1/*
2 *  Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
3 *  JZ4740 platform time support
4 *
5 *  This program is free software; you can redistribute it and/or modify it
6 *  under  the terms of the GNU General  Public License as published by the
7 *  Free Software Foundation;  either version 2 of the License, or (at your
8 *  option) any later version.
9 *
10 *  You should have received a copy of the GNU General Public License along
11 *  with this program; if not, write to the Free Software Foundation, Inc.,
12 *  675 Mass Ave, Cambridge, MA 02139, USA.
13 *
14 */
15
16#include <linux/interrupt.h>
17#include <linux/kernel.h>
18#include <linux/time.h>
19
20#include <linux/clockchips.h>
21
22#include <asm/mach-jz4740/irq.h>
23#include <asm/time.h>
24
25#include "clock.h"
26#include "timer.h"
27
28#define TIMER_CLOCKEVENT 0
29#define TIMER_CLOCKSOURCE 1
30
31static uint16_t jz4740_jiffies_per_tick;
32
33static cycle_t jz4740_clocksource_read(struct clocksource *cs)
34{
35	return jz4740_timer_get_count(TIMER_CLOCKSOURCE);
36}
37
38static struct clocksource jz4740_clocksource = {
39	.name = "jz4740-timer",
40	.rating = 200,
41	.read = jz4740_clocksource_read,
42	.mask = CLOCKSOURCE_MASK(16),
43	.flags = CLOCK_SOURCE_IS_CONTINUOUS,
44};
45
46static irqreturn_t jz4740_clockevent_irq(int irq, void *devid)
47{
48	struct clock_event_device *cd = devid;
49
50	jz4740_timer_ack_full(TIMER_CLOCKEVENT);
51
52	if (cd->mode != CLOCK_EVT_MODE_PERIODIC)
53		jz4740_timer_disable(TIMER_CLOCKEVENT);
54
55	cd->event_handler(cd);
56
57	return IRQ_HANDLED;
58}
59
60static void jz4740_clockevent_set_mode(enum clock_event_mode mode,
61	struct clock_event_device *cd)
62{
63	switch (mode) {
64	case CLOCK_EVT_MODE_PERIODIC:
65		jz4740_timer_set_count(TIMER_CLOCKEVENT, 0);
66		jz4740_timer_set_period(TIMER_CLOCKEVENT, jz4740_jiffies_per_tick);
67	case CLOCK_EVT_MODE_RESUME:
68		jz4740_timer_irq_full_enable(TIMER_CLOCKEVENT);
69		jz4740_timer_enable(TIMER_CLOCKEVENT);
70		break;
71	case CLOCK_EVT_MODE_ONESHOT:
72	case CLOCK_EVT_MODE_SHUTDOWN:
73		jz4740_timer_disable(TIMER_CLOCKEVENT);
74		break;
75	default:
76		break;
77	}
78}
79
80static int jz4740_clockevent_set_next(unsigned long evt,
81	struct clock_event_device *cd)
82{
83	jz4740_timer_set_count(TIMER_CLOCKEVENT, 0);
84	jz4740_timer_set_period(TIMER_CLOCKEVENT, evt);
85	jz4740_timer_enable(TIMER_CLOCKEVENT);
86
87	return 0;
88}
89
90static struct clock_event_device jz4740_clockevent = {
91	.name = "jz4740-timer",
92	.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
93	.set_next_event = jz4740_clockevent_set_next,
94	.set_mode = jz4740_clockevent_set_mode,
95	.rating = 200,
96	.irq = JZ4740_IRQ_TCU0,
97};
98
99static struct irqaction timer_irqaction = {
100	.handler	= jz4740_clockevent_irq,
101	.flags		= IRQF_PERCPU | IRQF_TIMER,
102	.name		= "jz4740-timerirq",
103	.dev_id		= &jz4740_clockevent,
104};
105
106void __init plat_time_init(void)
107{
108	int ret;
109	uint32_t clk_rate;
110	uint16_t ctrl;
111
112	jz4740_timer_init();
113
114	clk_rate = jz4740_clock_bdata.ext_rate >> 4;
115	jz4740_jiffies_per_tick = DIV_ROUND_CLOSEST(clk_rate, HZ);
116
117	clockevent_set_clock(&jz4740_clockevent, clk_rate);
118	jz4740_clockevent.min_delta_ns = clockevent_delta2ns(100, &jz4740_clockevent);
119	jz4740_clockevent.max_delta_ns = clockevent_delta2ns(0xffff, &jz4740_clockevent);
120	jz4740_clockevent.cpumask = cpumask_of(0);
121
122	clockevents_register_device(&jz4740_clockevent);
123
124	ret = clocksource_register_hz(&jz4740_clocksource, clk_rate);
125
126	if (ret)
127		printk(KERN_ERR "Failed to register clocksource: %d\n", ret);
128
129	setup_irq(JZ4740_IRQ_TCU0, &timer_irqaction);
130
131	ctrl = JZ_TIMER_CTRL_PRESCALE_16 | JZ_TIMER_CTRL_SRC_EXT;
132
133	jz4740_timer_set_ctrl(TIMER_CLOCKEVENT, ctrl);
134	jz4740_timer_set_ctrl(TIMER_CLOCKSOURCE, ctrl);
135
136	jz4740_timer_set_period(TIMER_CLOCKEVENT, jz4740_jiffies_per_tick);
137	jz4740_timer_irq_full_enable(TIMER_CLOCKEVENT);
138
139	jz4740_timer_set_period(TIMER_CLOCKSOURCE, 0xffff);
140
141	jz4740_timer_enable(TIMER_CLOCKEVENT);
142	jz4740_timer_enable(TIMER_CLOCKSOURCE);
143}
144