/* $Id: time.c,v 1.14 2004/06/01 05:38:11 starvik Exp $
*
* linux/arch/cris/kernel/time.c
*
* Copyright (C) 1991, 1992, 1995 Linus Torvalds
* Copyright (C) 1999, 2000, 2001 Axis Communications AB
*
* 1994-07-02 Alan Modra
* fixed set_rtc_mmss, fixed time.year for >= 2000, new mktime
* 1995-03-26 Markus Kuhn
* fixed 500 ms bug at call to set_rtc_mmss, fixed DS12887
* precision CMOS clock update
* 1996-05-03 Ingo Molnar
* fixed time warps in do_[slow|fast]_gettimeoffset()
* 1997-09-10 Updated NTP code according to technical memorandum Jan '96
* "A Kernel Model for Precision Timekeeping" by Dave Mills
*
* Linux/CRIS specific code:
*
* Authors: Bjorn Wesen
* Johan Adolfsson
*
*/
#include <asm/rtc.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/param.h>
#include <linux/jiffies.h>
#include <linux/bcd.h>
#include <linux/timex.h>
#include <linux/init.h>
u64 jiffies_64 = INITIAL_JIFFIES;
EXPORT_SYMBOL(jiffies_64);
int have_rtc; /* used to remember if we have an RTC or not */;
#define TICK_SIZE tick
extern unsigned long wall_jiffies;
extern unsigned long loops_per_jiffy; /* init/main.c */
unsigned long loops_per_usec;
extern unsigned long do_slow_gettimeoffset(void);
static unsigned long (*do_gettimeoffset)(void) = do_slow_gettimeoffset;
/*
* This version of gettimeofday has near microsecond resolution.
*
* Note: Division is quite slow on CRIS and do_gettimeofday is called
* rather often. Maybe we should do some kind of approximation here
* (a naive approximation would be to divide by 1024).
*/
void do_gettimeofday(struct timeval *tv)
{
unsigned long flags;
signed long usec, sec;
local_irq_save(flags);
local_irq_disable();
usec = do_gettimeoffset();
{
unsigned long lost = jiffies - wall_jiffies;
if (lost)
usec += lost * (1000000 / HZ);
}
/*
* If time_adjust is negative then NTP is slowing the clock
* so make sure not to go into next possible interval.
* Better to lose some accuracy than have time go backwards..
*/
if (unlikely(time_adjust < 0) && usec > tickadj)
usec = tickadj;
sec = xtime.tv_sec;
usec += xtime.tv_nsec / 1000;
local_irq_restore(flags);
while (usec >= 1000000) {
usec -= 1000000;
sec++;
}
tv->tv_sec = sec;
tv->tv_usec = usec;
}
EXPORT_SYMBOL(do_gettimeofday);
int do_settimeofday(struct timespec *tv)
{
time_t wtm_sec, sec = tv->tv_sec;
long wtm_nsec, nsec = tv->tv_nsec;
if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
return -EINVAL;
write_seqlock_irq(&xtime_lock);
/*
* This is revolting. We need to set "xtime" correctly. However, the
* value in this location is the value at the most recent update of
* wall time. Discover what correction gettimeofday() would have
* made, and then undo it!
*/
nsec -= do_gettimeoffset() * NSEC_PER_USEC;
nsec -= (jiffies - wall_jiffies) * TICK_NSEC;
wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
set_normalized_timespec(&xtime, sec, nsec);
set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
time_adjust = 0; /* stop active adjtime() */
time_status |= STA_UNSYNC;
time_maxerror = NTP_PHASE_LIMIT;
time_esterror = NTP_PHASE_LIMIT;
write_sequnlock_irq(&xtime_lock);
clock_was_set();
return 0;
}
EXPORT_SYMBOL(do_settimeofday);
/*
* BUG: This routine does not handle hour overflow properly; it just
* sets the minutes. Usually you'll only notice that after reboot!
*/
int set_rtc_mmss(unsigned long nowtime)
{
int retval = 0;
int real_seconds, real_minutes, cmos_minutes;
printk(KERN_DEBUG "set_rtc_mmss(%lu)\n", nowtime);
if(!have_rtc)
return 0;
cmos_minutes = CMOS_READ(RTC_MINUTES);
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) {
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;
}
return retval;
}
/* grab the time from the RTC chip */
unsigned long
get_cmos_time(void)
{
unsigned int year, mon, day, hour, min, sec;
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);
printk(KERN_DEBUG
"rtc: sec 0x%x min 0x%x hour 0x%x day 0x%x mon 0x%x year 0x%x\n",
sec, min, hour, day, mon, year);
BCD_TO_BIN(sec);
BCD_TO_BIN(min);
BCD_TO_BIN(hour);
BCD_TO_BIN(day);
BCD_TO_BIN(mon);
BCD_TO_BIN(year);
if ((year += 1900) < 1970)
year += 100;
return mktime(year, mon, day, hour, min, sec);
}
/* update xtime from the CMOS settings. used when /dev/rtc gets a SET_TIME.
* TODO: this doesn't reset the fancy NTP phase stuff as do_settimeofday does.
*/
void
update_xtime_from_cmos(void)
{
if(have_rtc) {
xtime.tv_sec = get_cmos_time();
xtime.tv_nsec = 0;
}
}
/*
* Scheduler clock - returns current time in nanosec units.
*/
unsigned long long sched_clock(void)
{
return (unsigned long long)jiffies * (1000000000 / HZ);
}
static int
__init init_udelay(void)
{
loops_per_usec = (loops_per_jiffy * HZ) / 1000000;
return 0;
}
__initcall(init_udelay);
