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
jz4740_clocksource_read(struct clocksource * cs)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
jz4740_read_sched_clock(void)50 static u64 notrace jz4740_read_sched_clock(void)
51 {
52 return jz4740_timer_get_count(TIMER_CLOCKSOURCE);
53 }
54
jz4740_clockevent_irq(int irq,void * devid)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
jz4740_clockevent_set_periodic(struct clock_event_device * evt)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
jz4740_clockevent_resume(struct clock_event_device * evt)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
jz4740_clockevent_shutdown(struct clock_event_device * evt)87 static int jz4740_clockevent_shutdown(struct clock_event_device *evt)
88 {
89 jz4740_timer_disable(TIMER_CLOCKEVENT);
90
91 return 0;
92 }
93
jz4740_clockevent_set_next(unsigned long evt,struct clock_event_device * cd)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 #ifdef 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
plat_time_init(void)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 }
177