1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
|
/*
* linux/arch/arm/kernel/smp_twd.c
*
* Copyright (C) 2002 ARM Ltd.
* All Rights Reserved
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/smp.h>
#include <linux/jiffies.h>
#include <linux/clockchips.h>
#include <linux/irq.h>
#include <linux/io.h>
#include <asm/smp_twd.h>
#include <asm/hardware/gic.h>
#define TWD_TIMER_LOAD 0x00
#define TWD_TIMER_COUNTER 0x04
#define TWD_TIMER_CONTROL 0x08
#define TWD_TIMER_INTSTAT 0x0C
#define TWD_WDOG_LOAD 0x20
#define TWD_WDOG_COUNTER 0x24
#define TWD_WDOG_CONTROL 0x28
#define TWD_WDOG_INTSTAT 0x2C
#define TWD_WDOG_RESETSTAT 0x30
#define TWD_WDOG_DISABLE 0x34
#define TWD_TIMER_CONTROL_ENABLE (1 << 0)
#define TWD_TIMER_CONTROL_ONESHOT (0 << 1)
#define TWD_TIMER_CONTROL_PERIODIC (1 << 1)
#define TWD_TIMER_CONTROL_IT_ENABLE (1 << 2)
/* set up by the platform code */
void __iomem *twd_base;
static unsigned long twd_timer_rate;
static void twd_set_mode(enum clock_event_mode mode,
struct clock_event_device *clk)
{
unsigned long ctrl;
switch (mode) {
case CLOCK_EVT_MODE_PERIODIC:
/* timer load already set up */
ctrl = TWD_TIMER_CONTROL_ENABLE | TWD_TIMER_CONTROL_IT_ENABLE
| TWD_TIMER_CONTROL_PERIODIC;
break;
case CLOCK_EVT_MODE_ONESHOT:
/* period set, and timer enabled in 'next_event' hook */
ctrl = TWD_TIMER_CONTROL_IT_ENABLE | TWD_TIMER_CONTROL_ONESHOT;
break;
case CLOCK_EVT_MODE_UNUSED:
case CLOCK_EVT_MODE_SHUTDOWN:
default:
ctrl = 0;
}
__raw_writel(ctrl, twd_base + TWD_TIMER_CONTROL);
}
static int twd_set_next_event(unsigned long evt,
struct clock_event_device *unused)
{
unsigned long ctrl = __raw_readl(twd_base + TWD_TIMER_CONTROL);
ctrl |= TWD_TIMER_CONTROL_ENABLE;
__raw_writel(evt, twd_base + TWD_TIMER_COUNTER);
__raw_writel(ctrl, twd_base + TWD_TIMER_CONTROL);
return 0;
}
/*
* local_timer_ack: checks for a local timer interrupt.
*
* If a local timer interrupt has occurred, acknowledge and return 1.
* Otherwise, return 0.
*/
int twd_timer_ack(void)
{
if (__raw_readl(twd_base + TWD_TIMER_INTSTAT)) {
__raw_writel(1, twd_base + TWD_TIMER_INTSTAT);
return 1;
}
return 0;
}
static void __cpuinit twd_calibrate_rate(void)
{
unsigned long load, count;
u64 waitjiffies;
/*
* If this is the first time round, we need to work out how fast
* the timer ticks
*/
if (twd_timer_rate == 0) {
printk(KERN_INFO "Calibrating local timer... ");
/* Wait for a tick to start */
waitjiffies = get_jiffies_64() + 1;
while (get_jiffies_64() < waitjiffies)
udelay(10);
/* OK, now the tick has started, let's get the timer going */
waitjiffies += 5;
/* enable, no interrupt or reload */
__raw_writel(0x1, twd_base + TWD_TIMER_CONTROL);
/* maximum value */
__raw_writel(0xFFFFFFFFU, twd_base + TWD_TIMER_COUNTER);
while (get_jiffies_64() < waitjiffies)
udelay(10);
count = __raw_readl(twd_base + TWD_TIMER_COUNTER);
twd_timer_rate = (0xFFFFFFFFU - count) * (HZ / 5);
printk("%lu.%02luMHz.\n", twd_timer_rate / 1000000,
(twd_timer_rate / 100000) % 100);
}
load = twd_timer_rate / HZ;
__raw_writel(load, twd_base + TWD_TIMER_LOAD);
}
/*
* Setup the local clock events for a CPU.
*/
void __cpuinit twd_timer_setup(struct clock_event_device *clk)
{
unsigned long flags;
twd_calibrate_rate();
clk->name = "local_timer";
clk->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
clk->rating = 350;
clk->set_mode = twd_set_mode;
clk->set_next_event = twd_set_next_event;
clk->shift = 20;
clk->mult = div_sc(twd_timer_rate, NSEC_PER_SEC, clk->shift);
clk->max_delta_ns = clockevent_delta2ns(0xffffffff, clk);
clk->min_delta_ns = clockevent_delta2ns(0xf, clk);
/* Make sure our local interrupt controller has this enabled */
local_irq_save(flags);
get_irq_chip(clk->irq)->unmask(clk->irq);
local_irq_restore(flags);
clockevents_register_device(clk);
}
#ifdef CONFIG_HOTPLUG_CPU
/*
* take a local timer down
*/
void twd_timer_stop(void)
{
__raw_writel(0, twd_base + TWD_TIMER_CONTROL);
}
#endif
|
