aboutsummaryrefslogtreecommitdiffstats
path: root/arch/v850/kernel/time.c
blob: cd06f47c0ea7404bfd29f15f31e222ca9c2f5260 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
/*
 * linux/arch/v850/kernel/time.c -- Arch-dependent timer functions
 *
 *  Copyright (C) 1991, 1992, 1995, 2001, 2002  Linus Torvalds
 *
 * This file contains the v850-specific time handling details.
 * Most of the stuff is located in the machine specific files.
 *
 * 1997-09-10	Updated NTP code according to technical memorandum Jan '96
 *		"A Kernel Model for Precision Timekeeping" by Dave Mills
 */

#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/param.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/time.h>
#include <linux/timex.h>
#include <linux/profile.h>

#include <asm/io.h>

#include "mach.h"

#define TICK_SIZE	(tick_nsec / 1000)

/*
 * Scheduler clock - returns current time in nanosec units.
 */
unsigned long long sched_clock(void)
{
	return (unsigned long long)jiffies * (1000000000 / HZ);
}

/*
 * timer_interrupt() needs to keep up the real-time clock,
 * as well as call the "do_timer()" routine every clocktick
 */
static irqreturn_t timer_interrupt (int irq, void *dummy, struct pt_regs *regs)
{
#if 0
	/* last time the cmos clock got updated */
	static long last_rtc_update=0;
#endif

	/* may need to kick the hardware timer */
	if (mach_tick)
	  mach_tick ();

	do_timer (1);
#ifndef CONFIG_SMP
	update_process_times(user_mode(regs));
#endif
	profile_tick(CPU_PROFILING, regs);
#if 0
	/*
	 * If we have an externally synchronized Linux clock, then update
	 * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
	 * called as close as possible to 500 ms before the new second starts.
	 */
	if (ntp_synced() &&
	    xtime.tv_sec > last_rtc_update + 660 &&
	    (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
	    (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) {
	  if (set_rtc_mmss (xtime.tv_sec) == 0)
	    last_rtc_update = xtime.tv_sec;
	  else
	    last_rtc_update = xtime.tv_sec - 600; /* do it again in 60 s */
	}
#ifdef CONFIG_HEARTBEAT
	/* use power LED as a heartbeat instead -- much more useful
	   for debugging -- based on the version for PReP by Cort */
	/* acts like an actual heart beat -- ie thump-thump-pause... */
	if (mach_heartbeat) {
	    static unsigned cnt = 0, period = 0, dist = 0;

	    if (cnt == 0 || cnt == dist)
		mach_heartbeat ( 1 );
	    else if (cnt == 7 || cnt == dist+7)
		mach_heartbeat ( 0 );

	    if (++cnt > period) {
		cnt = 0;
		/* The hyperbolic function below modifies the heartbeat period
		 * length in dependency of the current (5min) load. It goes
		 * through the points f(0)=126, f(1)=86, f(5)=51,
		 * f(inf)->30. */
		period = ((672<<FSHIFT)/(5*avenrun[0]+(7<<FSHIFT))) + 30;
		dist = period / 4;
	    }
	}
#endif /* CONFIG_HEARTBEAT */
#endif /* 0 */

	return IRQ_HANDLED;
}

/*
 * This version of gettimeofday has near microsecond resolution.
 */
void do_gettimeofday (struct timeval *tv)
{
#if 0 /* DAVIDM later if possible */
	extern volatile unsigned long lost_ticks;
	unsigned long lost;
#endif
	unsigned long flags;
	unsigned long usec, sec;
	unsigned long seq;

	do {
		seq = read_seqbegin_irqsave(&xtime_lock, flags);

#if 0
		usec = mach_gettimeoffset ? mach_gettimeoffset () : 0;
#else
		usec = 0;
#endif
#if 0 /* DAVIDM later if possible */
		lost = lost_ticks;
		if (lost)
			usec += lost * (1000000/HZ);
#endif
		sec = xtime.tv_sec;
		usec += xtime.tv_nsec / 1000;
	} while (read_seqretry_irqrestore(&xtime_lock, seq, flags));

	while (usec >= 1000000) {
		usec -= 1000000;
		sec++;
	}

	tv->tv_sec = sec;
	tv->tv_usec = usec;
}

EXPORT_SYMBOL(do_gettimeofday);

int do_settimeofday(struct timespec *tv)
{
	if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
		return -EINVAL;

	write_seqlock_irq (&xtime_lock);

	/* This is revolting. We need to set the xtime.tv_nsec
	 * correctly. However, the value in this location is
	 * is value at the last tick.
	 * Discover what correction gettimeofday
	 * would have done, and then undo it!
	 */
#if 0
	tv->tv_nsec -= mach_gettimeoffset() * 1000;
#endif

	while (tv->tv_nsec < 0) {
		tv->tv_nsec += NSEC_PER_SEC;
		tv->tv_sec--;
	}

	xtime.tv_sec = tv->tv_sec;
	xtime.tv_nsec = tv->tv_nsec;

	ntp_clear();

	write_sequnlock_irq (&xtime_lock);
	clock_was_set();
	return 0;
}

EXPORT_SYMBOL(do_settimeofday);

static int timer_dev_id;
static struct irqaction timer_irqaction = {
	timer_interrupt,
	IRQF_DISABLED,
	CPU_MASK_NONE,
	"timer",
	&timer_dev_id,
	NULL
};

void time_init (void)
{
	mach_gettimeofday (&xtime);
	mach_sched_init (&timer_irqaction);
}

Privacy Policy