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Diffstat (limited to 'arch/cris/kernel/time.c')
| -rw-r--r-- | arch/cris/kernel/time.c | 232 |
1 files changed, 232 insertions, 0 deletions
diff --git a/arch/cris/kernel/time.c b/arch/cris/kernel/time.c new file mode 100644 index 000000000000..6c28b0e7f7b4 --- /dev/null +++ b/arch/cris/kernel/time.c @@ -0,0 +1,232 @@ +/* $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); |