GNU Linux-libre 4.19.286-gnu1
[releases.git] / arch / mips / jz4740 / time.c
1 /*
2  *  Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
3  *  JZ4740 platform time support
4  *
5  *  This program is free software; you can redistribute it and/or modify it
6  *  under  the terms of the GNU General  Public License as published by the
7  *  Free Software Foundation;  either version 2 of the License, or (at your
8  *  option) any later version.
9  *
10  *  You should have received a copy of the GNU General Public License along
11  *  with this program; if not, write to the Free Software Foundation, Inc.,
12  *  675 Mass Ave, Cambridge, MA 02139, USA.
13  *
14  */
15
16 #include <linux/clk.h>
17 #include <linux/clk-provider.h>
18 #include <linux/interrupt.h>
19 #include <linux/kernel.h>
20 #include <linux/time.h>
21
22 #include <linux/clockchips.h>
23 #include <linux/sched_clock.h>
24
25 #include <asm/mach-jz4740/clock.h>
26 #include <asm/mach-jz4740/irq.h>
27 #include <asm/mach-jz4740/timer.h>
28 #include <asm/time.h>
29
30 #include "clock.h"
31
32 #define TIMER_CLOCKEVENT 0
33 #define TIMER_CLOCKSOURCE 1
34
35 static uint16_t jz4740_jiffies_per_tick;
36
37 static u64 jz4740_clocksource_read(struct clocksource *cs)
38 {
39         return jz4740_timer_get_count(TIMER_CLOCKSOURCE);
40 }
41
42 static struct clocksource jz4740_clocksource = {
43         .name = "jz4740-timer",
44         .rating = 200,
45         .read = jz4740_clocksource_read,
46         .mask = CLOCKSOURCE_MASK(16),
47         .flags = CLOCK_SOURCE_IS_CONTINUOUS,
48 };
49
50 static u64 notrace jz4740_read_sched_clock(void)
51 {
52         return jz4740_timer_get_count(TIMER_CLOCKSOURCE);
53 }
54
55 static irqreturn_t jz4740_clockevent_irq(int irq, void *devid)
56 {
57         struct clock_event_device *cd = devid;
58
59         jz4740_timer_ack_full(TIMER_CLOCKEVENT);
60
61         if (!clockevent_state_periodic(cd))
62                 jz4740_timer_disable(TIMER_CLOCKEVENT);
63
64         cd->event_handler(cd);
65
66         return IRQ_HANDLED;
67 }
68
69 static int jz4740_clockevent_set_periodic(struct clock_event_device *evt)
70 {
71         jz4740_timer_set_count(TIMER_CLOCKEVENT, 0);
72         jz4740_timer_set_period(TIMER_CLOCKEVENT, jz4740_jiffies_per_tick);
73         jz4740_timer_irq_full_enable(TIMER_CLOCKEVENT);
74         jz4740_timer_enable(TIMER_CLOCKEVENT);
75
76         return 0;
77 }
78
79 static int jz4740_clockevent_resume(struct clock_event_device *evt)
80 {
81         jz4740_timer_irq_full_enable(TIMER_CLOCKEVENT);
82         jz4740_timer_enable(TIMER_CLOCKEVENT);
83
84         return 0;
85 }
86
87 static int jz4740_clockevent_shutdown(struct clock_event_device *evt)
88 {
89         jz4740_timer_disable(TIMER_CLOCKEVENT);
90
91         return 0;
92 }
93
94 static int jz4740_clockevent_set_next(unsigned long evt,
95         struct clock_event_device *cd)
96 {
97         jz4740_timer_set_count(TIMER_CLOCKEVENT, 0);
98         jz4740_timer_set_period(TIMER_CLOCKEVENT, evt);
99         jz4740_timer_enable(TIMER_CLOCKEVENT);
100
101         return 0;
102 }
103
104 static struct clock_event_device jz4740_clockevent = {
105         .name = "jz4740-timer",
106         .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
107         .set_next_event = jz4740_clockevent_set_next,
108         .set_state_shutdown = jz4740_clockevent_shutdown,
109         .set_state_periodic = jz4740_clockevent_set_periodic,
110         .set_state_oneshot = jz4740_clockevent_shutdown,
111         .tick_resume = jz4740_clockevent_resume,
112         .rating = 200,
113 #ifdef CONFIG_MACH_JZ4740
114         .irq = JZ4740_IRQ_TCU0,
115 #endif
116 #if defined(CONFIG_MACH_JZ4770) || defined(CONFIG_MACH_JZ4780)
117         .irq = JZ4780_IRQ_TCU2,
118 #endif
119 };
120
121 static struct irqaction timer_irqaction = {
122         .handler        = jz4740_clockevent_irq,
123         .flags          = IRQF_PERCPU | IRQF_TIMER,
124         .name           = "jz4740-timerirq",
125         .dev_id         = &jz4740_clockevent,
126 };
127
128 void __init plat_time_init(void)
129 {
130         int ret;
131         uint32_t clk_rate;
132         uint16_t ctrl;
133         struct clk *ext_clk;
134
135         of_clk_init(NULL);
136         jz4740_timer_init();
137
138         ext_clk = clk_get(NULL, "ext");
139         if (IS_ERR(ext_clk))
140                 panic("unable to get ext clock");
141         clk_rate = clk_get_rate(ext_clk) >> 4;
142         clk_put(ext_clk);
143
144         jz4740_jiffies_per_tick = DIV_ROUND_CLOSEST(clk_rate, HZ);
145
146         clockevent_set_clock(&jz4740_clockevent, clk_rate);
147         jz4740_clockevent.min_delta_ns = clockevent_delta2ns(100, &jz4740_clockevent);
148         jz4740_clockevent.min_delta_ticks = 100;
149         jz4740_clockevent.max_delta_ns = clockevent_delta2ns(0xffff, &jz4740_clockevent);
150         jz4740_clockevent.max_delta_ticks = 0xffff;
151         jz4740_clockevent.cpumask = cpumask_of(0);
152
153         clockevents_register_device(&jz4740_clockevent);
154
155         ret = clocksource_register_hz(&jz4740_clocksource, clk_rate);
156
157         if (ret)
158                 printk(KERN_ERR "Failed to register clocksource: %d\n", ret);
159
160         sched_clock_register(jz4740_read_sched_clock, 16, clk_rate);
161
162         setup_irq(jz4740_clockevent.irq, &timer_irqaction);
163
164         ctrl = JZ_TIMER_CTRL_PRESCALE_16 | JZ_TIMER_CTRL_SRC_EXT;
165
166         jz4740_timer_set_ctrl(TIMER_CLOCKEVENT, ctrl);
167         jz4740_timer_set_ctrl(TIMER_CLOCKSOURCE, ctrl);
168
169         jz4740_timer_set_period(TIMER_CLOCKEVENT, jz4740_jiffies_per_tick);
170         jz4740_timer_irq_full_enable(TIMER_CLOCKEVENT);
171
172         jz4740_timer_set_period(TIMER_CLOCKSOURCE, 0xffff);
173
174         jz4740_timer_enable(TIMER_CLOCKEVENT);
175         jz4740_timer_enable(TIMER_CLOCKSOURCE);
176 }