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-rw-r--r--arch/m68k/kernel/time.c187
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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/config.h> /* CONFIG_HEARTBEAT */
14#include <linux/errno.h>
15#include <linux/module.h>
16#include <linux/sched.h>
17#include <linux/kernel.h>
18#include <linux/param.h>
19#include <linux/string.h>
20#include <linux/mm.h>
21#include <linux/rtc.h>
22
23#include <asm/machdep.h>
24#include <asm/io.h>
25
26#include <linux/time.h>
27#include <linux/timex.h>
28#include <linux/profile.h>
29
30u64 jiffies_64 = INITIAL_JIFFIES;
31
32EXPORT_SYMBOL(jiffies_64);
33
34static inline int set_rtc_mmss(unsigned long nowtime)
35{
36 if (mach_set_clock_mmss)
37 return mach_set_clock_mmss (nowtime);
38 return -1;
39}
40
41/*
42 * timer_interrupt() needs to keep up the real-time clock,
43 * as well as call the "do_timer()" routine every clocktick
44 */
45static irqreturn_t timer_interrupt(int irq, void *dummy, struct pt_regs * regs)
46{
47 do_timer(regs);
48#ifndef CONFIG_SMP
49 update_process_times(user_mode(regs));
50#endif
51 profile_tick(CPU_PROFILING, regs);
52
53#ifdef CONFIG_HEARTBEAT
54 /* use power LED as a heartbeat instead -- much more useful
55 for debugging -- based on the version for PReP by Cort */
56 /* acts like an actual heart beat -- ie thump-thump-pause... */
57 if (mach_heartbeat) {
58 static unsigned cnt = 0, period = 0, dist = 0;
59
60 if (cnt == 0 || cnt == dist)
61 mach_heartbeat( 1 );
62 else if (cnt == 7 || cnt == dist+7)
63 mach_heartbeat( 0 );
64
65 if (++cnt > period) {
66 cnt = 0;
67 /* The hyperbolic function below modifies the heartbeat period
68 * length in dependency of the current (5min) load. It goes
69 * through the points f(0)=126, f(1)=86, f(5)=51,
70 * f(inf)->30. */
71 period = ((672<<FSHIFT)/(5*avenrun[0]+(7<<FSHIFT))) + 30;
72 dist = period / 4;
73 }
74 }
75#endif /* CONFIG_HEARTBEAT */
76 return IRQ_HANDLED;
77}
78
79void time_init(void)
80{
81 struct rtc_time time;
82
83 if (mach_hwclk) {
84 mach_hwclk(0, &time);
85
86 if ((time.tm_year += 1900) < 1970)
87 time.tm_year += 100;
88 xtime.tv_sec = mktime(time.tm_year, time.tm_mon, time.tm_mday,
89 time.tm_hour, time.tm_min, time.tm_sec);
90 xtime.tv_nsec = 0;
91 }
92 wall_to_monotonic.tv_sec = -xtime.tv_sec;
93
94 mach_sched_init(timer_interrupt);
95}
96
97/*
98 * This version of gettimeofday has near microsecond resolution.
99 */
100void do_gettimeofday(struct timeval *tv)
101{
102 unsigned long flags;
103 extern unsigned long wall_jiffies;
104 unsigned long seq;
105 unsigned long usec, sec, lost;
106 unsigned long max_ntp_tick = tick_usec - tickadj;
107
108 do {
109 seq = read_seqbegin_irqsave(&xtime_lock, flags);
110
111 usec = mach_gettimeoffset();
112 lost = jiffies - wall_jiffies;
113
114 /*
115 * If time_adjust is negative then NTP is slowing the clock
116 * so make sure not to go into next possible interval.
117 * Better to lose some accuracy than have time go backwards..
118 */
119 if (unlikely(time_adjust < 0)) {
120 usec = min(usec, max_ntp_tick);
121
122 if (lost)
123 usec += lost * max_ntp_tick;
124 }
125 else if (unlikely(lost))
126 usec += lost * tick_usec;
127
128 sec = xtime.tv_sec;
129 usec += xtime.tv_nsec/1000;
130 } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
131
132
133 while (usec >= 1000000) {
134 usec -= 1000000;
135 sec++;
136 }
137
138 tv->tv_sec = sec;
139 tv->tv_usec = usec;
140}
141
142EXPORT_SYMBOL(do_gettimeofday);
143
144int do_settimeofday(struct timespec *tv)
145{
146 time_t wtm_sec, sec = tv->tv_sec;
147 long wtm_nsec, nsec = tv->tv_nsec;
148 extern unsigned long wall_jiffies;
149
150 if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
151 return -EINVAL;
152
153 write_seqlock_irq(&xtime_lock);
154 /* This is revolting. We need to set the xtime.tv_nsec
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!
159 */
160 nsec -= 1000 * (mach_gettimeoffset() +
161 (jiffies - wall_jiffies) * (1000000 / HZ));
162
163 wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
164 wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
165
166 set_normalized_timespec(&xtime, sec, nsec);
167 set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
168
169 time_adjust = 0; /* stop active adjtime() */
170 time_status |= STA_UNSYNC;
171 time_maxerror = NTP_PHASE_LIMIT;
172 time_esterror = NTP_PHASE_LIMIT;
173 write_sequnlock_irq(&xtime_lock);
174 clock_was_set();
175 return 0;
176}
177
178EXPORT_SYMBOL(do_settimeofday);
179
180/*
181 * Scheduler clock - returns current time in ns units.
182 */
183unsigned long long sched_clock(void)
184{
185 return (unsigned long long)jiffies*(1000000000/HZ);
186}
187