Commit | Line | Data |
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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 | ||
b4ffb190 | 35 | #include <linux/cdev.h> /* For character device */ |
43316044 | 36 | #include <linux/errno.h> /* For the -ENODEV/... values */ |
43316044 | 37 | #include <linux/fs.h> /* For file operations */ |
43316044 | 38 | #include <linux/init.h> /* For __init/__exit/... */ |
664a3923 | 39 | #include <linux/jiffies.h> /* For timeout functions */ |
b4ffb190 GR |
40 | #include <linux/kernel.h> /* For printk/panic/... */ |
41 | #include <linux/kref.h> /* For data references */ | |
42 | #include <linux/miscdevice.h> /* For handling misc devices */ | |
43 | #include <linux/module.h> /* For module stuff/... */ | |
44 | #include <linux/mutex.h> /* For mutexes */ | |
45 | #include <linux/slab.h> /* For memory functions */ | |
46 | #include <linux/types.h> /* For standard types (like size_t) */ | |
47 | #include <linux/watchdog.h> /* For watchdog specific items */ | |
664a3923 | 48 | #include <linux/workqueue.h> /* For workqueue */ |
43316044 WVS |
49 | #include <linux/uaccess.h> /* For copy_to_user/put_user/... */ |
50 | ||
6cfb5aa8 | 51 | #include "watchdog_core.h" |
ff84136c | 52 | #include "watchdog_pretimeout.h" |
09a46e73 | 53 | |
b4ffb190 GR |
54 | /* |
55 | * struct watchdog_core_data - watchdog core internal data | |
56 | * @kref: Reference count. | |
57 | * @cdev: The watchdog's Character device. | |
58 | * @wdd: Pointer to watchdog device. | |
59 | * @lock: Lock for watchdog core. | |
60 | * @status: Watchdog core internal status bits. | |
61 | */ | |
62 | struct watchdog_core_data { | |
63 | struct kref kref; | |
64 | struct cdev cdev; | |
65 | struct watchdog_device *wdd; | |
66 | struct mutex lock; | |
664a3923 | 67 | unsigned long last_keepalive; |
15013ad8 | 68 | unsigned long last_hw_keepalive; |
664a3923 | 69 | struct delayed_work work; |
b4ffb190 GR |
70 | unsigned long status; /* Internal status bits */ |
71 | #define _WDOG_DEV_OPEN 0 /* Opened ? */ | |
72 | #define _WDOG_ALLOW_RELEASE 1 /* Did we receive the magic char ? */ | |
90b826f1 | 73 | #define _WDOG_KEEPALIVE 2 /* Did we receive a keepalive ? */ |
b4ffb190 GR |
74 | }; |
75 | ||
45f5fed3 AC |
76 | /* the dev_t structure to store the dynamically allocated watchdog devices */ |
77 | static dev_t watchdog_devt; | |
b4ffb190 GR |
78 | /* Reference to watchdog device behind /dev/watchdog */ |
79 | static struct watchdog_core_data *old_wd_data; | |
43316044 | 80 | |
664a3923 GR |
81 | static struct workqueue_struct *watchdog_wq; |
82 | ||
83 | static inline bool watchdog_need_worker(struct watchdog_device *wdd) | |
84 | { | |
85 | /* All variables in milli-seconds */ | |
86 | unsigned int hm = wdd->max_hw_heartbeat_ms; | |
87 | unsigned int t = wdd->timeout * 1000; | |
88 | ||
89 | /* | |
90 | * A worker to generate heartbeat requests is needed if all of the | |
91 | * following conditions are true. | |
92 | * - Userspace activated the watchdog. | |
93 | * - The driver provided a value for the maximum hardware timeout, and | |
94 | * thus is aware that the framework supports generating heartbeat | |
95 | * requests. | |
96 | * - Userspace requests a longer timeout than the hardware can handle. | |
3fbfe926 RV |
97 | * |
98 | * Alternatively, if userspace has not opened the watchdog | |
99 | * device, we take care of feeding the watchdog if it is | |
100 | * running. | |
664a3923 | 101 | */ |
3fbfe926 RV |
102 | return (hm && watchdog_active(wdd) && t > hm) || |
103 | (t && !watchdog_active(wdd) && watchdog_hw_running(wdd)); | |
664a3923 GR |
104 | } |
105 | ||
106 | static long watchdog_next_keepalive(struct watchdog_device *wdd) | |
107 | { | |
108 | struct watchdog_core_data *wd_data = wdd->wd_data; | |
109 | unsigned int timeout_ms = wdd->timeout * 1000; | |
110 | unsigned long keepalive_interval; | |
111 | unsigned long last_heartbeat; | |
112 | unsigned long virt_timeout; | |
113 | unsigned int hw_heartbeat_ms; | |
114 | ||
115 | virt_timeout = wd_data->last_keepalive + msecs_to_jiffies(timeout_ms); | |
3fbfe926 | 116 | hw_heartbeat_ms = min_not_zero(timeout_ms, wdd->max_hw_heartbeat_ms); |
664a3923 GR |
117 | keepalive_interval = msecs_to_jiffies(hw_heartbeat_ms / 2); |
118 | ||
ee142889 GR |
119 | if (!watchdog_active(wdd)) |
120 | return keepalive_interval; | |
121 | ||
664a3923 GR |
122 | /* |
123 | * To ensure that the watchdog times out wdd->timeout seconds | |
124 | * after the most recent ping from userspace, the last | |
125 | * worker ping has to come in hw_heartbeat_ms before this timeout. | |
126 | */ | |
127 | last_heartbeat = virt_timeout - msecs_to_jiffies(hw_heartbeat_ms); | |
128 | return min_t(long, last_heartbeat - jiffies, keepalive_interval); | |
129 | } | |
130 | ||
131 | static inline void watchdog_update_worker(struct watchdog_device *wdd) | |
132 | { | |
133 | struct watchdog_core_data *wd_data = wdd->wd_data; | |
134 | ||
135 | if (watchdog_need_worker(wdd)) { | |
136 | long t = watchdog_next_keepalive(wdd); | |
137 | ||
138 | if (t > 0) | |
139 | mod_delayed_work(watchdog_wq, &wd_data->work, t); | |
140 | } else { | |
141 | cancel_delayed_work(&wd_data->work); | |
142 | } | |
143 | } | |
144 | ||
145 | static int __watchdog_ping(struct watchdog_device *wdd) | |
146 | { | |
15013ad8 GR |
147 | struct watchdog_core_data *wd_data = wdd->wd_data; |
148 | unsigned long earliest_keepalive = wd_data->last_hw_keepalive + | |
149 | msecs_to_jiffies(wdd->min_hw_heartbeat_ms); | |
664a3923 GR |
150 | int err; |
151 | ||
15013ad8 GR |
152 | if (time_is_after_jiffies(earliest_keepalive)) { |
153 | mod_delayed_work(watchdog_wq, &wd_data->work, | |
154 | earliest_keepalive - jiffies); | |
155 | return 0; | |
156 | } | |
157 | ||
158 | wd_data->last_hw_keepalive = jiffies; | |
159 | ||
664a3923 GR |
160 | if (wdd->ops->ping) |
161 | err = wdd->ops->ping(wdd); /* ping the watchdog */ | |
162 | else | |
163 | err = wdd->ops->start(wdd); /* restart watchdog */ | |
164 | ||
165 | watchdog_update_worker(wdd); | |
166 | ||
167 | return err; | |
168 | } | |
169 | ||
43316044 WVS |
170 | /* |
171 | * watchdog_ping: ping the watchdog. | |
bc794ac3 | 172 | * @wdd: the watchdog device to ping |
43316044 | 173 | * |
b4ffb190 GR |
174 | * The caller must hold wd_data->lock. |
175 | * | |
43316044 WVS |
176 | * If the watchdog has no own ping operation then it needs to be |
177 | * restarted via the start operation. This wrapper function does | |
178 | * exactly that. | |
234445b4 | 179 | * We only ping when the watchdog device is running. |
43316044 WVS |
180 | */ |
181 | ||
bc794ac3 | 182 | static int watchdog_ping(struct watchdog_device *wdd) |
43316044 | 183 | { |
664a3923 | 184 | struct watchdog_core_data *wd_data = wdd->wd_data; |
e907df32 | 185 | |
ee142889 | 186 | if (!watchdog_active(wdd) && !watchdog_hw_running(wdd)) |
b4ffb190 | 187 | return 0; |
7a879824 | 188 | |
90b826f1 GR |
189 | set_bit(_WDOG_KEEPALIVE, &wd_data->status); |
190 | ||
664a3923 GR |
191 | wd_data->last_keepalive = jiffies; |
192 | return __watchdog_ping(wdd); | |
193 | } | |
7a879824 | 194 | |
664a3923 GR |
195 | static void watchdog_ping_work(struct work_struct *work) |
196 | { | |
197 | struct watchdog_core_data *wd_data; | |
198 | struct watchdog_device *wdd; | |
199 | ||
200 | wd_data = container_of(to_delayed_work(work), struct watchdog_core_data, | |
201 | work); | |
202 | ||
203 | mutex_lock(&wd_data->lock); | |
204 | wdd = wd_data->wdd; | |
ee142889 | 205 | if (wdd && (watchdog_active(wdd) || watchdog_hw_running(wdd))) |
664a3923 GR |
206 | __watchdog_ping(wdd); |
207 | mutex_unlock(&wd_data->lock); | |
234445b4 WVS |
208 | } |
209 | ||
210 | /* | |
211 | * watchdog_start: wrapper to start the watchdog. | |
bc794ac3 | 212 | * @wdd: the watchdog device to start |
234445b4 | 213 | * |
b4ffb190 GR |
214 | * The caller must hold wd_data->lock. |
215 | * | |
234445b4 WVS |
216 | * Start the watchdog if it is not active and mark it active. |
217 | * This function returns zero on success or a negative errno code for | |
218 | * failure. | |
219 | */ | |
220 | ||
bc794ac3 | 221 | static int watchdog_start(struct watchdog_device *wdd) |
234445b4 | 222 | { |
664a3923 GR |
223 | struct watchdog_core_data *wd_data = wdd->wd_data; |
224 | unsigned long started_at; | |
b4ffb190 | 225 | int err; |
e907df32 | 226 | |
bc794ac3 | 227 | if (watchdog_active(wdd)) |
b4ffb190 | 228 | return 0; |
234445b4 | 229 | |
90b826f1 GR |
230 | set_bit(_WDOG_KEEPALIVE, &wd_data->status); |
231 | ||
664a3923 | 232 | started_at = jiffies; |
ee142889 GR |
233 | if (watchdog_hw_running(wdd) && wdd->ops->ping) |
234 | err = wdd->ops->ping(wdd); | |
235 | else | |
236 | err = wdd->ops->start(wdd); | |
664a3923 | 237 | if (err == 0) { |
bc794ac3 | 238 | set_bit(WDOG_ACTIVE, &wdd->status); |
664a3923 GR |
239 | wd_data->last_keepalive = started_at; |
240 | watchdog_update_worker(wdd); | |
241 | } | |
7a879824 | 242 | |
7a879824 | 243 | return err; |
234445b4 WVS |
244 | } |
245 | ||
246 | /* | |
247 | * watchdog_stop: wrapper to stop the watchdog. | |
bc794ac3 | 248 | * @wdd: the watchdog device to stop |
234445b4 | 249 | * |
b4ffb190 GR |
250 | * The caller must hold wd_data->lock. |
251 | * | |
234445b4 WVS |
252 | * Stop the watchdog if it is still active and unmark it active. |
253 | * This function returns zero on success or a negative errno code for | |
254 | * failure. | |
7e192b9c | 255 | * If the 'nowayout' feature was set, the watchdog cannot be stopped. |
234445b4 WVS |
256 | */ |
257 | ||
bc794ac3 | 258 | static int watchdog_stop(struct watchdog_device *wdd) |
234445b4 | 259 | { |
ee142889 | 260 | int err = 0; |
e907df32 | 261 | |
bc794ac3 | 262 | if (!watchdog_active(wdd)) |
b4ffb190 | 263 | return 0; |
7e192b9c | 264 | |
bc794ac3 | 265 | if (test_bit(WDOG_NO_WAY_OUT, &wdd->status)) { |
0254e953 GR |
266 | pr_info("watchdog%d: nowayout prevents watchdog being stopped!\n", |
267 | wdd->id); | |
b4ffb190 | 268 | return -EBUSY; |
7e192b9c | 269 | } |
234445b4 | 270 | |
3c10bbde GR |
271 | if (wdd->ops->stop) { |
272 | clear_bit(WDOG_HW_RUNNING, &wdd->status); | |
d0684c8a | 273 | err = wdd->ops->stop(wdd); |
3c10bbde | 274 | } else { |
d0684c8a | 275 | set_bit(WDOG_HW_RUNNING, &wdd->status); |
3c10bbde | 276 | } |
d0684c8a | 277 | |
664a3923 | 278 | if (err == 0) { |
bc794ac3 | 279 | clear_bit(WDOG_ACTIVE, &wdd->status); |
ee142889 | 280 | watchdog_update_worker(wdd); |
664a3923 | 281 | } |
7a879824 | 282 | |
7a879824 HG |
283 | return err; |
284 | } | |
285 | ||
286 | /* | |
287 | * watchdog_get_status: wrapper to get the watchdog status | |
bc794ac3 | 288 | * @wdd: the watchdog device to get the status from |
b4ffb190 GR |
289 | * |
290 | * The caller must hold wd_data->lock. | |
7a879824 HG |
291 | * |
292 | * Get the watchdog's status flags. | |
293 | */ | |
294 | ||
b4ffb190 | 295 | static unsigned int watchdog_get_status(struct watchdog_device *wdd) |
7a879824 | 296 | { |
90b826f1 GR |
297 | struct watchdog_core_data *wd_data = wdd->wd_data; |
298 | unsigned int status; | |
7a879824 | 299 | |
90b826f1 GR |
300 | if (wdd->ops->status) |
301 | status = wdd->ops->status(wdd); | |
302 | else | |
303 | status = wdd->bootstatus & (WDIOF_CARDRESET | | |
304 | WDIOF_OVERHEAT | | |
305 | WDIOF_FANFAULT | | |
306 | WDIOF_EXTERN1 | | |
307 | WDIOF_EXTERN2 | | |
308 | WDIOF_POWERUNDER | | |
309 | WDIOF_POWEROVER); | |
310 | ||
311 | if (test_bit(_WDOG_ALLOW_RELEASE, &wd_data->status)) | |
312 | status |= WDIOF_MAGICCLOSE; | |
313 | ||
314 | if (test_and_clear_bit(_WDOG_KEEPALIVE, &wd_data->status)) | |
315 | status |= WDIOF_KEEPALIVEPING; | |
316 | ||
317 | return status; | |
7a879824 HG |
318 | } |
319 | ||
320 | /* | |
321 | * watchdog_set_timeout: set the watchdog timer timeout | |
bc794ac3 | 322 | * @wdd: the watchdog device to set the timeout for |
7a879824 | 323 | * @timeout: timeout to set in seconds |
b4ffb190 GR |
324 | * |
325 | * The caller must hold wd_data->lock. | |
7a879824 HG |
326 | */ |
327 | ||
bc794ac3 | 328 | static int watchdog_set_timeout(struct watchdog_device *wdd, |
7a879824 HG |
329 | unsigned int timeout) |
330 | { | |
fb32e9b9 GR |
331 | int err = 0; |
332 | ||
333 | if (!(wdd->info->options & WDIOF_SETTIMEOUT)) | |
7a879824 HG |
334 | return -EOPNOTSUPP; |
335 | ||
bc794ac3 | 336 | if (watchdog_timeout_invalid(wdd, timeout)) |
7a879824 HG |
337 | return -EINVAL; |
338 | ||
df044e02 | 339 | if (wdd->ops->set_timeout) { |
fb32e9b9 | 340 | err = wdd->ops->set_timeout(wdd, timeout); |
df044e02 | 341 | } else { |
fb32e9b9 | 342 | wdd->timeout = timeout; |
df044e02 WS |
343 | /* Disable pretimeout if it doesn't fit the new timeout */ |
344 | if (wdd->pretimeout >= wdd->timeout) | |
345 | wdd->pretimeout = 0; | |
346 | } | |
fb32e9b9 | 347 | |
664a3923 GR |
348 | watchdog_update_worker(wdd); |
349 | ||
fb32e9b9 | 350 | return err; |
7a879824 HG |
351 | } |
352 | ||
df044e02 WS |
353 | /* |
354 | * watchdog_set_pretimeout: set the watchdog timer pretimeout | |
355 | * @wdd: the watchdog device to set the timeout for | |
356 | * @timeout: pretimeout to set in seconds | |
357 | */ | |
358 | ||
359 | static int watchdog_set_pretimeout(struct watchdog_device *wdd, | |
360 | unsigned int timeout) | |
361 | { | |
362 | int err = 0; | |
363 | ||
364 | if (!(wdd->info->options & WDIOF_PRETIMEOUT)) | |
365 | return -EOPNOTSUPP; | |
366 | ||
367 | if (watchdog_pretimeout_invalid(wdd, timeout)) | |
368 | return -EINVAL; | |
369 | ||
370 | if (wdd->ops->set_pretimeout) | |
371 | err = wdd->ops->set_pretimeout(wdd, timeout); | |
372 | else | |
373 | wdd->pretimeout = timeout; | |
374 | ||
375 | return err; | |
376 | } | |
377 | ||
7a879824 HG |
378 | /* |
379 | * watchdog_get_timeleft: wrapper to get the time left before a reboot | |
bc794ac3 | 380 | * @wdd: the watchdog device to get the remaining time from |
7a879824 HG |
381 | * @timeleft: the time that's left |
382 | * | |
b4ffb190 GR |
383 | * The caller must hold wd_data->lock. |
384 | * | |
7a879824 HG |
385 | * Get the time before a watchdog will reboot (if not pinged). |
386 | */ | |
387 | ||
bc794ac3 | 388 | static int watchdog_get_timeleft(struct watchdog_device *wdd, |
7a879824 HG |
389 | unsigned int *timeleft) |
390 | { | |
7a879824 | 391 | *timeleft = 0; |
b4ffb190 | 392 | |
bc794ac3 | 393 | if (!wdd->ops->get_timeleft) |
7a879824 HG |
394 | return -EOPNOTSUPP; |
395 | ||
bc794ac3 | 396 | *timeleft = wdd->ops->get_timeleft(wdd); |
7a879824 | 397 | |
b4ffb190 | 398 | return 0; |
7a879824 HG |
399 | } |
400 | ||
33b71126 PA |
401 | #ifdef CONFIG_WATCHDOG_SYSFS |
402 | static ssize_t nowayout_show(struct device *dev, struct device_attribute *attr, | |
403 | char *buf) | |
404 | { | |
405 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
406 | ||
407 | return sprintf(buf, "%d\n", !!test_bit(WDOG_NO_WAY_OUT, &wdd->status)); | |
408 | } | |
409 | static DEVICE_ATTR_RO(nowayout); | |
410 | ||
411 | static ssize_t status_show(struct device *dev, struct device_attribute *attr, | |
412 | char *buf) | |
413 | { | |
414 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
b4ffb190 GR |
415 | struct watchdog_core_data *wd_data = wdd->wd_data; |
416 | unsigned int status; | |
33b71126 | 417 | |
b4ffb190 GR |
418 | mutex_lock(&wd_data->lock); |
419 | status = watchdog_get_status(wdd); | |
420 | mutex_unlock(&wd_data->lock); | |
33b71126 | 421 | |
90b826f1 | 422 | return sprintf(buf, "0x%x\n", status); |
33b71126 PA |
423 | } |
424 | static DEVICE_ATTR_RO(status); | |
425 | ||
426 | static ssize_t bootstatus_show(struct device *dev, | |
427 | struct device_attribute *attr, char *buf) | |
428 | { | |
429 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
430 | ||
431 | return sprintf(buf, "%u\n", wdd->bootstatus); | |
432 | } | |
433 | static DEVICE_ATTR_RO(bootstatus); | |
434 | ||
435 | static ssize_t timeleft_show(struct device *dev, struct device_attribute *attr, | |
436 | char *buf) | |
437 | { | |
438 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
b4ffb190 | 439 | struct watchdog_core_data *wd_data = wdd->wd_data; |
33b71126 PA |
440 | ssize_t status; |
441 | unsigned int val; | |
442 | ||
b4ffb190 | 443 | mutex_lock(&wd_data->lock); |
33b71126 | 444 | status = watchdog_get_timeleft(wdd, &val); |
b4ffb190 | 445 | mutex_unlock(&wd_data->lock); |
33b71126 PA |
446 | if (!status) |
447 | status = sprintf(buf, "%u\n", val); | |
448 | ||
449 | return status; | |
450 | } | |
451 | static DEVICE_ATTR_RO(timeleft); | |
452 | ||
453 | static ssize_t timeout_show(struct device *dev, struct device_attribute *attr, | |
454 | char *buf) | |
455 | { | |
456 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
457 | ||
458 | return sprintf(buf, "%u\n", wdd->timeout); | |
459 | } | |
460 | static DEVICE_ATTR_RO(timeout); | |
461 | ||
df044e02 WS |
462 | static ssize_t pretimeout_show(struct device *dev, |
463 | struct device_attribute *attr, char *buf) | |
464 | { | |
465 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
466 | ||
467 | return sprintf(buf, "%u\n", wdd->pretimeout); | |
468 | } | |
469 | static DEVICE_ATTR_RO(pretimeout); | |
470 | ||
33b71126 PA |
471 | static ssize_t identity_show(struct device *dev, struct device_attribute *attr, |
472 | char *buf) | |
473 | { | |
474 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
475 | ||
476 | return sprintf(buf, "%s\n", wdd->info->identity); | |
477 | } | |
478 | static DEVICE_ATTR_RO(identity); | |
479 | ||
480 | static ssize_t state_show(struct device *dev, struct device_attribute *attr, | |
481 | char *buf) | |
482 | { | |
483 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
484 | ||
485 | if (watchdog_active(wdd)) | |
486 | return sprintf(buf, "active\n"); | |
487 | ||
488 | return sprintf(buf, "inactive\n"); | |
489 | } | |
490 | static DEVICE_ATTR_RO(state); | |
491 | ||
ff84136c VZ |
492 | static ssize_t pretimeout_governor_show(struct device *dev, |
493 | struct device_attribute *attr, | |
494 | char *buf) | |
495 | { | |
496 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
497 | ||
498 | return watchdog_pretimeout_governor_get(wdd, buf); | |
499 | } | |
53f96cee VZ |
500 | |
501 | static ssize_t pretimeout_governor_store(struct device *dev, | |
502 | struct device_attribute *attr, | |
503 | const char *buf, size_t count) | |
504 | { | |
505 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
506 | int ret = watchdog_pretimeout_governor_set(wdd, buf); | |
507 | ||
508 | if (!ret) | |
509 | ret = count; | |
510 | ||
511 | return ret; | |
512 | } | |
513 | static DEVICE_ATTR_RW(pretimeout_governor); | |
ff84136c | 514 | |
33b71126 PA |
515 | static umode_t wdt_is_visible(struct kobject *kobj, struct attribute *attr, |
516 | int n) | |
517 | { | |
518 | struct device *dev = container_of(kobj, struct device, kobj); | |
519 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
520 | umode_t mode = attr->mode; | |
521 | ||
90b826f1 | 522 | if (attr == &dev_attr_timeleft.attr && !wdd->ops->get_timeleft) |
33b71126 | 523 | mode = 0; |
df044e02 WS |
524 | else if (attr == &dev_attr_pretimeout.attr && |
525 | !(wdd->info->options & WDIOF_PRETIMEOUT)) | |
526 | mode = 0; | |
ff84136c VZ |
527 | else if (attr == &dev_attr_pretimeout_governor.attr && |
528 | (!(wdd->info->options & WDIOF_PRETIMEOUT) || | |
529 | !IS_ENABLED(CONFIG_WATCHDOG_PRETIMEOUT_GOV))) | |
530 | mode = 0; | |
33b71126 PA |
531 | |
532 | return mode; | |
533 | } | |
534 | static struct attribute *wdt_attrs[] = { | |
535 | &dev_attr_state.attr, | |
536 | &dev_attr_identity.attr, | |
537 | &dev_attr_timeout.attr, | |
df044e02 | 538 | &dev_attr_pretimeout.attr, |
33b71126 PA |
539 | &dev_attr_timeleft.attr, |
540 | &dev_attr_bootstatus.attr, | |
541 | &dev_attr_status.attr, | |
542 | &dev_attr_nowayout.attr, | |
ff84136c | 543 | &dev_attr_pretimeout_governor.attr, |
33b71126 PA |
544 | NULL, |
545 | }; | |
546 | ||
547 | static const struct attribute_group wdt_group = { | |
548 | .attrs = wdt_attrs, | |
549 | .is_visible = wdt_is_visible, | |
550 | }; | |
551 | __ATTRIBUTE_GROUPS(wdt); | |
552 | #else | |
553 | #define wdt_groups NULL | |
554 | #endif | |
555 | ||
7a879824 HG |
556 | /* |
557 | * watchdog_ioctl_op: call the watchdog drivers ioctl op if defined | |
bc794ac3 | 558 | * @wdd: the watchdog device to do the ioctl on |
7a879824 HG |
559 | * @cmd: watchdog command |
560 | * @arg: argument pointer | |
b4ffb190 GR |
561 | * |
562 | * The caller must hold wd_data->lock. | |
7a879824 HG |
563 | */ |
564 | ||
bc794ac3 | 565 | static int watchdog_ioctl_op(struct watchdog_device *wdd, unsigned int cmd, |
7a879824 HG |
566 | unsigned long arg) |
567 | { | |
bc794ac3 | 568 | if (!wdd->ops->ioctl) |
7a879824 HG |
569 | return -ENOIOCTLCMD; |
570 | ||
b4ffb190 | 571 | return wdd->ops->ioctl(wdd, cmd, arg); |
43316044 WVS |
572 | } |
573 | ||
574 | /* | |
575 | * watchdog_write: writes to the watchdog. | |
576 | * @file: file from VFS | |
577 | * @data: user address of data | |
578 | * @len: length of data | |
579 | * @ppos: pointer to the file offset | |
580 | * | |
581 | * A write to a watchdog device is defined as a keepalive ping. | |
017cf080 | 582 | * Writing the magic 'V' sequence allows the next close to turn |
7e192b9c | 583 | * off the watchdog (if 'nowayout' is not set). |
43316044 WVS |
584 | */ |
585 | ||
586 | static ssize_t watchdog_write(struct file *file, const char __user *data, | |
587 | size_t len, loff_t *ppos) | |
588 | { | |
b4ffb190 GR |
589 | struct watchdog_core_data *wd_data = file->private_data; |
590 | struct watchdog_device *wdd; | |
591 | int err; | |
43316044 WVS |
592 | size_t i; |
593 | char c; | |
594 | ||
595 | if (len == 0) | |
596 | return 0; | |
597 | ||
017cf080 WVS |
598 | /* |
599 | * Note: just in case someone wrote the magic character | |
600 | * five months ago... | |
601 | */ | |
b4ffb190 | 602 | clear_bit(_WDOG_ALLOW_RELEASE, &wd_data->status); |
017cf080 WVS |
603 | |
604 | /* scan to see whether or not we got the magic character */ | |
43316044 WVS |
605 | for (i = 0; i != len; i++) { |
606 | if (get_user(c, data + i)) | |
607 | return -EFAULT; | |
017cf080 | 608 | if (c == 'V') |
b4ffb190 | 609 | set_bit(_WDOG_ALLOW_RELEASE, &wd_data->status); |
43316044 WVS |
610 | } |
611 | ||
612 | /* someone wrote to us, so we send the watchdog a keepalive ping */ | |
b4ffb190 GR |
613 | |
614 | err = -ENODEV; | |
615 | mutex_lock(&wd_data->lock); | |
616 | wdd = wd_data->wdd; | |
617 | if (wdd) | |
618 | err = watchdog_ping(wdd); | |
619 | mutex_unlock(&wd_data->lock); | |
620 | ||
5ef79663 AU |
621 | if (err < 0) |
622 | return err; | |
43316044 WVS |
623 | |
624 | return len; | |
625 | } | |
626 | ||
2fa03560 WVS |
627 | /* |
628 | * watchdog_ioctl: handle the different ioctl's for the watchdog device. | |
629 | * @file: file handle to the device | |
630 | * @cmd: watchdog command | |
631 | * @arg: argument pointer | |
632 | * | |
633 | * The watchdog API defines a common set of functions for all watchdogs | |
634 | * according to their available features. | |
635 | */ | |
636 | ||
637 | static long watchdog_ioctl(struct file *file, unsigned int cmd, | |
638 | unsigned long arg) | |
639 | { | |
b4ffb190 | 640 | struct watchdog_core_data *wd_data = file->private_data; |
2fa03560 | 641 | void __user *argp = (void __user *)arg; |
b4ffb190 | 642 | struct watchdog_device *wdd; |
2fa03560 WVS |
643 | int __user *p = argp; |
644 | unsigned int val; | |
234445b4 | 645 | int err; |
2fa03560 | 646 | |
b4ffb190 GR |
647 | mutex_lock(&wd_data->lock); |
648 | ||
649 | wdd = wd_data->wdd; | |
650 | if (!wdd) { | |
651 | err = -ENODEV; | |
652 | goto out_ioctl; | |
653 | } | |
654 | ||
7a879824 HG |
655 | err = watchdog_ioctl_op(wdd, cmd, arg); |
656 | if (err != -ENOIOCTLCMD) | |
b4ffb190 | 657 | goto out_ioctl; |
78d88fc0 | 658 | |
2fa03560 WVS |
659 | switch (cmd) { |
660 | case WDIOC_GETSUPPORT: | |
b4ffb190 | 661 | err = copy_to_user(argp, wdd->info, |
2fa03560 | 662 | sizeof(struct watchdog_info)) ? -EFAULT : 0; |
b4ffb190 | 663 | break; |
2fa03560 | 664 | case WDIOC_GETSTATUS: |
b4ffb190 GR |
665 | val = watchdog_get_status(wdd); |
666 | err = put_user(val, p); | |
667 | break; | |
2fa03560 | 668 | case WDIOC_GETBOOTSTATUS: |
b4ffb190 GR |
669 | err = put_user(wdd->bootstatus, p); |
670 | break; | |
234445b4 | 671 | case WDIOC_SETOPTIONS: |
b4ffb190 GR |
672 | if (get_user(val, p)) { |
673 | err = -EFAULT; | |
674 | break; | |
675 | } | |
234445b4 WVS |
676 | if (val & WDIOS_DISABLECARD) { |
677 | err = watchdog_stop(wdd); | |
678 | if (err < 0) | |
b4ffb190 | 679 | break; |
234445b4 | 680 | } |
b4ffb190 | 681 | if (val & WDIOS_ENABLECARD) |
234445b4 | 682 | err = watchdog_start(wdd); |
b4ffb190 | 683 | break; |
c2dc00e4 | 684 | case WDIOC_KEEPALIVE: |
b4ffb190 GR |
685 | if (!(wdd->info->options & WDIOF_KEEPALIVEPING)) { |
686 | err = -EOPNOTSUPP; | |
687 | break; | |
688 | } | |
689 | err = watchdog_ping(wdd); | |
690 | break; | |
014d694e | 691 | case WDIOC_SETTIMEOUT: |
b4ffb190 GR |
692 | if (get_user(val, p)) { |
693 | err = -EFAULT; | |
694 | break; | |
695 | } | |
7a879824 | 696 | err = watchdog_set_timeout(wdd, val); |
014d694e | 697 | if (err < 0) |
b4ffb190 | 698 | break; |
014d694e WVS |
699 | /* If the watchdog is active then we send a keepalive ping |
700 | * to make sure that the watchdog keep's running (and if | |
701 | * possible that it takes the new timeout) */ | |
5ef79663 AU |
702 | err = watchdog_ping(wdd); |
703 | if (err < 0) | |
b4ffb190 | 704 | break; |
014d694e WVS |
705 | /* Fall */ |
706 | case WDIOC_GETTIMEOUT: | |
707 | /* timeout == 0 means that we don't know the timeout */ | |
b4ffb190 GR |
708 | if (wdd->timeout == 0) { |
709 | err = -EOPNOTSUPP; | |
710 | break; | |
711 | } | |
712 | err = put_user(wdd->timeout, p); | |
713 | break; | |
fd7b673c | 714 | case WDIOC_GETTIMELEFT: |
7a879824 | 715 | err = watchdog_get_timeleft(wdd, &val); |
b4ffb190 GR |
716 | if (err < 0) |
717 | break; | |
718 | err = put_user(val, p); | |
719 | break; | |
df044e02 WS |
720 | case WDIOC_SETPRETIMEOUT: |
721 | if (get_user(val, p)) { | |
722 | err = -EFAULT; | |
723 | break; | |
724 | } | |
725 | err = watchdog_set_pretimeout(wdd, val); | |
726 | break; | |
727 | case WDIOC_GETPRETIMEOUT: | |
728 | err = put_user(wdd->pretimeout, p); | |
729 | break; | |
2fa03560 | 730 | default: |
b4ffb190 GR |
731 | err = -ENOTTY; |
732 | break; | |
2fa03560 | 733 | } |
b4ffb190 GR |
734 | |
735 | out_ioctl: | |
736 | mutex_unlock(&wd_data->lock); | |
737 | return err; | |
2fa03560 WVS |
738 | } |
739 | ||
43316044 | 740 | /* |
45f5fed3 | 741 | * watchdog_open: open the /dev/watchdog* devices. |
43316044 WVS |
742 | * @inode: inode of device |
743 | * @file: file handle to device | |
744 | * | |
45f5fed3 | 745 | * When the /dev/watchdog* device gets opened, we start the watchdog. |
43316044 WVS |
746 | * Watch out: the /dev/watchdog device is single open, so we make sure |
747 | * it can only be opened once. | |
748 | */ | |
749 | ||
750 | static int watchdog_open(struct inode *inode, struct file *file) | |
751 | { | |
b4ffb190 | 752 | struct watchdog_core_data *wd_data; |
45f5fed3 | 753 | struct watchdog_device *wdd; |
b4ffb190 | 754 | int err; |
45f5fed3 AC |
755 | |
756 | /* Get the corresponding watchdog device */ | |
757 | if (imajor(inode) == MISC_MAJOR) | |
b4ffb190 | 758 | wd_data = old_wd_data; |
45f5fed3 | 759 | else |
b4ffb190 GR |
760 | wd_data = container_of(inode->i_cdev, struct watchdog_core_data, |
761 | cdev); | |
43316044 WVS |
762 | |
763 | /* the watchdog is single open! */ | |
b4ffb190 | 764 | if (test_and_set_bit(_WDOG_DEV_OPEN, &wd_data->status)) |
43316044 WVS |
765 | return -EBUSY; |
766 | ||
b4ffb190 GR |
767 | wdd = wd_data->wdd; |
768 | ||
43316044 WVS |
769 | /* |
770 | * If the /dev/watchdog device is open, we don't want the module | |
771 | * to be unloaded. | |
772 | */ | |
ee142889 | 773 | if (!watchdog_hw_running(wdd) && !try_module_get(wdd->ops->owner)) { |
b4ffb190 GR |
774 | err = -EBUSY; |
775 | goto out_clear; | |
776 | } | |
43316044 | 777 | |
234445b4 | 778 | err = watchdog_start(wdd); |
43316044 WVS |
779 | if (err < 0) |
780 | goto out_mod; | |
781 | ||
b4ffb190 | 782 | file->private_data = wd_data; |
45f5fed3 | 783 | |
ee142889 GR |
784 | if (!watchdog_hw_running(wdd)) |
785 | kref_get(&wd_data->kref); | |
e907df32 | 786 | |
43316044 WVS |
787 | /* dev/watchdog is a virtual (and thus non-seekable) filesystem */ |
788 | return nonseekable_open(inode, file); | |
789 | ||
790 | out_mod: | |
b4ffb190 GR |
791 | module_put(wd_data->wdd->ops->owner); |
792 | out_clear: | |
793 | clear_bit(_WDOG_DEV_OPEN, &wd_data->status); | |
43316044 WVS |
794 | return err; |
795 | } | |
796 | ||
b4ffb190 GR |
797 | static void watchdog_core_data_release(struct kref *kref) |
798 | { | |
799 | struct watchdog_core_data *wd_data; | |
800 | ||
801 | wd_data = container_of(kref, struct watchdog_core_data, kref); | |
802 | ||
803 | kfree(wd_data); | |
804 | } | |
805 | ||
43316044 | 806 | /* |
45f5fed3 AC |
807 | * watchdog_release: release the watchdog device. |
808 | * @inode: inode of device | |
809 | * @file: file handle to device | |
43316044 | 810 | * |
017cf080 | 811 | * This is the code for when /dev/watchdog gets closed. We will only |
7e192b9c WVS |
812 | * stop the watchdog when we have received the magic char (and nowayout |
813 | * was not set), else the watchdog will keep running. | |
43316044 WVS |
814 | */ |
815 | ||
816 | static int watchdog_release(struct inode *inode, struct file *file) | |
817 | { | |
b4ffb190 GR |
818 | struct watchdog_core_data *wd_data = file->private_data; |
819 | struct watchdog_device *wdd; | |
017cf080 | 820 | int err = -EBUSY; |
d1ed3ba4 | 821 | bool running; |
017cf080 | 822 | |
b4ffb190 GR |
823 | mutex_lock(&wd_data->lock); |
824 | ||
825 | wdd = wd_data->wdd; | |
826 | if (!wdd) | |
827 | goto done; | |
828 | ||
017cf080 WVS |
829 | /* |
830 | * We only stop the watchdog if we received the magic character | |
7e192b9c WVS |
831 | * or if WDIOF_MAGICCLOSE is not set. If nowayout was set then |
832 | * watchdog_stop will fail. | |
017cf080 | 833 | */ |
fcf95670 HP |
834 | if (!test_bit(WDOG_ACTIVE, &wdd->status)) |
835 | err = 0; | |
b4ffb190 | 836 | else if (test_and_clear_bit(_WDOG_ALLOW_RELEASE, &wd_data->status) || |
fcf95670 | 837 | !(wdd->info->options & WDIOF_MAGICCLOSE)) |
017cf080 | 838 | err = watchdog_stop(wdd); |
43316044 | 839 | |
017cf080 | 840 | /* If the watchdog was not stopped, send a keepalive ping */ |
234445b4 | 841 | if (err < 0) { |
0254e953 | 842 | pr_crit("watchdog%d: watchdog did not stop!\n", wdd->id); |
43316044 WVS |
843 | watchdog_ping(wdd); |
844 | } | |
845 | ||
ee142889 | 846 | watchdog_update_worker(wdd); |
664a3923 | 847 | |
43316044 | 848 | /* make sure that /dev/watchdog can be re-opened */ |
b4ffb190 | 849 | clear_bit(_WDOG_DEV_OPEN, &wd_data->status); |
e907df32 | 850 | |
b4ffb190 | 851 | done: |
d1ed3ba4 | 852 | running = wdd && watchdog_hw_running(wdd); |
b4ffb190 | 853 | mutex_unlock(&wd_data->lock); |
ee142889 GR |
854 | /* |
855 | * Allow the owner module to be unloaded again unless the watchdog | |
856 | * is still running. If the watchdog is still running, it can not | |
857 | * be stopped, and its driver must not be unloaded. | |
858 | */ | |
d1ed3ba4 GR |
859 | if (!running) { |
860 | module_put(wd_data->cdev.owner); | |
ee142889 GR |
861 | kref_put(&wd_data->kref, watchdog_core_data_release); |
862 | } | |
43316044 WVS |
863 | return 0; |
864 | } | |
865 | ||
866 | static const struct file_operations watchdog_fops = { | |
867 | .owner = THIS_MODULE, | |
868 | .write = watchdog_write, | |
2fa03560 | 869 | .unlocked_ioctl = watchdog_ioctl, |
43316044 WVS |
870 | .open = watchdog_open, |
871 | .release = watchdog_release, | |
872 | }; | |
873 | ||
874 | static struct miscdevice watchdog_miscdev = { | |
875 | .minor = WATCHDOG_MINOR, | |
876 | .name = "watchdog", | |
877 | .fops = &watchdog_fops, | |
878 | }; | |
879 | ||
880 | /* | |
32ecc639 | 881 | * watchdog_cdev_register: register watchdog character device |
bc794ac3 | 882 | * @wdd: watchdog device |
32ecc639 | 883 | * @devno: character device number |
43316044 | 884 | * |
32ecc639 | 885 | * Register a watchdog character device including handling the legacy |
45f5fed3 AC |
886 | * /dev/watchdog node. /dev/watchdog is actually a miscdevice and |
887 | * thus we set it up like that. | |
43316044 WVS |
888 | */ |
889 | ||
32ecc639 | 890 | static int watchdog_cdev_register(struct watchdog_device *wdd, dev_t devno) |
43316044 | 891 | { |
b4ffb190 | 892 | struct watchdog_core_data *wd_data; |
32ecc639 | 893 | int err; |
45f5fed3 | 894 | |
b4ffb190 GR |
895 | wd_data = kzalloc(sizeof(struct watchdog_core_data), GFP_KERNEL); |
896 | if (!wd_data) | |
897 | return -ENOMEM; | |
898 | kref_init(&wd_data->kref); | |
899 | mutex_init(&wd_data->lock); | |
900 | ||
901 | wd_data->wdd = wdd; | |
902 | wdd->wd_data = wd_data; | |
903 | ||
664a3923 GR |
904 | if (!watchdog_wq) |
905 | return -ENODEV; | |
906 | ||
907 | INIT_DELAYED_WORK(&wd_data->work, watchdog_ping_work); | |
908 | ||
bc794ac3 | 909 | if (wdd->id == 0) { |
b4ffb190 | 910 | old_wd_data = wd_data; |
bc794ac3 | 911 | watchdog_miscdev.parent = wdd->parent; |
45f5fed3 AC |
912 | err = misc_register(&watchdog_miscdev); |
913 | if (err != 0) { | |
914 | pr_err("%s: cannot register miscdev on minor=%d (err=%d).\n", | |
bc794ac3 | 915 | wdd->info->identity, WATCHDOG_MINOR, err); |
45f5fed3 AC |
916 | if (err == -EBUSY) |
917 | pr_err("%s: a legacy watchdog module is probably present.\n", | |
bc794ac3 | 918 | wdd->info->identity); |
b4ffb190 GR |
919 | old_wd_data = NULL; |
920 | kfree(wd_data); | |
45f5fed3 AC |
921 | return err; |
922 | } | |
43316044 WVS |
923 | } |
924 | ||
45f5fed3 | 925 | /* Fill in the data structures */ |
b4ffb190 GR |
926 | cdev_init(&wd_data->cdev, &watchdog_fops); |
927 | wd_data->cdev.owner = wdd->ops->owner; | |
45f5fed3 AC |
928 | |
929 | /* Add the device */ | |
b4ffb190 | 930 | err = cdev_add(&wd_data->cdev, devno, 1); |
45f5fed3 AC |
931 | if (err) { |
932 | pr_err("watchdog%d unable to add device %d:%d\n", | |
bc794ac3 GR |
933 | wdd->id, MAJOR(watchdog_devt), wdd->id); |
934 | if (wdd->id == 0) { | |
45f5fed3 | 935 | misc_deregister(&watchdog_miscdev); |
b4ffb190 GR |
936 | old_wd_data = NULL; |
937 | kref_put(&wd_data->kref, watchdog_core_data_release); | |
45f5fed3 | 938 | } |
ee142889 | 939 | return err; |
43316044 | 940 | } |
ee142889 | 941 | |
15013ad8 GR |
942 | /* Record time of most recent heartbeat as 'just before now'. */ |
943 | wd_data->last_hw_keepalive = jiffies - 1; | |
944 | ||
ee142889 GR |
945 | /* |
946 | * If the watchdog is running, prevent its driver from being unloaded, | |
947 | * and schedule an immediate ping. | |
948 | */ | |
949 | if (watchdog_hw_running(wdd)) { | |
950 | __module_get(wdd->ops->owner); | |
951 | kref_get(&wd_data->kref); | |
952 | queue_delayed_work(watchdog_wq, &wd_data->work, 0); | |
953 | } | |
954 | ||
955 | return 0; | |
43316044 WVS |
956 | } |
957 | ||
958 | /* | |
32ecc639 | 959 | * watchdog_cdev_unregister: unregister watchdog character device |
43316044 WVS |
960 | * @watchdog: watchdog device |
961 | * | |
32ecc639 GR |
962 | * Unregister watchdog character device and if needed the legacy |
963 | * /dev/watchdog device. | |
43316044 WVS |
964 | */ |
965 | ||
32ecc639 | 966 | static void watchdog_cdev_unregister(struct watchdog_device *wdd) |
43316044 | 967 | { |
b4ffb190 | 968 | struct watchdog_core_data *wd_data = wdd->wd_data; |
e907df32 | 969 | |
b4ffb190 | 970 | cdev_del(&wd_data->cdev); |
bc794ac3 | 971 | if (wdd->id == 0) { |
45f5fed3 | 972 | misc_deregister(&watchdog_miscdev); |
b4ffb190 | 973 | old_wd_data = NULL; |
43316044 | 974 | } |
b4ffb190 GR |
975 | |
976 | mutex_lock(&wd_data->lock); | |
977 | wd_data->wdd = NULL; | |
978 | wdd->wd_data = NULL; | |
979 | mutex_unlock(&wd_data->lock); | |
980 | ||
664a3923 GR |
981 | cancel_delayed_work_sync(&wd_data->work); |
982 | ||
b4ffb190 | 983 | kref_put(&wd_data->kref, watchdog_core_data_release); |
43316044 | 984 | } |
45f5fed3 | 985 | |
906d7a5c PA |
986 | static struct class watchdog_class = { |
987 | .name = "watchdog", | |
988 | .owner = THIS_MODULE, | |
33b71126 | 989 | .dev_groups = wdt_groups, |
906d7a5c PA |
990 | }; |
991 | ||
32ecc639 GR |
992 | /* |
993 | * watchdog_dev_register: register a watchdog device | |
994 | * @wdd: watchdog device | |
995 | * | |
996 | * Register a watchdog device including handling the legacy | |
997 | * /dev/watchdog node. /dev/watchdog is actually a miscdevice and | |
998 | * thus we set it up like that. | |
999 | */ | |
1000 | ||
1001 | int watchdog_dev_register(struct watchdog_device *wdd) | |
1002 | { | |
1003 | struct device *dev; | |
1004 | dev_t devno; | |
1005 | int ret; | |
1006 | ||
1007 | devno = MKDEV(MAJOR(watchdog_devt), wdd->id); | |
1008 | ||
1009 | ret = watchdog_cdev_register(wdd, devno); | |
1010 | if (ret) | |
1011 | return ret; | |
1012 | ||
faa58475 GR |
1013 | dev = device_create_with_groups(&watchdog_class, wdd->parent, |
1014 | devno, wdd, wdd->groups, | |
1015 | "watchdog%d", wdd->id); | |
32ecc639 GR |
1016 | if (IS_ERR(dev)) { |
1017 | watchdog_cdev_unregister(wdd); | |
1018 | return PTR_ERR(dev); | |
1019 | } | |
32ecc639 | 1020 | |
ff84136c VZ |
1021 | ret = watchdog_register_pretimeout(wdd); |
1022 | if (ret) { | |
1023 | device_destroy(&watchdog_class, devno); | |
1024 | watchdog_cdev_unregister(wdd); | |
1025 | } | |
1026 | ||
32ecc639 GR |
1027 | return ret; |
1028 | } | |
1029 | ||
1030 | /* | |
1031 | * watchdog_dev_unregister: unregister a watchdog device | |
1032 | * @watchdog: watchdog device | |
1033 | * | |
1034 | * Unregister watchdog device and if needed the legacy | |
1035 | * /dev/watchdog device. | |
1036 | */ | |
1037 | ||
1038 | void watchdog_dev_unregister(struct watchdog_device *wdd) | |
1039 | { | |
ff84136c | 1040 | watchdog_unregister_pretimeout(wdd); |
0254e953 | 1041 | device_destroy(&watchdog_class, wdd->wd_data->cdev.dev); |
b4ffb190 | 1042 | watchdog_cdev_unregister(wdd); |
32ecc639 GR |
1043 | } |
1044 | ||
45f5fed3 AC |
1045 | /* |
1046 | * watchdog_dev_init: init dev part of watchdog core | |
1047 | * | |
1048 | * Allocate a range of chardev nodes to use for watchdog devices | |
1049 | */ | |
1050 | ||
32ecc639 | 1051 | int __init watchdog_dev_init(void) |
45f5fed3 | 1052 | { |
906d7a5c PA |
1053 | int err; |
1054 | ||
664a3923 GR |
1055 | watchdog_wq = alloc_workqueue("watchdogd", |
1056 | WQ_HIGHPRI | WQ_MEM_RECLAIM, 0); | |
1057 | if (!watchdog_wq) { | |
1058 | pr_err("Failed to create watchdog workqueue\n"); | |
1059 | return -ENOMEM; | |
1060 | } | |
1061 | ||
906d7a5c PA |
1062 | err = class_register(&watchdog_class); |
1063 | if (err < 0) { | |
1064 | pr_err("couldn't register class\n"); | |
138913cb | 1065 | goto err_register; |
906d7a5c PA |
1066 | } |
1067 | ||
1068 | err = alloc_chrdev_region(&watchdog_devt, 0, MAX_DOGS, "watchdog"); | |
1069 | if (err < 0) { | |
45f5fed3 | 1070 | pr_err("watchdog: unable to allocate char dev region\n"); |
138913cb | 1071 | goto err_alloc; |
906d7a5c PA |
1072 | } |
1073 | ||
32ecc639 | 1074 | return 0; |
138913cb WY |
1075 | |
1076 | err_alloc: | |
1077 | class_unregister(&watchdog_class); | |
1078 | err_register: | |
1079 | destroy_workqueue(watchdog_wq); | |
1080 | return err; | |
45f5fed3 AC |
1081 | } |
1082 | ||
1083 | /* | |
1084 | * watchdog_dev_exit: exit dev part of watchdog core | |
1085 | * | |
1086 | * Release the range of chardev nodes used for watchdog devices | |
1087 | */ | |
1088 | ||
1089 | void __exit watchdog_dev_exit(void) | |
1090 | { | |
1091 | unregister_chrdev_region(watchdog_devt, MAX_DOGS); | |
906d7a5c | 1092 | class_unregister(&watchdog_class); |
664a3923 | 1093 | destroy_workqueue(watchdog_wq); |
45f5fed3 | 1094 | } |