aboutsummaryrefslogtreecommitdiff
path: root/arch/arm/plat-iop/time.c
blob: 558cdfaf76b6a22a4ff6ff3a5190263c662a3268 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
/*
 * arch/arm/plat-iop/time.c
 *
 * Timer code for IOP32x and IOP33x based systems
 *
 * Author: Deepak Saxena <dsaxena@mvista.com>
 *
 * Copyright 2002-2003 MontaVista Software Inc.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.
 */

#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/time.h>
#include <linux/init.h>
#include <linux/timex.h>
#include <linux/sched.h>
#include <linux/io.h>
#include <linux/clocksource.h>
#include <linux/clockchips.h>
#include <mach/hardware.h>
#include <asm/irq.h>
#include <asm/uaccess.h>
#include <asm/mach/irq.h>
#include <asm/mach/time.h>
#include <mach/time.h>

/*
 * Minimum clocksource/clockevent timer range in seconds
 */
#define IOP_MIN_RANGE 4

/*
 * IOP clocksource (free-running timer 1).
 */
static cycle_t notrace iop_clocksource_read(struct clocksource *unused)
{
	return 0xffffffffu - read_tcr1();
}

static struct clocksource iop_clocksource = {
	.name 		= "iop_timer1",
	.rating		= 300,
	.read		= iop_clocksource_read,
	.mask		= CLOCKSOURCE_MASK(32),
	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
};

/*
 * IOP sched_clock() implementation via its clocksource.
 */
unsigned long long sched_clock(void)
{
	cycle_t cyc = iop_clocksource_read(NULL);
	struct clocksource *cs = &iop_clocksource;

	return clocksource_cyc2ns(cyc, cs->mult, cs->shift);
}

/*
 * IOP clockevents (interrupting timer 0).
 */
static int iop_set_next_event(unsigned long delta,
			      struct clock_event_device *unused)
{
	u32 tmr = IOP_TMR_PRIVILEGED | IOP_TMR_RATIO_1_1;

	BUG_ON(delta == 0);
	write_tmr0(tmr & ~(IOP_TMR_EN | IOP_TMR_RELOAD));
	write_tcr0(delta);
	write_tmr0((tmr & ~IOP_TMR_RELOAD) | IOP_TMR_EN);

	return 0;
}

static unsigned long ticks_per_jiffy;

static void iop_set_mode(enum clock_event_mode mode,
			 struct clock_event_device *unused)
{
	u32 tmr = read_tmr0();

	switch (mode) {
	case CLOCK_EVT_MODE_PERIODIC:
		write_tmr0(tmr & ~IOP_TMR_EN);
		write_tcr0(ticks_per_jiffy - 1);
		tmr |= (IOP_TMR_RELOAD | IOP_TMR_EN);
		break;
	case CLOCK_EVT_MODE_ONESHOT:
		/* ->set_next_event sets period and enables timer */
		tmr &= ~(IOP_TMR_RELOAD | IOP_TMR_EN);
		break;
	case CLOCK_EVT_MODE_RESUME:
		tmr |= IOP_TMR_EN;
		break;
	case CLOCK_EVT_MODE_SHUTDOWN:
	case CLOCK_EVT_MODE_UNUSED:
	default:
		tmr &= ~IOP_TMR_EN;
		break;
	}

	write_tmr0(tmr);
}

static struct clock_event_device iop_clockevent = {
	.name		= "iop_timer0",
	.features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
	.rating         = 300,
	.set_next_event	= iop_set_next_event,
	.set_mode	= iop_set_mode,
};

static irqreturn_t
iop_timer_interrupt(int irq, void *dev_id)
{
	struct clock_event_device *evt = dev_id;

	write_tisr(1);
	evt->event_handler(evt);
	return IRQ_HANDLED;
}

static struct irqaction iop_timer_irq = {
	.name		= "IOP Timer Tick",
	.handler	= iop_timer_interrupt,
	.flags		= IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
	.dev_id		= &iop_clockevent,
};

static unsigned long iop_tick_rate;
unsigned long get_iop_tick_rate(void)
{
	return iop_tick_rate;
}
EXPORT_SYMBOL(get_iop_tick_rate);

void __init iop_init_time(unsigned long tick_rate)
{
	u32 timer_ctl;

	ticks_per_jiffy = DIV_ROUND_CLOSEST(tick_rate, HZ);
	iop_tick_rate = tick_rate;

	timer_ctl = IOP_TMR_EN | IOP_TMR_PRIVILEGED |
			IOP_TMR_RELOAD | IOP_TMR_RATIO_1_1;

	/*
	 * Set up interrupting clockevent timer 0.
	 */
	write_tmr0(timer_ctl & ~IOP_TMR_EN);
	setup_irq(IRQ_IOP_TIMER0, &iop_timer_irq);
	clockevents_calc_mult_shift(&iop_clockevent,
				    tick_rate, IOP_MIN_RANGE);
	iop_clockevent.max_delta_ns =
		clockevent_delta2ns(0xfffffffe, &iop_clockevent);
	iop_clockevent.min_delta_ns =
		clockevent_delta2ns(0xf, &iop_clockevent);
	iop_clockevent.cpumask = cpumask_of(0);
	clockevents_register_device(&iop_clockevent);
	write_trr0(ticks_per_jiffy - 1);
	write_tcr0(ticks_per_jiffy - 1);
	write_tmr0(timer_ctl);

	/*
	 * Set up free-running clocksource timer 1.
	 */
	write_trr1(0xffffffff);
	write_tcr1(0xffffffff);
	write_tmr1(timer_ctl);
	clocksource_calc_mult_shift(&iop_clocksource, tick_rate,
				    IOP_MIN_RANGE);
	clocksource_register(&iop_clocksource);
}