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
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
|
/*
* Watchdog driver for Atmel AT91RM9200 (Thunder)
*
* Copyright (C) 2003 SAN People (Pty) Ltd
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/config.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/watchdog.h>
#include <asm/bitops.h>
#include <asm/uaccess.h>
#define WDT_DEFAULT_TIME 5 /* 5 seconds */
#define WDT_MAX_TIME 256 /* 256 seconds */
static int wdt_time = WDT_DEFAULT_TIME;
static int nowayout = WATCHDOG_NOWAYOUT;
module_param(wdt_time, int, 0);
MODULE_PARM_DESC(wdt_time, "Watchdog time in seconds. (default="__MODULE_STRING(WDT_DEFAULT_TIME) ")");
module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
static unsigned long at91wdt_busy;
/* ......................................................................... */
/*
* Disable the watchdog.
*/
static void inline at91_wdt_stop(void)
{
at91_sys_write(AT91_ST_WDMR, AT91_ST_EXTEN);
}
/*
* Enable and reset the watchdog.
*/
static void inline at91_wdt_start(void)
{
at91_sys_write(AT91_ST_WDMR, AT91_ST_EXTEN | AT91_ST_RSTEN | (((65536 * wdt_time) >> 8) & AT91_ST_WDV));
at91_sys_write(AT91_ST_CR, AT91_ST_WDRST);
}
/*
* Reload the watchdog timer. (ie, pat the watchdog)
*/
static void inline at91_wdt_reload(void)
{
at91_sys_write(AT91_ST_CR, AT91_ST_WDRST);
}
/* ......................................................................... */
/*
* Watchdog device is opened, and watchdog starts running.
*/
static int at91_wdt_open(struct inode *inode, struct file *file)
{
if (test_and_set_bit(0, &at91wdt_busy))
return -EBUSY;
at91_wdt_start();
return nonseekable_open(inode, file);
}
/*
* Close the watchdog device.
* If CONFIG_WATCHDOG_NOWAYOUT is NOT defined then the watchdog is also
* disabled.
*/
static int at91_wdt_close(struct inode *inode, struct file *file)
{
if (!nowayout)
at91_wdt_stop(); /* Disable the watchdog when file is closed */
clear_bit(0, &at91wdt_busy);
return 0;
}
/*
* Change the watchdog time interval.
*/
static int at91_wdt_settimeout(int new_time)
{
/*
* All counting occurs at SLOW_CLOCK / 128 = 0.256 Hz
*
* Since WDV is a 16-bit counter, the maximum period is
* 65536 / 0.256 = 256 seconds.
*/
if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
return -EINVAL;
/* Set new watchdog time. It will be used when at91_wdt_start() is called. */
wdt_time = new_time;
return 0;
}
static struct watchdog_info at91_wdt_info = {
.identity = "at91 watchdog",
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
};
/*
* Handle commands from user-space.
*/
static int at91_wdt_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
void __user *argp = (void __user *)arg;
int __user *p = argp;
int new_value;
switch(cmd) {
case WDIOC_KEEPALIVE:
at91_wdt_reload(); /* pat the watchdog */
return 0;
case WDIOC_GETSUPPORT:
return copy_to_user(argp, &at91_wdt_info, sizeof(at91_wdt_info)) ? -EFAULT : 0;
case WDIOC_SETTIMEOUT:
if (get_user(new_value, p))
return -EFAULT;
if (at91_wdt_settimeout(new_value))
return -EINVAL;
/* Enable new time value */
at91_wdt_start();
/* Return current value */
return put_user(wdt_time, p);
case WDIOC_GETTIMEOUT:
return put_user(wdt_time, p);
case WDIOC_GETSTATUS:
case WDIOC_GETBOOTSTATUS:
return put_user(0, p);
case WDIOC_SETOPTIONS:
if (get_user(new_value, p))
return -EFAULT;
if (new_value & WDIOS_DISABLECARD)
at91_wdt_stop();
if (new_value & WDIOS_ENABLECARD)
at91_wdt_start();
return 0;
default:
return -ENOIOCTLCMD;
}
}
/*
* Pat the watchdog whenever device is written to.
*/
static ssize_t at91_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
{
at91_wdt_reload(); /* pat the watchdog */
return len;
}
/* ......................................................................... */
static struct file_operations at91wdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.ioctl = at91_wdt_ioctl,
.open = at91_wdt_open,
.release = at91_wdt_close,
.write = at91_wdt_write,
};
static struct miscdevice at91wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &at91wdt_fops,
};
static int __init at91_wdt_init(void)
{
int res;
/* Check that the heartbeat value is within range; if not reset to the default */
if (at91_wdt_settimeout(wdt_time)) {
at91_wdt_settimeout(WDT_DEFAULT_TIME);
printk(KERN_INFO "at91_wdt: wdt_time value must be 1 <= wdt_time <= 256, using %d\n", wdt_time);
}
res = misc_register(&at91wdt_miscdev);
if (res)
return res;
printk("AT91 Watchdog Timer enabled (%d seconds, nowayout=%d)\n", wdt_time, nowayout);
return 0;
}
static void __exit at91_wdt_exit(void)
{
misc_deregister(&at91wdt_miscdev);
}
module_init(at91_wdt_init);
module_exit(at91_wdt_exit);
MODULE_AUTHOR("Andrew Victor");
MODULE_DESCRIPTION("Watchdog driver for Atmel AT91RM9200");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
|
