summaryrefslogtreecommitdiffstats
path: root/arch/cris/kernel/time.c
blob: 0f9213cbd48e24f9068c62125b7b9814d09ce617 (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
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
/* $Id: time.c,v 1.18 2005/03/04 08:16:17 starvik Exp $
 *
 *  linux/arch/cris/kernel/time.c
 *
 *  Copyright (C) 1991, 1992, 1995  Linus Torvalds
 *  Copyright (C) 1999, 2000, 2001 Axis Communications AB
 *
 * 1994-07-02    Alan Modra
 *	fixed set_rtc_mmss, fixed time.year for >= 2000, new mktime
 * 1995-03-26    Markus Kuhn
 *      fixed 500 ms bug at call to set_rtc_mmss, fixed DS12887
 *      precision CMOS clock update
 * 1996-05-03    Ingo Molnar
 *      fixed time warps in do_[slow|fast]_gettimeoffset()
 * 1997-09-10	Updated NTP code according to technical memorandum Jan '96
 *		"A Kernel Model for Precision Timekeeping" by Dave Mills
 *
 * Linux/CRIS specific code:
 *
 * Authors:    Bjorn Wesen
 *             Johan Adolfsson  
 *
 */

#include <asm/rtc.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/param.h>
#include <linux/jiffies.h>
#include <linux/bcd.h>
#include <linux/timex.h>
#include <linux/init.h>
#include <linux/profile.h>
#include <linux/sched.h>	/* just for sched_clock() - funny that */

int have_rtc;  /* used to remember if we have an RTC or not */;

#define TICK_SIZE tick

extern unsigned long loops_per_jiffy; /* init/main.c */
unsigned long loops_per_usec;

extern unsigned long do_slow_gettimeoffset(void);
static unsigned long (*do_gettimeoffset)(void) = do_slow_gettimeoffset;

/*
 * This version of gettimeofday has near microsecond resolution.
 *
 * Note: Division is quite slow on CRIS and do_gettimeofday is called
 *       rather often. Maybe we should do some kind of approximation here
 *       (a naive approximation would be to divide by 1024).
 */
void do_gettimeofday(struct timeval *tv)
{
	unsigned long flags;
	signed long usec, sec;
	local_irq_save(flags);
	local_irq_disable();
	usec = do_gettimeoffset();

        /*
	 * If time_adjust is negative then NTP is slowing the clock
	 * so make sure not to go into next possible interval.
	 * Better to lose some accuracy than have time go backwards..
	 */
	if (unlikely(time_adjust < 0) && usec > tickadj)
		usec = tickadj;

	sec = xtime.tv_sec;
	usec += xtime.tv_nsec / 1000;
	local_irq_restore(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)
{
	time_t wtm_sec, sec = tv->tv_sec;
	long wtm_nsec, nsec = tv->tv_nsec;

	if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
		return -EINVAL;

	write_seqlock_irq(&xtime_lock);
	/*
	 * This is revolting. We need to set "xtime" correctly. However, the
	 * value in this location is the value at the most recent update of
	 * wall time.  Discover what correction gettimeofday() would have
	 * made, and then undo it!
	 */
	nsec -= do_gettimeoffset() * NSEC_PER_USEC;

	wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
	wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);

	set_normalized_timespec(&xtime, sec, nsec);
	set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);

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

EXPORT_SYMBOL(do_settimeofday);


/*
 * BUG: This routine does not handle hour overflow properly; it just
 *      sets the minutes. Usually you'll only notice that after reboot!
 */

int set_rtc_mmss(unsigned long nowtime)
{
	int retval = 0;
	int real_seconds, real_minutes, cmos_minutes;

	printk(KERN_DEBUG "set_rtc_mmss(%lu)\n", nowtime);

	if(!have_rtc)
		return 0;

	cmos_minutes = CMOS_READ(RTC_MINUTES);
	BCD_TO_BIN(cmos_minutes);

	/*
	 * since we're only adjusting minutes and seconds,
	 * don't interfere with hour overflow. This avoids
	 * messing with unknown time zones but requires your
	 * RTC not to be off by more than 15 minutes
	 */
	real_seconds = nowtime % 60;
	real_minutes = nowtime / 60;
	if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1)
		real_minutes += 30;		/* correct for half hour time zone */
	real_minutes %= 60;

	if (abs(real_minutes - cmos_minutes) < 30) {
		BIN_TO_BCD(real_seconds);
		BIN_TO_BCD(real_minutes);
		CMOS_WRITE(real_seconds,RTC_SECONDS);
		CMOS_WRITE(real_minutes,RTC_MINUTES);
	} else {
		printk(KERN_WARNING
		       "set_rtc_mmss: can't update from %d to %d\n",
		       cmos_minutes, real_minutes);
		retval = -1;
	}

	return retval;
}

/* grab the time from the RTC chip */

unsigned long
get_cmos_time(void)
{
	unsigned int year, mon, day, hour, min, sec;

	sec = CMOS_READ(RTC_SECONDS);
	min = CMOS_READ(RTC_MINUTES);
	hour = CMOS_READ(RTC_HOURS);
	day = CMOS_READ(RTC_DAY_OF_MONTH);
	mon = CMOS_READ(RTC_MONTH);
	year = CMOS_READ(RTC_YEAR);

	printk(KERN_DEBUG
	       "rtc: sec 0x%x min 0x%x hour 0x%x day 0x%x mon 0x%x year 0x%x\n",
	       sec, min, hour, day, mon, year);

	BCD_TO_BIN(sec);
	BCD_TO_BIN(min);
	BCD_TO_BIN(hour);
	BCD_TO_BIN(day);
	BCD_TO_BIN(mon);
	BCD_TO_BIN(year);

	if ((year += 1900) < 1970)
		year += 100;

	return mktime(year, mon, day, hour, min, sec);
}

/* update xtime from the CMOS settings. used when /dev/rtc gets a SET_TIME.
 * TODO: this doesn't reset the fancy NTP phase stuff as do_settimeofday does.
 */

void
update_xtime_from_cmos(void)
{
	if(have_rtc) {
		xtime.tv_sec = get_cmos_time();
		xtime.tv_nsec = 0;
	}
}

extern void cris_profile_sample(struct pt_regs* regs);

void
cris_do_profile(struct pt_regs* regs)
{

#if CONFIG_SYSTEM_PROFILER
        cris_profile_sample(regs);
#endif

#if CONFIG_PROFILING
        profile_tick(CPU_PROFILING, regs);
#endif
}

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

static int
__init init_udelay(void)
{
	loops_per_usec = (loops_per_jiffy * HZ) / 1000000;
	return 0;
}

__initcall(init_udelay);