2 * linux/arch/v850/kernel/time.c -- Arch-dependent timer functions
4 * Copyright (C) 1991, 1992, 1995, 2001, 2002 Linus Torvalds
6 * This file contains the v850-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/kernel.h>
16 #include <linux/module.h>
17 #include <linux/param.h>
18 #include <linux/string.h>
20 #include <linux/interrupt.h>
21 #include <linux/time.h>
22 #include <linux/timex.h>
23 #include <linux/profile.h>
29 u64 jiffies_64 = INITIAL_JIFFIES;
31 EXPORT_SYMBOL(jiffies_64);
33 #define TICK_SIZE (tick_nsec / 1000)
36 * Scheduler clock - returns current time in nanosec units.
38 unsigned long long sched_clock(void)
40 return (unsigned long long)jiffies * (1000000000 / HZ);
44 * timer_interrupt() needs to keep up the real-time clock,
45 * as well as call the "do_timer()" routine every clocktick
47 static irqreturn_t timer_interrupt (int irq, void *dummy, struct pt_regs *regs)
50 /* last time the cmos clock got updated */
51 static long last_rtc_update=0;
54 /* may need to kick the hardware timer */
59 profile_tick(CPU_PROFILING, regs);
62 * If we have an externally synchronized Linux clock, then update
63 * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
64 * called as close as possible to 500 ms before the new second starts.
66 if ((time_status & STA_UNSYNC) == 0 &&
67 xtime.tv_sec > last_rtc_update + 660 &&
68 (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
69 (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) {
70 if (set_rtc_mmss (xtime.tv_sec) == 0)
71 last_rtc_update = xtime.tv_sec;
73 last_rtc_update = xtime.tv_sec - 600; /* do it again in 60 s */
75 #ifdef CONFIG_HEARTBEAT
76 /* use power LED as a heartbeat instead -- much more useful
77 for debugging -- based on the version for PReP by Cort */
78 /* acts like an actual heart beat -- ie thump-thump-pause... */
80 static unsigned cnt = 0, period = 0, dist = 0;
82 if (cnt == 0 || cnt == dist)
84 else if (cnt == 7 || cnt == dist+7)
89 /* The hyperbolic function below modifies the heartbeat period
90 * length in dependency of the current (5min) load. It goes
91 * through the points f(0)=126, f(1)=86, f(5)=51,
93 period = ((672<<FSHIFT)/(5*avenrun[0]+(7<<FSHIFT))) + 30;
97 #endif /* CONFIG_HEARTBEAT */
104 * This version of gettimeofday has near microsecond resolution.
106 void do_gettimeofday (struct timeval *tv)
108 #if 0 /* DAVIDM later if possible */
109 extern volatile unsigned long lost_ticks;
113 unsigned long usec, sec;
117 seq = read_seqbegin_irqsave(&xtime_lock, flags);
120 usec = mach_gettimeoffset ? mach_gettimeoffset () : 0;
124 #if 0 /* DAVIDM later if possible */
127 usec += lost * (1000000/HZ);
130 usec += xtime.tv_nsec / 1000;
131 } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
133 while (usec >= 1000000) {
142 EXPORT_SYMBOL(do_gettimeofday);
144 int do_settimeofday(struct timespec *tv)
146 if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
149 write_seqlock_irq (&xtime_lock);
151 /* This is revolting. We need to set the xtime.tv_nsec
152 * correctly. However, the value in this location is
153 * is value at the last tick.
154 * Discover what correction gettimeofday
155 * would have done, and then undo it!
158 tv->tv_nsec -= mach_gettimeoffset() * 1000;
161 while (tv->tv_nsec < 0) {
162 tv->tv_nsec += NSEC_PER_SEC;
166 xtime.tv_sec = tv->tv_sec;
167 xtime.tv_nsec = tv->tv_nsec;
169 time_adjust = 0; /* stop active adjtime () */
170 time_status |= STA_UNSYNC;
171 time_maxerror = NTP_PHASE_LIMIT;
172 time_esterror = NTP_PHASE_LIMIT;
174 write_sequnlock_irq (&xtime_lock);
179 EXPORT_SYMBOL(do_settimeofday);
181 static int timer_dev_id;
182 static struct irqaction timer_irqaction = {
191 void time_init (void)
193 mach_gettimeofday (&xtime);
194 mach_sched_init (&timer_irqaction);