summaryrefslogtreecommitdiff
path: root/arch/sh/kernel/time_32.c
blob: 2bc04bfee73891045e92df6506287aa5ce1e102b (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
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
/*
 *  arch/sh/kernel/time.c
 *
 *  Copyright (C) 1999  Tetsuya Okada & Niibe Yutaka
 *  Copyright (C) 2000  Philipp Rumpf <prumpf@tux.org>
 *  Copyright (C) 2002 - 2007  Paul Mundt
 *  Copyright (C) 2002  M. R. Brown  <mrbrown@linux-sh.org>
 *
 *  Some code taken from i386 version.
 *    Copyright (C) 1991, 1992, 1995  Linus Torvalds
 */
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/profile.h>
#include <linux/timex.h>
#include <linux/sched.h>
#include <linux/clockchips.h>
#include <asm/clock.h>
#include <asm/rtc.h>
#include <asm/timer.h>
#include <asm/kgdb.h>

struct sys_timer *sys_timer;

/* Move this somewhere more sensible.. */
DEFINE_SPINLOCK(rtc_lock);
EXPORT_SYMBOL(rtc_lock);

/* Dummy RTC ops */
static void null_rtc_get_time(struct timespec *tv)
{
	tv->tv_sec = mktime(2000, 1, 1, 0, 0, 0);
	tv->tv_nsec = 0;
}

static int null_rtc_set_time(const time_t secs)
{
	return 0;
}

/*
 * Null high precision timer functions for systems lacking one.
 */
static cycle_t null_hpt_read(void)
{
	return 0;
}

void (*rtc_sh_get_time)(struct timespec *) = null_rtc_get_time;
int (*rtc_sh_set_time)(const time_t) = null_rtc_set_time;

#ifndef CONFIG_GENERIC_TIME
void do_gettimeofday(struct timeval *tv)
{
	unsigned long flags;
	unsigned long seq;
	unsigned long usec, sec;

	do {
		/*
		 * Turn off IRQs when grabbing xtime_lock, so that
		 * the sys_timer get_offset code doesn't have to handle it.
		 */
		seq = read_seqbegin_irqsave(&xtime_lock, flags);
		usec = get_timer_offset();
		sec = xtime.tv_sec;
		usec += xtime.tv_nsec / NSEC_PER_USEC;
	} 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)
{
	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 -= get_timer_offset() * 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);
#endif /* !CONFIG_GENERIC_TIME */

#ifndef CONFIG_GENERIC_CLOCKEVENTS
/* last time the RTC clock got updated */
static long last_rtc_update;

/*
 * handle_timer_tick() needs to keep up the real-time clock,
 * as well as call the "do_timer()" routine every clocktick
 */
void handle_timer_tick(void)
{
	do_timer(1);
#ifndef CONFIG_SMP
	update_process_times(user_mode(get_irq_regs()));
#endif
	if (current->pid)
		profile_tick(CPU_PROFILING);

#ifdef CONFIG_HEARTBEAT
	if (sh_mv.mv_heartbeat != NULL)
		sh_mv.mv_heartbeat();
#endif

	/*
	 * If we have an externally synchronized Linux clock, then update
	 * RTC 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 (rtc_sh_set_time(xtime.tv_sec) == 0)
			last_rtc_update = xtime.tv_sec;
		else
			/* do it again in 60s */
			last_rtc_update = xtime.tv_sec - 600;
	}
}
#endif /* !CONFIG_GENERIC_CLOCKEVENTS */

#ifdef CONFIG_PM
int timer_suspend(struct sys_device *dev, pm_message_t state)
{
	struct sys_timer *sys_timer = container_of(dev, struct sys_timer, dev);

	sys_timer->ops->stop();

	return 0;
}

int timer_resume(struct sys_device *dev)
{
	struct sys_timer *sys_timer = container_of(dev, struct sys_timer, dev);

	sys_timer->ops->start();

	return 0;
}
#else
#define timer_suspend NULL
#define timer_resume NULL
#endif

static struct sysdev_class timer_sysclass = {
	.name	 = "timer",
	.suspend = timer_suspend,
	.resume	 = timer_resume,
};

static int __init timer_init_sysfs(void)
{
	int ret = sysdev_class_register(&timer_sysclass);
	if (ret != 0)
		return ret;

	sys_timer->dev.cls = &timer_sysclass;
	return sysdev_register(&sys_timer->dev);
}
device_initcall(timer_init_sysfs);

void (*board_time_init)(void);

/*
 * Shamelessly based on the MIPS and Sparc64 work.
 */
static unsigned long timer_ticks_per_nsec_quotient __read_mostly;
unsigned long sh_hpt_frequency = 0;

#define NSEC_PER_CYC_SHIFT	10

struct clocksource clocksource_sh = {
	.name		= "SuperH",
	.rating		= 200,
	.mask		= CLOCKSOURCE_MASK(32),
	.read		= null_hpt_read,
	.shift		= 16,
	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
};

static void __init init_sh_clocksource(void)
{
	if (!sh_hpt_frequency || clocksource_sh.read == null_hpt_read)
		return;

	clocksource_sh.mult = clocksource_hz2mult(sh_hpt_frequency,
						  clocksource_sh.shift);

	timer_ticks_per_nsec_quotient =
		clocksource_hz2mult(sh_hpt_frequency, NSEC_PER_CYC_SHIFT);

	clocksource_register(&clocksource_sh);
}

#ifdef CONFIG_GENERIC_TIME
unsigned long long sched_clock(void)
{
	unsigned long long ticks = clocksource_sh.read();
	return (ticks * timer_ticks_per_nsec_quotient) >> NSEC_PER_CYC_SHIFT;
}
#endif

void __init time_init(void)
{
	if (board_time_init)
		board_time_init();

	clk_init();

	rtc_sh_get_time(&xtime);
	set_normalized_timespec(&wall_to_monotonic,
				-xtime.tv_sec, -xtime.tv_nsec);

	/*
	 * Find the timer to use as the system timer, it will be
	 * initialized for us.
	 */
	sys_timer = get_sys_timer();
	printk(KERN_INFO "Using %s for system timer\n", sys_timer->name);

	if (sys_timer->ops->read)
		clocksource_sh.read = sys_timer->ops->read;

	init_sh_clocksource();

	if (sh_hpt_frequency)
		printk("Using %lu.%03lu MHz high precision timer.\n",
		       ((sh_hpt_frequency + 500) / 1000) / 1000,
		       ((sh_hpt_frequency + 500) / 1000) % 1000);

#if defined(CONFIG_SH_KGDB)
	/*
	 * Set up kgdb as requested. We do it here because the serial
	 * init uses the timer vars we just set up for figuring baud.
	 */
	kgdb_init();
#endif
}