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/sched.h>
16 #include <linux/kernel.h>
17 #include <linux/param.h>
18 #include <linux/string.h>
21 #include <asm/machdep.h>
24 #include <linux/timex.h>
27 static inline int set_rtc_mmss(unsigned long nowtime
)
29 if (mach_set_clock_mmss
)
30 return mach_set_clock_mmss (nowtime
);
34 static inline void do_profile (unsigned long pc
)
36 if (prof_buffer
&& current
->pid
) {
38 pc
-= (unsigned long) &_stext
;
44 * Don't ignore out-of-bounds PC values silently,
45 * put them into the last histogram slot, so if
46 * present, they will show up as a sharp peak.
48 ++prof_buffer
[prof_len
-1];
53 * timer_interrupt() needs to keep up the real-time clock,
54 * as well as call the "do_timer()" routine every clocktick
56 static void timer_interrupt(int irq
, void *dummy
, struct pt_regs
* regs
)
58 /* last time the cmos clock got updated */
59 static long last_rtc_update
=0;
67 * If we have an externally synchronized Linux clock, then update
68 * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
69 * called as close as possible to 500 ms before the new second starts.
71 if ((time_status
& STA_UNSYNC
) == 0 &&
72 xtime
.tv_sec
> last_rtc_update
+ 660 &&
73 xtime
.tv_usec
>= 500000 - ((unsigned) tick
) / 2 &&
74 xtime
.tv_usec
<= 500000 + ((unsigned) tick
) / 2) {
75 if (set_rtc_mmss(xtime
.tv_sec
) == 0)
76 last_rtc_update
= xtime
.tv_sec
;
78 last_rtc_update
= xtime
.tv_sec
- 600; /* do it again in 60 s */
80 #ifdef CONFIG_HEARTBEAT
81 /* use power LED as a heartbeat instead -- much more useful
82 for debugging -- based on the version for PReP by Cort */
83 /* acts like an actual heart beat -- ie thump-thump-pause... */
85 static unsigned cnt
= 0, period
= 0, dist
= 0;
87 if (cnt
== 0 || cnt
== dist
)
89 else if (cnt
== 7 || cnt
== dist
+7)
94 /* The hyperbolic function below modifies the heartbeat period
95 * length in dependency of the current (5min) load. It goes
96 * through the points f(0)=126, f(1)=86, f(5)=51,
98 period
= ((672<<FSHIFT
)/(5*avenrun
[0]+(7<<FSHIFT
))) + 30;
102 #endif /* CONFIG_HEARTBEAT */
107 unsigned int year
, mon
, day
, hour
, min
, sec
;
109 extern void arch_gettod(int *year
, int *mon
, int *day
, int *hour
,
112 arch_gettod (&year
, &mon
, &day
, &hour
, &min
, &sec
);
114 if ((year
+= 1900) < 1970)
116 xtime
.tv_sec
= mktime(year
, mon
, day
, hour
, min
, sec
);
119 mach_sched_init(timer_interrupt
);
122 extern rwlock_t xtime_lock
;
125 * This version of gettimeofday has near microsecond resolution.
127 void do_gettimeofday(struct timeval
*tv
)
129 extern volatile unsigned long lost_ticks
;
131 unsigned long usec
, sec
, lost
;
133 read_lock_irqsave(&xtime_lock
, flags
);
134 usec
= mach_gettimeoffset();
137 usec
+= lost
* (1000000/HZ
);
139 usec
+= xtime
.tv_usec
;
140 read_unlock_irqrestore(&xtime_lock
, flags
);
142 while (usec
>= 1000000) {
151 void do_settimeofday(struct timeval
*tv
)
153 write_lock_irq(&xtime_lock
);
154 /* This is revolting. We need to set the xtime.tv_usec
155 * correctly. However, the value in this location is
156 * is value at the last tick.
157 * Discover what correction gettimeofday
158 * would have done, and then undo it!
160 tv
->tv_usec
-= mach_gettimeoffset();
162 while (tv
->tv_usec
< 0) {
163 tv
->tv_usec
+= 1000000;
168 time_adjust
= 0; /* stop active adjtime() */
169 time_status
|= STA_UNSYNC
;
170 time_maxerror
= NTP_PHASE_LIMIT
;
171 time_esterror
= NTP_PHASE_LIMIT
;
172 write_unlock_irq(&xtime_lock
);