1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * linux/arch/arm/mach-footbridge/dc21285-timer.c
4 *
5 * Copyright (C) 1998 Russell King.
6 * Copyright (C) 1998 Phil Blundell
7 */
8 #include <linux/clockchips.h>
9 #include <linux/clocksource.h>
10 #include <linux/init.h>
11 #include <linux/interrupt.h>
12 #include <linux/irq.h>
13 #include <linux/sched_clock.h>
14
15 #include <asm/irq.h>
16
17 #include <asm/hardware/dec21285.h>
18 #include <asm/mach/time.h>
19 #include <asm/system_info.h>
20
21 #include "common.h"
22
23 static u64 cksrc_dc21285_read(struct clocksource *cs)
24 {
25 return cs->mask - *CSR_TIMER2_VALUE;
26 }
27
28 static int cksrc_dc21285_enable(struct clocksource *cs)
29 {
30 *CSR_TIMER2_LOAD = cs->mask;
31 *CSR_TIMER2_CLR = 0;
32 *CSR_TIMER2_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_DIV16;
33 return 0;
34 }
35
36 static void cksrc_dc21285_disable(struct clocksource *cs)
37 {
38 *CSR_TIMER2_CNTL = 0;
39 }
40
41 static struct clocksource cksrc_dc21285 = {
42 .name = "dc21285_timer2",
43 .rating = 200,
44 .read = cksrc_dc21285_read,
45 .enable = cksrc_dc21285_enable,
46 .disable = cksrc_dc21285_disable,
47 .mask = CLOCKSOURCE_MASK(24),
48 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
49 };
50
51 static int ckevt_dc21285_set_next_event(unsigned long delta,
52 struct clock_event_device *c)
53 {
54 *CSR_TIMER1_CLR = 0;
55 *CSR_TIMER1_LOAD = delta;
56 *CSR_TIMER1_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_DIV16;
57
58 return 0;
59 }
60
61 static int ckevt_dc21285_shutdown(struct clock_event_device *c)
62 {
63 *CSR_TIMER1_CNTL = 0;
64 return 0;
65 }
66
67 static int ckevt_dc21285_set_periodic(struct clock_event_device *c)
68 {
69 *CSR_TIMER1_CLR = 0;
70 *CSR_TIMER1_LOAD = (mem_fclk_21285 + 8 * HZ) / (16 * HZ);
71 *CSR_TIMER1_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_AUTORELOAD |
72 TIMER_CNTL_DIV16;
73 return 0;
74 }
75
76 static struct clock_event_device ckevt_dc21285 = {
77 .name = "dc21285_timer1",
78 .features = CLOCK_EVT_FEAT_PERIODIC |
79 CLOCK_EVT_FEAT_ONESHOT,
80 .rating = 200,
81 .irq = IRQ_TIMER1,
82 .set_next_event = ckevt_dc21285_set_next_event,
83 .set_state_shutdown = ckevt_dc21285_shutdown,
84 .set_state_periodic = ckevt_dc21285_set_periodic,
85 .set_state_oneshot = ckevt_dc21285_shutdown,
86 .tick_resume = ckevt_dc21285_set_periodic,
87 };
88
89 static irqreturn_t timer1_interrupt(int irq, void *dev_id)
90 {
91 struct clock_event_device *ce = dev_id;
92
93 *CSR_TIMER1_CLR = 0;
94
95 /* Stop the timer if in one-shot mode */
96 if (clockevent_state_oneshot(ce))
97 *CSR_TIMER1_CNTL = 0;
98
99 ce->event_handler(ce);
100
101 return IRQ_HANDLED;
102 }
103
104 /*
105 * Set up timer interrupt.
106 */
107 void __init footbridge_timer_init(void)
108 {
109 struct clock_event_device *ce = &ckevt_dc21285;
110 unsigned rate = DIV_ROUND_CLOSEST(mem_fclk_21285, 16);
111
112 clocksource_register_hz(&cksrc_dc21285, rate);
113
114 if (request_irq(ce->irq, timer1_interrupt, IRQF_TIMER | IRQF_IRQPOLL,
115 "dc21285_timer1", &ckevt_dc21285))
116 pr_err("Failed to request irq %d (dc21285_timer1)", ce->irq);
117
118 ce->cpumask = cpumask_of(smp_processor_id());
119 clockevents_config_and_register(ce, rate, 0x4, 0xffffff);
120 }
121
122 static u64 notrace footbridge_read_sched_clock(void)
123 {
124 return ~*CSR_TIMER3_VALUE;
125 }
126
127 void __init footbridge_sched_clock(void)
128 {
129 unsigned rate = DIV_ROUND_CLOSEST(mem_fclk_21285, 16);
130
131 *CSR_TIMER3_LOAD = 0;
132 *CSR_TIMER3_CLR = 0;
133 *CSR_TIMER3_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_DIV16;
134
135 sched_clock_register(footbridge_read_sched_clock, 24, rate);
136 }
137
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