1/*
2 * arch/arm/plat-iop/time.c
3 *
4 * Timer code for IOP32x and IOP33x based systems
5 *
6 * Author: Deepak Saxena <dsaxena@mvista.com>
7 *
8 * Copyright 2002-2003 MontaVista Software Inc.
9 *
10 * This program is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU General Public License as published by the
12 * Free Software Foundation; either version 2 of the License, or (at your
13 * option) any later version.
14 */
15
16#include <linux/kernel.h>
17#include <linux/interrupt.h>
18#include <linux/time.h>
19#include <linux/init.h>
20#include <linux/timex.h>
21#include <linux/io.h>
22#include <linux/clocksource.h>
23#include <linux/clockchips.h>
24#include <linux/export.h>
25#include <linux/sched_clock.h>
26#include <mach/hardware.h>
27#include <asm/irq.h>
28#include <asm/uaccess.h>
29#include <asm/mach/irq.h>
30#include <asm/mach/time.h>
31#include <mach/time.h>
32
33/*
34 * Minimum clocksource/clockevent timer range in seconds
35 */
36#define IOP_MIN_RANGE 4
37
38/*
39 * IOP clocksource (free-running timer 1).
40 */
41static cycle_t notrace iop_clocksource_read(struct clocksource *unused)
42{
43	return 0xffffffffu - read_tcr1();
44}
45
46static struct clocksource iop_clocksource = {
47	.name 		= "iop_timer1",
48	.rating		= 300,
49	.read		= iop_clocksource_read,
50	.mask		= CLOCKSOURCE_MASK(32),
51	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
52};
53
54/*
55 * IOP sched_clock() implementation via its clocksource.
56 */
57static u64 notrace iop_read_sched_clock(void)
58{
59	return 0xffffffffu - read_tcr1();
60}
61
62/*
63 * IOP clockevents (interrupting timer 0).
64 */
65static int iop_set_next_event(unsigned long delta,
66			      struct clock_event_device *unused)
67{
68	u32 tmr = IOP_TMR_PRIVILEGED | IOP_TMR_RATIO_1_1;
69
70	BUG_ON(delta == 0);
71	write_tmr0(tmr & ~(IOP_TMR_EN | IOP_TMR_RELOAD));
72	write_tcr0(delta);
73	write_tmr0((tmr & ~IOP_TMR_RELOAD) | IOP_TMR_EN);
74
75	return 0;
76}
77
78static unsigned long ticks_per_jiffy;
79
80static void iop_set_mode(enum clock_event_mode mode,
81			 struct clock_event_device *unused)
82{
83	u32 tmr = read_tmr0();
84
85	switch (mode) {
86	case CLOCK_EVT_MODE_PERIODIC:
87		write_tmr0(tmr & ~IOP_TMR_EN);
88		write_tcr0(ticks_per_jiffy - 1);
89		write_trr0(ticks_per_jiffy - 1);
90		tmr |= (IOP_TMR_RELOAD | IOP_TMR_EN);
91		break;
92	case CLOCK_EVT_MODE_ONESHOT:
93		/* ->set_next_event sets period and enables timer */
94		tmr &= ~(IOP_TMR_RELOAD | IOP_TMR_EN);
95		break;
96	case CLOCK_EVT_MODE_RESUME:
97		tmr |= IOP_TMR_EN;
98		break;
99	case CLOCK_EVT_MODE_SHUTDOWN:
100	case CLOCK_EVT_MODE_UNUSED:
101	default:
102		tmr &= ~IOP_TMR_EN;
103		break;
104	}
105
106	write_tmr0(tmr);
107}
108
109static struct clock_event_device iop_clockevent = {
110	.name		= "iop_timer0",
111	.features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
112	.rating         = 300,
113	.set_next_event	= iop_set_next_event,
114	.set_mode	= iop_set_mode,
115};
116
117static irqreturn_t
118iop_timer_interrupt(int irq, void *dev_id)
119{
120	struct clock_event_device *evt = dev_id;
121
122	write_tisr(1);
123	evt->event_handler(evt);
124	return IRQ_HANDLED;
125}
126
127static struct irqaction iop_timer_irq = {
128	.name		= "IOP Timer Tick",
129	.handler	= iop_timer_interrupt,
130	.flags		= IRQF_TIMER | IRQF_IRQPOLL,
131	.dev_id		= &iop_clockevent,
132};
133
134static unsigned long iop_tick_rate;
135unsigned long get_iop_tick_rate(void)
136{
137	return iop_tick_rate;
138}
139EXPORT_SYMBOL(get_iop_tick_rate);
140
141void __init iop_init_time(unsigned long tick_rate)
142{
143	u32 timer_ctl;
144
145	sched_clock_register(iop_read_sched_clock, 32, tick_rate);
146
147	ticks_per_jiffy = DIV_ROUND_CLOSEST(tick_rate, HZ);
148	iop_tick_rate = tick_rate;
149
150	timer_ctl = IOP_TMR_EN | IOP_TMR_PRIVILEGED |
151			IOP_TMR_RELOAD | IOP_TMR_RATIO_1_1;
152
153	/*
154	 * Set up interrupting clockevent timer 0.
155	 */
156	write_tmr0(timer_ctl & ~IOP_TMR_EN);
157	write_tisr(1);
158	setup_irq(IRQ_IOP_TIMER0, &iop_timer_irq);
159	iop_clockevent.cpumask = cpumask_of(0);
160	clockevents_config_and_register(&iop_clockevent, tick_rate,
161					0xf, 0xfffffffe);
162
163	/*
164	 * Set up free-running clocksource timer 1.
165	 */
166	write_trr1(0xffffffff);
167	write_tcr1(0xffffffff);
168	write_tmr1(timer_ctl);
169	clocksource_register_hz(&iop_clocksource, tick_rate);
170}
171