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
30static 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 */
41static 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
75void 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 */
96void 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
130EXPORT_SYMBOL(do_gettimeofday);
131
132int 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
161EXPORT_SYMBOL(do_settimeofday);
162