1/*
2 *  linux/arch/m68knommu/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/profile.h>
21#include <linux/time.h>
22#include <linux/timex.h>
23
24#include <asm/machdep.h>
25#include <asm/io.h>
26#include <asm/irq_regs.h>
27
28#define	TICK_SIZE (tick_nsec / 1000)
29
30
31static inline int set_rtc_mmss(unsigned long nowtime)
32{
33	if (mach_set_clock_mmss)
34		return mach_set_clock_mmss (nowtime);
35	return -1;
36}
37
38/*
39 * timer_interrupt() needs to keep up the real-time clock,
40 * as well as call the "do_timer()" routine every clocktick
41 */
42static irqreturn_t timer_interrupt(int irq, void *dummy)
43{
44	/* last time the cmos clock got updated */
45	static long last_rtc_update=0;
46
47	/* may need to kick the hardware timer */
48	if (mach_tick)
49	  mach_tick();
50
51	write_seqlock(&xtime_lock);
52
53	do_timer(1);
54#ifndef CONFIG_SMP
55	update_process_times(user_mode(get_irq_regs()));
56#endif
57	if (current->pid)
58		profile_tick(CPU_PROFILING);
59
60	/*
61	 * If we have an externally synchronized Linux clock, then update
62	 * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
63	 * called as close as possible to 500 ms before the new second starts.
64	 */
65	if (ntp_synced() &&
66	    xtime.tv_sec > last_rtc_update + 660 &&
67	    (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
68	    (xtime.tv_nsec  / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) {
69	  if (set_rtc_mmss(xtime.tv_sec) == 0)
70	    last_rtc_update = xtime.tv_sec;
71	  else
72	    last_rtc_update = xtime.tv_sec - 600; /* do it again in 60 s */
73	}
74#ifdef CONFIG_HEARTBEAT
75	/* use power LED as a heartbeat instead -- much more useful
76	   for debugging -- based on the version for PReP by Cort */
77	/* acts like an actual heart beat -- ie thump-thump-pause... */
78	if (mach_heartbeat) {
79	    static unsigned cnt = 0, period = 0, dist = 0;
80
81	    if (cnt == 0 || cnt == dist)
82		mach_heartbeat( 1 );
83	    else if (cnt == 7 || cnt == dist+7)
84		mach_heartbeat( 0 );
85
86	    if (++cnt > period) {
87		cnt = 0;
88		/* The hyperbolic function below modifies the heartbeat period
89		 * length in dependency of the current (5min) load. It goes
90		 * through the points f(0)=126, f(1)=86, f(5)=51,
91		 * f(inf)->30. */
92		period = ((672<<FSHIFT)/(5*avenrun[0]+(7<<FSHIFT))) + 30;
93		dist = period / 4;
94	    }
95	}
96#endif /* CONFIG_HEARTBEAT */
97
98	write_sequnlock(&xtime_lock);
99	return(IRQ_HANDLED);
100}
101
102void time_init(void)
103{
104	unsigned int year, mon, day, hour, min, sec;
105
106	extern void arch_gettod(int *year, int *mon, int *day, int *hour,
107				int *min, int *sec);
108
109	arch_gettod(&year, &mon, &day, &hour, &min, &sec);
110
111	if ((year += 1900) < 1970)
112		year += 100;
113	xtime.tv_sec = mktime(year, mon, day, hour, min, sec);
114	xtime.tv_nsec = 0;
115	wall_to_monotonic.tv_sec = -xtime.tv_sec;
116
117	mach_sched_init(timer_interrupt);
118}
119
120/*
121 * This version of gettimeofday has near microsecond resolution.
122 */
123void do_gettimeofday(struct timeval *tv)
124{
125	unsigned long flags;
126	unsigned long seq;
127	unsigned long usec, sec;
128
129	do {
130		seq = read_seqbegin_irqsave(&xtime_lock, flags);
131		usec = mach_gettimeoffset ? mach_gettimeoffset() : 0;
132		sec = xtime.tv_sec;
133		usec += (xtime.tv_nsec / 1000);
134	} while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
135
136	while (usec >= 1000000) {
137		usec -= 1000000;
138		sec++;
139	}
140
141	tv->tv_sec = sec;
142	tv->tv_usec = usec;
143}
144
145EXPORT_SYMBOL(do_gettimeofday);
146
147int do_settimeofday(struct timespec *tv)
148{
149	time_t wtm_sec, sec = tv->tv_sec;
150	long wtm_nsec, nsec = tv->tv_nsec;
151
152	if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
153		return -EINVAL;
154
155	write_seqlock_irq(&xtime_lock);
156	/*
157	 * This is revolting. We need to set the xtime.tv_usec
158	 * correctly. However, the value in this location is
159	 * is value at the last tick.
160	 * Discover what correction gettimeofday
161	 * would have done, and then undo it!
162	 */
163	if (mach_gettimeoffset)
164		nsec -= (mach_gettimeoffset() * 1000);
165
166	wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
167	wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
168
169	set_normalized_timespec(&xtime, sec, nsec);
170	set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
171
172	ntp_clear();
173	write_sequnlock_irq(&xtime_lock);
174	clock_was_set();
175	return 0;
176}
177EXPORT_SYMBOL(do_settimeofday);
178