1 /*
2 * linux/arch/m68k/kernel/time.c
3 *
4 * Copyright (C) 1991, 1992, 1995 Linus Torvalds
5 *
6 * This file contains the m68k-specific time handling details.
7 * Most of the stuff is located in the machine specific files.
8 *
9 * 1997-09-10 Updated NTP code according to technical memorandum Jan '96
10 * "A Kernel Model for Precision Timekeeping" by Dave Mills
11 */
12
13 #include <linux/errno.h>
14 #include <linux/module.h>
15 #include <linux/sched.h>
16 #include <linux/kernel.h>
17 #include <linux/param.h>
18 #include <linux/string.h>
19 #include <linux/mm.h>
20 #include <linux/rtc.h>
21
22 #include <asm/machdep.h>
23 #include <asm/io.h>
24 #include <asm/irq_regs.h>
25
26 #include <linux/time.h>
27 #include <linux/timex.h>
28 #include <linux/profile.h>
29
set_rtc_mmss(unsigned long nowtime)30 static inline int set_rtc_mmss(unsigned long nowtime)
31 {
32 if (mach_set_clock_mmss)
33 return mach_set_clock_mmss (nowtime);
34 return -1;
35 }
36
37 /*
38 * timer_interrupt() needs to keep up the real-time clock,
39 * as well as call the "do_timer()" routine every clocktick
40 */
timer_interrupt(int irq,void * dummy)41 static irqreturn_t timer_interrupt(int irq, void *dummy)
42 {
43 do_timer(1);
44 #ifndef CONFIG_SMP
45 update_process_times(user_mode(get_irq_regs()));
46 #endif
47 profile_tick(CPU_PROFILING);
48
49 #ifdef CONFIG_HEARTBEAT
50 /* use power LED as a heartbeat instead -- much more useful
51 for debugging -- based on the version for PReP by Cort */
52 /* acts like an actual heart beat -- ie thump-thump-pause... */
53 if (mach_heartbeat) {
54 static unsigned cnt = 0, period = 0, dist = 0;
55
56 if (cnt == 0 || cnt == dist)
57 mach_heartbeat( 1 );
58 else if (cnt == 7 || cnt == dist+7)
59 mach_heartbeat( 0 );
60
61 if (++cnt > period) {
62 cnt = 0;
63 /* The hyperbolic function below modifies the heartbeat period
64 * length in dependency of the current (5min) load. It goes
65 * through the points f(0)=126, f(1)=86, f(5)=51,
66 * f(inf)->30. */
67 period = ((672<<FSHIFT)/(5*avenrun[0]+(7<<FSHIFT))) + 30;
68 dist = period / 4;
69 }
70 }
71 #endif /* CONFIG_HEARTBEAT */
72 return IRQ_HANDLED;
73 }
74
time_init(void)75 void __init time_init(void)
76 {
77 struct rtc_time time;
78
79 if (mach_hwclk) {
80 mach_hwclk(0, &time);
81
82 if ((time.tm_year += 1900) < 1970)
83 time.tm_year += 100;
84 xtime.tv_sec = mktime(time.tm_year, time.tm_mon, time.tm_mday,
85 time.tm_hour, time.tm_min, time.tm_sec);
86 xtime.tv_nsec = 0;
87 }
88 wall_to_monotonic.tv_sec = -xtime.tv_sec;
89
90 mach_sched_init(timer_interrupt);
91 }
92
93 /*
94 * This version of gettimeofday has near microsecond resolution.
95 */
do_gettimeofday(struct timeval * tv)96 void do_gettimeofday(struct timeval *tv)
97 {
98 unsigned long flags;
99 unsigned long seq;
100 unsigned long usec, sec;
101 unsigned long max_ntp_tick = tick_usec - tickadj;
102
103 do {
104 seq = read_seqbegin_irqsave(&xtime_lock, flags);
105
106 usec = mach_gettimeoffset();
107
108 /*
109 * If time_adjust is negative then NTP is slowing the clock
110 * so make sure not to go into next possible interval.
111 * Better to lose some accuracy than have time go backwards..
112 */
113 if (unlikely(time_adjust < 0))
114 usec = min(usec, max_ntp_tick);
115
116 sec = xtime.tv_sec;
117 usec += xtime.tv_nsec/1000;
118 } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
119
120
121 while (usec >= 1000000) {
122 usec -= 1000000;
123 sec++;
124 }
125
126 tv->tv_sec = sec;
127 tv->tv_usec = usec;
128 }
129
130 EXPORT_SYMBOL(do_gettimeofday);
131
do_settimeofday(struct timespec * tv)132 int do_settimeofday(struct timespec *tv)
133 {
134 time_t wtm_sec, sec = tv->tv_sec;
135 long wtm_nsec, nsec = tv->tv_nsec;
136
137 if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
138 return -EINVAL;
139
140 write_seqlock_irq(&xtime_lock);
141 /* This is revolting. We need to set the xtime.tv_nsec
142 * correctly. However, the value in this location is
143 * is value at the last tick.
144 * Discover what correction gettimeofday
145 * would have done, and then undo it!
146 */
147 nsec -= 1000 * mach_gettimeoffset();
148
149 wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
150 wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
151
152 set_normalized_timespec(&xtime, sec, nsec);
153 set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
154
155 ntp_clear();
156 write_sequnlock_irq(&xtime_lock);
157 clock_was_set();
158 return 0;
159 }
160
161 EXPORT_SYMBOL(do_settimeofday);
162