xref: /openbmc/linux/arch/mips/kernel/cevt-gt641xx.c (revision b830f94f) 
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  GT641xx clockevent routines.
4  *
5  *  Copyright (C) 2007	Yoichi Yuasa <yuasa@linux-mips.org>
6  */
7 #include <linux/clockchips.h>
8 #include <linux/init.h>
9 #include <linux/interrupt.h>
10 #include <linux/spinlock.h>
11 #include <linux/irq.h>
12 
13 #include <asm/gt64120.h>
14 #include <asm/time.h>
15 
16 static DEFINE_RAW_SPINLOCK(gt641xx_timer_lock);
17 static unsigned int gt641xx_base_clock;
18 
19 void gt641xx_set_base_clock(unsigned int clock)
20 {
21 	gt641xx_base_clock = clock;
22 }
23 
24 int gt641xx_timer0_state(void)
25 {
26 	if (GT_READ(GT_TC0_OFS))
27 		return 0;
28 
29 	GT_WRITE(GT_TC0_OFS, gt641xx_base_clock / HZ);
30 	GT_WRITE(GT_TC_CONTROL_OFS, GT_TC_CONTROL_ENTC0_MSK);
31 
32 	return 1;
33 }
34 
35 static int gt641xx_timer0_set_next_event(unsigned long delta,
36 					 struct clock_event_device *evt)
37 {
38 	u32 ctrl;
39 
40 	raw_spin_lock(&gt641xx_timer_lock);
41 
42 	ctrl = GT_READ(GT_TC_CONTROL_OFS);
43 	ctrl &= ~(GT_TC_CONTROL_ENTC0_MSK | GT_TC_CONTROL_SELTC0_MSK);
44 	ctrl |= GT_TC_CONTROL_ENTC0_MSK;
45 
46 	GT_WRITE(GT_TC0_OFS, delta);
47 	GT_WRITE(GT_TC_CONTROL_OFS, ctrl);
48 
49 	raw_spin_unlock(&gt641xx_timer_lock);
50 
51 	return 0;
52 }
53 
54 static int gt641xx_timer0_shutdown(struct clock_event_device *evt)
55 {
56 	u32 ctrl;
57 
58 	raw_spin_lock(&gt641xx_timer_lock);
59 
60 	ctrl = GT_READ(GT_TC_CONTROL_OFS);
61 	ctrl &= ~(GT_TC_CONTROL_ENTC0_MSK | GT_TC_CONTROL_SELTC0_MSK);
62 	GT_WRITE(GT_TC_CONTROL_OFS, ctrl);
63 
64 	raw_spin_unlock(&gt641xx_timer_lock);
65 	return 0;
66 }
67 
68 static int gt641xx_timer0_set_oneshot(struct clock_event_device *evt)
69 {
70 	u32 ctrl;
71 
72 	raw_spin_lock(&gt641xx_timer_lock);
73 
74 	ctrl = GT_READ(GT_TC_CONTROL_OFS);
75 	ctrl &= ~GT_TC_CONTROL_SELTC0_MSK;
76 	ctrl |= GT_TC_CONTROL_ENTC0_MSK;
77 	GT_WRITE(GT_TC_CONTROL_OFS, ctrl);
78 
79 	raw_spin_unlock(&gt641xx_timer_lock);
80 	return 0;
81 }
82 
83 static int gt641xx_timer0_set_periodic(struct clock_event_device *evt)
84 {
85 	u32 ctrl;
86 
87 	raw_spin_lock(&gt641xx_timer_lock);
88 
89 	ctrl = GT_READ(GT_TC_CONTROL_OFS);
90 	ctrl |= GT_TC_CONTROL_ENTC0_MSK | GT_TC_CONTROL_SELTC0_MSK;
91 	GT_WRITE(GT_TC_CONTROL_OFS, ctrl);
92 
93 	raw_spin_unlock(&gt641xx_timer_lock);
94 	return 0;
95 }
96 
97 static void gt641xx_timer0_event_handler(struct clock_event_device *dev)
98 {
99 }
100 
101 static struct clock_event_device gt641xx_timer0_clockevent = {
102 	.name			= "gt641xx-timer0",
103 	.features		= CLOCK_EVT_FEAT_PERIODIC |
104 				  CLOCK_EVT_FEAT_ONESHOT,
105 	.irq			= GT641XX_TIMER0_IRQ,
106 	.set_next_event		= gt641xx_timer0_set_next_event,
107 	.set_state_shutdown	= gt641xx_timer0_shutdown,
108 	.set_state_periodic	= gt641xx_timer0_set_periodic,
109 	.set_state_oneshot	= gt641xx_timer0_set_oneshot,
110 	.tick_resume		= gt641xx_timer0_shutdown,
111 	.event_handler		= gt641xx_timer0_event_handler,
112 };
113 
114 static irqreturn_t gt641xx_timer0_interrupt(int irq, void *dev_id)
115 {
116 	struct clock_event_device *cd = &gt641xx_timer0_clockevent;
117 
118 	cd->event_handler(cd);
119 
120 	return IRQ_HANDLED;
121 }
122 
123 static struct irqaction gt641xx_timer0_irqaction = {
124 	.handler	= gt641xx_timer0_interrupt,
125 	.flags		= IRQF_PERCPU | IRQF_TIMER,
126 	.name		= "gt641xx_timer0",
127 };
128 
129 static int __init gt641xx_timer0_clockevent_init(void)
130 {
131 	struct clock_event_device *cd;
132 
133 	if (!gt641xx_base_clock)
134 		return 0;
135 
136 	GT_WRITE(GT_TC0_OFS, gt641xx_base_clock / HZ);
137 
138 	cd = &gt641xx_timer0_clockevent;
139 	cd->rating = 200 + gt641xx_base_clock / 10000000;
140 	clockevent_set_clock(cd, gt641xx_base_clock);
141 	cd->max_delta_ns = clockevent_delta2ns(0x7fffffff, cd);
142 	cd->max_delta_ticks = 0x7fffffff;
143 	cd->min_delta_ns = clockevent_delta2ns(0x300, cd);
144 	cd->min_delta_ticks = 0x300;
145 	cd->cpumask = cpumask_of(0);
146 
147 	clockevents_register_device(&gt641xx_timer0_clockevent);
148 
149 	return setup_irq(GT641XX_TIMER0_IRQ, &gt641xx_timer0_irqaction);
150 }
151 arch_initcall(gt641xx_timer0_clockevent_init);
152