1 /*
2  *  linux/arch/arm/mach-footbridge/dc21285-timer.c
3  *
4  *  Copyright (C) 1998 Russell King.
5  *  Copyright (C) 1998 Phil Blundell
6  */
7 #include <linux/clockchips.h>
8 #include <linux/clocksource.h>
9 #include <linux/init.h>
10 #include <linux/interrupt.h>
11 #include <linux/irq.h>
12 #include <linux/sched_clock.h>
13 
14 #include <asm/irq.h>
15 
16 #include <asm/hardware/dec21285.h>
17 #include <asm/mach/time.h>
18 #include <asm/system_info.h>
19 
20 #include "common.h"
21 
22 static cycle_t cksrc_dc21285_read(struct clocksource *cs)
23 {
24 	return cs->mask - *CSR_TIMER2_VALUE;
25 }
26 
27 static int cksrc_dc21285_enable(struct clocksource *cs)
28 {
29 	*CSR_TIMER2_LOAD = cs->mask;
30 	*CSR_TIMER2_CLR = 0;
31 	*CSR_TIMER2_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_DIV16;
32 	return 0;
33 }
34 
35 static void cksrc_dc21285_disable(struct clocksource *cs)
36 {
37 	*CSR_TIMER2_CNTL = 0;
38 }
39 
40 static struct clocksource cksrc_dc21285 = {
41 	.name		= "dc21285_timer2",
42 	.rating		= 200,
43 	.read		= cksrc_dc21285_read,
44 	.enable		= cksrc_dc21285_enable,
45 	.disable	= cksrc_dc21285_disable,
46 	.mask		= CLOCKSOURCE_MASK(24),
47 	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
48 };
49 
50 static int ckevt_dc21285_set_next_event(unsigned long delta,
51 	struct clock_event_device *c)
52 {
53 	*CSR_TIMER1_CLR = 0;
54 	*CSR_TIMER1_LOAD = delta;
55 	*CSR_TIMER1_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_DIV16;
56 
57 	return 0;
58 }
59 
60 static void ckevt_dc21285_set_mode(enum clock_event_mode mode,
61 	struct clock_event_device *c)
62 {
63 	switch (mode) {
64 	case CLOCK_EVT_MODE_RESUME:
65 	case CLOCK_EVT_MODE_PERIODIC:
66 		*CSR_TIMER1_CLR = 0;
67 		*CSR_TIMER1_LOAD = (mem_fclk_21285 + 8 * HZ) / (16 * HZ);
68 		*CSR_TIMER1_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_AUTORELOAD |
69 				   TIMER_CNTL_DIV16;
70 		break;
71 
72 	case CLOCK_EVT_MODE_ONESHOT:
73 	case CLOCK_EVT_MODE_UNUSED:
74 	case CLOCK_EVT_MODE_SHUTDOWN:
75 		*CSR_TIMER1_CNTL = 0;
76 		break;
77 	}
78 }
79 
80 static struct clock_event_device ckevt_dc21285 = {
81 	.name		= "dc21285_timer1",
82 	.features	= CLOCK_EVT_FEAT_PERIODIC |
83 			  CLOCK_EVT_FEAT_ONESHOT,
84 	.rating		= 200,
85 	.irq		= IRQ_TIMER1,
86 	.set_next_event	= ckevt_dc21285_set_next_event,
87 	.set_mode	= ckevt_dc21285_set_mode,
88 };
89 
90 static irqreturn_t timer1_interrupt(int irq, void *dev_id)
91 {
92 	struct clock_event_device *ce = dev_id;
93 
94 	*CSR_TIMER1_CLR = 0;
95 
96 	/* Stop the timer if in one-shot mode */
97 	if (ce->mode == CLOCK_EVT_MODE_ONESHOT)
98 		*CSR_TIMER1_CNTL = 0;
99 
100 	ce->event_handler(ce);
101 
102 	return IRQ_HANDLED;
103 }
104 
105 static struct irqaction footbridge_timer_irq = {
106 	.name		= "dc21285_timer1",
107 	.handler	= timer1_interrupt,
108 	.flags		= IRQF_TIMER | IRQF_IRQPOLL,
109 	.dev_id		= &ckevt_dc21285,
110 };
111 
112 /*
113  * Set up timer interrupt.
114  */
115 void __init footbridge_timer_init(void)
116 {
117 	struct clock_event_device *ce = &ckevt_dc21285;
118 	unsigned rate = DIV_ROUND_CLOSEST(mem_fclk_21285, 16);
119 
120 	clocksource_register_hz(&cksrc_dc21285, rate);
121 
122 	setup_irq(ce->irq, &footbridge_timer_irq);
123 
124 	ce->cpumask = cpumask_of(smp_processor_id());
125 	clockevents_config_and_register(ce, rate, 0x4, 0xffffff);
126 }
127 
128 static u64 notrace footbridge_read_sched_clock(void)
129 {
130 	return ~*CSR_TIMER3_VALUE;
131 }
132 
133 void __init footbridge_sched_clock(void)
134 {
135 	unsigned rate = DIV_ROUND_CLOSEST(mem_fclk_21285, 16);
136 
137 	*CSR_TIMER3_LOAD = 0;
138 	*CSR_TIMER3_CLR = 0;
139 	*CSR_TIMER3_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_DIV16;
140 
141 	sched_clock_register(footbridge_read_sched_clock, 24, rate);
142 }
143