1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19#include <linux/config.h>
20#include <linux/module.h>
21#include <linux/moduleparam.h>
22#include <linux/types.h>
23#include <linux/kernel.h>
24#include <linux/fs.h>
25#include <linux/miscdevice.h>
26#include <linux/watchdog.h>
27#include <linux/init.h>
28#include <linux/bitops.h>
29
30#include <asm/hardware.h>
31#include <asm/uaccess.h>
32
33#ifdef CONFIG_WATCHDOG_NOWAYOUT
34static int nowayout = 1;
35#else
36static int nowayout = 0;
37#endif
38static unsigned int heartbeat = 60;
39static unsigned long wdt_status;
40
41#define WDT_IN_USE 0
42#define WDT_OK_TO_CLOSE 1
43
44static unsigned long wdt_tick_rate;
45
46static void
47wdt_enable(void)
48{
49 ixp2000_reg_write(IXP2000_RESET0, *(IXP2000_RESET0) | WDT_RESET_ENABLE);
50 ixp2000_reg_write(IXP2000_TWDE, WDT_ENABLE);
51 ixp2000_reg_write(IXP2000_T4_CLD, heartbeat * wdt_tick_rate);
52 ixp2000_reg_write(IXP2000_T4_CTL, TIMER_DIVIDER_256 | TIMER_ENABLE);
53}
54
55static void
56wdt_disable(void)
57{
58 ixp2000_reg_write(IXP2000_T4_CTL, 0);
59}
60
61static void
62wdt_keepalive(void)
63{
64 ixp2000_reg_write(IXP2000_T4_CLD, heartbeat * wdt_tick_rate);
65}
66
67static int
68ixp2000_wdt_open(struct inode *inode, struct file *file)
69{
70 if (test_and_set_bit(WDT_IN_USE, &wdt_status))
71 return -EBUSY;
72
73 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
74
75 wdt_enable();
76
77 return nonseekable_open(inode, file);
78}
79
80static ssize_t
81ixp2000_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
82{
83 if (len) {
84 if (!nowayout) {
85 size_t i;
86
87 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
88
89 for (i = 0; i != len; i++) {
90 char c;
91
92 if (get_user(c, data + i))
93 return -EFAULT;
94 if (c == 'V')
95 set_bit(WDT_OK_TO_CLOSE, &wdt_status);
96 }
97 }
98 wdt_keepalive();
99 }
100
101 return len;
102}
103
104
105static struct watchdog_info ident = {
106 .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |
107 WDIOF_KEEPALIVEPING,
108 .identity = "IXP2000 Watchdog",
109};
110
111static int
112ixp2000_wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
113 unsigned long arg)
114{
115 int ret = -ENOIOCTLCMD;
116 int time;
117
118 switch (cmd) {
119 case WDIOC_GETSUPPORT:
120 ret = copy_to_user((struct watchdog_info *)arg, &ident,
121 sizeof(ident)) ? -EFAULT : 0;
122 break;
123
124 case WDIOC_GETSTATUS:
125 ret = put_user(0, (int *)arg);
126 break;
127
128 case WDIOC_GETBOOTSTATUS:
129 ret = put_user(0, (int *)arg);
130 break;
131
132 case WDIOC_SETTIMEOUT:
133 ret = get_user(time, (int *)arg);
134 if (ret)
135 break;
136
137 if (time <= 0 || time > 60) {
138 ret = -EINVAL;
139 break;
140 }
141
142 heartbeat = time;
143 wdt_keepalive();
144
145
146 case WDIOC_GETTIMEOUT:
147 ret = put_user(heartbeat, (int *)arg);
148 break;
149
150 case WDIOC_KEEPALIVE:
151 wdt_enable();
152 ret = 0;
153 break;
154 }
155
156 return ret;
157}
158
159static int
160ixp2000_wdt_release(struct inode *inode, struct file *file)
161{
162 if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) {
163 wdt_disable();
164 } else {
165 printk(KERN_CRIT "WATCHDOG: Device closed unexpectdly - "
166 "timer will not stop\n");
167 }
168
169 clear_bit(WDT_IN_USE, &wdt_status);
170 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
171
172 return 0;
173}
174
175
176static struct file_operations ixp2000_wdt_fops =
177{
178 .owner = THIS_MODULE,
179 .llseek = no_llseek,
180 .write = ixp2000_wdt_write,
181 .ioctl = ixp2000_wdt_ioctl,
182 .open = ixp2000_wdt_open,
183 .release = ixp2000_wdt_release,
184};
185
186static struct miscdevice ixp2000_wdt_miscdev =
187{
188 .minor = WATCHDOG_MINOR,
189 .name = "IXP2000 Watchdog",
190 .fops = &ixp2000_wdt_fops,
191};
192
193static int __init ixp2000_wdt_init(void)
194{
195 wdt_tick_rate = (*IXP2000_T1_CLD * HZ)/ 256;;
196
197 return misc_register(&ixp2000_wdt_miscdev);
198}
199
200static void __exit ixp2000_wdt_exit(void)
201{
202 misc_deregister(&ixp2000_wdt_miscdev);
203}
204
205module_init(ixp2000_wdt_init);
206module_exit(ixp2000_wdt_exit);
207
208MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net">);
209MODULE_DESCRIPTION("IXP2000 Network Processor Watchdog");
210
211module_param(heartbeat, int, 0);
212MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 60s)");
213
214module_param(nowayout, int, 0);
215MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
216
217MODULE_LICENSE("GPL");
218MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
219
220
