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);
43 static inline void do_profile (unsigned long pc)
45 if (prof_buffer && current->pid) {
47 pc -= (unsigned long) &_stext;
53 * Don't ignore out-of-bounds PC values silently,
54 * put them into the last histogram slot, so if
55 * present, they will show up as a sharp peak.
57 ++prof_buffer[prof_len-1];
62 * timer_interrupt() needs to keep up the real-time clock,
63 * as well as call the "do_timer()" routine every clocktick
65 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;
72 /* may need to kick the hardware timer */
78 if (! user_mode (regs))
79 do_profile (regs->pc);
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)
104 mach_heartbeat ( 1 );
105 else if (cnt == 7 || cnt == dist+7)
106 mach_heartbeat ( 0 );
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 */
125 * This version of gettimeofday has near microsecond resolution.
127 void do_gettimeofday (struct timeval *tv)
129 #if 0 /* DAVIDM later if possible */
130 extern volatile unsigned long lost_ticks;
134 unsigned long usec, sec;
138 seq = read_seqbegin_irqsave(&xtime_lock, flags);
141 usec = mach_gettimeoffset ? mach_gettimeoffset () : 0;
145 #if 0 /* DAVIDM later if possible */
148 usec += lost * (1000000/HZ);
151 usec += xtime.tv_nsec / 1000;
152 } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
154 while (usec >= 1000000) {
163 EXPORT_SYMBOL(do_gettimeofday);
165 int do_settimeofday(struct timespec *tv)
167 if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
170 write_seqlock_irq (&xtime_lock);
172 /* This is revolting. We need to set the xtime.tv_nsec
173 * correctly. However, the value in this location is
174 * is value at the last tick.
175 * Discover what correction gettimeofday
176 * would have done, and then undo it!
179 tv->tv_nsec -= mach_gettimeoffset() * 1000;
182 while (tv->tv_nsec < 0) {
183 tv->tv_nsec += NSEC_PER_SEC;
187 xtime.tv_sec = tv->tv_sec;
188 xtime.tv_nsec = tv->tv_nsec;
190 time_adjust = 0; /* stop active adjtime () */
191 time_status |= STA_UNSYNC;
192 time_maxerror = NTP_PHASE_LIMIT;
193 time_esterror = NTP_PHASE_LIMIT;
195 write_sequnlock_irq (&xtime_lock);
200 EXPORT_SYMBOL(do_settimeofday);
202 static int timer_dev_id;
203 static struct irqaction timer_irqaction = {
212 void time_init (void)
214 mach_gettimeofday (&xtime);
215 mach_sched_init (&timer_irqaction);