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/interrupt.h>
17 #include <linux/kernel.h>
18 #include <linux/time.h>
19
20 #include <linux/clockchips.h>
21
22 #include <asm/mach-jz4740/irq.h>
23 #include <asm/mach-jz4740/timer.h>
24 #include <asm/time.h>
25
26 #include "clock.h"
27
28 #define TIMER_CLOCKEVENT 0
29 #define TIMER_CLOCKSOURCE 1
30
31 static uint16_t jz4740_jiffies_per_tick;
32
jz4740_clocksource_read(struct clocksource * cs)33 static cycle_t jz4740_clocksource_read(struct clocksource *cs)
34 {
35 return jz4740_timer_get_count(TIMER_CLOCKSOURCE);
36 }
37
38 static struct clocksource jz4740_clocksource = {
39 .name = "jz4740-timer",
40 .rating = 200,
41 .read = jz4740_clocksource_read,
42 .mask = CLOCKSOURCE_MASK(16),
43 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
44 };
45
jz4740_clockevent_irq(int irq,void * devid)46 static irqreturn_t jz4740_clockevent_irq(int irq, void *devid)
47 {
48 struct clock_event_device *cd = devid;
49
50 jz4740_timer_ack_full(TIMER_CLOCKEVENT);
51
52 if (cd->mode != CLOCK_EVT_MODE_PERIODIC)
53 jz4740_timer_disable(TIMER_CLOCKEVENT);
54
55 cd->event_handler(cd);
56
57 return IRQ_HANDLED;
58 }
59
jz4740_clockevent_set_mode(enum clock_event_mode mode,struct clock_event_device * cd)60 static void jz4740_clockevent_set_mode(enum clock_event_mode mode,
61 struct clock_event_device *cd)
62 {
63 switch (mode) {
64 case CLOCK_EVT_MODE_PERIODIC:
65 jz4740_timer_set_count(TIMER_CLOCKEVENT, 0);
66 jz4740_timer_set_period(TIMER_CLOCKEVENT, jz4740_jiffies_per_tick);
67 case CLOCK_EVT_MODE_RESUME:
68 jz4740_timer_irq_full_enable(TIMER_CLOCKEVENT);
69 jz4740_timer_enable(TIMER_CLOCKEVENT);
70 break;
71 case CLOCK_EVT_MODE_ONESHOT:
72 case CLOCK_EVT_MODE_SHUTDOWN:
73 jz4740_timer_disable(TIMER_CLOCKEVENT);
74 break;
75 default:
76 break;
77 }
78 }
79
jz4740_clockevent_set_next(unsigned long evt,struct clock_event_device * cd)80 static int jz4740_clockevent_set_next(unsigned long evt,
81 struct clock_event_device *cd)
82 {
83 jz4740_timer_set_count(TIMER_CLOCKEVENT, 0);
84 jz4740_timer_set_period(TIMER_CLOCKEVENT, evt);
85 jz4740_timer_enable(TIMER_CLOCKEVENT);
86
87 return 0;
88 }
89
90 static struct clock_event_device jz4740_clockevent = {
91 .name = "jz4740-timer",
92 .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
93 .set_next_event = jz4740_clockevent_set_next,
94 .set_mode = jz4740_clockevent_set_mode,
95 .rating = 200,
96 .irq = JZ4740_IRQ_TCU0,
97 };
98
99 static struct irqaction timer_irqaction = {
100 .handler = jz4740_clockevent_irq,
101 .flags = IRQF_PERCPU | IRQF_TIMER,
102 .name = "jz4740-timerirq",
103 .dev_id = &jz4740_clockevent,
104 };
105
plat_time_init(void)106 void __init plat_time_init(void)
107 {
108 int ret;
109 uint32_t clk_rate;
110 uint16_t ctrl;
111
112 jz4740_timer_init();
113
114 clk_rate = jz4740_clock_bdata.ext_rate >> 4;
115 jz4740_jiffies_per_tick = DIV_ROUND_CLOSEST(clk_rate, HZ);
116
117 clockevent_set_clock(&jz4740_clockevent, clk_rate);
118 jz4740_clockevent.min_delta_ns = clockevent_delta2ns(100, &jz4740_clockevent);
119 jz4740_clockevent.max_delta_ns = clockevent_delta2ns(0xffff, &jz4740_clockevent);
120 jz4740_clockevent.cpumask = cpumask_of(0);
121
122 clockevents_register_device(&jz4740_clockevent);
123
124 ret = clocksource_register_hz(&jz4740_clocksource, clk_rate);
125
126 if (ret)
127 printk(KERN_ERR "Failed to register clocksource: %d\n", ret);
128
129 setup_irq(JZ4740_IRQ_TCU0, &timer_irqaction);
130
131 ctrl = JZ_TIMER_CTRL_PRESCALE_16 | JZ_TIMER_CTRL_SRC_EXT;
132
133 jz4740_timer_set_ctrl(TIMER_CLOCKEVENT, ctrl);
134 jz4740_timer_set_ctrl(TIMER_CLOCKSOURCE, ctrl);
135
136 jz4740_timer_set_period(TIMER_CLOCKEVENT, jz4740_jiffies_per_tick);
137 jz4740_timer_irq_full_enable(TIMER_CLOCKEVENT);
138
139 jz4740_timer_set_period(TIMER_CLOCKSOURCE, 0xffff);
140
141 jz4740_timer_enable(TIMER_CLOCKEVENT);
142 jz4740_timer_enable(TIMER_CLOCKSOURCE);
143 }
144