2 * linux/arch/m68knommu/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>
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/profile.h>
22 #include <linux/time.h>
23 #include <linux/timex.h>
25 #include <asm/machdep.h>
28 #define TICK_SIZE (tick_nsec / 1000)
30 u64 jiffies_64 = INITIAL_JIFFIES;
32 EXPORT_SYMBOL(jiffies_64);
34 extern unsigned long wall_jiffies;
37 static inline int set_rtc_mmss(unsigned long nowtime)
39 if (mach_set_clock_mmss)
40 return mach_set_clock_mmss (nowtime);
44 static inline void do_profile (unsigned long pc)
46 if (prof_buffer && current->pid) {
48 pc -= (unsigned long) &_stext;
54 * Don't ignore out-of-bounds PC values silently,
55 * put them into the last histogram slot, so if
56 * present, they will show up as a sharp peak.
58 ++prof_buffer[prof_len-1];
63 * timer_interrupt() needs to keep up the real-time clock,
64 * as well as call the "do_timer()" routine every clocktick
66 static irqreturn_t timer_interrupt(int irq, void *dummy, struct pt_regs * regs)
68 /* last time the cmos clock got updated */
69 static long last_rtc_update=0;
71 /* may need to kick the hardware timer */
75 write_seqlock(&xtime_lock);
83 * If we have an externally synchronized Linux clock, then update
84 * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
85 * called as close as possible to 500 ms before the new second starts.
87 if ((time_status & STA_UNSYNC) == 0 &&
88 xtime.tv_sec > last_rtc_update + 660 &&
89 (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
90 (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) {
91 if (set_rtc_mmss(xtime.tv_sec) == 0)
92 last_rtc_update = xtime.tv_sec;
94 last_rtc_update = xtime.tv_sec - 600; /* do it again in 60 s */
96 #ifdef CONFIG_HEARTBEAT
97 /* use power LED as a heartbeat instead -- much more useful
98 for debugging -- based on the version for PReP by Cort */
99 /* acts like an actual heart beat -- ie thump-thump-pause... */
100 if (mach_heartbeat) {
101 static unsigned cnt = 0, period = 0, dist = 0;
103 if (cnt == 0 || cnt == dist)
105 else if (cnt == 7 || cnt == dist+7)
108 if (++cnt > period) {
110 /* The hyperbolic function below modifies the heartbeat period
111 * length in dependency of the current (5min) load. It goes
112 * through the points f(0)=126, f(1)=86, f(5)=51,
114 period = ((672<<FSHIFT)/(5*avenrun[0]+(7<<FSHIFT))) + 30;
118 #endif /* CONFIG_HEARTBEAT */
120 write_sequnlock(&xtime_lock);
126 unsigned int year, mon, day, hour, min, sec;
128 extern void arch_gettod(int *year, int *mon, int *day, int *hour,
131 arch_gettod(&year, &mon, &day, &hour, &min, &sec);
133 if ((year += 1900) < 1970)
135 xtime.tv_sec = mktime(year, mon, day, hour, min, sec);
137 wall_to_monotonic.tv_sec = -xtime.tv_sec;
139 mach_sched_init(timer_interrupt);
143 * This version of gettimeofday has near microsecond resolution.
145 void do_gettimeofday(struct timeval *tv)
148 unsigned long lost, seq;
149 unsigned long usec, sec;
152 seq = read_seqbegin_irqsave(&xtime_lock, flags);
153 usec = mach_gettimeoffset ? mach_gettimeoffset() : 0;
154 lost = jiffies - wall_jiffies;
156 usec += lost * (1000000 / HZ);
158 usec += (xtime.tv_nsec / 1000);
159 } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
161 while (usec >= 1000000) {
170 EXPORT_SYMBOL(do_gettimeofday);
172 int do_settimeofday(struct timespec *tv)
174 time_t wtm_sec, sec = tv->tv_sec;
175 long wtm_nsec, nsec = tv->tv_nsec;
177 if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
180 write_seqlock_irq(&xtime_lock);
182 * This is revolting. We need to set the xtime.tv_usec
183 * correctly. However, the value in this location is
184 * is value at the last tick.
185 * Discover what correction gettimeofday
186 * would have done, and then undo it!
188 if (mach_gettimeoffset)
189 nsec -= (mach_gettimeoffset() * 1000);
191 wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
192 wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
194 set_normalized_timespec(&xtime, sec, nsec);
195 set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
197 time_adjust = 0; /* stop active adjtime() */
198 time_status |= STA_UNSYNC;
199 time_maxerror = NTP_PHASE_LIMIT;
200 time_esterror = NTP_PHASE_LIMIT;
201 write_sequnlock_irq(&xtime_lock);
207 * Scheduler clock - returns current time in nanosec units.
209 unsigned long long sched_clock(void)
211 return (unsigned long long)jiffies * (1000000000 / HZ);
214 EXPORT_SYMBOL(do_settimeofday);