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d0173278 | 1 | // SPDX-License-Identifier: GPL-2.0+ |
43316044 WVS |
2 | /* |
3 | * watchdog_dev.c | |
4 | * | |
5 | * (c) Copyright 2008-2011 Alan Cox <alan@lxorguk.ukuu.org.uk>, | |
6 | * All Rights Reserved. | |
7 | * | |
8 | * (c) Copyright 2008-2011 Wim Van Sebroeck <wim@iguana.be>. | |
9 | * | |
10 | * | |
11 | * This source code is part of the generic code that can be used | |
12 | * by all the watchdog timer drivers. | |
13 | * | |
14 | * This part of the generic code takes care of the following | |
15 | * misc device: /dev/watchdog. | |
16 | * | |
17 | * Based on source code of the following authors: | |
18 | * Matt Domsch <Matt_Domsch@dell.com>, | |
19 | * Rob Radez <rob@osinvestor.com>, | |
20 | * Rusty Lynch <rusty@linux.co.intel.com> | |
21 | * Satyam Sharma <satyam@infradead.org> | |
22 | * Randy Dunlap <randy.dunlap@oracle.com> | |
23 | * | |
43316044 WVS |
24 | * Neither Alan Cox, CymruNet Ltd., Wim Van Sebroeck nor Iguana vzw. |
25 | * admit liability nor provide warranty for any of this software. | |
26 | * This material is provided "AS-IS" and at no charge. | |
27 | */ | |
28 | ||
29 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
30 | ||
b4ffb190 | 31 | #include <linux/cdev.h> /* For character device */ |
43316044 | 32 | #include <linux/errno.h> /* For the -ENODEV/... values */ |
43316044 | 33 | #include <linux/fs.h> /* For file operations */ |
43316044 | 34 | #include <linux/init.h> /* For __init/__exit/... */ |
1ff68820 | 35 | #include <linux/hrtimer.h> /* For hrtimers */ |
b4ffb190 | 36 | #include <linux/kernel.h> /* For printk/panic/... */ |
1ff68820 | 37 | #include <linux/kthread.h> /* For kthread_work */ |
b4ffb190 GR |
38 | #include <linux/miscdevice.h> /* For handling misc devices */ |
39 | #include <linux/module.h> /* For module stuff/... */ | |
40 | #include <linux/mutex.h> /* For mutexes */ | |
41 | #include <linux/slab.h> /* For memory functions */ | |
42 | #include <linux/types.h> /* For standard types (like size_t) */ | |
43 | #include <linux/watchdog.h> /* For watchdog specific items */ | |
43316044 WVS |
44 | #include <linux/uaccess.h> /* For copy_to_user/put_user/... */ |
45 | ||
38a1222a CL |
46 | #include <uapi/linux/sched/types.h> /* For struct sched_param */ |
47 | ||
6cfb5aa8 | 48 | #include "watchdog_core.h" |
ff84136c | 49 | #include "watchdog_pretimeout.h" |
09a46e73 | 50 | |
b4ffb190 GR |
51 | /* |
52 | * struct watchdog_core_data - watchdog core internal data | |
72139dfa | 53 | * @dev: The watchdog's internal device |
b4ffb190 GR |
54 | * @cdev: The watchdog's Character device. |
55 | * @wdd: Pointer to watchdog device. | |
56 | * @lock: Lock for watchdog core. | |
57 | * @status: Watchdog core internal status bits. | |
58 | */ | |
59 | struct watchdog_core_data { | |
72139dfa | 60 | struct device dev; |
b4ffb190 GR |
61 | struct cdev cdev; |
62 | struct watchdog_device *wdd; | |
63 | struct mutex lock; | |
1ff68820 CL |
64 | ktime_t last_keepalive; |
65 | ktime_t last_hw_keepalive; | |
4d1c6a0e | 66 | ktime_t open_deadline; |
1ff68820 CL |
67 | struct hrtimer timer; |
68 | struct kthread_work work; | |
b4ffb190 GR |
69 | unsigned long status; /* Internal status bits */ |
70 | #define _WDOG_DEV_OPEN 0 /* Opened ? */ | |
71 | #define _WDOG_ALLOW_RELEASE 1 /* Did we receive the magic char ? */ | |
90b826f1 | 72 | #define _WDOG_KEEPALIVE 2 /* Did we receive a keepalive ? */ |
b4ffb190 GR |
73 | }; |
74 | ||
45f5fed3 AC |
75 | /* the dev_t structure to store the dynamically allocated watchdog devices */ |
76 | static dev_t watchdog_devt; | |
b4ffb190 GR |
77 | /* Reference to watchdog device behind /dev/watchdog */ |
78 | static struct watchdog_core_data *old_wd_data; | |
43316044 | 79 | |
38a1222a | 80 | static struct kthread_worker *watchdog_kworker; |
664a3923 | 81 | |
2501b015 SR |
82 | static bool handle_boot_enabled = |
83 | IS_ENABLED(CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED); | |
84 | ||
487e4e08 | 85 | static unsigned open_timeout = CONFIG_WATCHDOG_OPEN_TIMEOUT; |
4d1c6a0e RV |
86 | |
87 | static bool watchdog_past_open_deadline(struct watchdog_core_data *data) | |
88 | { | |
89 | return ktime_after(ktime_get(), data->open_deadline); | |
90 | } | |
91 | ||
92 | static void watchdog_set_open_deadline(struct watchdog_core_data *data) | |
93 | { | |
94 | data->open_deadline = open_timeout ? | |
95 | ktime_get() + ktime_set(open_timeout, 0) : KTIME_MAX; | |
96 | } | |
97 | ||
664a3923 GR |
98 | static inline bool watchdog_need_worker(struct watchdog_device *wdd) |
99 | { | |
100 | /* All variables in milli-seconds */ | |
101 | unsigned int hm = wdd->max_hw_heartbeat_ms; | |
102 | unsigned int t = wdd->timeout * 1000; | |
103 | ||
104 | /* | |
105 | * A worker to generate heartbeat requests is needed if all of the | |
106 | * following conditions are true. | |
107 | * - Userspace activated the watchdog. | |
108 | * - The driver provided a value for the maximum hardware timeout, and | |
109 | * thus is aware that the framework supports generating heartbeat | |
110 | * requests. | |
111 | * - Userspace requests a longer timeout than the hardware can handle. | |
3fbfe926 RV |
112 | * |
113 | * Alternatively, if userspace has not opened the watchdog | |
114 | * device, we take care of feeding the watchdog if it is | |
115 | * running. | |
664a3923 | 116 | */ |
3fbfe926 RV |
117 | return (hm && watchdog_active(wdd) && t > hm) || |
118 | (t && !watchdog_active(wdd) && watchdog_hw_running(wdd)); | |
664a3923 GR |
119 | } |
120 | ||
1ff68820 | 121 | static ktime_t watchdog_next_keepalive(struct watchdog_device *wdd) |
664a3923 GR |
122 | { |
123 | struct watchdog_core_data *wd_data = wdd->wd_data; | |
124 | unsigned int timeout_ms = wdd->timeout * 1000; | |
1ff68820 CL |
125 | ktime_t keepalive_interval; |
126 | ktime_t last_heartbeat, latest_heartbeat; | |
127 | ktime_t virt_timeout; | |
664a3923 GR |
128 | unsigned int hw_heartbeat_ms; |
129 | ||
c2eac35b RV |
130 | if (watchdog_active(wdd)) |
131 | virt_timeout = ktime_add(wd_data->last_keepalive, | |
132 | ms_to_ktime(timeout_ms)); | |
133 | else | |
134 | virt_timeout = wd_data->open_deadline; | |
135 | ||
3fbfe926 | 136 | hw_heartbeat_ms = min_not_zero(timeout_ms, wdd->max_hw_heartbeat_ms); |
1ff68820 | 137 | keepalive_interval = ms_to_ktime(hw_heartbeat_ms / 2); |
664a3923 GR |
138 | |
139 | /* | |
140 | * To ensure that the watchdog times out wdd->timeout seconds | |
141 | * after the most recent ping from userspace, the last | |
142 | * worker ping has to come in hw_heartbeat_ms before this timeout. | |
143 | */ | |
1ff68820 CL |
144 | last_heartbeat = ktime_sub(virt_timeout, ms_to_ktime(hw_heartbeat_ms)); |
145 | latest_heartbeat = ktime_sub(last_heartbeat, ktime_get()); | |
146 | if (ktime_before(latest_heartbeat, keepalive_interval)) | |
147 | return latest_heartbeat; | |
148 | return keepalive_interval; | |
664a3923 GR |
149 | } |
150 | ||
151 | static inline void watchdog_update_worker(struct watchdog_device *wdd) | |
152 | { | |
153 | struct watchdog_core_data *wd_data = wdd->wd_data; | |
154 | ||
155 | if (watchdog_need_worker(wdd)) { | |
1ff68820 | 156 | ktime_t t = watchdog_next_keepalive(wdd); |
664a3923 GR |
157 | |
158 | if (t > 0) | |
a19f8933 JC |
159 | hrtimer_start(&wd_data->timer, t, |
160 | HRTIMER_MODE_REL_HARD); | |
664a3923 | 161 | } else { |
1ff68820 | 162 | hrtimer_cancel(&wd_data->timer); |
664a3923 GR |
163 | } |
164 | } | |
165 | ||
166 | static int __watchdog_ping(struct watchdog_device *wdd) | |
167 | { | |
15013ad8 | 168 | struct watchdog_core_data *wd_data = wdd->wd_data; |
1ff68820 | 169 | ktime_t earliest_keepalive, now; |
664a3923 GR |
170 | int err; |
171 | ||
1ff68820 CL |
172 | earliest_keepalive = ktime_add(wd_data->last_hw_keepalive, |
173 | ms_to_ktime(wdd->min_hw_heartbeat_ms)); | |
174 | now = ktime_get(); | |
175 | ||
176 | if (ktime_after(earliest_keepalive, now)) { | |
177 | hrtimer_start(&wd_data->timer, | |
178 | ktime_sub(earliest_keepalive, now), | |
a19f8933 | 179 | HRTIMER_MODE_REL_HARD); |
15013ad8 GR |
180 | return 0; |
181 | } | |
182 | ||
1ff68820 | 183 | wd_data->last_hw_keepalive = now; |
15013ad8 | 184 | |
664a3923 GR |
185 | if (wdd->ops->ping) |
186 | err = wdd->ops->ping(wdd); /* ping the watchdog */ | |
187 | else | |
188 | err = wdd->ops->start(wdd); /* restart watchdog */ | |
189 | ||
190 | watchdog_update_worker(wdd); | |
191 | ||
192 | return err; | |
193 | } | |
194 | ||
43316044 WVS |
195 | /* |
196 | * watchdog_ping: ping the watchdog. | |
bc794ac3 | 197 | * @wdd: the watchdog device to ping |
43316044 | 198 | * |
b4ffb190 GR |
199 | * The caller must hold wd_data->lock. |
200 | * | |
43316044 WVS |
201 | * If the watchdog has no own ping operation then it needs to be |
202 | * restarted via the start operation. This wrapper function does | |
203 | * exactly that. | |
234445b4 | 204 | * We only ping when the watchdog device is running. |
43316044 WVS |
205 | */ |
206 | ||
bc794ac3 | 207 | static int watchdog_ping(struct watchdog_device *wdd) |
43316044 | 208 | { |
664a3923 | 209 | struct watchdog_core_data *wd_data = wdd->wd_data; |
e907df32 | 210 | |
ee142889 | 211 | if (!watchdog_active(wdd) && !watchdog_hw_running(wdd)) |
b4ffb190 | 212 | return 0; |
7a879824 | 213 | |
90b826f1 GR |
214 | set_bit(_WDOG_KEEPALIVE, &wd_data->status); |
215 | ||
1ff68820 | 216 | wd_data->last_keepalive = ktime_get(); |
664a3923 GR |
217 | return __watchdog_ping(wdd); |
218 | } | |
7a879824 | 219 | |
c013b65a RV |
220 | static bool watchdog_worker_should_ping(struct watchdog_core_data *wd_data) |
221 | { | |
222 | struct watchdog_device *wdd = wd_data->wdd; | |
223 | ||
4d1c6a0e RV |
224 | if (!wdd) |
225 | return false; | |
226 | ||
227 | if (watchdog_active(wdd)) | |
228 | return true; | |
229 | ||
230 | return watchdog_hw_running(wdd) && !watchdog_past_open_deadline(wd_data); | |
c013b65a RV |
231 | } |
232 | ||
38a1222a | 233 | static void watchdog_ping_work(struct kthread_work *work) |
664a3923 GR |
234 | { |
235 | struct watchdog_core_data *wd_data; | |
664a3923 | 236 | |
1ff68820 | 237 | wd_data = container_of(work, struct watchdog_core_data, work); |
664a3923 GR |
238 | |
239 | mutex_lock(&wd_data->lock); | |
c013b65a RV |
240 | if (watchdog_worker_should_ping(wd_data)) |
241 | __watchdog_ping(wd_data->wdd); | |
664a3923 | 242 | mutex_unlock(&wd_data->lock); |
234445b4 WVS |
243 | } |
244 | ||
1ff68820 CL |
245 | static enum hrtimer_restart watchdog_timer_expired(struct hrtimer *timer) |
246 | { | |
247 | struct watchdog_core_data *wd_data; | |
248 | ||
249 | wd_data = container_of(timer, struct watchdog_core_data, timer); | |
250 | ||
251 | kthread_queue_work(watchdog_kworker, &wd_data->work); | |
252 | return HRTIMER_NORESTART; | |
253 | } | |
254 | ||
234445b4 WVS |
255 | /* |
256 | * watchdog_start: wrapper to start the watchdog. | |
bc794ac3 | 257 | * @wdd: the watchdog device to start |
234445b4 | 258 | * |
b4ffb190 GR |
259 | * The caller must hold wd_data->lock. |
260 | * | |
234445b4 WVS |
261 | * Start the watchdog if it is not active and mark it active. |
262 | * This function returns zero on success or a negative errno code for | |
263 | * failure. | |
264 | */ | |
265 | ||
bc794ac3 | 266 | static int watchdog_start(struct watchdog_device *wdd) |
234445b4 | 267 | { |
664a3923 | 268 | struct watchdog_core_data *wd_data = wdd->wd_data; |
1ff68820 | 269 | ktime_t started_at; |
b4ffb190 | 270 | int err; |
e907df32 | 271 | |
bc794ac3 | 272 | if (watchdog_active(wdd)) |
b4ffb190 | 273 | return 0; |
234445b4 | 274 | |
90b826f1 GR |
275 | set_bit(_WDOG_KEEPALIVE, &wd_data->status); |
276 | ||
1ff68820 | 277 | started_at = ktime_get(); |
ee142889 GR |
278 | if (watchdog_hw_running(wdd) && wdd->ops->ping) |
279 | err = wdd->ops->ping(wdd); | |
280 | else | |
281 | err = wdd->ops->start(wdd); | |
664a3923 | 282 | if (err == 0) { |
bc794ac3 | 283 | set_bit(WDOG_ACTIVE, &wdd->status); |
664a3923 | 284 | wd_data->last_keepalive = started_at; |
982bb705 | 285 | wd_data->last_hw_keepalive = started_at; |
664a3923 GR |
286 | watchdog_update_worker(wdd); |
287 | } | |
7a879824 | 288 | |
7a879824 | 289 | return err; |
234445b4 WVS |
290 | } |
291 | ||
292 | /* | |
293 | * watchdog_stop: wrapper to stop the watchdog. | |
bc794ac3 | 294 | * @wdd: the watchdog device to stop |
234445b4 | 295 | * |
b4ffb190 GR |
296 | * The caller must hold wd_data->lock. |
297 | * | |
234445b4 WVS |
298 | * Stop the watchdog if it is still active and unmark it active. |
299 | * This function returns zero on success or a negative errno code for | |
300 | * failure. | |
7e192b9c | 301 | * If the 'nowayout' feature was set, the watchdog cannot be stopped. |
234445b4 WVS |
302 | */ |
303 | ||
bc794ac3 | 304 | static int watchdog_stop(struct watchdog_device *wdd) |
234445b4 | 305 | { |
ee142889 | 306 | int err = 0; |
e907df32 | 307 | |
bc794ac3 | 308 | if (!watchdog_active(wdd)) |
b4ffb190 | 309 | return 0; |
7e192b9c | 310 | |
bc794ac3 | 311 | if (test_bit(WDOG_NO_WAY_OUT, &wdd->status)) { |
0254e953 GR |
312 | pr_info("watchdog%d: nowayout prevents watchdog being stopped!\n", |
313 | wdd->id); | |
b4ffb190 | 314 | return -EBUSY; |
7e192b9c | 315 | } |
234445b4 | 316 | |
3c10bbde GR |
317 | if (wdd->ops->stop) { |
318 | clear_bit(WDOG_HW_RUNNING, &wdd->status); | |
d0684c8a | 319 | err = wdd->ops->stop(wdd); |
3c10bbde | 320 | } else { |
d0684c8a | 321 | set_bit(WDOG_HW_RUNNING, &wdd->status); |
3c10bbde | 322 | } |
d0684c8a | 323 | |
664a3923 | 324 | if (err == 0) { |
bc794ac3 | 325 | clear_bit(WDOG_ACTIVE, &wdd->status); |
ee142889 | 326 | watchdog_update_worker(wdd); |
664a3923 | 327 | } |
7a879824 | 328 | |
7a879824 HG |
329 | return err; |
330 | } | |
331 | ||
332 | /* | |
333 | * watchdog_get_status: wrapper to get the watchdog status | |
bc794ac3 | 334 | * @wdd: the watchdog device to get the status from |
b4ffb190 GR |
335 | * |
336 | * The caller must hold wd_data->lock. | |
7a879824 HG |
337 | * |
338 | * Get the watchdog's status flags. | |
339 | */ | |
340 | ||
b4ffb190 | 341 | static unsigned int watchdog_get_status(struct watchdog_device *wdd) |
7a879824 | 342 | { |
90b826f1 GR |
343 | struct watchdog_core_data *wd_data = wdd->wd_data; |
344 | unsigned int status; | |
7a879824 | 345 | |
90b826f1 GR |
346 | if (wdd->ops->status) |
347 | status = wdd->ops->status(wdd); | |
348 | else | |
349 | status = wdd->bootstatus & (WDIOF_CARDRESET | | |
350 | WDIOF_OVERHEAT | | |
351 | WDIOF_FANFAULT | | |
352 | WDIOF_EXTERN1 | | |
353 | WDIOF_EXTERN2 | | |
354 | WDIOF_POWERUNDER | | |
355 | WDIOF_POWEROVER); | |
356 | ||
357 | if (test_bit(_WDOG_ALLOW_RELEASE, &wd_data->status)) | |
358 | status |= WDIOF_MAGICCLOSE; | |
359 | ||
360 | if (test_and_clear_bit(_WDOG_KEEPALIVE, &wd_data->status)) | |
361 | status |= WDIOF_KEEPALIVEPING; | |
362 | ||
363 | return status; | |
7a879824 HG |
364 | } |
365 | ||
366 | /* | |
367 | * watchdog_set_timeout: set the watchdog timer timeout | |
bc794ac3 | 368 | * @wdd: the watchdog device to set the timeout for |
7a879824 | 369 | * @timeout: timeout to set in seconds |
b4ffb190 GR |
370 | * |
371 | * The caller must hold wd_data->lock. | |
7a879824 HG |
372 | */ |
373 | ||
bc794ac3 | 374 | static int watchdog_set_timeout(struct watchdog_device *wdd, |
7a879824 HG |
375 | unsigned int timeout) |
376 | { | |
fb32e9b9 GR |
377 | int err = 0; |
378 | ||
379 | if (!(wdd->info->options & WDIOF_SETTIMEOUT)) | |
7a879824 HG |
380 | return -EOPNOTSUPP; |
381 | ||
bc794ac3 | 382 | if (watchdog_timeout_invalid(wdd, timeout)) |
7a879824 HG |
383 | return -EINVAL; |
384 | ||
df044e02 | 385 | if (wdd->ops->set_timeout) { |
fb32e9b9 | 386 | err = wdd->ops->set_timeout(wdd, timeout); |
df044e02 | 387 | } else { |
fb32e9b9 | 388 | wdd->timeout = timeout; |
df044e02 WS |
389 | /* Disable pretimeout if it doesn't fit the new timeout */ |
390 | if (wdd->pretimeout >= wdd->timeout) | |
391 | wdd->pretimeout = 0; | |
392 | } | |
fb32e9b9 | 393 | |
664a3923 GR |
394 | watchdog_update_worker(wdd); |
395 | ||
fb32e9b9 | 396 | return err; |
7a879824 HG |
397 | } |
398 | ||
df044e02 WS |
399 | /* |
400 | * watchdog_set_pretimeout: set the watchdog timer pretimeout | |
401 | * @wdd: the watchdog device to set the timeout for | |
402 | * @timeout: pretimeout to set in seconds | |
403 | */ | |
404 | ||
405 | static int watchdog_set_pretimeout(struct watchdog_device *wdd, | |
406 | unsigned int timeout) | |
407 | { | |
408 | int err = 0; | |
409 | ||
410 | if (!(wdd->info->options & WDIOF_PRETIMEOUT)) | |
411 | return -EOPNOTSUPP; | |
412 | ||
413 | if (watchdog_pretimeout_invalid(wdd, timeout)) | |
414 | return -EINVAL; | |
415 | ||
416 | if (wdd->ops->set_pretimeout) | |
417 | err = wdd->ops->set_pretimeout(wdd, timeout); | |
418 | else | |
419 | wdd->pretimeout = timeout; | |
420 | ||
421 | return err; | |
422 | } | |
423 | ||
7a879824 HG |
424 | /* |
425 | * watchdog_get_timeleft: wrapper to get the time left before a reboot | |
bc794ac3 | 426 | * @wdd: the watchdog device to get the remaining time from |
7a879824 HG |
427 | * @timeleft: the time that's left |
428 | * | |
b4ffb190 GR |
429 | * The caller must hold wd_data->lock. |
430 | * | |
7a879824 HG |
431 | * Get the time before a watchdog will reboot (if not pinged). |
432 | */ | |
433 | ||
bc794ac3 | 434 | static int watchdog_get_timeleft(struct watchdog_device *wdd, |
7a879824 HG |
435 | unsigned int *timeleft) |
436 | { | |
7a879824 | 437 | *timeleft = 0; |
b4ffb190 | 438 | |
bc794ac3 | 439 | if (!wdd->ops->get_timeleft) |
7a879824 HG |
440 | return -EOPNOTSUPP; |
441 | ||
bc794ac3 | 442 | *timeleft = wdd->ops->get_timeleft(wdd); |
7a879824 | 443 | |
b4ffb190 | 444 | return 0; |
7a879824 HG |
445 | } |
446 | ||
33b71126 PA |
447 | #ifdef CONFIG_WATCHDOG_SYSFS |
448 | static ssize_t nowayout_show(struct device *dev, struct device_attribute *attr, | |
449 | char *buf) | |
450 | { | |
451 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
452 | ||
453 | return sprintf(buf, "%d\n", !!test_bit(WDOG_NO_WAY_OUT, &wdd->status)); | |
454 | } | |
bc44fa73 RV |
455 | |
456 | static ssize_t nowayout_store(struct device *dev, struct device_attribute *attr, | |
457 | const char *buf, size_t len) | |
458 | { | |
459 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
460 | unsigned int value; | |
461 | int ret; | |
462 | ||
463 | ret = kstrtouint(buf, 0, &value); | |
464 | if (ret) | |
465 | return ret; | |
466 | if (value > 1) | |
467 | return -EINVAL; | |
468 | /* nowayout cannot be disabled once set */ | |
469 | if (test_bit(WDOG_NO_WAY_OUT, &wdd->status) && !value) | |
470 | return -EPERM; | |
471 | watchdog_set_nowayout(wdd, value); | |
472 | return len; | |
473 | } | |
474 | static DEVICE_ATTR_RW(nowayout); | |
33b71126 PA |
475 | |
476 | static ssize_t status_show(struct device *dev, struct device_attribute *attr, | |
477 | char *buf) | |
478 | { | |
479 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
b4ffb190 GR |
480 | struct watchdog_core_data *wd_data = wdd->wd_data; |
481 | unsigned int status; | |
33b71126 | 482 | |
b4ffb190 GR |
483 | mutex_lock(&wd_data->lock); |
484 | status = watchdog_get_status(wdd); | |
485 | mutex_unlock(&wd_data->lock); | |
33b71126 | 486 | |
90b826f1 | 487 | return sprintf(buf, "0x%x\n", status); |
33b71126 PA |
488 | } |
489 | static DEVICE_ATTR_RO(status); | |
490 | ||
491 | static ssize_t bootstatus_show(struct device *dev, | |
492 | struct device_attribute *attr, char *buf) | |
493 | { | |
494 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
495 | ||
496 | return sprintf(buf, "%u\n", wdd->bootstatus); | |
497 | } | |
498 | static DEVICE_ATTR_RO(bootstatus); | |
499 | ||
500 | static ssize_t timeleft_show(struct device *dev, struct device_attribute *attr, | |
501 | char *buf) | |
502 | { | |
503 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
b4ffb190 | 504 | struct watchdog_core_data *wd_data = wdd->wd_data; |
33b71126 PA |
505 | ssize_t status; |
506 | unsigned int val; | |
507 | ||
b4ffb190 | 508 | mutex_lock(&wd_data->lock); |
33b71126 | 509 | status = watchdog_get_timeleft(wdd, &val); |
b4ffb190 | 510 | mutex_unlock(&wd_data->lock); |
33b71126 PA |
511 | if (!status) |
512 | status = sprintf(buf, "%u\n", val); | |
513 | ||
514 | return status; | |
515 | } | |
516 | static DEVICE_ATTR_RO(timeleft); | |
517 | ||
518 | static ssize_t timeout_show(struct device *dev, struct device_attribute *attr, | |
519 | char *buf) | |
520 | { | |
521 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
522 | ||
523 | return sprintf(buf, "%u\n", wdd->timeout); | |
524 | } | |
525 | static DEVICE_ATTR_RO(timeout); | |
526 | ||
df044e02 WS |
527 | static ssize_t pretimeout_show(struct device *dev, |
528 | struct device_attribute *attr, char *buf) | |
529 | { | |
530 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
531 | ||
532 | return sprintf(buf, "%u\n", wdd->pretimeout); | |
533 | } | |
534 | static DEVICE_ATTR_RO(pretimeout); | |
535 | ||
33b71126 PA |
536 | static ssize_t identity_show(struct device *dev, struct device_attribute *attr, |
537 | char *buf) | |
538 | { | |
539 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
540 | ||
541 | return sprintf(buf, "%s\n", wdd->info->identity); | |
542 | } | |
543 | static DEVICE_ATTR_RO(identity); | |
544 | ||
545 | static ssize_t state_show(struct device *dev, struct device_attribute *attr, | |
546 | char *buf) | |
547 | { | |
548 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
549 | ||
550 | if (watchdog_active(wdd)) | |
551 | return sprintf(buf, "active\n"); | |
552 | ||
553 | return sprintf(buf, "inactive\n"); | |
554 | } | |
555 | static DEVICE_ATTR_RO(state); | |
556 | ||
89873a71 VZ |
557 | static ssize_t pretimeout_available_governors_show(struct device *dev, |
558 | struct device_attribute *attr, char *buf) | |
559 | { | |
560 | return watchdog_pretimeout_available_governors_get(buf); | |
561 | } | |
562 | static DEVICE_ATTR_RO(pretimeout_available_governors); | |
563 | ||
ff84136c VZ |
564 | static ssize_t pretimeout_governor_show(struct device *dev, |
565 | struct device_attribute *attr, | |
566 | char *buf) | |
567 | { | |
568 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
569 | ||
570 | return watchdog_pretimeout_governor_get(wdd, buf); | |
571 | } | |
53f96cee VZ |
572 | |
573 | static ssize_t pretimeout_governor_store(struct device *dev, | |
574 | struct device_attribute *attr, | |
575 | const char *buf, size_t count) | |
576 | { | |
577 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
578 | int ret = watchdog_pretimeout_governor_set(wdd, buf); | |
579 | ||
580 | if (!ret) | |
581 | ret = count; | |
582 | ||
583 | return ret; | |
584 | } | |
585 | static DEVICE_ATTR_RW(pretimeout_governor); | |
ff84136c | 586 | |
33b71126 PA |
587 | static umode_t wdt_is_visible(struct kobject *kobj, struct attribute *attr, |
588 | int n) | |
589 | { | |
590 | struct device *dev = container_of(kobj, struct device, kobj); | |
591 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
592 | umode_t mode = attr->mode; | |
593 | ||
90b826f1 | 594 | if (attr == &dev_attr_timeleft.attr && !wdd->ops->get_timeleft) |
33b71126 | 595 | mode = 0; |
df044e02 WS |
596 | else if (attr == &dev_attr_pretimeout.attr && |
597 | !(wdd->info->options & WDIOF_PRETIMEOUT)) | |
598 | mode = 0; | |
89873a71 VZ |
599 | else if ((attr == &dev_attr_pretimeout_governor.attr || |
600 | attr == &dev_attr_pretimeout_available_governors.attr) && | |
ff84136c VZ |
601 | (!(wdd->info->options & WDIOF_PRETIMEOUT) || |
602 | !IS_ENABLED(CONFIG_WATCHDOG_PRETIMEOUT_GOV))) | |
603 | mode = 0; | |
33b71126 PA |
604 | |
605 | return mode; | |
606 | } | |
607 | static struct attribute *wdt_attrs[] = { | |
608 | &dev_attr_state.attr, | |
609 | &dev_attr_identity.attr, | |
610 | &dev_attr_timeout.attr, | |
df044e02 | 611 | &dev_attr_pretimeout.attr, |
33b71126 PA |
612 | &dev_attr_timeleft.attr, |
613 | &dev_attr_bootstatus.attr, | |
614 | &dev_attr_status.attr, | |
615 | &dev_attr_nowayout.attr, | |
ff84136c | 616 | &dev_attr_pretimeout_governor.attr, |
89873a71 | 617 | &dev_attr_pretimeout_available_governors.attr, |
33b71126 PA |
618 | NULL, |
619 | }; | |
620 | ||
621 | static const struct attribute_group wdt_group = { | |
622 | .attrs = wdt_attrs, | |
623 | .is_visible = wdt_is_visible, | |
624 | }; | |
625 | __ATTRIBUTE_GROUPS(wdt); | |
626 | #else | |
627 | #define wdt_groups NULL | |
628 | #endif | |
629 | ||
7a879824 HG |
630 | /* |
631 | * watchdog_ioctl_op: call the watchdog drivers ioctl op if defined | |
bc794ac3 | 632 | * @wdd: the watchdog device to do the ioctl on |
7a879824 HG |
633 | * @cmd: watchdog command |
634 | * @arg: argument pointer | |
b4ffb190 GR |
635 | * |
636 | * The caller must hold wd_data->lock. | |
7a879824 HG |
637 | */ |
638 | ||
bc794ac3 | 639 | static int watchdog_ioctl_op(struct watchdog_device *wdd, unsigned int cmd, |
7a879824 HG |
640 | unsigned long arg) |
641 | { | |
bc794ac3 | 642 | if (!wdd->ops->ioctl) |
7a879824 HG |
643 | return -ENOIOCTLCMD; |
644 | ||
b4ffb190 | 645 | return wdd->ops->ioctl(wdd, cmd, arg); |
43316044 WVS |
646 | } |
647 | ||
648 | /* | |
649 | * watchdog_write: writes to the watchdog. | |
650 | * @file: file from VFS | |
651 | * @data: user address of data | |
652 | * @len: length of data | |
653 | * @ppos: pointer to the file offset | |
654 | * | |
655 | * A write to a watchdog device is defined as a keepalive ping. | |
017cf080 | 656 | * Writing the magic 'V' sequence allows the next close to turn |
7e192b9c | 657 | * off the watchdog (if 'nowayout' is not set). |
43316044 WVS |
658 | */ |
659 | ||
660 | static ssize_t watchdog_write(struct file *file, const char __user *data, | |
661 | size_t len, loff_t *ppos) | |
662 | { | |
b4ffb190 GR |
663 | struct watchdog_core_data *wd_data = file->private_data; |
664 | struct watchdog_device *wdd; | |
665 | int err; | |
43316044 WVS |
666 | size_t i; |
667 | char c; | |
668 | ||
669 | if (len == 0) | |
670 | return 0; | |
671 | ||
017cf080 WVS |
672 | /* |
673 | * Note: just in case someone wrote the magic character | |
674 | * five months ago... | |
675 | */ | |
b4ffb190 | 676 | clear_bit(_WDOG_ALLOW_RELEASE, &wd_data->status); |
017cf080 WVS |
677 | |
678 | /* scan to see whether or not we got the magic character */ | |
43316044 WVS |
679 | for (i = 0; i != len; i++) { |
680 | if (get_user(c, data + i)) | |
681 | return -EFAULT; | |
017cf080 | 682 | if (c == 'V') |
b4ffb190 | 683 | set_bit(_WDOG_ALLOW_RELEASE, &wd_data->status); |
43316044 WVS |
684 | } |
685 | ||
686 | /* someone wrote to us, so we send the watchdog a keepalive ping */ | |
b4ffb190 GR |
687 | |
688 | err = -ENODEV; | |
689 | mutex_lock(&wd_data->lock); | |
690 | wdd = wd_data->wdd; | |
691 | if (wdd) | |
692 | err = watchdog_ping(wdd); | |
693 | mutex_unlock(&wd_data->lock); | |
694 | ||
5ef79663 AU |
695 | if (err < 0) |
696 | return err; | |
43316044 WVS |
697 | |
698 | return len; | |
699 | } | |
700 | ||
2fa03560 WVS |
701 | /* |
702 | * watchdog_ioctl: handle the different ioctl's for the watchdog device. | |
703 | * @file: file handle to the device | |
704 | * @cmd: watchdog command | |
705 | * @arg: argument pointer | |
706 | * | |
707 | * The watchdog API defines a common set of functions for all watchdogs | |
708 | * according to their available features. | |
709 | */ | |
710 | ||
711 | static long watchdog_ioctl(struct file *file, unsigned int cmd, | |
712 | unsigned long arg) | |
713 | { | |
b4ffb190 | 714 | struct watchdog_core_data *wd_data = file->private_data; |
2fa03560 | 715 | void __user *argp = (void __user *)arg; |
b4ffb190 | 716 | struct watchdog_device *wdd; |
2fa03560 WVS |
717 | int __user *p = argp; |
718 | unsigned int val; | |
234445b4 | 719 | int err; |
2fa03560 | 720 | |
b4ffb190 GR |
721 | mutex_lock(&wd_data->lock); |
722 | ||
723 | wdd = wd_data->wdd; | |
724 | if (!wdd) { | |
725 | err = -ENODEV; | |
726 | goto out_ioctl; | |
727 | } | |
728 | ||
7a879824 HG |
729 | err = watchdog_ioctl_op(wdd, cmd, arg); |
730 | if (err != -ENOIOCTLCMD) | |
b4ffb190 | 731 | goto out_ioctl; |
78d88fc0 | 732 | |
2fa03560 WVS |
733 | switch (cmd) { |
734 | case WDIOC_GETSUPPORT: | |
b4ffb190 | 735 | err = copy_to_user(argp, wdd->info, |
2fa03560 | 736 | sizeof(struct watchdog_info)) ? -EFAULT : 0; |
b4ffb190 | 737 | break; |
2fa03560 | 738 | case WDIOC_GETSTATUS: |
b4ffb190 GR |
739 | val = watchdog_get_status(wdd); |
740 | err = put_user(val, p); | |
741 | break; | |
2fa03560 | 742 | case WDIOC_GETBOOTSTATUS: |
b4ffb190 GR |
743 | err = put_user(wdd->bootstatus, p); |
744 | break; | |
234445b4 | 745 | case WDIOC_SETOPTIONS: |
b4ffb190 GR |
746 | if (get_user(val, p)) { |
747 | err = -EFAULT; | |
748 | break; | |
749 | } | |
234445b4 WVS |
750 | if (val & WDIOS_DISABLECARD) { |
751 | err = watchdog_stop(wdd); | |
752 | if (err < 0) | |
b4ffb190 | 753 | break; |
234445b4 | 754 | } |
b4ffb190 | 755 | if (val & WDIOS_ENABLECARD) |
234445b4 | 756 | err = watchdog_start(wdd); |
b4ffb190 | 757 | break; |
c2dc00e4 | 758 | case WDIOC_KEEPALIVE: |
b4ffb190 GR |
759 | if (!(wdd->info->options & WDIOF_KEEPALIVEPING)) { |
760 | err = -EOPNOTSUPP; | |
761 | break; | |
762 | } | |
763 | err = watchdog_ping(wdd); | |
764 | break; | |
014d694e | 765 | case WDIOC_SETTIMEOUT: |
b4ffb190 GR |
766 | if (get_user(val, p)) { |
767 | err = -EFAULT; | |
768 | break; | |
769 | } | |
7a879824 | 770 | err = watchdog_set_timeout(wdd, val); |
014d694e | 771 | if (err < 0) |
b4ffb190 | 772 | break; |
014d694e WVS |
773 | /* If the watchdog is active then we send a keepalive ping |
774 | * to make sure that the watchdog keep's running (and if | |
775 | * possible that it takes the new timeout) */ | |
5ef79663 AU |
776 | err = watchdog_ping(wdd); |
777 | if (err < 0) | |
b4ffb190 | 778 | break; |
e2af3092 | 779 | /* fall through */ |
014d694e WVS |
780 | case WDIOC_GETTIMEOUT: |
781 | /* timeout == 0 means that we don't know the timeout */ | |
b4ffb190 GR |
782 | if (wdd->timeout == 0) { |
783 | err = -EOPNOTSUPP; | |
784 | break; | |
785 | } | |
786 | err = put_user(wdd->timeout, p); | |
787 | break; | |
fd7b673c | 788 | case WDIOC_GETTIMELEFT: |
7a879824 | 789 | err = watchdog_get_timeleft(wdd, &val); |
b4ffb190 GR |
790 | if (err < 0) |
791 | break; | |
792 | err = put_user(val, p); | |
793 | break; | |
df044e02 WS |
794 | case WDIOC_SETPRETIMEOUT: |
795 | if (get_user(val, p)) { | |
796 | err = -EFAULT; | |
797 | break; | |
798 | } | |
799 | err = watchdog_set_pretimeout(wdd, val); | |
800 | break; | |
801 | case WDIOC_GETPRETIMEOUT: | |
802 | err = put_user(wdd->pretimeout, p); | |
803 | break; | |
2fa03560 | 804 | default: |
b4ffb190 GR |
805 | err = -ENOTTY; |
806 | break; | |
2fa03560 | 807 | } |
b4ffb190 GR |
808 | |
809 | out_ioctl: | |
810 | mutex_unlock(&wd_data->lock); | |
811 | return err; | |
2fa03560 WVS |
812 | } |
813 | ||
43316044 | 814 | /* |
45f5fed3 | 815 | * watchdog_open: open the /dev/watchdog* devices. |
43316044 WVS |
816 | * @inode: inode of device |
817 | * @file: file handle to device | |
818 | * | |
45f5fed3 | 819 | * When the /dev/watchdog* device gets opened, we start the watchdog. |
43316044 WVS |
820 | * Watch out: the /dev/watchdog device is single open, so we make sure |
821 | * it can only be opened once. | |
822 | */ | |
823 | ||
824 | static int watchdog_open(struct inode *inode, struct file *file) | |
825 | { | |
b4ffb190 | 826 | struct watchdog_core_data *wd_data; |
45f5fed3 | 827 | struct watchdog_device *wdd; |
4bcd615f | 828 | bool hw_running; |
b4ffb190 | 829 | int err; |
45f5fed3 AC |
830 | |
831 | /* Get the corresponding watchdog device */ | |
832 | if (imajor(inode) == MISC_MAJOR) | |
b4ffb190 | 833 | wd_data = old_wd_data; |
45f5fed3 | 834 | else |
b4ffb190 GR |
835 | wd_data = container_of(inode->i_cdev, struct watchdog_core_data, |
836 | cdev); | |
43316044 WVS |
837 | |
838 | /* the watchdog is single open! */ | |
b4ffb190 | 839 | if (test_and_set_bit(_WDOG_DEV_OPEN, &wd_data->status)) |
43316044 WVS |
840 | return -EBUSY; |
841 | ||
b4ffb190 GR |
842 | wdd = wd_data->wdd; |
843 | ||
43316044 WVS |
844 | /* |
845 | * If the /dev/watchdog device is open, we don't want the module | |
846 | * to be unloaded. | |
847 | */ | |
4bcd615f GR |
848 | hw_running = watchdog_hw_running(wdd); |
849 | if (!hw_running && !try_module_get(wdd->ops->owner)) { | |
b4ffb190 GR |
850 | err = -EBUSY; |
851 | goto out_clear; | |
852 | } | |
43316044 | 853 | |
234445b4 | 854 | err = watchdog_start(wdd); |
43316044 WVS |
855 | if (err < 0) |
856 | goto out_mod; | |
857 | ||
b4ffb190 | 858 | file->private_data = wd_data; |
45f5fed3 | 859 | |
4bcd615f | 860 | if (!hw_running) |
72139dfa | 861 | get_device(&wd_data->dev); |
e907df32 | 862 | |
4d1c6a0e RV |
863 | /* |
864 | * open_timeout only applies for the first open from | |
865 | * userspace. Set open_deadline to infinity so that the kernel | |
866 | * will take care of an always-running hardware watchdog in | |
867 | * case the device gets magic-closed or WDIOS_DISABLECARD is | |
868 | * applied. | |
869 | */ | |
870 | wd_data->open_deadline = KTIME_MAX; | |
871 | ||
43316044 | 872 | /* dev/watchdog is a virtual (and thus non-seekable) filesystem */ |
c5bf68fe | 873 | return stream_open(inode, file); |
43316044 WVS |
874 | |
875 | out_mod: | |
b4ffb190 GR |
876 | module_put(wd_data->wdd->ops->owner); |
877 | out_clear: | |
878 | clear_bit(_WDOG_DEV_OPEN, &wd_data->status); | |
43316044 WVS |
879 | return err; |
880 | } | |
881 | ||
72139dfa | 882 | static void watchdog_core_data_release(struct device *dev) |
b4ffb190 GR |
883 | { |
884 | struct watchdog_core_data *wd_data; | |
885 | ||
72139dfa | 886 | wd_data = container_of(dev, struct watchdog_core_data, dev); |
b4ffb190 GR |
887 | |
888 | kfree(wd_data); | |
889 | } | |
890 | ||
43316044 | 891 | /* |
45f5fed3 AC |
892 | * watchdog_release: release the watchdog device. |
893 | * @inode: inode of device | |
894 | * @file: file handle to device | |
43316044 | 895 | * |
017cf080 | 896 | * This is the code for when /dev/watchdog gets closed. We will only |
7e192b9c WVS |
897 | * stop the watchdog when we have received the magic char (and nowayout |
898 | * was not set), else the watchdog will keep running. | |
43316044 WVS |
899 | */ |
900 | ||
901 | static int watchdog_release(struct inode *inode, struct file *file) | |
902 | { | |
b4ffb190 GR |
903 | struct watchdog_core_data *wd_data = file->private_data; |
904 | struct watchdog_device *wdd; | |
017cf080 | 905 | int err = -EBUSY; |
d1ed3ba4 | 906 | bool running; |
017cf080 | 907 | |
b4ffb190 GR |
908 | mutex_lock(&wd_data->lock); |
909 | ||
910 | wdd = wd_data->wdd; | |
911 | if (!wdd) | |
912 | goto done; | |
913 | ||
017cf080 WVS |
914 | /* |
915 | * We only stop the watchdog if we received the magic character | |
7e192b9c WVS |
916 | * or if WDIOF_MAGICCLOSE is not set. If nowayout was set then |
917 | * watchdog_stop will fail. | |
017cf080 | 918 | */ |
0be01476 | 919 | if (!watchdog_active(wdd)) |
fcf95670 | 920 | err = 0; |
b4ffb190 | 921 | else if (test_and_clear_bit(_WDOG_ALLOW_RELEASE, &wd_data->status) || |
fcf95670 | 922 | !(wdd->info->options & WDIOF_MAGICCLOSE)) |
017cf080 | 923 | err = watchdog_stop(wdd); |
43316044 | 924 | |
017cf080 | 925 | /* If the watchdog was not stopped, send a keepalive ping */ |
234445b4 | 926 | if (err < 0) { |
0254e953 | 927 | pr_crit("watchdog%d: watchdog did not stop!\n", wdd->id); |
43316044 WVS |
928 | watchdog_ping(wdd); |
929 | } | |
930 | ||
ee142889 | 931 | watchdog_update_worker(wdd); |
664a3923 | 932 | |
43316044 | 933 | /* make sure that /dev/watchdog can be re-opened */ |
b4ffb190 | 934 | clear_bit(_WDOG_DEV_OPEN, &wd_data->status); |
e907df32 | 935 | |
b4ffb190 | 936 | done: |
d1ed3ba4 | 937 | running = wdd && watchdog_hw_running(wdd); |
b4ffb190 | 938 | mutex_unlock(&wd_data->lock); |
ee142889 GR |
939 | /* |
940 | * Allow the owner module to be unloaded again unless the watchdog | |
941 | * is still running. If the watchdog is still running, it can not | |
942 | * be stopped, and its driver must not be unloaded. | |
943 | */ | |
d1ed3ba4 GR |
944 | if (!running) { |
945 | module_put(wd_data->cdev.owner); | |
72139dfa | 946 | put_device(&wd_data->dev); |
ee142889 | 947 | } |
43316044 WVS |
948 | return 0; |
949 | } | |
950 | ||
951 | static const struct file_operations watchdog_fops = { | |
952 | .owner = THIS_MODULE, | |
953 | .write = watchdog_write, | |
2fa03560 | 954 | .unlocked_ioctl = watchdog_ioctl, |
b6dfb247 | 955 | .compat_ioctl = compat_ptr_ioctl, |
43316044 WVS |
956 | .open = watchdog_open, |
957 | .release = watchdog_release, | |
958 | }; | |
959 | ||
960 | static struct miscdevice watchdog_miscdev = { | |
961 | .minor = WATCHDOG_MINOR, | |
962 | .name = "watchdog", | |
963 | .fops = &watchdog_fops, | |
964 | }; | |
965 | ||
72139dfa KH |
966 | static struct class watchdog_class = { |
967 | .name = "watchdog", | |
968 | .owner = THIS_MODULE, | |
969 | .dev_groups = wdt_groups, | |
970 | }; | |
971 | ||
43316044 | 972 | /* |
32ecc639 | 973 | * watchdog_cdev_register: register watchdog character device |
bc794ac3 | 974 | * @wdd: watchdog device |
43316044 | 975 | * |
32ecc639 | 976 | * Register a watchdog character device including handling the legacy |
45f5fed3 AC |
977 | * /dev/watchdog node. /dev/watchdog is actually a miscdevice and |
978 | * thus we set it up like that. | |
43316044 WVS |
979 | */ |
980 | ||
72139dfa | 981 | static int watchdog_cdev_register(struct watchdog_device *wdd) |
43316044 | 982 | { |
b4ffb190 | 983 | struct watchdog_core_data *wd_data; |
32ecc639 | 984 | int err; |
45f5fed3 | 985 | |
b4ffb190 GR |
986 | wd_data = kzalloc(sizeof(struct watchdog_core_data), GFP_KERNEL); |
987 | if (!wd_data) | |
988 | return -ENOMEM; | |
b4ffb190 GR |
989 | mutex_init(&wd_data->lock); |
990 | ||
991 | wd_data->wdd = wdd; | |
992 | wdd->wd_data = wd_data; | |
993 | ||
38a1222a | 994 | if (IS_ERR_OR_NULL(watchdog_kworker)) |
664a3923 GR |
995 | return -ENODEV; |
996 | ||
1ff68820 | 997 | kthread_init_work(&wd_data->work, watchdog_ping_work); |
a19f8933 | 998 | hrtimer_init(&wd_data->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD); |
1ff68820 | 999 | wd_data->timer.function = watchdog_timer_expired; |
664a3923 | 1000 | |
bc794ac3 | 1001 | if (wdd->id == 0) { |
b4ffb190 | 1002 | old_wd_data = wd_data; |
bc794ac3 | 1003 | watchdog_miscdev.parent = wdd->parent; |
45f5fed3 AC |
1004 | err = misc_register(&watchdog_miscdev); |
1005 | if (err != 0) { | |
1006 | pr_err("%s: cannot register miscdev on minor=%d (err=%d).\n", | |
bc794ac3 | 1007 | wdd->info->identity, WATCHDOG_MINOR, err); |
45f5fed3 AC |
1008 | if (err == -EBUSY) |
1009 | pr_err("%s: a legacy watchdog module is probably present.\n", | |
bc794ac3 | 1010 | wdd->info->identity); |
b4ffb190 GR |
1011 | old_wd_data = NULL; |
1012 | kfree(wd_data); | |
45f5fed3 AC |
1013 | return err; |
1014 | } | |
43316044 WVS |
1015 | } |
1016 | ||
72139dfa KH |
1017 | device_initialize(&wd_data->dev); |
1018 | wd_data->dev.devt = MKDEV(MAJOR(watchdog_devt), wdd->id); | |
1019 | wd_data->dev.class = &watchdog_class; | |
1020 | wd_data->dev.parent = wdd->parent; | |
1021 | wd_data->dev.groups = wdd->groups; | |
1022 | wd_data->dev.release = watchdog_core_data_release; | |
1023 | dev_set_drvdata(&wd_data->dev, wdd); | |
1024 | dev_set_name(&wd_data->dev, "watchdog%d", wdd->id); | |
1025 | ||
45f5fed3 | 1026 | /* Fill in the data structures */ |
b4ffb190 | 1027 | cdev_init(&wd_data->cdev, &watchdog_fops); |
45f5fed3 AC |
1028 | |
1029 | /* Add the device */ | |
72139dfa | 1030 | err = cdev_device_add(&wd_data->cdev, &wd_data->dev); |
45f5fed3 AC |
1031 | if (err) { |
1032 | pr_err("watchdog%d unable to add device %d:%d\n", | |
bc794ac3 GR |
1033 | wdd->id, MAJOR(watchdog_devt), wdd->id); |
1034 | if (wdd->id == 0) { | |
45f5fed3 | 1035 | misc_deregister(&watchdog_miscdev); |
b4ffb190 | 1036 | old_wd_data = NULL; |
72139dfa | 1037 | put_device(&wd_data->dev); |
45f5fed3 | 1038 | } |
ee142889 | 1039 | return err; |
43316044 | 1040 | } |
ee142889 | 1041 | |
72139dfa KH |
1042 | wd_data->cdev.owner = wdd->ops->owner; |
1043 | ||
15013ad8 | 1044 | /* Record time of most recent heartbeat as 'just before now'. */ |
1ff68820 | 1045 | wd_data->last_hw_keepalive = ktime_sub(ktime_get(), 1); |
4d1c6a0e | 1046 | watchdog_set_open_deadline(wd_data); |
15013ad8 | 1047 | |
ee142889 GR |
1048 | /* |
1049 | * If the watchdog is running, prevent its driver from being unloaded, | |
1050 | * and schedule an immediate ping. | |
1051 | */ | |
1052 | if (watchdog_hw_running(wdd)) { | |
914d65f3 | 1053 | __module_get(wdd->ops->owner); |
72139dfa | 1054 | get_device(&wd_data->dev); |
914d65f3 | 1055 | if (handle_boot_enabled) |
a19f8933 JC |
1056 | hrtimer_start(&wd_data->timer, 0, |
1057 | HRTIMER_MODE_REL_HARD); | |
914d65f3 | 1058 | else |
2501b015 | 1059 | pr_info("watchdog%d running and kernel based pre-userspace handler disabled\n", |
914d65f3 | 1060 | wdd->id); |
ee142889 GR |
1061 | } |
1062 | ||
1063 | return 0; | |
43316044 WVS |
1064 | } |
1065 | ||
1066 | /* | |
32ecc639 | 1067 | * watchdog_cdev_unregister: unregister watchdog character device |
43316044 WVS |
1068 | * @watchdog: watchdog device |
1069 | * | |
32ecc639 GR |
1070 | * Unregister watchdog character device and if needed the legacy |
1071 | * /dev/watchdog device. | |
43316044 WVS |
1072 | */ |
1073 | ||
32ecc639 | 1074 | static void watchdog_cdev_unregister(struct watchdog_device *wdd) |
43316044 | 1075 | { |
b4ffb190 | 1076 | struct watchdog_core_data *wd_data = wdd->wd_data; |
e907df32 | 1077 | |
72139dfa | 1078 | cdev_device_del(&wd_data->cdev, &wd_data->dev); |
bc794ac3 | 1079 | if (wdd->id == 0) { |
45f5fed3 | 1080 | misc_deregister(&watchdog_miscdev); |
b4ffb190 | 1081 | old_wd_data = NULL; |
43316044 | 1082 | } |
b4ffb190 | 1083 | |
bb292ac1 GR |
1084 | if (watchdog_active(wdd) && |
1085 | test_bit(WDOG_STOP_ON_UNREGISTER, &wdd->status)) { | |
1086 | watchdog_stop(wdd); | |
1087 | } | |
1088 | ||
953b9dd7 WS |
1089 | mutex_lock(&wd_data->lock); |
1090 | wd_data->wdd = NULL; | |
1091 | wdd->wd_data = NULL; | |
1092 | mutex_unlock(&wd_data->lock); | |
1093 | ||
1ff68820 CL |
1094 | hrtimer_cancel(&wd_data->timer); |
1095 | kthread_cancel_work_sync(&wd_data->work); | |
664a3923 | 1096 | |
72139dfa | 1097 | put_device(&wd_data->dev); |
43316044 | 1098 | } |
45f5fed3 | 1099 | |
32ecc639 GR |
1100 | /* |
1101 | * watchdog_dev_register: register a watchdog device | |
1102 | * @wdd: watchdog device | |
1103 | * | |
1104 | * Register a watchdog device including handling the legacy | |
1105 | * /dev/watchdog node. /dev/watchdog is actually a miscdevice and | |
1106 | * thus we set it up like that. | |
1107 | */ | |
1108 | ||
1109 | int watchdog_dev_register(struct watchdog_device *wdd) | |
1110 | { | |
32ecc639 GR |
1111 | int ret; |
1112 | ||
72139dfa | 1113 | ret = watchdog_cdev_register(wdd); |
32ecc639 GR |
1114 | if (ret) |
1115 | return ret; | |
1116 | ||
ff84136c | 1117 | ret = watchdog_register_pretimeout(wdd); |
69503e58 | 1118 | if (ret) |
ff84136c | 1119 | watchdog_cdev_unregister(wdd); |
ff84136c | 1120 | |
32ecc639 GR |
1121 | return ret; |
1122 | } | |
1123 | ||
1124 | /* | |
1125 | * watchdog_dev_unregister: unregister a watchdog device | |
1126 | * @watchdog: watchdog device | |
1127 | * | |
1128 | * Unregister watchdog device and if needed the legacy | |
1129 | * /dev/watchdog device. | |
1130 | */ | |
1131 | ||
1132 | void watchdog_dev_unregister(struct watchdog_device *wdd) | |
1133 | { | |
ff84136c | 1134 | watchdog_unregister_pretimeout(wdd); |
b4ffb190 | 1135 | watchdog_cdev_unregister(wdd); |
32ecc639 GR |
1136 | } |
1137 | ||
45f5fed3 AC |
1138 | /* |
1139 | * watchdog_dev_init: init dev part of watchdog core | |
1140 | * | |
1141 | * Allocate a range of chardev nodes to use for watchdog devices | |
1142 | */ | |
1143 | ||
32ecc639 | 1144 | int __init watchdog_dev_init(void) |
45f5fed3 | 1145 | { |
906d7a5c | 1146 | int err; |
38a1222a | 1147 | struct sched_param param = {.sched_priority = MAX_RT_PRIO - 1,}; |
906d7a5c | 1148 | |
38a1222a CL |
1149 | watchdog_kworker = kthread_create_worker(0, "watchdogd"); |
1150 | if (IS_ERR(watchdog_kworker)) { | |
1151 | pr_err("Failed to create watchdog kworker\n"); | |
1152 | return PTR_ERR(watchdog_kworker); | |
664a3923 | 1153 | } |
38a1222a | 1154 | sched_setscheduler(watchdog_kworker->task, SCHED_FIFO, ¶m); |
664a3923 | 1155 | |
906d7a5c PA |
1156 | err = class_register(&watchdog_class); |
1157 | if (err < 0) { | |
1158 | pr_err("couldn't register class\n"); | |
138913cb | 1159 | goto err_register; |
906d7a5c PA |
1160 | } |
1161 | ||
1162 | err = alloc_chrdev_region(&watchdog_devt, 0, MAX_DOGS, "watchdog"); | |
1163 | if (err < 0) { | |
45f5fed3 | 1164 | pr_err("watchdog: unable to allocate char dev region\n"); |
138913cb | 1165 | goto err_alloc; |
906d7a5c PA |
1166 | } |
1167 | ||
32ecc639 | 1168 | return 0; |
138913cb WY |
1169 | |
1170 | err_alloc: | |
1171 | class_unregister(&watchdog_class); | |
1172 | err_register: | |
38a1222a | 1173 | kthread_destroy_worker(watchdog_kworker); |
138913cb | 1174 | return err; |
45f5fed3 AC |
1175 | } |
1176 | ||
1177 | /* | |
1178 | * watchdog_dev_exit: exit dev part of watchdog core | |
1179 | * | |
1180 | * Release the range of chardev nodes used for watchdog devices | |
1181 | */ | |
1182 | ||
1183 | void __exit watchdog_dev_exit(void) | |
1184 | { | |
1185 | unregister_chrdev_region(watchdog_devt, MAX_DOGS); | |
906d7a5c | 1186 | class_unregister(&watchdog_class); |
38a1222a | 1187 | kthread_destroy_worker(watchdog_kworker); |
45f5fed3 | 1188 | } |
2501b015 SR |
1189 | |
1190 | module_param(handle_boot_enabled, bool, 0444); | |
1191 | MODULE_PARM_DESC(handle_boot_enabled, | |
1192 | "Watchdog core auto-updates boot enabled watchdogs before userspace takes over (default=" | |
1193 | __MODULE_STRING(IS_ENABLED(CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED)) ")"); | |
4d1c6a0e RV |
1194 | |
1195 | module_param(open_timeout, uint, 0644); | |
1196 | MODULE_PARM_DESC(open_timeout, | |
487e4e08 RV |
1197 | "Maximum time (in seconds, 0 means infinity) for userspace to take over a running watchdog (default=" |
1198 | __MODULE_STRING(CONFIG_WATCHDOG_OPEN_TIMEOUT) ")"); |