153 lines
4.5 KiB
C
153 lines
4.5 KiB
C
/*
|
|
* linux/arch/sh/kernel/rtc-mpc1211.c -- MPC-1211 on-chip RTC support
|
|
*
|
|
* Copyright (C) 2002 Saito.K & Jeanne
|
|
*
|
|
*/
|
|
|
|
#include <linux/init.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/time.h>
|
|
#include <linux/mc146818rtc.h>
|
|
|
|
#ifndef BCD_TO_BIN
|
|
#define BCD_TO_BIN(val) ((val)=((val)&15) + ((val)>>4)*10)
|
|
#endif
|
|
|
|
#ifndef BIN_TO_BCD
|
|
#define BIN_TO_BCD(val) ((val)=(((val)/10)<<4) + (val)%10)
|
|
#endif
|
|
|
|
/* arc/i386/kernel/time.c */
|
|
unsigned long get_cmos_time(void)
|
|
{
|
|
unsigned int year, mon, day, hour, min, sec;
|
|
int i;
|
|
|
|
spin_lock(&rtc_lock);
|
|
/* The Linux interpretation of the CMOS clock register contents:
|
|
* When the Update-In-Progress (UIP) flag goes from 1 to 0, the
|
|
* RTC registers show the second which has precisely just started.
|
|
* Let's hope other operating systems interpret the RTC the same way.
|
|
*/
|
|
/* read RTC exactly on falling edge of update flag */
|
|
for (i = 0 ; i < 1000000 ; i++) /* may take up to 1 second... */
|
|
if (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP)
|
|
break;
|
|
for (i = 0 ; i < 1000000 ; i++) /* must try at least 2.228 ms */
|
|
if (!(CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP))
|
|
break;
|
|
do { /* Isn't this overkill ? UIP above should guarantee consistency */
|
|
sec = CMOS_READ(RTC_SECONDS);
|
|
min = CMOS_READ(RTC_MINUTES);
|
|
hour = CMOS_READ(RTC_HOURS);
|
|
day = CMOS_READ(RTC_DAY_OF_MONTH);
|
|
mon = CMOS_READ(RTC_MONTH);
|
|
year = CMOS_READ(RTC_YEAR);
|
|
} while (sec != CMOS_READ(RTC_SECONDS));
|
|
if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
|
|
{
|
|
BCD_TO_BIN(sec);
|
|
BCD_TO_BIN(min);
|
|
BCD_TO_BIN(hour);
|
|
BCD_TO_BIN(day);
|
|
BCD_TO_BIN(mon);
|
|
BCD_TO_BIN(year);
|
|
}
|
|
spin_unlock(&rtc_lock);
|
|
if ((year += 1900) < 1970)
|
|
year += 100;
|
|
return mktime(year, mon, day, hour, min, sec);
|
|
}
|
|
|
|
void mpc1211_rtc_gettimeofday(struct timeval *tv)
|
|
{
|
|
|
|
tv->tv_sec = get_cmos_time();
|
|
tv->tv_usec = 0;
|
|
}
|
|
|
|
/* arc/i386/kernel/time.c */
|
|
/*
|
|
* In order to set the CMOS clock precisely, set_rtc_mmss has to be
|
|
* called 500 ms after the second nowtime has started, because when
|
|
* nowtime is written into the registers of the CMOS clock, it will
|
|
* jump to the next second precisely 500 ms later. Check the Motorola
|
|
* MC146818A or Dallas DS12887 data sheet for details.
|
|
*
|
|
* BUG: This routine does not handle hour overflow properly; it just
|
|
* sets the minutes. Usually you'll only notice that after reboot!
|
|
*/
|
|
static int set_rtc_mmss(unsigned long nowtime)
|
|
{
|
|
int retval = 0;
|
|
int real_seconds, real_minutes, cmos_minutes;
|
|
unsigned char save_control, save_freq_select;
|
|
|
|
/* gets recalled with irq locally disabled */
|
|
spin_lock(&rtc_lock);
|
|
save_control = CMOS_READ(RTC_CONTROL); /* tell the clock it's being set */
|
|
CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
|
|
|
|
save_freq_select = CMOS_READ(RTC_FREQ_SELECT); /* stop and reset prescaler */
|
|
CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
|
|
|
|
cmos_minutes = CMOS_READ(RTC_MINUTES);
|
|
if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
|
|
BCD_TO_BIN(cmos_minutes);
|
|
|
|
/*
|
|
* since we're only adjusting minutes and seconds,
|
|
* don't interfere with hour overflow. This avoids
|
|
* messing with unknown time zones but requires your
|
|
* RTC not to be off by more than 15 minutes
|
|
*/
|
|
real_seconds = nowtime % 60;
|
|
real_minutes = nowtime / 60;
|
|
if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1)
|
|
real_minutes += 30; /* correct for half hour time zone */
|
|
real_minutes %= 60;
|
|
|
|
if (abs(real_minutes - cmos_minutes) < 30) {
|
|
if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
|
|
BIN_TO_BCD(real_seconds);
|
|
BIN_TO_BCD(real_minutes);
|
|
}
|
|
CMOS_WRITE(real_seconds,RTC_SECONDS);
|
|
CMOS_WRITE(real_minutes,RTC_MINUTES);
|
|
} else {
|
|
printk(KERN_WARNING
|
|
"set_rtc_mmss: can't update from %d to %d\n",
|
|
cmos_minutes, real_minutes);
|
|
retval = -1;
|
|
}
|
|
|
|
/* The following flags have to be released exactly in this order,
|
|
* otherwise the DS12887 (popular MC146818A clone with integrated
|
|
* battery and quartz) will not reset the oscillator and will not
|
|
* update precisely 500 ms later. You won't find this mentioned in
|
|
* the Dallas Semiconductor data sheets, but who believes data
|
|
* sheets anyway ... -- Markus Kuhn
|
|
*/
|
|
CMOS_WRITE(save_control, RTC_CONTROL);
|
|
CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
|
|
spin_unlock(&rtc_lock);
|
|
|
|
return retval;
|
|
}
|
|
|
|
int mpc1211_rtc_settimeofday(const struct timeval *tv)
|
|
{
|
|
unsigned long nowtime = tv->tv_sec;
|
|
|
|
return set_rtc_mmss(nowtime);
|
|
}
|
|
|
|
void mpc1211_time_init(void)
|
|
{
|
|
rtc_get_time = mpc1211_rtc_gettimeofday;
|
|
rtc_set_time = mpc1211_rtc_settimeofday;
|
|
}
|
|
|