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29#include <linux/module.h>
30#include <linux/moduleparam.h>
31#include <linux/miscdevice.h>
32#include <linux/watchdog.h>
33#include <linux/fs.h>
34#include <linux/ioport.h>
35#include <linux/notifier.h>
36#include <linux/reboot.h>
37#include <linux/init.h>
38#include <linux/spinlock.h>
39#include <linux/io.h>
40#include <linux/uaccess.h>
41
42#define WATCHDOG_NAME "Wafer 5823 WDT"
43#define PFX WATCHDOG_NAME ": "
44#define WD_TIMO 60
45
46static unsigned long wafwdt_is_open;
47static char expect_close;
48static DEFINE_SPINLOCK(wafwdt_lock);
49
50
51
52
53
54
55
56
57
58
59static int wdt_stop = 0x843;
60static int wdt_start = 0x443;
61
62static int timeout = WD_TIMO;
63module_param(timeout, int, 0);
64MODULE_PARM_DESC(timeout,
65 "Watchdog timeout in seconds. 1 <= timeout <= 255, default="
66 __MODULE_STRING(WD_TIMO) ".");
67
68static int nowayout = WATCHDOG_NOWAYOUT;
69module_param(nowayout, int, 0);
70MODULE_PARM_DESC(nowayout,
71 "Watchdog cannot be stopped once started (default="
72 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
73
74static void wafwdt_ping(void)
75{
76
77 spin_lock(&wafwdt_lock);
78 inb_p(wdt_stop);
79 inb_p(wdt_start);
80 spin_unlock(&wafwdt_lock);
81}
82
83static void wafwdt_start(void)
84{
85
86 outb_p(timeout, wdt_start);
87 inb_p(wdt_start);
88}
89
90static void wafwdt_stop(void)
91{
92
93 inb_p(wdt_stop);
94}
95
96static ssize_t wafwdt_write(struct file *file, const char __user *buf,
97 size_t count, loff_t *ppos)
98{
99
100 if (count) {
101 if (!nowayout) {
102 size_t i;
103
104
105 expect_close = 0;
106
107
108
109 for (i = 0; i != count; i++) {
110 char c;
111 if (get_user(c, buf + i))
112 return -EFAULT;
113 if (c == 'V')
114 expect_close = 42;
115 }
116 }
117
118
119 wafwdt_ping();
120 }
121 return count;
122}
123
124static long wafwdt_ioctl(struct file *file, unsigned int cmd,
125 unsigned long arg)
126{
127 int new_timeout;
128 void __user *argp = (void __user *)arg;
129 int __user *p = argp;
130 static const struct watchdog_info ident = {
131 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
132 WDIOF_MAGICCLOSE,
133 .firmware_version = 1,
134 .identity = "Wafer 5823 WDT",
135 };
136
137 switch (cmd) {
138 case WDIOC_GETSUPPORT:
139 if (copy_to_user(argp, &ident, sizeof(ident)))
140 return -EFAULT;
141 break;
142
143 case WDIOC_GETSTATUS:
144 case WDIOC_GETBOOTSTATUS:
145 return put_user(0, p);
146
147 case WDIOC_SETOPTIONS:
148 {
149 int options, retval = -EINVAL;
150
151 if (get_user(options, p))
152 return -EFAULT;
153
154 if (options & WDIOS_DISABLECARD) {
155 wafwdt_start();
156 retval = 0;
157 }
158
159 if (options & WDIOS_ENABLECARD) {
160 wafwdt_stop();
161 retval = 0;
162 }
163
164 return retval;
165 }
166
167 case WDIOC_KEEPALIVE:
168 wafwdt_ping();
169 break;
170
171 case WDIOC_SETTIMEOUT:
172 if (get_user(new_timeout, p))
173 return -EFAULT;
174 if ((new_timeout < 1) || (new_timeout > 255))
175 return -EINVAL;
176 timeout = new_timeout;
177 wafwdt_stop();
178 wafwdt_start();
179
180 case WDIOC_GETTIMEOUT:
181 return put_user(timeout, p);
182
183 default:
184 return -ENOTTY;
185 }
186 return 0;
187}
188
189static int wafwdt_open(struct inode *inode, struct file *file)
190{
191 if (test_and_set_bit(0, &wafwdt_is_open))
192 return -EBUSY;
193
194
195
196
197 wafwdt_start();
198 return nonseekable_open(inode, file);
199}
200
201static int wafwdt_close(struct inode *inode, struct file *file)
202{
203 if (expect_close == 42)
204 wafwdt_stop();
205 else {
206 printk(KERN_CRIT PFX
207 "WDT device closed unexpectedly. WDT will not stop!\n");
208 wafwdt_ping();
209 }
210 clear_bit(0, &wafwdt_is_open);
211 expect_close = 0;
212 return 0;
213}
214
215
216
217
218
219static int wafwdt_notify_sys(struct notifier_block *this, unsigned long code,
220 void *unused)
221{
222 if (code == SYS_DOWN || code == SYS_HALT)
223 wafwdt_stop();
224 return NOTIFY_DONE;
225}
226
227
228
229
230
231static const struct file_operations wafwdt_fops = {
232 .owner = THIS_MODULE,
233 .llseek = no_llseek,
234 .write = wafwdt_write,
235 .unlocked_ioctl = wafwdt_ioctl,
236 .open = wafwdt_open,
237 .release = wafwdt_close,
238};
239
240static struct miscdevice wafwdt_miscdev = {
241 .minor = WATCHDOG_MINOR,
242 .name = "watchdog",
243 .fops = &wafwdt_fops,
244};
245
246
247
248
249
250
251static struct notifier_block wafwdt_notifier = {
252 .notifier_call = wafwdt_notify_sys,
253};
254
255static int __init wafwdt_init(void)
256{
257 int ret;
258
259 printk(KERN_INFO
260 "WDT driver for Wafer 5823 single board computer initialising.\n");
261
262 if (timeout < 1 || timeout > 255) {
263 timeout = WD_TIMO;
264 printk(KERN_INFO PFX
265 "timeout value must be 1 <= x <= 255, using %d\n",
266 timeout);
267 }
268
269 if (wdt_stop != wdt_start) {
270 if (!request_region(wdt_stop, 1, "Wafer 5823 WDT")) {
271 printk(KERN_ERR PFX
272 "I/O address 0x%04x already in use\n",
273 wdt_stop);
274 ret = -EIO;
275 goto error;
276 }
277 }
278
279 if (!request_region(wdt_start, 1, "Wafer 5823 WDT")) {
280 printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
281 wdt_start);
282 ret = -EIO;
283 goto error2;
284 }
285
286 ret = register_reboot_notifier(&wafwdt_notifier);
287 if (ret != 0) {
288 printk(KERN_ERR PFX
289 "cannot register reboot notifier (err=%d)\n", ret);
290 goto error3;
291 }
292
293 ret = misc_register(&wafwdt_miscdev);
294 if (ret != 0) {
295 printk(KERN_ERR PFX
296 "cannot register miscdev on minor=%d (err=%d)\n",
297 WATCHDOG_MINOR, ret);
298 goto error4;
299 }
300
301 printk(KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
302 timeout, nowayout);
303
304 return ret;
305error4:
306 unregister_reboot_notifier(&wafwdt_notifier);
307error3:
308 release_region(wdt_start, 1);
309error2:
310 if (wdt_stop != wdt_start)
311 release_region(wdt_stop, 1);
312error:
313 return ret;
314}
315
316static void __exit wafwdt_exit(void)
317{
318 misc_deregister(&wafwdt_miscdev);
319 unregister_reboot_notifier(&wafwdt_notifier);
320 if (wdt_stop != wdt_start)
321 release_region(wdt_stop, 1);
322 release_region(wdt_start, 1);
323}
324
325module_init(wafwdt_init);
326module_exit(wafwdt_exit);
327
328MODULE_AUTHOR("Justin Cormack");
329MODULE_DESCRIPTION("ICP Wafer 5823 Single Board Computer WDT driver");
330MODULE_LICENSE("GPL");
331MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
332
333
334
