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
229
230
|
/*
* Intel 21285 watchdog driver
* Copyright (c) Phil Blundell <pb@nexus.co.uk>, 1998
*
* based on
*
* SoftDog 0.05: A Software Watchdog Device
*
* (c) Copyright 1996 Alan Cox <alan@redhat.com>, 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
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
*/
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/reboot.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/uaccess.h>
#include <linux/irq.h>
#include <asm/hardware.h>
#include <asm/mach-types.h>
#include <asm/hardware/dec21285.h>
/*
* Define this to stop the watchdog actually rebooting the machine.
*/
#undef ONLY_TESTING
static unsigned int soft_margin = 60; /* in seconds */
static unsigned int reload;
static unsigned long timer_alive;
#ifdef ONLY_TESTING
/*
* If the timer expires..
*/
static void watchdog_fire(int irq, void *dev_id)
{
printk(KERN_CRIT "Watchdog: Would Reboot.\n");
*CSR_TIMER4_CNTL = 0;
*CSR_TIMER4_CLR = 0;
}
#endif
/*
* Refresh the timer.
*/
static void watchdog_ping(void)
{
*CSR_TIMER4_LOAD = reload;
}
/*
* Allow only one person to hold it open
*/
static int watchdog_open(struct inode *inode, struct file *file)
{
int ret;
if (*CSR_SA110_CNTL & (1 << 13))
return -EBUSY;
if (test_and_set_bit(1, &timer_alive))
return -EBUSY;
reload = soft_margin * (mem_fclk_21285 / 256);
*CSR_TIMER4_CLR = 0;
watchdog_ping();
*CSR_TIMER4_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_AUTORELOAD
| TIMER_CNTL_DIV256;
#ifdef ONLY_TESTING
ret = request_irq(IRQ_TIMER4, watchdog_fire, 0, "watchdog", NULL);
if (ret) {
*CSR_TIMER4_CNTL = 0;
clear_bit(1, &timer_alive);
}
#else
/*
* Setting this bit is irreversible; once enabled, there is
* no way to disable the watchdog.
*/
*CSR_SA110_CNTL |= 1 << 13;
ret = 0;
#endif
nonseekable_open(inode, file);
return ret;
}
/*
* Shut off the timer.
* Note: if we really have enabled the watchdog, there
* is no way to turn off.
*/
static int watchdog_release(struct inode *inode, struct file *file)
{
#ifdef ONLY_TESTING
free_irq(IRQ_TIMER4, NULL);
clear_bit(1, &timer_alive);
#endif
return 0;
}
static ssize_t watchdog_write(struct file *file, const char *data,
size_t len, loff_t *ppos)
{
/*
* Refresh the timer.
*/
if (len)
watchdog_ping();
return len;
}
static const struct watchdog_info ident = {
.options = WDIOF_SETTIMEOUT,
.identity = "Footbridge Watchdog",
};
static long watchdog_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
unsigned int new_margin;
int ret = -ENOTTY;
switch (cmd) {
case WDIOC_GETSUPPORT:
ret = 0;
if (copy_to_user((void *)arg, &ident, sizeof(ident)))
ret = -EFAULT;
break;
case WDIOC_GETSTATUS:
case WDIOC_GETBOOTSTATUS:
ret = put_user(0, (int *)arg);
break;
case WDIOC_KEEPALIVE:
watchdog_ping();
ret = 0;
break;
case WDIOC_SETTIMEOUT:
ret = get_user(new_margin, (int *)arg);
if (ret)
break;
/* Arbitrary, can't find the card's limits */
if (new_margin < 0 || new_margin > 60) {
ret = -EINVAL;
break;
}
soft_margin = new_margin;
reload = soft_margin * (mem_fclk_21285 / 256);
watchdog_ping();
/* Fall */
case WDIOC_GETTIMEOUT:
ret = put_user(soft_margin, (int *)arg);
break;
}
return ret;
}
static const struct file_operations watchdog_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = watchdog_write,
.unlocked_ioctl = watchdog_ioctl,
.open = watchdog_open,
.release = watchdog_release,
};
static struct miscdevice watchdog_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &watchdog_fops,
};
static int __init footbridge_watchdog_init(void)
{
int retval;
if (machine_is_netwinder())
return -ENODEV;
retval = misc_register(&watchdog_miscdev);
if (retval < 0)
return retval;
printk(KERN_INFO
"Footbridge Watchdog Timer: 0.01, timer margin: %d sec\n",
soft_margin);
if (machine_is_cats())
printk(KERN_WARN
"Warning: Watchdog reset may not work on this machine.\n");
return 0;
}
static void __exit footbridge_watchdog_exit(void)
{
misc_deregister(&watchdog_miscdev);
}
MODULE_AUTHOR("Phil Blundell <pb@nexus.co.uk>");
MODULE_DESCRIPTION("Footbridge watchdog driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
module_param(soft_margin, int, 0);
MODULE_PARM_DESC(soft_margin, "Watchdog timeout in seconds");
module_init(footbridge_watchdog_init);
module_exit(footbridge_watchdog_exit);
|
