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/*
* include/asm-i386/mach-pc9800/mach_time.h
*
* Machine specific set RTC function for PC-9800.
* Written by Osamu Tomita <tomita@cinet.co.jp>
*/
#ifndef _MACH_TIME_H
#define _MACH_TIME_H
#include <linux/bcd.h>
#include <linux/upd4990a.h>
/* for check timing call set_rtc_mmss() */
/* used in arch/i386/time.c::do_timer_interrupt() */
/*
* Because PC-9800's RTC (NEC uPD4990A) does not allow setting
* time partially, we always have to read-modify-write the
* entire time (including year) so that set_rtc_mmss() will
* take quite much time to execute. You may want to relax
* RTC resetting interval (currently ~11 minuts)...
*/
#define USEC_AFTER 1000000
#define USEC_BEFORE 0
static inline int mach_set_rtc_mmss(unsigned long nowtime)
{
int retval = 0;
int real_seconds, real_minutes, cmos_minutes;
struct upd4990a_raw_data data;
upd4990a_get_time(&data, 1);
cmos_minutes = BCD2BIN(data.min);
/*
* 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) {
u8 temp_seconds = (real_seconds / 10) * 16 + real_seconds % 10;
u8 temp_minutes = (real_minutes / 10) * 16 + real_minutes % 10;
if (data.sec != temp_seconds || data.min != temp_minutes) {
data.sec = temp_seconds;
data.min = temp_minutes;
upd4990a_set_time(&data, 1);
}
} else {
printk(KERN_WARNING
"set_rtc_mmss: can't update from %d to %d\n",
cmos_minutes, real_minutes);
retval = -1;
}
/* uPD4990A users' manual says we should issue Register Hold
* command after reading time, or future Time Read command
* may not work. When we have set the time, this also starts
* the clock.
*/
upd4990a_serial_command(UPD4990A_REGISTER_HOLD);
return retval;
}
static inline unsigned long mach_get_cmos_time(void)
{
int i;
u8 prev, cur;
unsigned int year;
struct upd4990a_raw_data data;
/* Connect uPD4990A's DATA OUT pin to its 1Hz reference clock. */
upd4990a_serial_command(UPD4990A_REGISTER_HOLD);
/* Catch rising edge of reference clock. */
prev = ~UPD4990A_READ_DATA();
for (i = 0; i < 1800000; i++) { /* may take up to 1 second... */
__asm__ ("outb %%al,%0" : : "N" (0x5f)); /* 0.6usec delay */
cur = UPD4990A_READ_DATA();
if (!(prev & cur & 1))
break;
prev = ~cur;
}
upd4990a_get_time(&data, 0);
if ((year = BCD2BIN(data.year) + 1900) < 1995)
year += 100;
return mktime(year, data.mon, BCD2BIN(data.mday), BCD2BIN(data.hour),
BCD2BIN(data.min), BCD2BIN(data.sec));
}
#endif /* !_MACH_TIME_H */