aboutsummaryrefslogtreecommitdiff
path: root/arch/sh/kernel/time.c
blob: c206c9504c4bb40da950a374ead73943f9ab36a4 (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
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
/*
 *  arch/sh/kernel/time.c
 *
 *  Copyright (C) 1999  Tetsuya Okada & Niibe Yutaka
 *  Copyright (C) 2000  Philipp Rumpf <prumpf@tux.org>
 *  Copyright (C) 2002 - 2006  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 <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;
}

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

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

#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 */

/* 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;
	}
}

#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 = {
	set_kset_name("timer"),
	.suspend = timer_suspend,
	.resume	 = timer_resume,
};

#ifdef CONFIG_NO_IDLE_HZ
static int timer_dyn_tick_enable(void)
{
	struct dyn_tick_timer *dyn_tick = sys_timer->dyn_tick;
	unsigned long flags;
	int ret = -ENODEV;

	if (dyn_tick) {
		spin_lock_irqsave(&dyn_tick->lock, flags);
		ret = 0;
		if (!(dyn_tick->state & DYN_TICK_ENABLED)) {
			ret = dyn_tick->enable();

			if (ret == 0)
				dyn_tick->state |= DYN_TICK_ENABLED;
		}
		spin_unlock_irqrestore(&dyn_tick->lock, flags);
	}

	return ret;
}

static int timer_dyn_tick_disable(void)
{
	struct dyn_tick_timer *dyn_tick = sys_timer->dyn_tick;
	unsigned long flags;
	int ret = -ENODEV;

	if (dyn_tick) {
		spin_lock_irqsave(&dyn_tick->lock, flags);
		ret = 0;
		if (dyn_tick->state & DYN_TICK_ENABLED) {
			ret = dyn_tick->disable();

			if (ret == 0)
				dyn_tick->state &= ~DYN_TICK_ENABLED;
		}
		spin_unlock_irqrestore(&dyn_tick->lock, flags);
	}

	return ret;
}

/*
 * Reprogram the system timer for at least the calculated time interval.
 * This function should be called from the idle thread with IRQs disabled,
 * immediately before sleeping.
 */
void timer_dyn_reprogram(void)
{
	struct dyn_tick_timer *dyn_tick = sys_timer->dyn_tick;
	unsigned long next, seq, flags;

	if (!dyn_tick)
		return;

	spin_lock_irqsave(&dyn_tick->lock, flags);
	if (dyn_tick->state & DYN_TICK_ENABLED) {
		next = next_timer_interrupt();
		do {
			seq = read_seqbegin(&xtime_lock);
			dyn_tick->reprogram(next - jiffies);
		} while (read_seqretry(&xtime_lock, seq));
	}
	spin_unlock_irqrestore(&dyn_tick->lock, flags);
}

static ssize_t timer_show_dyn_tick(struct sys_device *dev, char *buf)
{
	return sprintf(buf, "%i\n",
		       (sys_timer->dyn_tick->state & DYN_TICK_ENABLED) >> 1);
}

static ssize_t timer_set_dyn_tick(struct sys_device *dev, const char *buf,
				  size_t count)
{
	unsigned int enable = simple_strtoul(buf, NULL, 2);

	if (enable)
		timer_dyn_tick_enable();
	else
		timer_dyn_tick_disable();

	return count;
}
static SYSDEV_ATTR(dyn_tick, 0644, timer_show_dyn_tick, timer_set_dyn_tick);

/*
 * dyntick=enable|disable
 */
static char dyntick_str[4] __initdata = "";

static int __init dyntick_setup(char *str)
{
	if (str)
		strlcpy(dyntick_str, str, sizeof(dyntick_str));
	return 1;
}

__setup("dyntick=", dyntick_setup);
#endif

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;
	ret = sysdev_register(&sys_timer->dev);

#ifdef CONFIG_NO_IDLE_HZ
	if (ret == 0 && sys_timer->dyn_tick) {
		ret = sysdev_create_file(&sys_timer->dev, &attr_dyn_tick);

		/*
		 * Turn on dynamic tick after calibrate delay
		 * for correct bogomips
		 */
		if (ret == 0 && dyntick_str[0] == 'e')
			ret = timer_dyn_tick_enable();
	}
#endif

	return ret;
}
device_initcall(timer_init_sysfs);

void (*board_time_init)(void);

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);

#ifdef CONFIG_NO_IDLE_HZ
	if (sys_timer->dyn_tick)
		spin_lock_init(&sys_timer->dyn_tick->lock);
#endif

#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
}