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/clk.h>
 17#include <linux/clk-provider.h>
 18#include <linux/interrupt.h>
 19#include <linux/kernel.h>
 20#include <linux/time.h>
 21
 22#include <linux/clockchips.h>
 23#include <linux/sched_clock.h>
 24
 25#include <asm/mach-jz4740/clock.h>
 26#include <asm/mach-jz4740/irq.h>
 27#include <asm/mach-jz4740/timer.h>
 28#include <asm/time.h>
 29
 30#include "clock.h"
 31
 32#define TIMER_CLOCKEVENT 0
 33#define TIMER_CLOCKSOURCE 1
 34
 35static uint16_t jz4740_jiffies_per_tick;
 36
 37static u64 jz4740_clocksource_read(struct clocksource *cs)
 38{
 39	return jz4740_timer_get_count(TIMER_CLOCKSOURCE);
 40}
 41
 42static struct clocksource jz4740_clocksource = {
 43	.name = "jz4740-timer",
 44	.rating = 200,
 45	.read = jz4740_clocksource_read,
 46	.mask = CLOCKSOURCE_MASK(16),
 47	.flags = CLOCK_SOURCE_IS_CONTINUOUS,
 48};
 49
 50static u64 notrace jz4740_read_sched_clock(void)
 51{
 52	return jz4740_timer_get_count(TIMER_CLOCKSOURCE);
 53}
 54
 55static irqreturn_t jz4740_clockevent_irq(int irq, void *devid)
 56{
 57	struct clock_event_device *cd = devid;
 58
 59	jz4740_timer_ack_full(TIMER_CLOCKEVENT);
 60
 61	if (!clockevent_state_periodic(cd))
 62		jz4740_timer_disable(TIMER_CLOCKEVENT);
 63
 64	cd->event_handler(cd);
 65
 66	return IRQ_HANDLED;
 67}
 68
 69static int jz4740_clockevent_set_periodic(struct clock_event_device *evt)
 70{
 71	jz4740_timer_set_count(TIMER_CLOCKEVENT, 0);
 72	jz4740_timer_set_period(TIMER_CLOCKEVENT, jz4740_jiffies_per_tick);
 73	jz4740_timer_irq_full_enable(TIMER_CLOCKEVENT);
 74	jz4740_timer_enable(TIMER_CLOCKEVENT);
 75
 76	return 0;
 77}
 78
 79static int jz4740_clockevent_resume(struct clock_event_device *evt)
 80{
 81	jz4740_timer_irq_full_enable(TIMER_CLOCKEVENT);
 82	jz4740_timer_enable(TIMER_CLOCKEVENT);
 83
 84	return 0;
 85}
 86
 87static int jz4740_clockevent_shutdown(struct clock_event_device *evt)
 88{
 89	jz4740_timer_disable(TIMER_CLOCKEVENT);
 90
 91	return 0;
 92}
 93
 94static int jz4740_clockevent_set_next(unsigned long evt,
 95	struct clock_event_device *cd)
 96{
 97	jz4740_timer_set_count(TIMER_CLOCKEVENT, 0);
 98	jz4740_timer_set_period(TIMER_CLOCKEVENT, evt);
 99	jz4740_timer_enable(TIMER_CLOCKEVENT);
100
101	return 0;
102}
103
104static struct clock_event_device jz4740_clockevent = {
105	.name = "jz4740-timer",
106	.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
107	.set_next_event = jz4740_clockevent_set_next,
108	.set_state_shutdown = jz4740_clockevent_shutdown,
109	.set_state_periodic = jz4740_clockevent_set_periodic,
110	.set_state_oneshot = jz4740_clockevent_shutdown,
111	.tick_resume = jz4740_clockevent_resume,
112	.rating = 200,
113#ifdef CONFIG_MACH_JZ4740
114	.irq = JZ4740_IRQ_TCU0,
115#endif
116#if defined(CONFIG_MACH_JZ4770) || defined(CONFIG_MACH_JZ4780)
117	.irq = JZ4780_IRQ_TCU2,
118#endif
119};
120
121static struct irqaction timer_irqaction = {
122	.handler	= jz4740_clockevent_irq,
123	.flags		= IRQF_PERCPU | IRQF_TIMER,
124	.name		= "jz4740-timerirq",
125	.dev_id		= &jz4740_clockevent,
126};
127
128void __init plat_time_init(void)
129{
130	int ret;
131	uint32_t clk_rate;
132	uint16_t ctrl;
133	struct clk *ext_clk;
134
135	of_clk_init(NULL);
136	jz4740_timer_init();
137
138	ext_clk = clk_get(NULL, "ext");
139	if (IS_ERR(ext_clk))
140		panic("unable to get ext clock");
141	clk_rate = clk_get_rate(ext_clk) >> 4;
142	clk_put(ext_clk);
143
144	jz4740_jiffies_per_tick = DIV_ROUND_CLOSEST(clk_rate, HZ);
145
146	clockevent_set_clock(&jz4740_clockevent, clk_rate);
147	jz4740_clockevent.min_delta_ns = clockevent_delta2ns(100, &jz4740_clockevent);
148	jz4740_clockevent.min_delta_ticks = 100;
149	jz4740_clockevent.max_delta_ns = clockevent_delta2ns(0xffff, &jz4740_clockevent);
150	jz4740_clockevent.max_delta_ticks = 0xffff;
151	jz4740_clockevent.cpumask = cpumask_of(0);
152
153	clockevents_register_device(&jz4740_clockevent);
154
155	ret = clocksource_register_hz(&jz4740_clocksource, clk_rate);
156
157	if (ret)
158		printk(KERN_ERR "Failed to register clocksource: %d\n", ret);
159
160	sched_clock_register(jz4740_read_sched_clock, 16, clk_rate);
161
162	setup_irq(jz4740_clockevent.irq, &timer_irqaction);
163
164	ctrl = JZ_TIMER_CTRL_PRESCALE_16 | JZ_TIMER_CTRL_SRC_EXT;
165
166	jz4740_timer_set_ctrl(TIMER_CLOCKEVENT, ctrl);
167	jz4740_timer_set_ctrl(TIMER_CLOCKSOURCE, ctrl);
168
169	jz4740_timer_set_period(TIMER_CLOCKEVENT, jz4740_jiffies_per_tick);
170	jz4740_timer_irq_full_enable(TIMER_CLOCKEVENT);
171
172	jz4740_timer_set_period(TIMER_CLOCKSOURCE, 0xffff);
173
174	jz4740_timer_enable(TIMER_CLOCKEVENT);
175	jz4740_timer_enable(TIMER_CLOCKSOURCE);
176}