1 /*
2 * linux/arch/arm/mach-w90x900/time.c
3 *
4 * Based on linux/arch/arm/plat-s3c24xx/time.c by Ben Dooks
5 *
6 * Copyright (c) 2009 Nuvoton technology corporation
7 * All rights reserved.
8 *
9 * Wan ZongShun <mcuos.com@gmail.com>
10 *
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2 of the License, or
14 * (at your option) any later version.
15 *
16 */
17
18 #include <linux/kernel.h>
19 #include <linux/sched.h>
20 #include <linux/init.h>
21 #include <linux/interrupt.h>
22 #include <linux/err.h>
23 #include <linux/clk.h>
24 #include <linux/io.h>
25 #include <linux/leds.h>
26 #include <linux/clocksource.h>
27 #include <linux/clockchips.h>
28
29 #include <asm/mach-types.h>
30 #include <asm/mach/irq.h>
31 #include <asm/mach/time.h>
32
33 #include <mach/map.h>
34 #include <mach/regs-timer.h>
35
36 #include "nuc9xx.h"
37
38 #define RESETINT 0x1f
39 #define PERIOD (0x01 << 27)
40 #define ONESHOT (0x00 << 27)
41 #define COUNTEN (0x01 << 30)
42 #define INTEN (0x01 << 29)
43
44 #define TICKS_PER_SEC 100
45 #define PRESCALE 0x63 /* Divider = prescale + 1 */
46
47 #define TDR_SHIFT 24
48
49 static unsigned int timer0_load;
50
nuc900_clockevent_setmode(enum clock_event_mode mode,struct clock_event_device * clk)51 static void nuc900_clockevent_setmode(enum clock_event_mode mode,
52 struct clock_event_device *clk)
53 {
54 unsigned int val;
55
56 val = __raw_readl(REG_TCSR0);
57 val &= ~(0x03 << 27);
58
59 switch (mode) {
60 case CLOCK_EVT_MODE_PERIODIC:
61 __raw_writel(timer0_load, REG_TICR0);
62 val |= (PERIOD | COUNTEN | INTEN | PRESCALE);
63 break;
64
65 case CLOCK_EVT_MODE_ONESHOT:
66 val |= (ONESHOT | COUNTEN | INTEN | PRESCALE);
67 break;
68
69 case CLOCK_EVT_MODE_UNUSED:
70 case CLOCK_EVT_MODE_SHUTDOWN:
71 case CLOCK_EVT_MODE_RESUME:
72 break;
73 }
74
75 __raw_writel(val, REG_TCSR0);
76 }
77
nuc900_clockevent_setnextevent(unsigned long evt,struct clock_event_device * clk)78 static int nuc900_clockevent_setnextevent(unsigned long evt,
79 struct clock_event_device *clk)
80 {
81 unsigned int val;
82
83 __raw_writel(evt, REG_TICR0);
84
85 val = __raw_readl(REG_TCSR0);
86 val |= (COUNTEN | INTEN | PRESCALE);
87 __raw_writel(val, REG_TCSR0);
88
89 return 0;
90 }
91
92 static struct clock_event_device nuc900_clockevent_device = {
93 .name = "nuc900-timer0",
94 .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
95 .set_mode = nuc900_clockevent_setmode,
96 .set_next_event = nuc900_clockevent_setnextevent,
97 .rating = 300,
98 };
99
100 /*IRQ handler for the timer*/
101
nuc900_timer0_interrupt(int irq,void * dev_id)102 static irqreturn_t nuc900_timer0_interrupt(int irq, void *dev_id)
103 {
104 struct clock_event_device *evt = &nuc900_clockevent_device;
105
106 __raw_writel(0x01, REG_TISR); /* clear TIF0 */
107
108 evt->event_handler(evt);
109 return IRQ_HANDLED;
110 }
111
112 static struct irqaction nuc900_timer0_irq = {
113 .name = "nuc900-timer0",
114 .flags = IRQF_TIMER | IRQF_IRQPOLL,
115 .handler = nuc900_timer0_interrupt,
116 };
117
nuc900_clockevents_init(void)118 static void __init nuc900_clockevents_init(void)
119 {
120 unsigned int rate;
121 struct clk *clk = clk_get(NULL, "timer0");
122
123 BUG_ON(IS_ERR(clk));
124
125 __raw_writel(0x00, REG_TCSR0);
126
127 clk_enable(clk);
128 rate = clk_get_rate(clk) / (PRESCALE + 1);
129
130 timer0_load = (rate / TICKS_PER_SEC);
131
132 __raw_writel(RESETINT, REG_TISR);
133 setup_irq(IRQ_TIMER0, &nuc900_timer0_irq);
134
135 nuc900_clockevent_device.cpumask = cpumask_of(0);
136
137 clockevents_config_and_register(&nuc900_clockevent_device, rate,
138 0xf, 0xffffffff);
139 }
140
nuc900_clocksource_init(void)141 static void __init nuc900_clocksource_init(void)
142 {
143 unsigned int val;
144 unsigned int rate;
145 struct clk *clk = clk_get(NULL, "timer1");
146
147 BUG_ON(IS_ERR(clk));
148
149 __raw_writel(0x00, REG_TCSR1);
150
151 clk_enable(clk);
152 rate = clk_get_rate(clk) / (PRESCALE + 1);
153
154 __raw_writel(0xffffffff, REG_TICR1);
155
156 val = __raw_readl(REG_TCSR1);
157 val |= (COUNTEN | PERIOD | PRESCALE);
158 __raw_writel(val, REG_TCSR1);
159
160 clocksource_mmio_init(REG_TDR1, "nuc900-timer1", rate, 200,
161 TDR_SHIFT, clocksource_mmio_readl_down);
162 }
163
nuc900_timer_init(void)164 void __init nuc900_timer_init(void)
165 {
166 nuc900_clocksource_init();
167 nuc900_clockevents_init();
168 }
169