp, sizeof(struct rtc_time)))
return -EFAULT;
yrs = rtc_tm.tm_year;
if (yrs < 1900)
yrs += 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;
leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400));
if ((mon > 12) || (mon < 1) || (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 >= 2070)
return -EINVAL;
local_irq_save(flags);
/* Ensure clock and real-time-mode-register are accessible */
msr = rtc->msr & 0xc0;
rtc->msr = 0x40;
rtc->t0cr_rtmr = yrs%4;
rtc->bcd_tenms = 0;
rtc->bcd_sec = bin2bcd(sec);
rtc->bcd_min = bin2bcd(min);
rtc->bcd_hr = bin2bcd(hrs);
rtc->bcd_dom = bin2bcd(day);
rtc->bcd_mth = bin2bcd(mon);
rtc->bcd_year = bin2bcd(yrs%100);
if (rtc_tm.tm_wday >= 0)
rtc->bcd_dow = bin2bcd(rtc_tm.tm_wday+1);
rtc->t0cr_rtmr = yrs%4 | 0x08;
rtc->msr = msr;
local_irq_restore(flags);
return 0;
}
default:
return -EINVAL;
}
}
/*
* We enforce only one user at a time here with the open/close.
*/
static int rtc_open(struct inode *inode, struct file *file)
{
if (!atomic_dec_and_test(&rtc_status)) {
atomic_inc(&rtc_status);
return -EBUSY;
}
return 0;
}
static int rtc_release(struct inode *inode, struct file *file)
{
atomic_inc(&rtc_status);
return 0;
}
/*
* The various file operations we support.
*/
static const struct file_operations rtc_fops = {
.unlocked_ioctl = rtc_ioctl,
.open = rtc_open,
.release = rtc_release,
.llseek = noop_llseek,
};
static struct miscdevice rtc_dev = {
.minor = RTC_MINOR,
.name = "rtc",
.fops = &rtc_fops
};
static int __init rtc_DP8570A_init(void)
{
if (!MACH_IS_BVME6000)
return -ENODEV;
printk(KERN_INFO "DP8570A Real Time Clock Driver v%s\n", RTC_VERSION);
return misc_register(&rtc_dev);
}
module_init(rtc_DP8570A_init);