diff options
Diffstat (limited to 'arch/m68k/kernel/time.c')
| -rw-r--r-- | arch/m68k/kernel/time.c | 187 |
1 files changed, 187 insertions, 0 deletions
diff --git a/arch/m68k/kernel/time.c b/arch/m68k/kernel/time.c new file mode 100644 index 000000000000..e47e19588525 --- /dev/null +++ b/arch/m68k/kernel/time.c @@ -0,0 +1,187 @@ +/* + * linux/arch/m68k/kernel/time.c + * + * Copyright (C) 1991, 1992, 1995 Linus Torvalds + * + * This file contains the m68k-specific time handling details. + * Most of the stuff is located in the machine specific files. + * + * 1997-09-10 Updated NTP code according to technical memorandum Jan '96 + * "A Kernel Model for Precision Timekeeping" by Dave Mills + */ + +#include <linux/config.h> /* CONFIG_HEARTBEAT */ +#include <linux/errno.h> +#include <linux/module.h> +#include <linux/sched.h> +#include <linux/kernel.h> +#include <linux/param.h> +#include <linux/string.h> +#include <linux/mm.h> +#include <linux/rtc.h> + +#include <asm/machdep.h> +#include <asm/io.h> + +#include <linux/time.h> +#include <linux/timex.h> +#include <linux/profile.h> + +u64 jiffies_64 = INITIAL_JIFFIES; + +EXPORT_SYMBOL(jiffies_64); + +static inline int set_rtc_mmss(unsigned long nowtime) +{ + if (mach_set_clock_mmss) + return mach_set_clock_mmss (nowtime); + return -1; +} + +/* + * timer_interrupt() needs to keep up the real-time clock, + * as well as call the "do_timer()" routine every clocktick + */ +static irqreturn_t timer_interrupt(int irq, void *dummy, struct pt_regs * regs) +{ + do_timer(regs); +#ifndef CONFIG_SMP + update_process_times(user_mode(regs)); +#endif + profile_tick(CPU_PROFILING, regs); + +#ifdef CONFIG_HEARTBEAT + /* use power LED as a heartbeat instead -- much more useful + for debugging -- based on the version for PReP by Cort */ + /* acts like an actual heart beat -- ie thump-thump-pause... */ + if (mach_heartbeat) { + static unsigned cnt = 0, period = 0, dist = 0; + + if (cnt == 0 || cnt == dist) + mach_heartbeat( 1 ); + else if (cnt == 7 || cnt == dist+7) + mach_heartbeat( 0 ); + + if (++cnt > period) { + cnt = 0; + /* The hyperbolic function below modifies the heartbeat period + * length in dependency of the current (5min) load. It goes + * through the points f(0)=126, f(1)=86, f(5)=51, + * f(inf)->30. */ + period = ((672<<FSHIFT)/(5*avenrun[0]+(7<<FSHIFT))) + 30; + dist = period / 4; + } + } +#endif /* CONFIG_HEARTBEAT */ + return IRQ_HANDLED; +} + +void time_init(void) +{ + struct rtc_time time; + + if (mach_hwclk) { + mach_hwclk(0, &time); + + if ((time.tm_year += 1900) < 1970) + time.tm_year += 100; + xtime.tv_sec = mktime(time.tm_year, time.tm_mon, time.tm_mday, + time.tm_hour, time.tm_min, time.tm_sec); + xtime.tv_nsec = 0; + } + wall_to_monotonic.tv_sec = -xtime.tv_sec; + + mach_sched_init(timer_interrupt); +} + +/* + * This version of gettimeofday has near microsecond resolution. + */ +void do_gettimeofday(struct timeval *tv) +{ + unsigned long flags; + extern unsigned long wall_jiffies; + unsigned long seq; + unsigned long usec, sec, lost; + unsigned long max_ntp_tick = tick_usec - tickadj; + + do { + seq = read_seqbegin_irqsave(&xtime_lock, flags); + + usec = mach_gettimeoffset(); + lost = jiffies - wall_jiffies; + + /* + * 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 = min(usec, max_ntp_tick); + + if (lost) + usec += lost * max_ntp_tick; + } + else if (unlikely(lost)) + usec += lost * tick_usec; + + sec = xtime.tv_sec; + usec += xtime.tv_nsec/1000; + } while (read_seqretry_irqrestore(&xtime_lock, seq, 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; + extern unsigned long wall_jiffies; + + if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) + return -EINVAL; + + write_seqlock_irq(&xtime_lock); + /* This is revolting. We need to set the xtime.tv_nsec + * correctly. However, the value in this location is + * is value at the last tick. + * Discover what correction gettimeofday + * would have done, and then undo it! + */ + nsec -= 1000 * (mach_gettimeoffset() + + (jiffies - wall_jiffies) * (1000000 / HZ)); + + 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); + +/* + * Scheduler clock - returns current time in ns units. + */ +unsigned long long sched_clock(void) +{ + return (unsigned long long)jiffies*(1000000000/HZ); +} + |