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. | |
bc794ac3 | 54 | * @wdd: the watchdog device to ping |
43316044 WVS |
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 | ||
bc794ac3 | 62 | static int watchdog_ping(struct watchdog_device *wdd) |
43316044 | 63 | { |
7a879824 HG |
64 | int err = 0; |
65 | ||
bc794ac3 | 66 | mutex_lock(&wdd->lock); |
f4e9c82f | 67 | |
bc794ac3 | 68 | if (test_bit(WDOG_UNREGISTERED, &wdd->status)) { |
e907df32 HG |
69 | err = -ENODEV; |
70 | goto out_ping; | |
71 | } | |
72 | ||
bc794ac3 | 73 | if (!watchdog_active(wdd)) |
7a879824 HG |
74 | goto out_ping; |
75 | ||
bc794ac3 GR |
76 | if (wdd->ops->ping) |
77 | err = wdd->ops->ping(wdd); /* ping the watchdog */ | |
7a879824 | 78 | else |
bc794ac3 | 79 | err = wdd->ops->start(wdd); /* restart watchdog */ |
7a879824 HG |
80 | |
81 | out_ping: | |
bc794ac3 | 82 | mutex_unlock(&wdd->lock); |
7a879824 | 83 | return err; |
234445b4 WVS |
84 | } |
85 | ||
86 | /* | |
87 | * watchdog_start: wrapper to start the watchdog. | |
bc794ac3 | 88 | * @wdd: the watchdog device to start |
234445b4 WVS |
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 | ||
bc794ac3 | 95 | static int watchdog_start(struct watchdog_device *wdd) |
234445b4 | 96 | { |
7a879824 | 97 | int err = 0; |
234445b4 | 98 | |
bc794ac3 | 99 | mutex_lock(&wdd->lock); |
f4e9c82f | 100 | |
bc794ac3 | 101 | if (test_bit(WDOG_UNREGISTERED, &wdd->status)) { |
e907df32 HG |
102 | err = -ENODEV; |
103 | goto out_start; | |
104 | } | |
105 | ||
bc794ac3 | 106 | if (watchdog_active(wdd)) |
7a879824 | 107 | goto out_start; |
234445b4 | 108 | |
bc794ac3 | 109 | err = wdd->ops->start(wdd); |
7a879824 | 110 | if (err == 0) |
bc794ac3 | 111 | set_bit(WDOG_ACTIVE, &wdd->status); |
7a879824 HG |
112 | |
113 | out_start: | |
bc794ac3 | 114 | mutex_unlock(&wdd->lock); |
7a879824 | 115 | return err; |
234445b4 WVS |
116 | } |
117 | ||
118 | /* | |
119 | * watchdog_stop: wrapper to stop the watchdog. | |
bc794ac3 | 120 | * @wdd: the watchdog device to stop |
234445b4 WVS |
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 | ||
bc794ac3 | 128 | static int watchdog_stop(struct watchdog_device *wdd) |
234445b4 | 129 | { |
7a879824 HG |
130 | int err = 0; |
131 | ||
bc794ac3 | 132 | mutex_lock(&wdd->lock); |
f4e9c82f | 133 | |
bc794ac3 | 134 | if (test_bit(WDOG_UNREGISTERED, &wdd->status)) { |
e907df32 HG |
135 | err = -ENODEV; |
136 | goto out_stop; | |
137 | } | |
138 | ||
bc794ac3 | 139 | if (!watchdog_active(wdd)) |
7a879824 | 140 | goto out_stop; |
7e192b9c | 141 | |
bc794ac3 GR |
142 | if (test_bit(WDOG_NO_WAY_OUT, &wdd->status)) { |
143 | dev_info(wdd->dev, "nowayout prevents watchdog being stopped!\n"); | |
7a879824 HG |
144 | err = -EBUSY; |
145 | goto out_stop; | |
7e192b9c | 146 | } |
234445b4 | 147 | |
bc794ac3 | 148 | err = wdd->ops->stop(wdd); |
7a879824 | 149 | if (err == 0) |
bc794ac3 | 150 | clear_bit(WDOG_ACTIVE, &wdd->status); |
7a879824 HG |
151 | |
152 | out_stop: | |
bc794ac3 | 153 | mutex_unlock(&wdd->lock); |
7a879824 HG |
154 | return err; |
155 | } | |
156 | ||
157 | /* | |
158 | * watchdog_get_status: wrapper to get the watchdog status | |
bc794ac3 | 159 | * @wdd: the watchdog device to get the status from |
7a879824 HG |
160 | * @status: the status of the watchdog device |
161 | * | |
162 | * Get the watchdog's status flags. | |
163 | */ | |
164 | ||
bc794ac3 | 165 | static int watchdog_get_status(struct watchdog_device *wdd, |
7a879824 HG |
166 | unsigned int *status) |
167 | { | |
168 | int err = 0; | |
169 | ||
170 | *status = 0; | |
bc794ac3 | 171 | if (!wdd->ops->status) |
7a879824 HG |
172 | return -EOPNOTSUPP; |
173 | ||
bc794ac3 | 174 | mutex_lock(&wdd->lock); |
f4e9c82f | 175 | |
bc794ac3 | 176 | if (test_bit(WDOG_UNREGISTERED, &wdd->status)) { |
e907df32 HG |
177 | err = -ENODEV; |
178 | goto out_status; | |
179 | } | |
180 | ||
bc794ac3 | 181 | *status = wdd->ops->status(wdd); |
7a879824 | 182 | |
e907df32 | 183 | out_status: |
bc794ac3 | 184 | mutex_unlock(&wdd->lock); |
7a879824 HG |
185 | return err; |
186 | } | |
187 | ||
188 | /* | |
189 | * watchdog_set_timeout: set the watchdog timer timeout | |
bc794ac3 | 190 | * @wdd: the watchdog device to set the timeout for |
7a879824 HG |
191 | * @timeout: timeout to set in seconds |
192 | */ | |
193 | ||
bc794ac3 | 194 | static int watchdog_set_timeout(struct watchdog_device *wdd, |
7a879824 HG |
195 | unsigned int timeout) |
196 | { | |
197 | int err; | |
198 | ||
bc794ac3 | 199 | if (!wdd->ops->set_timeout || !(wdd->info->options & WDIOF_SETTIMEOUT)) |
7a879824 HG |
200 | return -EOPNOTSUPP; |
201 | ||
bc794ac3 | 202 | if (watchdog_timeout_invalid(wdd, timeout)) |
7a879824 HG |
203 | return -EINVAL; |
204 | ||
bc794ac3 | 205 | mutex_lock(&wdd->lock); |
f4e9c82f | 206 | |
bc794ac3 | 207 | if (test_bit(WDOG_UNREGISTERED, &wdd->status)) { |
e907df32 HG |
208 | err = -ENODEV; |
209 | goto out_timeout; | |
210 | } | |
211 | ||
bc794ac3 | 212 | err = wdd->ops->set_timeout(wdd, timeout); |
7a879824 | 213 | |
e907df32 | 214 | out_timeout: |
bc794ac3 | 215 | mutex_unlock(&wdd->lock); |
7a879824 HG |
216 | return err; |
217 | } | |
218 | ||
219 | /* | |
220 | * watchdog_get_timeleft: wrapper to get the time left before a reboot | |
bc794ac3 | 221 | * @wdd: the watchdog device to get the remaining time from |
7a879824 HG |
222 | * @timeleft: the time that's left |
223 | * | |
224 | * Get the time before a watchdog will reboot (if not pinged). | |
225 | */ | |
226 | ||
bc794ac3 | 227 | static int watchdog_get_timeleft(struct watchdog_device *wdd, |
7a879824 HG |
228 | unsigned int *timeleft) |
229 | { | |
230 | int err = 0; | |
231 | ||
232 | *timeleft = 0; | |
bc794ac3 | 233 | if (!wdd->ops->get_timeleft) |
7a879824 HG |
234 | return -EOPNOTSUPP; |
235 | ||
bc794ac3 | 236 | mutex_lock(&wdd->lock); |
f4e9c82f | 237 | |
bc794ac3 | 238 | if (test_bit(WDOG_UNREGISTERED, &wdd->status)) { |
e907df32 HG |
239 | err = -ENODEV; |
240 | goto out_timeleft; | |
241 | } | |
242 | ||
bc794ac3 | 243 | *timeleft = wdd->ops->get_timeleft(wdd); |
7a879824 | 244 | |
e907df32 | 245 | out_timeleft: |
bc794ac3 | 246 | mutex_unlock(&wdd->lock); |
7a879824 HG |
247 | return err; |
248 | } | |
249 | ||
250 | /* | |
251 | * watchdog_ioctl_op: call the watchdog drivers ioctl op if defined | |
bc794ac3 | 252 | * @wdd: the watchdog device to do the ioctl on |
7a879824 HG |
253 | * @cmd: watchdog command |
254 | * @arg: argument pointer | |
255 | */ | |
256 | ||
bc794ac3 | 257 | static int watchdog_ioctl_op(struct watchdog_device *wdd, unsigned int cmd, |
7a879824 HG |
258 | unsigned long arg) |
259 | { | |
260 | int err; | |
261 | ||
bc794ac3 | 262 | if (!wdd->ops->ioctl) |
7a879824 HG |
263 | return -ENOIOCTLCMD; |
264 | ||
bc794ac3 | 265 | mutex_lock(&wdd->lock); |
f4e9c82f | 266 | |
bc794ac3 | 267 | if (test_bit(WDOG_UNREGISTERED, &wdd->status)) { |
e907df32 HG |
268 | err = -ENODEV; |
269 | goto out_ioctl; | |
270 | } | |
271 | ||
bc794ac3 | 272 | err = wdd->ops->ioctl(wdd, cmd, arg); |
7a879824 | 273 | |
e907df32 | 274 | out_ioctl: |
bc794ac3 | 275 | mutex_unlock(&wdd->lock); |
7a879824 | 276 | return err; |
43316044 WVS |
277 | } |
278 | ||
279 | /* | |
280 | * watchdog_write: writes to the watchdog. | |
281 | * @file: file from VFS | |
282 | * @data: user address of data | |
283 | * @len: length of data | |
284 | * @ppos: pointer to the file offset | |
285 | * | |
286 | * A write to a watchdog device is defined as a keepalive ping. | |
017cf080 | 287 | * Writing the magic 'V' sequence allows the next close to turn |
7e192b9c | 288 | * off the watchdog (if 'nowayout' is not set). |
43316044 WVS |
289 | */ |
290 | ||
291 | static ssize_t watchdog_write(struct file *file, const char __user *data, | |
292 | size_t len, loff_t *ppos) | |
293 | { | |
45f5fed3 | 294 | struct watchdog_device *wdd = file->private_data; |
43316044 WVS |
295 | size_t i; |
296 | char c; | |
5ef79663 | 297 | int err; |
43316044 WVS |
298 | |
299 | if (len == 0) | |
300 | return 0; | |
301 | ||
017cf080 WVS |
302 | /* |
303 | * Note: just in case someone wrote the magic character | |
304 | * five months ago... | |
305 | */ | |
306 | clear_bit(WDOG_ALLOW_RELEASE, &wdd->status); | |
307 | ||
308 | /* scan to see whether or not we got the magic character */ | |
43316044 WVS |
309 | for (i = 0; i != len; i++) { |
310 | if (get_user(c, data + i)) | |
311 | return -EFAULT; | |
017cf080 WVS |
312 | if (c == 'V') |
313 | set_bit(WDOG_ALLOW_RELEASE, &wdd->status); | |
43316044 WVS |
314 | } |
315 | ||
316 | /* someone wrote to us, so we send the watchdog a keepalive ping */ | |
5ef79663 AU |
317 | err = watchdog_ping(wdd); |
318 | if (err < 0) | |
319 | return err; | |
43316044 WVS |
320 | |
321 | return len; | |
322 | } | |
323 | ||
2fa03560 WVS |
324 | /* |
325 | * watchdog_ioctl: handle the different ioctl's for the watchdog device. | |
326 | * @file: file handle to the device | |
327 | * @cmd: watchdog command | |
328 | * @arg: argument pointer | |
329 | * | |
330 | * The watchdog API defines a common set of functions for all watchdogs | |
331 | * according to their available features. | |
332 | */ | |
333 | ||
334 | static long watchdog_ioctl(struct file *file, unsigned int cmd, | |
335 | unsigned long arg) | |
336 | { | |
45f5fed3 | 337 | struct watchdog_device *wdd = file->private_data; |
2fa03560 WVS |
338 | void __user *argp = (void __user *)arg; |
339 | int __user *p = argp; | |
340 | unsigned int val; | |
234445b4 | 341 | int err; |
2fa03560 | 342 | |
7a879824 HG |
343 | err = watchdog_ioctl_op(wdd, cmd, arg); |
344 | if (err != -ENOIOCTLCMD) | |
345 | return err; | |
78d88fc0 | 346 | |
2fa03560 WVS |
347 | switch (cmd) { |
348 | case WDIOC_GETSUPPORT: | |
349 | return copy_to_user(argp, wdd->info, | |
350 | sizeof(struct watchdog_info)) ? -EFAULT : 0; | |
351 | case WDIOC_GETSTATUS: | |
7a879824 | 352 | err = watchdog_get_status(wdd, &val); |
8b9468d4 | 353 | if (err == -ENODEV) |
7a879824 | 354 | return err; |
2fa03560 WVS |
355 | return put_user(val, p); |
356 | case WDIOC_GETBOOTSTATUS: | |
357 | return put_user(wdd->bootstatus, p); | |
234445b4 WVS |
358 | case WDIOC_SETOPTIONS: |
359 | if (get_user(val, p)) | |
360 | return -EFAULT; | |
361 | if (val & WDIOS_DISABLECARD) { | |
362 | err = watchdog_stop(wdd); | |
363 | if (err < 0) | |
364 | return err; | |
365 | } | |
366 | if (val & WDIOS_ENABLECARD) { | |
367 | err = watchdog_start(wdd); | |
368 | if (err < 0) | |
369 | return err; | |
370 | } | |
371 | return 0; | |
c2dc00e4 WVS |
372 | case WDIOC_KEEPALIVE: |
373 | if (!(wdd->info->options & WDIOF_KEEPALIVEPING)) | |
374 | return -EOPNOTSUPP; | |
5ef79663 | 375 | return watchdog_ping(wdd); |
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) */ | |
5ef79663 AU |
385 | err = watchdog_ping(wdd); |
386 | if (err < 0) | |
387 | return err; | |
014d694e WVS |
388 | /* Fall */ |
389 | case WDIOC_GETTIMEOUT: | |
390 | /* timeout == 0 means that we don't know the timeout */ | |
391 | if (wdd->timeout == 0) | |
392 | return -EOPNOTSUPP; | |
393 | return put_user(wdd->timeout, p); | |
fd7b673c | 394 | case WDIOC_GETTIMELEFT: |
7a879824 HG |
395 | err = watchdog_get_timeleft(wdd, &val); |
396 | if (err) | |
397 | return err; | |
398 | return put_user(val, p); | |
2fa03560 WVS |
399 | default: |
400 | return -ENOTTY; | |
401 | } | |
402 | } | |
403 | ||
43316044 | 404 | /* |
45f5fed3 | 405 | * watchdog_open: open the /dev/watchdog* devices. |
43316044 WVS |
406 | * @inode: inode of device |
407 | * @file: file handle to device | |
408 | * | |
45f5fed3 | 409 | * When the /dev/watchdog* device gets opened, we start the watchdog. |
43316044 WVS |
410 | * Watch out: the /dev/watchdog device is single open, so we make sure |
411 | * it can only be opened once. | |
412 | */ | |
413 | ||
414 | static int watchdog_open(struct inode *inode, struct file *file) | |
415 | { | |
416 | int err = -EBUSY; | |
45f5fed3 AC |
417 | struct watchdog_device *wdd; |
418 | ||
419 | /* Get the corresponding watchdog device */ | |
420 | if (imajor(inode) == MISC_MAJOR) | |
421 | wdd = old_wdd; | |
422 | else | |
423 | wdd = container_of(inode->i_cdev, struct watchdog_device, cdev); | |
43316044 WVS |
424 | |
425 | /* the watchdog is single open! */ | |
426 | if (test_and_set_bit(WDOG_DEV_OPEN, &wdd->status)) | |
427 | return -EBUSY; | |
428 | ||
429 | /* | |
430 | * If the /dev/watchdog device is open, we don't want the module | |
431 | * to be unloaded. | |
432 | */ | |
433 | if (!try_module_get(wdd->ops->owner)) | |
434 | goto out; | |
435 | ||
234445b4 | 436 | err = watchdog_start(wdd); |
43316044 WVS |
437 | if (err < 0) |
438 | goto out_mod; | |
439 | ||
45f5fed3 AC |
440 | file->private_data = wdd; |
441 | ||
e907df32 HG |
442 | if (wdd->ops->ref) |
443 | wdd->ops->ref(wdd); | |
444 | ||
43316044 WVS |
445 | /* dev/watchdog is a virtual (and thus non-seekable) filesystem */ |
446 | return nonseekable_open(inode, file); | |
447 | ||
448 | out_mod: | |
449 | module_put(wdd->ops->owner); | |
450 | out: | |
451 | clear_bit(WDOG_DEV_OPEN, &wdd->status); | |
452 | return err; | |
453 | } | |
454 | ||
455 | /* | |
45f5fed3 AC |
456 | * watchdog_release: release the watchdog device. |
457 | * @inode: inode of device | |
458 | * @file: file handle to device | |
43316044 | 459 | * |
017cf080 | 460 | * This is the code for when /dev/watchdog gets closed. We will only |
7e192b9c WVS |
461 | * stop the watchdog when we have received the magic char (and nowayout |
462 | * was not set), else the watchdog will keep running. | |
43316044 WVS |
463 | */ |
464 | ||
465 | static int watchdog_release(struct inode *inode, struct file *file) | |
466 | { | |
45f5fed3 | 467 | struct watchdog_device *wdd = file->private_data; |
017cf080 WVS |
468 | int err = -EBUSY; |
469 | ||
470 | /* | |
471 | * We only stop the watchdog if we received the magic character | |
7e192b9c WVS |
472 | * or if WDIOF_MAGICCLOSE is not set. If nowayout was set then |
473 | * watchdog_stop will fail. | |
017cf080 | 474 | */ |
fcf95670 HP |
475 | if (!test_bit(WDOG_ACTIVE, &wdd->status)) |
476 | err = 0; | |
477 | else if (test_and_clear_bit(WDOG_ALLOW_RELEASE, &wdd->status) || | |
478 | !(wdd->info->options & WDIOF_MAGICCLOSE)) | |
017cf080 | 479 | err = watchdog_stop(wdd); |
43316044 | 480 | |
017cf080 | 481 | /* If the watchdog was not stopped, send a keepalive ping */ |
234445b4 | 482 | if (err < 0) { |
e907df32 HG |
483 | mutex_lock(&wdd->lock); |
484 | if (!test_bit(WDOG_UNREGISTERED, &wdd->status)) | |
485 | dev_crit(wdd->dev, "watchdog did not stop!\n"); | |
486 | mutex_unlock(&wdd->lock); | |
43316044 WVS |
487 | watchdog_ping(wdd); |
488 | } | |
489 | ||
490 | /* Allow the owner module to be unloaded again */ | |
491 | module_put(wdd->ops->owner); | |
492 | ||
493 | /* make sure that /dev/watchdog can be re-opened */ | |
494 | clear_bit(WDOG_DEV_OPEN, &wdd->status); | |
495 | ||
e907df32 HG |
496 | /* Note wdd may be gone after this, do not use after this! */ |
497 | if (wdd->ops->unref) | |
498 | wdd->ops->unref(wdd); | |
499 | ||
43316044 WVS |
500 | return 0; |
501 | } | |
502 | ||
503 | static const struct file_operations watchdog_fops = { | |
504 | .owner = THIS_MODULE, | |
505 | .write = watchdog_write, | |
2fa03560 | 506 | .unlocked_ioctl = watchdog_ioctl, |
43316044 WVS |
507 | .open = watchdog_open, |
508 | .release = watchdog_release, | |
509 | }; | |
510 | ||
511 | static struct miscdevice watchdog_miscdev = { | |
512 | .minor = WATCHDOG_MINOR, | |
513 | .name = "watchdog", | |
514 | .fops = &watchdog_fops, | |
515 | }; | |
516 | ||
517 | /* | |
45f5fed3 | 518 | * watchdog_dev_register: register a watchdog device |
bc794ac3 | 519 | * @wdd: watchdog device |
43316044 | 520 | * |
45f5fed3 AC |
521 | * Register a watchdog device including handling the legacy |
522 | * /dev/watchdog node. /dev/watchdog is actually a miscdevice and | |
523 | * thus we set it up like that. | |
43316044 WVS |
524 | */ |
525 | ||
bc794ac3 | 526 | int watchdog_dev_register(struct watchdog_device *wdd) |
43316044 | 527 | { |
45f5fed3 AC |
528 | int err, devno; |
529 | ||
bc794ac3 GR |
530 | if (wdd->id == 0) { |
531 | old_wdd = wdd; | |
532 | watchdog_miscdev.parent = wdd->parent; | |
45f5fed3 AC |
533 | err = misc_register(&watchdog_miscdev); |
534 | if (err != 0) { | |
535 | pr_err("%s: cannot register miscdev on minor=%d (err=%d).\n", | |
bc794ac3 | 536 | wdd->info->identity, WATCHDOG_MINOR, err); |
45f5fed3 AC |
537 | if (err == -EBUSY) |
538 | pr_err("%s: a legacy watchdog module is probably present.\n", | |
bc794ac3 | 539 | wdd->info->identity); |
60403f7a | 540 | old_wdd = NULL; |
45f5fed3 AC |
541 | return err; |
542 | } | |
43316044 WVS |
543 | } |
544 | ||
45f5fed3 | 545 | /* Fill in the data structures */ |
bc794ac3 GR |
546 | devno = MKDEV(MAJOR(watchdog_devt), wdd->id); |
547 | cdev_init(&wdd->cdev, &watchdog_fops); | |
548 | wdd->cdev.owner = wdd->ops->owner; | |
45f5fed3 AC |
549 | |
550 | /* Add the device */ | |
bc794ac3 | 551 | err = cdev_add(&wdd->cdev, devno, 1); |
45f5fed3 AC |
552 | if (err) { |
553 | pr_err("watchdog%d unable to add device %d:%d\n", | |
bc794ac3 GR |
554 | wdd->id, MAJOR(watchdog_devt), wdd->id); |
555 | if (wdd->id == 0) { | |
45f5fed3 AC |
556 | misc_deregister(&watchdog_miscdev); |
557 | old_wdd = NULL; | |
558 | } | |
43316044 | 559 | } |
43316044 WVS |
560 | return err; |
561 | } | |
562 | ||
563 | /* | |
45f5fed3 | 564 | * watchdog_dev_unregister: unregister a watchdog device |
43316044 WVS |
565 | * @watchdog: watchdog device |
566 | * | |
45f5fed3 | 567 | * Unregister the watchdog and if needed the legacy /dev/watchdog device. |
43316044 WVS |
568 | */ |
569 | ||
bc794ac3 | 570 | int watchdog_dev_unregister(struct watchdog_device *wdd) |
43316044 | 571 | { |
bc794ac3 GR |
572 | mutex_lock(&wdd->lock); |
573 | set_bit(WDOG_UNREGISTERED, &wdd->status); | |
574 | mutex_unlock(&wdd->lock); | |
e907df32 | 575 | |
bc794ac3 GR |
576 | cdev_del(&wdd->cdev); |
577 | if (wdd->id == 0) { | |
45f5fed3 AC |
578 | misc_deregister(&watchdog_miscdev); |
579 | old_wdd = NULL; | |
43316044 | 580 | } |
43316044 WVS |
581 | return 0; |
582 | } | |
45f5fed3 AC |
583 | |
584 | /* | |
585 | * watchdog_dev_init: init dev part of watchdog core | |
586 | * | |
587 | * Allocate a range of chardev nodes to use for watchdog devices | |
588 | */ | |
589 | ||
590 | int __init watchdog_dev_init(void) | |
591 | { | |
592 | int err = alloc_chrdev_region(&watchdog_devt, 0, MAX_DOGS, "watchdog"); | |
593 | if (err < 0) | |
594 | pr_err("watchdog: unable to allocate char dev region\n"); | |
595 | return err; | |
596 | } | |
597 | ||
598 | /* | |
599 | * watchdog_dev_exit: exit dev part of watchdog core | |
600 | * | |
601 | * Release the range of chardev nodes used for watchdog devices | |
602 | */ | |
603 | ||
604 | void __exit watchdog_dev_exit(void) | |
605 | { | |
606 | unregister_chrdev_region(watchdog_devt, MAX_DOGS); | |
607 | } |