2 * linux/arch/m68k/kernel/time.c
4 * Copyright (C) 1991, 1992, 1995 Linus Torvalds
6 * This file contains the m68k-specific time handling details.
7 * Most of the stuff is located in the machine specific files.
9 * 1997-09-10 Updated NTP code according to technical memorandum Jan '96
10 * "A Kernel Model for Precision Timekeeping" by Dave Mills
13 #include <linux/config.h> /* CONFIG_HEARTBEAT */
14 #include <linux/errno.h>
15 #include <linux/module.h>
16 #include <linux/sched.h>
17 #include <linux/kernel.h>
18 #include <linux/param.h>
19 #include <linux/string.h>
21 #include <linux/rtc.h>
23 #include <asm/machdep.h>
26 #include <linux/time.h>
27 #include <linux/timex.h>
28 #include <linux/profile.h>
30 u64 jiffies_64 = INITIAL_JIFFIES;
32 EXPORT_SYMBOL(jiffies_64);
34 static inline int set_rtc_mmss(unsigned long nowtime)
36 if (mach_set_clock_mmss)
37 return mach_set_clock_mmss (nowtime);
41 static inline void do_profile (unsigned long pc)
43 if (prof_buffer && current->pid) {
45 pc -= (unsigned long) &_stext;
51 * Don't ignore out-of-bounds PC values silently,
52 * put them into the last histogram slot, so if
53 * present, they will show up as a sharp peak.
55 ++prof_buffer[prof_len-1];
60 * timer_interrupt() needs to keep up the real-time clock,
61 * as well as call the "do_timer()" routine every clocktick
63 static irqreturn_t timer_interrupt(int irq, void *dummy, struct pt_regs * regs)
70 #ifdef CONFIG_HEARTBEAT
71 /* use power LED as a heartbeat instead -- much more useful
72 for debugging -- based on the version for PReP by Cort */
73 /* acts like an actual heart beat -- ie thump-thump-pause... */
75 static unsigned cnt = 0, period = 0, dist = 0;
77 if (cnt == 0 || cnt == dist)
79 else if (cnt == 7 || cnt == dist+7)
84 /* The hyperbolic function below modifies the heartbeat period
85 * length in dependency of the current (5min) load. It goes
86 * through the points f(0)=126, f(1)=86, f(5)=51,
88 period = ((672<<FSHIFT)/(5*avenrun[0]+(7<<FSHIFT))) + 30;
92 #endif /* CONFIG_HEARTBEAT */
101 mach_hwclk(0, &time);
103 if ((time.tm_year += 1900) < 1970)
105 xtime.tv_sec = mktime(time.tm_year, time.tm_mon, time.tm_mday,
106 time.tm_hour, time.tm_min, time.tm_sec);
109 wall_to_monotonic.tv_sec = -xtime.tv_sec;
111 mach_sched_init(timer_interrupt);
115 * This version of gettimeofday has near microsecond resolution.
117 void do_gettimeofday(struct timeval *tv)
120 extern unsigned long wall_jiffies;
122 unsigned long usec, sec, lost;
123 unsigned long max_ntp_tick = tick_usec - tickadj;
126 seq = read_seqbegin_irqsave(&xtime_lock, flags);
128 usec = mach_gettimeoffset();
129 lost = jiffies - wall_jiffies;
132 * If time_adjust is negative then NTP is slowing the clock
133 * so make sure not to go into next possible interval.
134 * Better to lose some accuracy than have time go backwards..
136 if (unlikely(time_adjust < 0)) {
137 usec = min(usec, max_ntp_tick);
140 usec += lost * max_ntp_tick;
142 else if (unlikely(lost))
143 usec += lost * tick_usec;
146 usec += xtime.tv_nsec/1000;
147 } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
150 while (usec >= 1000000) {
159 EXPORT_SYMBOL(do_gettimeofday);
161 int do_settimeofday(struct timespec *tv)
163 time_t wtm_sec, sec = tv->tv_sec;
164 long wtm_nsec, nsec = tv->tv_nsec;
165 extern unsigned long wall_jiffies;
167 if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
170 write_seqlock_irq(&xtime_lock);
171 /* This is revolting. We need to set the xtime.tv_nsec
172 * correctly. However, the value in this location is
173 * is value at the last tick.
174 * Discover what correction gettimeofday
175 * would have done, and then undo it!
177 nsec -= 1000 * (mach_gettimeoffset() +
178 (jiffies - wall_jiffies) * (1000000 / HZ));
180 wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
181 wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
183 set_normalized_timespec(&xtime, sec, nsec);
184 set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
186 time_adjust = 0; /* stop active adjtime() */
187 time_status |= STA_UNSYNC;
188 time_maxerror = NTP_PHASE_LIMIT;
189 time_esterror = NTP_PHASE_LIMIT;
190 write_sequnlock_irq(&xtime_lock);
195 EXPORT_SYMBOL(do_settimeofday);
198 * Scheduler clock - returns current time in ns units.
200 unsigned long long sched_clock(void)
202 return (unsigned long long)jiffies*(1000000000/HZ);