aboutsummaryrefslogtreecommitdiffstats
path: root/arch/blackfin/kernel/time.c
blob: 1bbacfbd4c5d7c6198496fa939a7920dc36319d4 (plain) (blame)
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
/*
 * arch/blackfin/kernel/time.c
 *
 * This file contains the Blackfin-specific time handling details.
 * Most of the stuff is located in the machine specific files.
 *
 * Copyright 2004-2008 Analog Devices Inc.
 * Licensed under the GPL-2 or later.
 */

#include <linux/module.h>
#include <linux/profile.h>
#include <linux/interrupt.h>
#include <linux/time.h>
#include <linux/irq.h>
#include <linux/delay.h>

#include <asm/blackfin.h>
#include <asm/time.h>
#include <asm/gptimers.h>

/* This is an NTP setting */
#define	TICK_SIZE (tick_nsec / 1000)

static struct irqaction bfin_timer_irq = {
	.name = "Blackfin Timer Tick",
#ifdef CONFIG_IRQ_PER_CPU
	.flags = IRQF_DISABLED | IRQF_PERCPU,
#else
	.flags = IRQF_DISABLED
#endif
};

#if defined(CONFIG_TICK_SOURCE_SYSTMR0) || defined(CONFIG_IPIPE)
void __init setup_system_timer0(void)
{
	/* Power down the core timer, just to play safe. */
	bfin_write_TCNTL(0);

	disable_gptimers(TIMER0bit);
	set_gptimer_status(0, TIMER_STATUS_TRUN0);
	while (get_gptimer_status(0) & TIMER_STATUS_TRUN0)
		udelay(10);

	set_gptimer_config(0, 0x59); /* IRQ enable, periodic, PWM_OUT, SCLKed, OUT PAD disabled */
	set_gptimer_period(TIMER0_id, get_sclk() / HZ);
	set_gptimer_pwidth(TIMER0_id, 1);
	SSYNC();
	enable_gptimers(TIMER0bit);
}
#else
void __init setup_core_timer(void)
{
	u32 tcount;

	/* power up the timer, but don't enable it just yet */
	bfin_write_TCNTL(1);
	CSYNC();

	/* the TSCALE prescaler counter */
	bfin_write_TSCALE(TIME_SCALE - 1);

	tcount = ((get_cclk() / (HZ * TIME_SCALE)) - 1);
	bfin_write_TPERIOD(tcount);
	bfin_write_TCOUNT(tcount);

	/* now enable the timer */
	CSYNC();

	bfin_write_TCNTL(7);
}
#endif

static void __init
time_sched_init(irqreturn_t(*timer_routine) (int, void *))
{
#if defined(CONFIG_TICK_SOURCE_SYSTMR0) || defined(CONFIG_IPIPE)
	setup_system_timer0();
	bfin_timer_irq.handler = timer_routine;
	setup_irq(IRQ_TIMER0, &bfin_timer_irq);
#else
	setup_core_timer();
	bfin_timer_irq.handler = timer_routine;
	setup_irq(IRQ_CORETMR, &bfin_timer_irq);
#endif
}

/*
 * Should return useconds since last timer tick
 */
#ifndef CONFIG_GENERIC_TIME
static unsigned long gettimeoffset(void)
{
	unsigned long offset;
	unsigned long clocks_per_jiffy;

#if defined(CONFIG_TICK_SOURCE_SYSTMR0) || defined(CONFIG_IPIPE)
	clocks_per_jiffy = bfin_read_TIMER0_PERIOD();
	offset = bfin_read_TIMER0_COUNTER() / \
		(((clocks_per_jiffy + 1) * HZ) / USEC_PER_SEC);

	if ((get_gptimer_status(0) & TIMER_STATUS_TIMIL0) && offset < (100000 / HZ / 2))
		offset += (USEC_PER_SEC / HZ);
#else
	clocks_per_jiffy = bfin_read_TPERIOD();
	offset = (clocks_per_jiffy - bfin_read_TCOUNT()) / \
		(((clocks_per_jiffy + 1) * HZ) / USEC_PER_SEC);

	/* Check if we just wrapped the counters and maybe missed a tick */
	if ((bfin_read_ILAT() & (1 << IRQ_CORETMR))
		&& (offset < (100000 / HZ / 2)))
		offset += (USEC_PER_SEC / HZ);
#endif
	return offset;
}
#endif

static inline int set_rtc_mmss(unsigned long nowtime)
{
	return 0;
}

/*
 * timer_interrupt() needs to keep up the real-time clock,
 * as well as call the "do_timer()" routine every clocktick
 */
#ifdef CONFIG_CORE_TIMER_IRQ_L1
__attribute__((l1_text))
#endif
irqreturn_t timer_interrupt(int irq, void *dummy)
{
	/* last time the cmos clock got updated */
	static long last_rtc_update;

	write_seqlock(&xtime_lock);
#if defined(CONFIG_TICK_SOURCE_SYSTMR0) && !defined(CONFIG_IPIPE)
	/*
	 * TIMIL0 is latched in __ipipe_grab_irq() when the I-Pipe is
	 * enabled.
	 */
	if (get_gptimer_status(0) & TIMER_STATUS_TIMIL0) {
#endif
		do_timer(1);

		/*
		 * 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 / NSEC_PER_USEC) >=
		    500000 - ((unsigned)TICK_SIZE) / 2
		    && (xtime.tv_nsec / NSEC_PER_USEC) <=
		    500000 + ((unsigned)TICK_SIZE) / 2) {
			if (set_rtc_mmss(xtime.tv_sec) == 0)
				last_rtc_update = xtime.tv_sec;
			else
				/* Do it again in 60s. */
				last_rtc_update = xtime.tv_sec - 600;
		}
#if defined(CONFIG_TICK_SOURCE_SYSTMR0) && !defined(CONFIG_IPIPE)
		set_gptimer_status(0, TIMER_STATUS_TIMIL0);
	}
#endif
	write_sequnlock(&xtime_lock);

#ifdef CONFIG_IPIPE
	update_root_process_times(get_irq_regs());
#else
	update_process_times(user_mode(get_irq_regs()));
#endif
	profile_tick(CPU_PROFILING);

	return IRQ_HANDLED;
}

void __init time_init(void)
{
	time_t secs_since_1970 = (365 * 37 + 9) * 24 * 60 * 60;	/* 1 Jan 2007 */

#ifdef CONFIG_RTC_DRV_BFIN
	/* [#2663] hack to filter junk RTC values that would cause
	 * userspace to have to deal with time values greater than
	 * 2^31 seconds (which uClibc cannot cope with yet)
	 */
	if ((bfin_read_RTC_STAT() & 0xC0000000) == 0xC0000000) {
		printk(KERN_NOTICE "bfin-rtc: invalid date; resetting\n");
		bfin_write_RTC_STAT(0);
	}
#endif

	/* Initialize xtime. From now on, xtime is updated with timer interrupts */
	xtime.tv_sec = secs_since_1970;
	xtime.tv_nsec = 0;

	wall_to_monotonic.tv_sec = -xtime.tv_sec;

	time_sched_init(timer_interrupt);
}

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

	do {
		seq = read_seqbegin_irqsave(&xtime_lock, flags);
		usec = gettimeoffset();
		sec = xtime.tv_sec;
		usec += (xtime.tv_nsec / NSEC_PER_USEC);
	}
	while (read_seqretry_irqrestore(&xtime_lock, seq, flags));

	while (usec >= USEC_PER_SEC) {
		usec -= USEC_PER_SEC;
		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 the xtime.tv_usec
	 * 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!
	 */
	nsec -= (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);
#endif /* !CONFIG_GENERIC_TIME */

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