summaryrefslogtreecommitdiffstats
path: root/arch/mips/jz4740/time.c
blob: 39bb4bbf43e7073e9327a634f221f5c1942b2855 (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
/*
 *  Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
 *  JZ4740 platform time support
 *
 *  This program is free software; you can redistribute it and/or modify it
 *  under  the terms of the GNU General  Public License as published by the
 *  Free Software Foundation;  either version 2 of the License, or (at your
 *  option) any later version.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */

#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/time.h>

#include <linux/clockchips.h>

#include <asm/mach-jz4740/irq.h>
#include <asm/mach-jz4740/timer.h>
#include <asm/time.h>

#include "clock.h"

#define TIMER_CLOCKEVENT 0
#define TIMER_CLOCKSOURCE 1

static uint16_t jz4740_jiffies_per_tick;

static cycle_t jz4740_clocksource_read(struct clocksource *cs)
{
	return jz4740_timer_get_count(TIMER_CLOCKSOURCE);
}

static struct clocksource jz4740_clocksource = {
	.name = "jz4740-timer",
	.rating = 200,
	.read = jz4740_clocksource_read,
	.mask = CLOCKSOURCE_MASK(16),
	.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};

static irqreturn_t jz4740_clockevent_irq(int irq, void *devid)
{
	struct clock_event_device *cd = devid;

	jz4740_timer_ack_full(TIMER_CLOCKEVENT);

	if (cd->mode != CLOCK_EVT_MODE_PERIODIC)
		jz4740_timer_disable(TIMER_CLOCKEVENT);

	cd->event_handler(cd);

	return IRQ_HANDLED;
}

static void jz4740_clockevent_set_mode(enum clock_event_mode mode,
	struct clock_event_device *cd)
{
	switch (mode) {
	case CLOCK_EVT_MODE_PERIODIC:
		jz4740_timer_set_count(TIMER_CLOCKEVENT, 0);
		jz4740_timer_set_period(TIMER_CLOCKEVENT, jz4740_jiffies_per_tick);
	case CLOCK_EVT_MODE_RESUME:
		jz4740_timer_irq_full_enable(TIMER_CLOCKEVENT);
		jz4740_timer_enable(TIMER_CLOCKEVENT);
		break;
	case CLOCK_EVT_MODE_ONESHOT:
	case CLOCK_EVT_MODE_SHUTDOWN:
		jz4740_timer_disable(TIMER_CLOCKEVENT);
		break;
	default:
		break;
	}
}

static int jz4740_clockevent_set_next(unsigned long evt,
	struct clock_event_device *cd)
{
	jz4740_timer_set_count(TIMER_CLOCKEVENT, 0);
	jz4740_timer_set_period(TIMER_CLOCKEVENT, evt);
	jz4740_timer_enable(TIMER_CLOCKEVENT);

	return 0;
}

static struct clock_event_device jz4740_clockevent = {
	.name = "jz4740-timer",
	.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
	.set_next_event = jz4740_clockevent_set_next,
	.set_mode = jz4740_clockevent_set_mode,
	.rating = 200,
	.irq = JZ4740_IRQ_TCU0,
};

static struct irqaction timer_irqaction = {
	.handler	= jz4740_clockevent_irq,
	.flags		= IRQF_PERCPU | IRQF_TIMER,
	.name		= "jz4740-timerirq",
	.dev_id		= &jz4740_clockevent,
};

void __init plat_time_init(void)
{
	int ret;
	uint32_t clk_rate;
	uint16_t ctrl;

	jz4740_timer_init();

	clk_rate = jz4740_clock_bdata.ext_rate >> 4;
	jz4740_jiffies_per_tick = DIV_ROUND_CLOSEST(clk_rate, HZ);

	clockevent_set_clock(&jz4740_clockevent, clk_rate);
	jz4740_clockevent.min_delta_ns = clockevent_delta2ns(100, &jz4740_clockevent);
	jz4740_clockevent.max_delta_ns = clockevent_delta2ns(0xffff, &jz4740_clockevent);
	jz4740_clockevent.cpumask = cpumask_of(0);

	clockevents_register_device(&jz4740_clockevent);

	ret = clocksource_register_hz(&jz4740_clocksource, clk_rate);

	if (ret)
		printk(KERN_ERR "Failed to register clocksource: %d\n", ret);

	setup_irq(JZ4740_IRQ_TCU0, &timer_irqaction);

	ctrl = JZ_TIMER_CTRL_PRESCALE_16 | JZ_TIMER_CTRL_SRC_EXT;

	jz4740_timer_set_ctrl(TIMER_CLOCKEVENT, ctrl);
	jz4740_timer_set_ctrl(TIMER_CLOCKSOURCE, ctrl);

	jz4740_timer_set_period(TIMER_CLOCKEVENT, jz4740_jiffies_per_tick);
	jz4740_timer_irq_full_enable(TIMER_CLOCKEVENT);

	jz4740_timer_set_period(TIMER_CLOCKSOURCE, 0xffff);

	jz4740_timer_enable(TIMER_CLOCKEVENT);
	jz4740_timer_enable(TIMER_CLOCKSOURCE);
}
OpenPOWER on IntegriCloud