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 */
41 static cycle_t notrace iop_clocksource_read(struct clocksource *unused)
42 {
43 return 0xffffffffu - read_tcr1();
44 }
45
46 static 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 */
57 static u64 notrace iop_read_sched_clock(void)
58 {
59 return 0xffffffffu - read_tcr1();
60 }
61
62 /*
63 * IOP clockevents (interrupting timer 0).
64 */
65 static 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
78 static unsigned long ticks_per_jiffy;
79
80 static 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
109 static 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
117 static irqreturn_t
118 iop_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
127 static 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
134 static unsigned long iop_tick_rate;
135 unsigned long get_iop_tick_rate(void)
136 {
137 return iop_tick_rate;
138 }
139 EXPORT_SYMBOL(get_iop_tick_rate);
140
141 void __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
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