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#include <linux/sched_clock.h>
22
23#include <asm/mach-jz4740/irq.h>
24#include <asm/mach-jz4740/timer.h>
25#include <asm/time.h>
26
27#include "clock.h"
28
29#define TIMER_CLOCKEVENT 0
30#define TIMER_CLOCKSOURCE 1
31
32static uint16_t jz4740_jiffies_per_tick;
33
34static cycle_t jz4740_clocksource_read(struct clocksource *cs)
35{
36	return jz4740_timer_get_count(TIMER_CLOCKSOURCE);
37}
38
39static struct clocksource jz4740_clocksource = {
40	.name = "jz4740-timer",
41	.rating = 200,
42	.read = jz4740_clocksource_read,
43	.mask = CLOCKSOURCE_MASK(16),
44	.flags = CLOCK_SOURCE_IS_CONTINUOUS,
45};
46
47static u64 notrace jz4740_read_sched_clock(void)
48{
49	return jz4740_timer_get_count(TIMER_CLOCKSOURCE);
50}
51
52static irqreturn_t jz4740_clockevent_irq(int irq, void *devid)
53{
54	struct clock_event_device *cd = devid;
55
56	jz4740_timer_ack_full(TIMER_CLOCKEVENT);
57
58	if (cd->mode != CLOCK_EVT_MODE_PERIODIC)
59		jz4740_timer_disable(TIMER_CLOCKEVENT);
60
61	cd->event_handler(cd);
62
63	return IRQ_HANDLED;
64}
65
66static void jz4740_clockevent_set_mode(enum clock_event_mode mode,
67	struct clock_event_device *cd)
68{
69	switch (mode) {
70	case CLOCK_EVT_MODE_PERIODIC:
71		jz4740_timer_set_count(TIMER_CLOCKEVENT, 0);
72		jz4740_timer_set_period(TIMER_CLOCKEVENT, jz4740_jiffies_per_tick);
73	case CLOCK_EVT_MODE_RESUME:
74		jz4740_timer_irq_full_enable(TIMER_CLOCKEVENT);
75		jz4740_timer_enable(TIMER_CLOCKEVENT);
76		break;
77	case CLOCK_EVT_MODE_ONESHOT:
78	case CLOCK_EVT_MODE_SHUTDOWN:
79		jz4740_timer_disable(TIMER_CLOCKEVENT);
80		break;
81	default:
82		break;
83	}
84}
85
86static int jz4740_clockevent_set_next(unsigned long evt,
87	struct clock_event_device *cd)
88{
89	jz4740_timer_set_count(TIMER_CLOCKEVENT, 0);
90	jz4740_timer_set_period(TIMER_CLOCKEVENT, evt);
91	jz4740_timer_enable(TIMER_CLOCKEVENT);
92
93	return 0;
94}
95
96static struct clock_event_device jz4740_clockevent = {
97	.name = "jz4740-timer",
98	.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
99	.set_next_event = jz4740_clockevent_set_next,
100	.set_mode = jz4740_clockevent_set_mode,
101	.rating = 200,
102	.irq = JZ4740_IRQ_TCU0,
103};
104
105static struct irqaction timer_irqaction = {
106	.handler	= jz4740_clockevent_irq,
107	.flags		= IRQF_PERCPU | IRQF_TIMER,
108	.name		= "jz4740-timerirq",
109	.dev_id		= &jz4740_clockevent,
110};
111
112void __init plat_time_init(void)
113{
114	int ret;
115	uint32_t clk_rate;
116	uint16_t ctrl;
117
118	jz4740_timer_init();
119
120	clk_rate = jz4740_clock_bdata.ext_rate >> 4;
121	jz4740_jiffies_per_tick = DIV_ROUND_CLOSEST(clk_rate, HZ);
122
123	clockevent_set_clock(&jz4740_clockevent, clk_rate);
124	jz4740_clockevent.min_delta_ns = clockevent_delta2ns(100, &jz4740_clockevent);
125	jz4740_clockevent.max_delta_ns = clockevent_delta2ns(0xffff, &jz4740_clockevent);
126	jz4740_clockevent.cpumask = cpumask_of(0);
127
128	clockevents_register_device(&jz4740_clockevent);
129
130	ret = clocksource_register_hz(&jz4740_clocksource, clk_rate);
131
132	if (ret)
133		printk(KERN_ERR "Failed to register clocksource: %d\n", ret);
134
135	sched_clock_register(jz4740_read_sched_clock, 16, clk_rate);
136
137	setup_irq(JZ4740_IRQ_TCU0, &timer_irqaction);
138
139	ctrl = JZ_TIMER_CTRL_PRESCALE_16 | JZ_TIMER_CTRL_SRC_EXT;
140
141	jz4740_timer_set_ctrl(TIMER_CLOCKEVENT, ctrl);
142	jz4740_timer_set_ctrl(TIMER_CLOCKSOURCE, ctrl);
143
144	jz4740_timer_set_period(TIMER_CLOCKEVENT, jz4740_jiffies_per_tick);
145	jz4740_timer_irq_full_enable(TIMER_CLOCKEVENT);
146
147	jz4740_timer_set_period(TIMER_CLOCKSOURCE, 0xffff);
148
149	jz4740_timer_enable(TIMER_CLOCKEVENT);
150	jz4740_timer_enable(TIMER_CLOCKSOURCE);
151}
152