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1 /* $Id: time.c,v 1.18 2005/03/04 08:16:17 starvik Exp $
3 * linux/arch/cris/kernel/time.c
5 * Copyright (C) 1991, 1992, 1995 Linus Torvalds
6 * Copyright (C) 1999, 2000, 2001 Axis Communications AB
8 * 1994-07-02 Alan Modra
9 * fixed set_rtc_mmss, fixed time.year for >= 2000, new mktime
10 * 1995-03-26 Markus Kuhn
11 * fixed 500 ms bug at call to set_rtc_mmss, fixed DS12887
12 * precision CMOS clock update
13 * 1996-05-03 Ingo Molnar
14 * fixed time warps in do_[slow|fast]_gettimeoffset()
15 * 1997-09-10 Updated NTP code according to technical memorandum Jan '96
16 * "A Kernel Model for Precision Timekeeping" by Dave Mills
18 * Linux/CRIS specific code:
20 * Authors: Bjorn Wesen
26 #include <linux/errno.h>
27 #include <linux/module.h>
28 #include <linux/param.h>
29 #include <linux/jiffies.h>
30 #include <linux/bcd.h>
31 #include <linux/timex.h>
32 #include <linux/init.h>
33 #include <linux/profile.h>
34 #include <linux/sched.h> /* just for sched_clock() - funny that */
36 int have_rtc
; /* used to remember if we have an RTC or not */;
38 #define TICK_SIZE tick
40 extern unsigned long wall_jiffies
;
41 extern unsigned long loops_per_jiffy
; /* init/main.c */
42 unsigned long loops_per_usec
;
44 extern unsigned long do_slow_gettimeoffset(void);
45 static unsigned long (*do_gettimeoffset
)(void) = do_slow_gettimeoffset
;
48 * This version of gettimeofday has near microsecond resolution.
50 * Note: Division is quite slow on CRIS and do_gettimeofday is called
51 * rather often. Maybe we should do some kind of approximation here
52 * (a naive approximation would be to divide by 1024).
54 void do_gettimeofday(struct timeval
*tv
)
57 signed long usec
, sec
;
58 local_irq_save(flags
);
60 usec
= do_gettimeoffset();
62 unsigned long lost
= jiffies
- wall_jiffies
;
64 usec
+= lost
* (1000000 / HZ
);
68 * If time_adjust is negative then NTP is slowing the clock
69 * so make sure not to go into next possible interval.
70 * Better to lose some accuracy than have time go backwards..
72 if (unlikely(time_adjust
< 0) && usec
> tickadj
)
76 usec
+= xtime
.tv_nsec
/ 1000;
77 local_irq_restore(flags
);
79 while (usec
>= 1000000) {
88 EXPORT_SYMBOL(do_gettimeofday
);
90 int do_settimeofday(struct timespec
*tv
)
92 time_t wtm_sec
, sec
= tv
->tv_sec
;
93 long wtm_nsec
, nsec
= tv
->tv_nsec
;
95 if ((unsigned long)tv
->tv_nsec
>= NSEC_PER_SEC
)
98 write_seqlock_irq(&xtime_lock
);
100 * This is revolting. We need to set "xtime" correctly. However, the
101 * value in this location is the value at the most recent update of
102 * wall time. Discover what correction gettimeofday() would have
103 * made, and then undo it!
105 nsec
-= do_gettimeoffset() * NSEC_PER_USEC
;
106 nsec
-= (jiffies
- wall_jiffies
) * TICK_NSEC
;
108 wtm_sec
= wall_to_monotonic
.tv_sec
+ (xtime
.tv_sec
- sec
);
109 wtm_nsec
= wall_to_monotonic
.tv_nsec
+ (xtime
.tv_nsec
- nsec
);
111 set_normalized_timespec(&xtime
, sec
, nsec
);
112 set_normalized_timespec(&wall_to_monotonic
, wtm_sec
, wtm_nsec
);
115 write_sequnlock_irq(&xtime_lock
);
120 EXPORT_SYMBOL(do_settimeofday
);
124 * BUG: This routine does not handle hour overflow properly; it just
125 * sets the minutes. Usually you'll only notice that after reboot!
128 int set_rtc_mmss(unsigned long nowtime
)
131 int real_seconds
, real_minutes
, cmos_minutes
;
133 printk(KERN_DEBUG
"set_rtc_mmss(%lu)\n", nowtime
);
138 cmos_minutes
= CMOS_READ(RTC_MINUTES
);
139 BCD_TO_BIN(cmos_minutes
);
142 * since we're only adjusting minutes and seconds,
143 * don't interfere with hour overflow. This avoids
144 * messing with unknown time zones but requires your
145 * RTC not to be off by more than 15 minutes
147 real_seconds
= nowtime
% 60;
148 real_minutes
= nowtime
/ 60;
149 if (((abs(real_minutes
- cmos_minutes
) + 15)/30) & 1)
150 real_minutes
+= 30; /* correct for half hour time zone */
153 if (abs(real_minutes
- cmos_minutes
) < 30) {
154 BIN_TO_BCD(real_seconds
);
155 BIN_TO_BCD(real_minutes
);
156 CMOS_WRITE(real_seconds
,RTC_SECONDS
);
157 CMOS_WRITE(real_minutes
,RTC_MINUTES
);
160 "set_rtc_mmss: can't update from %d to %d\n",
161 cmos_minutes
, real_minutes
);
168 /* grab the time from the RTC chip */
173 unsigned int year
, mon
, day
, hour
, min
, sec
;
175 sec
= CMOS_READ(RTC_SECONDS
);
176 min
= CMOS_READ(RTC_MINUTES
);
177 hour
= CMOS_READ(RTC_HOURS
);
178 day
= CMOS_READ(RTC_DAY_OF_MONTH
);
179 mon
= CMOS_READ(RTC_MONTH
);
180 year
= CMOS_READ(RTC_YEAR
);
183 "rtc: sec 0x%x min 0x%x hour 0x%x day 0x%x mon 0x%x year 0x%x\n",
184 sec
, min
, hour
, day
, mon
, year
);
193 if ((year
+= 1900) < 1970)
196 return mktime(year
, mon
, day
, hour
, min
, sec
);
199 /* update xtime from the CMOS settings. used when /dev/rtc gets a SET_TIME.
200 * TODO: this doesn't reset the fancy NTP phase stuff as do_settimeofday does.
204 update_xtime_from_cmos(void)
207 xtime
.tv_sec
= get_cmos_time();
212 extern void cris_profile_sample(struct pt_regs
* regs
);
215 cris_do_profile(struct pt_regs
* regs
)
218 #if CONFIG_SYSTEM_PROFILER
219 cris_profile_sample(regs
);
223 profile_tick(CPU_PROFILING
, regs
);
228 * Scheduler clock - returns current time in nanosec units.
230 unsigned long long sched_clock(void)
232 return (unsigned long long)jiffies
* (1000000000 / HZ
);
236 __init
init_udelay(void)
238 loops_per_usec
= (loops_per_jiffy
* HZ
) / 1000000;
242 __initcall(init_udelay
);