Commit | Line | Data |
---|---|---|
43316044 WVS |
1 | /* |
2 | * watchdog_dev.c | |
3 | * | |
4 | * (c) Copyright 2008-2011 Alan Cox <alan@lxorguk.ukuu.org.uk>, | |
5 | * All Rights Reserved. | |
6 | * | |
7 | * (c) Copyright 2008-2011 Wim Van Sebroeck <wim@iguana.be>. | |
8 | * | |
9 | * | |
10 | * This source code is part of the generic code that can be used | |
11 | * by all the watchdog timer drivers. | |
12 | * | |
13 | * This part of the generic code takes care of the following | |
14 | * misc device: /dev/watchdog. | |
15 | * | |
16 | * Based on source code of the following authors: | |
17 | * Matt Domsch <Matt_Domsch@dell.com>, | |
18 | * Rob Radez <rob@osinvestor.com>, | |
19 | * Rusty Lynch <rusty@linux.co.intel.com> | |
20 | * Satyam Sharma <satyam@infradead.org> | |
21 | * Randy Dunlap <randy.dunlap@oracle.com> | |
22 | * | |
23 | * This program is free software; you can redistribute it and/or | |
24 | * modify it under the terms of the GNU General Public License | |
25 | * as published by the Free Software Foundation; either version | |
26 | * 2 of the License, or (at your option) any later version. | |
27 | * | |
28 | * Neither Alan Cox, CymruNet Ltd., Wim Van Sebroeck nor Iguana vzw. | |
29 | * admit liability nor provide warranty for any of this software. | |
30 | * This material is provided "AS-IS" and at no charge. | |
31 | */ | |
32 | ||
33 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
34 | ||
35 | #include <linux/module.h> /* For module stuff/... */ | |
36 | #include <linux/types.h> /* For standard types (like size_t) */ | |
37 | #include <linux/errno.h> /* For the -ENODEV/... values */ | |
38 | #include <linux/kernel.h> /* For printk/panic/... */ | |
39 | #include <linux/fs.h> /* For file operations */ | |
40 | #include <linux/watchdog.h> /* For watchdog specific items */ | |
41 | #include <linux/miscdevice.h> /* For handling misc devices */ | |
42 | #include <linux/init.h> /* For __init/__exit/... */ | |
43 | #include <linux/uaccess.h> /* For copy_to_user/put_user/... */ | |
44 | ||
6cfb5aa8 | 45 | #include "watchdog_core.h" |
09a46e73 | 46 | |
45f5fed3 AC |
47 | /* the dev_t structure to store the dynamically allocated watchdog devices */ |
48 | static dev_t watchdog_devt; | |
43316044 | 49 | /* the watchdog device behind /dev/watchdog */ |
45f5fed3 | 50 | static struct watchdog_device *old_wdd; |
43316044 WVS |
51 | |
52 | /* | |
53 | * watchdog_ping: ping the watchdog. | |
54 | * @wddev: the watchdog device to ping | |
55 | * | |
56 | * If the watchdog has no own ping operation then it needs to be | |
57 | * restarted via the start operation. This wrapper function does | |
58 | * exactly that. | |
234445b4 | 59 | * We only ping when the watchdog device is running. |
43316044 WVS |
60 | */ |
61 | ||
62 | static int watchdog_ping(struct watchdog_device *wddev) | |
63 | { | |
7a879824 HG |
64 | int err = 0; |
65 | ||
f4e9c82f HG |
66 | mutex_lock(&wddev->lock); |
67 | ||
e907df32 HG |
68 | if (test_bit(WDOG_UNREGISTERED, &wddev->status)) { |
69 | err = -ENODEV; | |
70 | goto out_ping; | |
71 | } | |
72 | ||
7a879824 HG |
73 | if (!watchdog_active(wddev)) |
74 | goto out_ping; | |
75 | ||
76 | if (wddev->ops->ping) | |
77 | err = wddev->ops->ping(wddev); /* ping the watchdog */ | |
78 | else | |
79 | err = wddev->ops->start(wddev); /* restart watchdog */ | |
80 | ||
81 | out_ping: | |
f4e9c82f | 82 | mutex_unlock(&wddev->lock); |
7a879824 | 83 | return err; |
234445b4 WVS |
84 | } |
85 | ||
86 | /* | |
87 | * watchdog_start: wrapper to start the watchdog. | |
88 | * @wddev: the watchdog device to start | |
89 | * | |
90 | * Start the watchdog if it is not active and mark it active. | |
91 | * This function returns zero on success or a negative errno code for | |
92 | * failure. | |
93 | */ | |
94 | ||
95 | static int watchdog_start(struct watchdog_device *wddev) | |
96 | { | |
7a879824 | 97 | int err = 0; |
234445b4 | 98 | |
f4e9c82f HG |
99 | mutex_lock(&wddev->lock); |
100 | ||
e907df32 HG |
101 | if (test_bit(WDOG_UNREGISTERED, &wddev->status)) { |
102 | err = -ENODEV; | |
103 | goto out_start; | |
104 | } | |
105 | ||
7a879824 HG |
106 | if (watchdog_active(wddev)) |
107 | goto out_start; | |
234445b4 | 108 | |
7a879824 HG |
109 | err = wddev->ops->start(wddev); |
110 | if (err == 0) | |
cb7efc02 | 111 | set_bit(WDOG_ACTIVE, &wddev->status); |
7a879824 HG |
112 | |
113 | out_start: | |
f4e9c82f | 114 | mutex_unlock(&wddev->lock); |
7a879824 | 115 | return err; |
234445b4 WVS |
116 | } |
117 | ||
118 | /* | |
119 | * watchdog_stop: wrapper to stop the watchdog. | |
120 | * @wddev: the watchdog device to stop | |
121 | * | |
122 | * Stop the watchdog if it is still active and unmark it active. | |
123 | * This function returns zero on success or a negative errno code for | |
124 | * failure. | |
7e192b9c | 125 | * If the 'nowayout' feature was set, the watchdog cannot be stopped. |
234445b4 WVS |
126 | */ |
127 | ||
128 | static int watchdog_stop(struct watchdog_device *wddev) | |
129 | { | |
7a879824 HG |
130 | int err = 0; |
131 | ||
f4e9c82f HG |
132 | mutex_lock(&wddev->lock); |
133 | ||
e907df32 HG |
134 | if (test_bit(WDOG_UNREGISTERED, &wddev->status)) { |
135 | err = -ENODEV; | |
136 | goto out_stop; | |
137 | } | |
138 | ||
7a879824 HG |
139 | if (!watchdog_active(wddev)) |
140 | goto out_stop; | |
7e192b9c | 141 | |
cb7efc02 | 142 | if (test_bit(WDOG_NO_WAY_OUT, &wddev->status)) { |
3dfd6218 | 143 | dev_info(wddev->dev, "nowayout prevents watchdog being stopped!\n"); |
7a879824 HG |
144 | err = -EBUSY; |
145 | goto out_stop; | |
7e192b9c | 146 | } |
234445b4 | 147 | |
7a879824 HG |
148 | err = wddev->ops->stop(wddev); |
149 | if (err == 0) | |
cb7efc02 | 150 | clear_bit(WDOG_ACTIVE, &wddev->status); |
7a879824 HG |
151 | |
152 | out_stop: | |
f4e9c82f | 153 | mutex_unlock(&wddev->lock); |
7a879824 HG |
154 | return err; |
155 | } | |
156 | ||
157 | /* | |
158 | * watchdog_get_status: wrapper to get the watchdog status | |
159 | * @wddev: the watchdog device to get the status from | |
160 | * @status: the status of the watchdog device | |
161 | * | |
162 | * Get the watchdog's status flags. | |
163 | */ | |
164 | ||
165 | static int watchdog_get_status(struct watchdog_device *wddev, | |
166 | unsigned int *status) | |
167 | { | |
168 | int err = 0; | |
169 | ||
170 | *status = 0; | |
171 | if (!wddev->ops->status) | |
172 | return -EOPNOTSUPP; | |
173 | ||
f4e9c82f HG |
174 | mutex_lock(&wddev->lock); |
175 | ||
e907df32 HG |
176 | if (test_bit(WDOG_UNREGISTERED, &wddev->status)) { |
177 | err = -ENODEV; | |
178 | goto out_status; | |
179 | } | |
180 | ||
7a879824 HG |
181 | *status = wddev->ops->status(wddev); |
182 | ||
e907df32 | 183 | out_status: |
f4e9c82f | 184 | mutex_unlock(&wddev->lock); |
7a879824 HG |
185 | return err; |
186 | } | |
187 | ||
188 | /* | |
189 | * watchdog_set_timeout: set the watchdog timer timeout | |
190 | * @wddev: the watchdog device to set the timeout for | |
191 | * @timeout: timeout to set in seconds | |
192 | */ | |
193 | ||
194 | static int watchdog_set_timeout(struct watchdog_device *wddev, | |
195 | unsigned int timeout) | |
196 | { | |
197 | int err; | |
198 | ||
199 | if ((wddev->ops->set_timeout == NULL) || | |
200 | !(wddev->info->options & WDIOF_SETTIMEOUT)) | |
201 | return -EOPNOTSUPP; | |
202 | ||
203 | if ((wddev->max_timeout != 0) && | |
204 | (timeout < wddev->min_timeout || timeout > wddev->max_timeout)) | |
205 | return -EINVAL; | |
206 | ||
f4e9c82f HG |
207 | mutex_lock(&wddev->lock); |
208 | ||
e907df32 HG |
209 | if (test_bit(WDOG_UNREGISTERED, &wddev->status)) { |
210 | err = -ENODEV; | |
211 | goto out_timeout; | |
212 | } | |
213 | ||
7a879824 HG |
214 | err = wddev->ops->set_timeout(wddev, timeout); |
215 | ||
e907df32 | 216 | out_timeout: |
f4e9c82f | 217 | mutex_unlock(&wddev->lock); |
7a879824 HG |
218 | return err; |
219 | } | |
220 | ||
221 | /* | |
222 | * watchdog_get_timeleft: wrapper to get the time left before a reboot | |
223 | * @wddev: the watchdog device to get the remaining time from | |
224 | * @timeleft: the time that's left | |
225 | * | |
226 | * Get the time before a watchdog will reboot (if not pinged). | |
227 | */ | |
228 | ||
229 | static int watchdog_get_timeleft(struct watchdog_device *wddev, | |
230 | unsigned int *timeleft) | |
231 | { | |
232 | int err = 0; | |
233 | ||
234 | *timeleft = 0; | |
235 | if (!wddev->ops->get_timeleft) | |
236 | return -EOPNOTSUPP; | |
237 | ||
f4e9c82f HG |
238 | mutex_lock(&wddev->lock); |
239 | ||
e907df32 HG |
240 | if (test_bit(WDOG_UNREGISTERED, &wddev->status)) { |
241 | err = -ENODEV; | |
242 | goto out_timeleft; | |
243 | } | |
244 | ||
7a879824 HG |
245 | *timeleft = wddev->ops->get_timeleft(wddev); |
246 | ||
e907df32 | 247 | out_timeleft: |
f4e9c82f | 248 | mutex_unlock(&wddev->lock); |
7a879824 HG |
249 | return err; |
250 | } | |
251 | ||
252 | /* | |
253 | * watchdog_ioctl_op: call the watchdog drivers ioctl op if defined | |
254 | * @wddev: the watchdog device to do the ioctl on | |
255 | * @cmd: watchdog command | |
256 | * @arg: argument pointer | |
257 | */ | |
258 | ||
259 | static int watchdog_ioctl_op(struct watchdog_device *wddev, unsigned int cmd, | |
260 | unsigned long arg) | |
261 | { | |
262 | int err; | |
263 | ||
264 | if (!wddev->ops->ioctl) | |
265 | return -ENOIOCTLCMD; | |
266 | ||
f4e9c82f HG |
267 | mutex_lock(&wddev->lock); |
268 | ||
e907df32 HG |
269 | if (test_bit(WDOG_UNREGISTERED, &wddev->status)) { |
270 | err = -ENODEV; | |
271 | goto out_ioctl; | |
272 | } | |
273 | ||
7a879824 HG |
274 | err = wddev->ops->ioctl(wddev, cmd, arg); |
275 | ||
e907df32 | 276 | out_ioctl: |
f4e9c82f | 277 | mutex_unlock(&wddev->lock); |
7a879824 | 278 | return err; |
43316044 WVS |
279 | } |
280 | ||
281 | /* | |
282 | * watchdog_write: writes to the watchdog. | |
283 | * @file: file from VFS | |
284 | * @data: user address of data | |
285 | * @len: length of data | |
286 | * @ppos: pointer to the file offset | |
287 | * | |
288 | * A write to a watchdog device is defined as a keepalive ping. | |
017cf080 | 289 | * Writing the magic 'V' sequence allows the next close to turn |
7e192b9c | 290 | * off the watchdog (if 'nowayout' is not set). |
43316044 WVS |
291 | */ |
292 | ||
293 | static ssize_t watchdog_write(struct file *file, const char __user *data, | |
294 | size_t len, loff_t *ppos) | |
295 | { | |
45f5fed3 | 296 | struct watchdog_device *wdd = file->private_data; |
43316044 WVS |
297 | size_t i; |
298 | char c; | |
299 | ||
300 | if (len == 0) | |
301 | return 0; | |
302 | ||
017cf080 WVS |
303 | /* |
304 | * Note: just in case someone wrote the magic character | |
305 | * five months ago... | |
306 | */ | |
307 | clear_bit(WDOG_ALLOW_RELEASE, &wdd->status); | |
308 | ||
309 | /* scan to see whether or not we got the magic character */ | |
43316044 WVS |
310 | for (i = 0; i != len; i++) { |
311 | if (get_user(c, data + i)) | |
312 | return -EFAULT; | |
017cf080 WVS |
313 | if (c == 'V') |
314 | set_bit(WDOG_ALLOW_RELEASE, &wdd->status); | |
43316044 WVS |
315 | } |
316 | ||
317 | /* someone wrote to us, so we send the watchdog a keepalive ping */ | |
318 | watchdog_ping(wdd); | |
319 | ||
320 | return len; | |
321 | } | |
322 | ||
2fa03560 WVS |
323 | /* |
324 | * watchdog_ioctl: handle the different ioctl's for the watchdog device. | |
325 | * @file: file handle to the device | |
326 | * @cmd: watchdog command | |
327 | * @arg: argument pointer | |
328 | * | |
329 | * The watchdog API defines a common set of functions for all watchdogs | |
330 | * according to their available features. | |
331 | */ | |
332 | ||
333 | static long watchdog_ioctl(struct file *file, unsigned int cmd, | |
334 | unsigned long arg) | |
335 | { | |
45f5fed3 | 336 | struct watchdog_device *wdd = file->private_data; |
2fa03560 WVS |
337 | void __user *argp = (void __user *)arg; |
338 | int __user *p = argp; | |
339 | unsigned int val; | |
234445b4 | 340 | int err; |
2fa03560 | 341 | |
7a879824 HG |
342 | err = watchdog_ioctl_op(wdd, cmd, arg); |
343 | if (err != -ENOIOCTLCMD) | |
344 | return err; | |
78d88fc0 | 345 | |
2fa03560 WVS |
346 | switch (cmd) { |
347 | case WDIOC_GETSUPPORT: | |
348 | return copy_to_user(argp, wdd->info, | |
349 | sizeof(struct watchdog_info)) ? -EFAULT : 0; | |
350 | case WDIOC_GETSTATUS: | |
7a879824 | 351 | err = watchdog_get_status(wdd, &val); |
8b9468d4 | 352 | if (err == -ENODEV) |
7a879824 | 353 | return err; |
2fa03560 WVS |
354 | return put_user(val, p); |
355 | case WDIOC_GETBOOTSTATUS: | |
356 | return put_user(wdd->bootstatus, p); | |
234445b4 WVS |
357 | case WDIOC_SETOPTIONS: |
358 | if (get_user(val, p)) | |
359 | return -EFAULT; | |
360 | if (val & WDIOS_DISABLECARD) { | |
361 | err = watchdog_stop(wdd); | |
362 | if (err < 0) | |
363 | return err; | |
364 | } | |
365 | if (val & WDIOS_ENABLECARD) { | |
366 | err = watchdog_start(wdd); | |
367 | if (err < 0) | |
368 | return err; | |
369 | } | |
370 | return 0; | |
c2dc00e4 WVS |
371 | case WDIOC_KEEPALIVE: |
372 | if (!(wdd->info->options & WDIOF_KEEPALIVEPING)) | |
373 | return -EOPNOTSUPP; | |
374 | watchdog_ping(wdd); | |
375 | return 0; | |
014d694e | 376 | case WDIOC_SETTIMEOUT: |
014d694e WVS |
377 | if (get_user(val, p)) |
378 | return -EFAULT; | |
7a879824 | 379 | err = watchdog_set_timeout(wdd, val); |
014d694e WVS |
380 | if (err < 0) |
381 | return err; | |
014d694e WVS |
382 | /* If the watchdog is active then we send a keepalive ping |
383 | * to make sure that the watchdog keep's running (and if | |
384 | * possible that it takes the new timeout) */ | |
385 | watchdog_ping(wdd); | |
386 | /* Fall */ | |
387 | case WDIOC_GETTIMEOUT: | |
388 | /* timeout == 0 means that we don't know the timeout */ | |
389 | if (wdd->timeout == 0) | |
390 | return -EOPNOTSUPP; | |
391 | return put_user(wdd->timeout, p); | |
fd7b673c | 392 | case WDIOC_GETTIMELEFT: |
7a879824 HG |
393 | err = watchdog_get_timeleft(wdd, &val); |
394 | if (err) | |
395 | return err; | |
396 | return put_user(val, p); | |
2fa03560 WVS |
397 | default: |
398 | return -ENOTTY; | |
399 | } | |
400 | } | |
401 | ||
43316044 | 402 | /* |
45f5fed3 | 403 | * watchdog_open: open the /dev/watchdog* devices. |
43316044 WVS |
404 | * @inode: inode of device |
405 | * @file: file handle to device | |
406 | * | |
45f5fed3 | 407 | * When the /dev/watchdog* device gets opened, we start the watchdog. |
43316044 WVS |
408 | * Watch out: the /dev/watchdog device is single open, so we make sure |
409 | * it can only be opened once. | |
410 | */ | |
411 | ||
412 | static int watchdog_open(struct inode *inode, struct file *file) | |
413 | { | |
414 | int err = -EBUSY; | |
45f5fed3 AC |
415 | struct watchdog_device *wdd; |
416 | ||
417 | /* Get the corresponding watchdog device */ | |
418 | if (imajor(inode) == MISC_MAJOR) | |
419 | wdd = old_wdd; | |
420 | else | |
421 | wdd = container_of(inode->i_cdev, struct watchdog_device, cdev); | |
43316044 WVS |
422 | |
423 | /* the watchdog is single open! */ | |
424 | if (test_and_set_bit(WDOG_DEV_OPEN, &wdd->status)) | |
425 | return -EBUSY; | |
426 | ||
427 | /* | |
428 | * If the /dev/watchdog device is open, we don't want the module | |
429 | * to be unloaded. | |
430 | */ | |
431 | if (!try_module_get(wdd->ops->owner)) | |
432 | goto out; | |
433 | ||
234445b4 | 434 | err = watchdog_start(wdd); |
43316044 WVS |
435 | if (err < 0) |
436 | goto out_mod; | |
437 | ||
45f5fed3 AC |
438 | file->private_data = wdd; |
439 | ||
e907df32 HG |
440 | if (wdd->ops->ref) |
441 | wdd->ops->ref(wdd); | |
442 | ||
43316044 WVS |
443 | /* dev/watchdog is a virtual (and thus non-seekable) filesystem */ |
444 | return nonseekable_open(inode, file); | |
445 | ||
446 | out_mod: | |
447 | module_put(wdd->ops->owner); | |
448 | out: | |
449 | clear_bit(WDOG_DEV_OPEN, &wdd->status); | |
450 | return err; | |
451 | } | |
452 | ||
453 | /* | |
45f5fed3 AC |
454 | * watchdog_release: release the watchdog device. |
455 | * @inode: inode of device | |
456 | * @file: file handle to device | |
43316044 | 457 | * |
017cf080 | 458 | * This is the code for when /dev/watchdog gets closed. We will only |
7e192b9c WVS |
459 | * stop the watchdog when we have received the magic char (and nowayout |
460 | * was not set), else the watchdog will keep running. | |
43316044 WVS |
461 | */ |
462 | ||
463 | static int watchdog_release(struct inode *inode, struct file *file) | |
464 | { | |
45f5fed3 | 465 | struct watchdog_device *wdd = file->private_data; |
017cf080 WVS |
466 | int err = -EBUSY; |
467 | ||
468 | /* | |
469 | * We only stop the watchdog if we received the magic character | |
7e192b9c WVS |
470 | * or if WDIOF_MAGICCLOSE is not set. If nowayout was set then |
471 | * watchdog_stop will fail. | |
017cf080 WVS |
472 | */ |
473 | if (test_and_clear_bit(WDOG_ALLOW_RELEASE, &wdd->status) || | |
474 | !(wdd->info->options & WDIOF_MAGICCLOSE)) | |
475 | err = watchdog_stop(wdd); | |
43316044 | 476 | |
017cf080 | 477 | /* If the watchdog was not stopped, send a keepalive ping */ |
234445b4 | 478 | if (err < 0) { |
e907df32 HG |
479 | mutex_lock(&wdd->lock); |
480 | if (!test_bit(WDOG_UNREGISTERED, &wdd->status)) | |
481 | dev_crit(wdd->dev, "watchdog did not stop!\n"); | |
482 | mutex_unlock(&wdd->lock); | |
43316044 WVS |
483 | watchdog_ping(wdd); |
484 | } | |
485 | ||
486 | /* Allow the owner module to be unloaded again */ | |
487 | module_put(wdd->ops->owner); | |
488 | ||
489 | /* make sure that /dev/watchdog can be re-opened */ | |
490 | clear_bit(WDOG_DEV_OPEN, &wdd->status); | |
491 | ||
e907df32 HG |
492 | /* Note wdd may be gone after this, do not use after this! */ |
493 | if (wdd->ops->unref) | |
494 | wdd->ops->unref(wdd); | |
495 | ||
43316044 WVS |
496 | return 0; |
497 | } | |
498 | ||
499 | static const struct file_operations watchdog_fops = { | |
500 | .owner = THIS_MODULE, | |
501 | .write = watchdog_write, | |
2fa03560 | 502 | .unlocked_ioctl = watchdog_ioctl, |
43316044 WVS |
503 | .open = watchdog_open, |
504 | .release = watchdog_release, | |
505 | }; | |
506 | ||
507 | static struct miscdevice watchdog_miscdev = { | |
508 | .minor = WATCHDOG_MINOR, | |
509 | .name = "watchdog", | |
510 | .fops = &watchdog_fops, | |
511 | }; | |
512 | ||
513 | /* | |
45f5fed3 | 514 | * watchdog_dev_register: register a watchdog device |
43316044 WVS |
515 | * @watchdog: watchdog device |
516 | * | |
45f5fed3 AC |
517 | * Register a watchdog device including handling the legacy |
518 | * /dev/watchdog node. /dev/watchdog is actually a miscdevice and | |
519 | * thus we set it up like that. | |
43316044 WVS |
520 | */ |
521 | ||
522 | int watchdog_dev_register(struct watchdog_device *watchdog) | |
523 | { | |
45f5fed3 AC |
524 | int err, devno; |
525 | ||
526 | if (watchdog->id == 0) { | |
d6b469d9 | 527 | watchdog_miscdev.parent = watchdog->parent; |
45f5fed3 AC |
528 | err = misc_register(&watchdog_miscdev); |
529 | if (err != 0) { | |
530 | pr_err("%s: cannot register miscdev on minor=%d (err=%d).\n", | |
531 | watchdog->info->identity, WATCHDOG_MINOR, err); | |
532 | if (err == -EBUSY) | |
533 | pr_err("%s: a legacy watchdog module is probably present.\n", | |
534 | watchdog->info->identity); | |
535 | return err; | |
536 | } | |
537 | old_wdd = watchdog; | |
43316044 WVS |
538 | } |
539 | ||
45f5fed3 AC |
540 | /* Fill in the data structures */ |
541 | devno = MKDEV(MAJOR(watchdog_devt), watchdog->id); | |
542 | cdev_init(&watchdog->cdev, &watchdog_fops); | |
543 | watchdog->cdev.owner = watchdog->ops->owner; | |
544 | ||
545 | /* Add the device */ | |
546 | err = cdev_add(&watchdog->cdev, devno, 1); | |
547 | if (err) { | |
548 | pr_err("watchdog%d unable to add device %d:%d\n", | |
549 | watchdog->id, MAJOR(watchdog_devt), watchdog->id); | |
550 | if (watchdog->id == 0) { | |
551 | misc_deregister(&watchdog_miscdev); | |
552 | old_wdd = NULL; | |
553 | } | |
43316044 | 554 | } |
43316044 WVS |
555 | return err; |
556 | } | |
557 | ||
558 | /* | |
45f5fed3 | 559 | * watchdog_dev_unregister: unregister a watchdog device |
43316044 WVS |
560 | * @watchdog: watchdog device |
561 | * | |
45f5fed3 | 562 | * Unregister the watchdog and if needed the legacy /dev/watchdog device. |
43316044 WVS |
563 | */ |
564 | ||
565 | int watchdog_dev_unregister(struct watchdog_device *watchdog) | |
566 | { | |
e907df32 HG |
567 | mutex_lock(&watchdog->lock); |
568 | set_bit(WDOG_UNREGISTERED, &watchdog->status); | |
569 | mutex_unlock(&watchdog->lock); | |
570 | ||
45f5fed3 AC |
571 | cdev_del(&watchdog->cdev); |
572 | if (watchdog->id == 0) { | |
573 | misc_deregister(&watchdog_miscdev); | |
574 | old_wdd = NULL; | |
43316044 | 575 | } |
43316044 WVS |
576 | return 0; |
577 | } | |
45f5fed3 AC |
578 | |
579 | /* | |
580 | * watchdog_dev_init: init dev part of watchdog core | |
581 | * | |
582 | * Allocate a range of chardev nodes to use for watchdog devices | |
583 | */ | |
584 | ||
585 | int __init watchdog_dev_init(void) | |
586 | { | |
587 | int err = alloc_chrdev_region(&watchdog_devt, 0, MAX_DOGS, "watchdog"); | |
588 | if (err < 0) | |
589 | pr_err("watchdog: unable to allocate char dev region\n"); | |
590 | return err; | |
591 | } | |
592 | ||
593 | /* | |
594 | * watchdog_dev_exit: exit dev part of watchdog core | |
595 | * | |
596 | * Release the range of chardev nodes used for watchdog devices | |
597 | */ | |
598 | ||
599 | void __exit watchdog_dev_exit(void) | |
600 | { | |
601 | unregister_chrdev_region(watchdog_devt, MAX_DOGS); | |
602 | } |