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}