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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 GR |
36 | #include <linux/kernel.h> /* For printk/panic/... */ |
37 | #include <linux/kref.h> /* For data references */ | |
1ff68820 | 38 | #include <linux/kthread.h> /* For kthread_work */ |
b4ffb190 GR |
39 | #include <linux/miscdevice.h> /* For handling misc devices */ |
40 | #include <linux/module.h> /* For module stuff/... */ | |
41 | #include <linux/mutex.h> /* For mutexes */ | |
44ea3942 | 42 | #include <linux/reboot.h> /* For reboot notifier */ |
b4ffb190 GR |
43 | #include <linux/slab.h> /* For memory functions */ |
44 | #include <linux/types.h> /* For standard types (like size_t) */ | |
45 | #include <linux/watchdog.h> /* For watchdog specific items */ | |
43316044 WVS |
46 | #include <linux/uaccess.h> /* For copy_to_user/put_user/... */ |
47 | ||
38a1222a CL |
48 | #include <uapi/linux/sched/types.h> /* For struct sched_param */ |
49 | ||
6cfb5aa8 | 50 | #include "watchdog_core.h" |
ff84136c | 51 | #include "watchdog_pretimeout.h" |
09a46e73 | 52 | |
b4ffb190 GR |
53 | /* |
54 | * struct watchdog_core_data - watchdog core internal data | |
55 | * @kref: Reference count. | |
56 | * @cdev: The watchdog's Character device. | |
57 | * @wdd: Pointer to watchdog device. | |
58 | * @lock: Lock for watchdog core. | |
59 | * @status: Watchdog core internal status bits. | |
60 | */ | |
61 | struct watchdog_core_data { | |
62 | struct kref kref; | |
63 | struct cdev cdev; | |
64 | struct watchdog_device *wdd; | |
65 | struct mutex lock; | |
1ff68820 CL |
66 | ktime_t last_keepalive; |
67 | ktime_t last_hw_keepalive; | |
4d1c6a0e | 68 | ktime_t open_deadline; |
1ff68820 CL |
69 | struct hrtimer timer; |
70 | struct kthread_work work; | |
b4ffb190 GR |
71 | unsigned long status; /* Internal status bits */ |
72 | #define _WDOG_DEV_OPEN 0 /* Opened ? */ | |
73 | #define _WDOG_ALLOW_RELEASE 1 /* Did we receive the magic char ? */ | |
90b826f1 | 74 | #define _WDOG_KEEPALIVE 2 /* Did we receive a keepalive ? */ |
b4ffb190 GR |
75 | }; |
76 | ||
45f5fed3 AC |
77 | /* the dev_t structure to store the dynamically allocated watchdog devices */ |
78 | static dev_t watchdog_devt; | |
b4ffb190 GR |
79 | /* Reference to watchdog device behind /dev/watchdog */ |
80 | static struct watchdog_core_data *old_wd_data; | |
43316044 | 81 | |
38a1222a | 82 | static struct kthread_worker *watchdog_kworker; |
664a3923 | 83 | |
2501b015 SR |
84 | static bool handle_boot_enabled = |
85 | IS_ENABLED(CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED); | |
86 | ||
487e4e08 | 87 | static unsigned open_timeout = CONFIG_WATCHDOG_OPEN_TIMEOUT; |
4d1c6a0e RV |
88 | |
89 | static bool watchdog_past_open_deadline(struct watchdog_core_data *data) | |
90 | { | |
91 | return ktime_after(ktime_get(), data->open_deadline); | |
92 | } | |
93 | ||
94 | static void watchdog_set_open_deadline(struct watchdog_core_data *data) | |
95 | { | |
96 | data->open_deadline = open_timeout ? | |
97 | ktime_get() + ktime_set(open_timeout, 0) : KTIME_MAX; | |
98 | } | |
99 | ||
664a3923 GR |
100 | static inline bool watchdog_need_worker(struct watchdog_device *wdd) |
101 | { | |
102 | /* All variables in milli-seconds */ | |
103 | unsigned int hm = wdd->max_hw_heartbeat_ms; | |
104 | unsigned int t = wdd->timeout * 1000; | |
105 | ||
106 | /* | |
107 | * A worker to generate heartbeat requests is needed if all of the | |
108 | * following conditions are true. | |
109 | * - Userspace activated the watchdog. | |
110 | * - The driver provided a value for the maximum hardware timeout, and | |
111 | * thus is aware that the framework supports generating heartbeat | |
112 | * requests. | |
113 | * - Userspace requests a longer timeout than the hardware can handle. | |
3fbfe926 RV |
114 | * |
115 | * Alternatively, if userspace has not opened the watchdog | |
116 | * device, we take care of feeding the watchdog if it is | |
117 | * running. | |
664a3923 | 118 | */ |
3fbfe926 RV |
119 | return (hm && watchdog_active(wdd) && t > hm) || |
120 | (t && !watchdog_active(wdd) && watchdog_hw_running(wdd)); | |
664a3923 GR |
121 | } |
122 | ||
1ff68820 | 123 | static ktime_t watchdog_next_keepalive(struct watchdog_device *wdd) |
664a3923 GR |
124 | { |
125 | struct watchdog_core_data *wd_data = wdd->wd_data; | |
126 | unsigned int timeout_ms = wdd->timeout * 1000; | |
1ff68820 CL |
127 | ktime_t keepalive_interval; |
128 | ktime_t last_heartbeat, latest_heartbeat; | |
129 | ktime_t virt_timeout; | |
664a3923 GR |
130 | unsigned int hw_heartbeat_ms; |
131 | ||
c2eac35b RV |
132 | if (watchdog_active(wdd)) |
133 | virt_timeout = ktime_add(wd_data->last_keepalive, | |
134 | ms_to_ktime(timeout_ms)); | |
135 | else | |
136 | virt_timeout = wd_data->open_deadline; | |
137 | ||
3fbfe926 | 138 | hw_heartbeat_ms = min_not_zero(timeout_ms, wdd->max_hw_heartbeat_ms); |
1ff68820 | 139 | keepalive_interval = ms_to_ktime(hw_heartbeat_ms / 2); |
664a3923 GR |
140 | |
141 | /* | |
142 | * To ensure that the watchdog times out wdd->timeout seconds | |
143 | * after the most recent ping from userspace, the last | |
144 | * worker ping has to come in hw_heartbeat_ms before this timeout. | |
145 | */ | |
1ff68820 CL |
146 | last_heartbeat = ktime_sub(virt_timeout, ms_to_ktime(hw_heartbeat_ms)); |
147 | latest_heartbeat = ktime_sub(last_heartbeat, ktime_get()); | |
148 | if (ktime_before(latest_heartbeat, keepalive_interval)) | |
149 | return latest_heartbeat; | |
150 | return keepalive_interval; | |
664a3923 GR |
151 | } |
152 | ||
153 | static inline void watchdog_update_worker(struct watchdog_device *wdd) | |
154 | { | |
155 | struct watchdog_core_data *wd_data = wdd->wd_data; | |
156 | ||
157 | if (watchdog_need_worker(wdd)) { | |
1ff68820 | 158 | ktime_t t = watchdog_next_keepalive(wdd); |
664a3923 GR |
159 | |
160 | if (t > 0) | |
1ff68820 | 161 | hrtimer_start(&wd_data->timer, t, HRTIMER_MODE_REL); |
664a3923 | 162 | } else { |
1ff68820 | 163 | hrtimer_cancel(&wd_data->timer); |
664a3923 GR |
164 | } |
165 | } | |
166 | ||
167 | static int __watchdog_ping(struct watchdog_device *wdd) | |
168 | { | |
15013ad8 | 169 | struct watchdog_core_data *wd_data = wdd->wd_data; |
1ff68820 | 170 | ktime_t earliest_keepalive, now; |
664a3923 GR |
171 | int err; |
172 | ||
1ff68820 CL |
173 | earliest_keepalive = ktime_add(wd_data->last_hw_keepalive, |
174 | ms_to_ktime(wdd->min_hw_heartbeat_ms)); | |
175 | now = ktime_get(); | |
176 | ||
177 | if (ktime_after(earliest_keepalive, now)) { | |
178 | hrtimer_start(&wd_data->timer, | |
179 | ktime_sub(earliest_keepalive, now), | |
180 | HRTIMER_MODE_REL); | |
15013ad8 GR |
181 | return 0; |
182 | } | |
183 | ||
1ff68820 | 184 | wd_data->last_hw_keepalive = now; |
15013ad8 | 185 | |
664a3923 GR |
186 | if (wdd->ops->ping) |
187 | err = wdd->ops->ping(wdd); /* ping the watchdog */ | |
188 | else | |
189 | err = wdd->ops->start(wdd); /* restart watchdog */ | |
190 | ||
191 | watchdog_update_worker(wdd); | |
192 | ||
193 | return err; | |
194 | } | |
195 | ||
43316044 WVS |
196 | /* |
197 | * watchdog_ping: ping the watchdog. | |
bc794ac3 | 198 | * @wdd: the watchdog device to ping |
43316044 | 199 | * |
b4ffb190 GR |
200 | * The caller must hold wd_data->lock. |
201 | * | |
43316044 WVS |
202 | * If the watchdog has no own ping operation then it needs to be |
203 | * restarted via the start operation. This wrapper function does | |
204 | * exactly that. | |
234445b4 | 205 | * We only ping when the watchdog device is running. |
43316044 WVS |
206 | */ |
207 | ||
bc794ac3 | 208 | static int watchdog_ping(struct watchdog_device *wdd) |
43316044 | 209 | { |
664a3923 | 210 | struct watchdog_core_data *wd_data = wdd->wd_data; |
e907df32 | 211 | |
ee142889 | 212 | if (!watchdog_active(wdd) && !watchdog_hw_running(wdd)) |
b4ffb190 | 213 | return 0; |
7a879824 | 214 | |
90b826f1 GR |
215 | set_bit(_WDOG_KEEPALIVE, &wd_data->status); |
216 | ||
1ff68820 | 217 | wd_data->last_keepalive = ktime_get(); |
664a3923 GR |
218 | return __watchdog_ping(wdd); |
219 | } | |
7a879824 | 220 | |
c013b65a RV |
221 | static bool watchdog_worker_should_ping(struct watchdog_core_data *wd_data) |
222 | { | |
223 | struct watchdog_device *wdd = wd_data->wdd; | |
224 | ||
4d1c6a0e RV |
225 | if (!wdd) |
226 | return false; | |
227 | ||
228 | if (watchdog_active(wdd)) | |
229 | return true; | |
230 | ||
231 | return watchdog_hw_running(wdd) && !watchdog_past_open_deadline(wd_data); | |
c013b65a RV |
232 | } |
233 | ||
38a1222a | 234 | static void watchdog_ping_work(struct kthread_work *work) |
664a3923 GR |
235 | { |
236 | struct watchdog_core_data *wd_data; | |
664a3923 | 237 | |
1ff68820 | 238 | wd_data = container_of(work, struct watchdog_core_data, work); |
664a3923 GR |
239 | |
240 | mutex_lock(&wd_data->lock); | |
c013b65a RV |
241 | if (watchdog_worker_should_ping(wd_data)) |
242 | __watchdog_ping(wd_data->wdd); | |
664a3923 | 243 | mutex_unlock(&wd_data->lock); |
234445b4 WVS |
244 | } |
245 | ||
1ff68820 CL |
246 | static enum hrtimer_restart watchdog_timer_expired(struct hrtimer *timer) |
247 | { | |
248 | struct watchdog_core_data *wd_data; | |
249 | ||
250 | wd_data = container_of(timer, struct watchdog_core_data, timer); | |
251 | ||
252 | kthread_queue_work(watchdog_kworker, &wd_data->work); | |
253 | return HRTIMER_NORESTART; | |
254 | } | |
255 | ||
234445b4 WVS |
256 | /* |
257 | * watchdog_start: wrapper to start the watchdog. | |
bc794ac3 | 258 | * @wdd: the watchdog device to start |
234445b4 | 259 | * |
b4ffb190 GR |
260 | * The caller must hold wd_data->lock. |
261 | * | |
234445b4 WVS |
262 | * Start the watchdog if it is not active and mark it active. |
263 | * This function returns zero on success or a negative errno code for | |
264 | * failure. | |
265 | */ | |
266 | ||
bc794ac3 | 267 | static int watchdog_start(struct watchdog_device *wdd) |
234445b4 | 268 | { |
664a3923 | 269 | struct watchdog_core_data *wd_data = wdd->wd_data; |
1ff68820 | 270 | ktime_t started_at; |
b4ffb190 | 271 | int err; |
e907df32 | 272 | |
bc794ac3 | 273 | if (watchdog_active(wdd)) |
b4ffb190 | 274 | return 0; |
234445b4 | 275 | |
90b826f1 GR |
276 | set_bit(_WDOG_KEEPALIVE, &wd_data->status); |
277 | ||
1ff68820 | 278 | started_at = ktime_get(); |
ee142889 GR |
279 | if (watchdog_hw_running(wdd) && wdd->ops->ping) |
280 | err = wdd->ops->ping(wdd); | |
281 | else | |
282 | err = wdd->ops->start(wdd); | |
664a3923 | 283 | if (err == 0) { |
bc794ac3 | 284 | set_bit(WDOG_ACTIVE, &wdd->status); |
664a3923 GR |
285 | wd_data->last_keepalive = started_at; |
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 | } | |
455 | static DEVICE_ATTR_RO(nowayout); | |
456 | ||
457 | static ssize_t status_show(struct device *dev, struct device_attribute *attr, | |
458 | char *buf) | |
459 | { | |
460 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
b4ffb190 GR |
461 | struct watchdog_core_data *wd_data = wdd->wd_data; |
462 | unsigned int status; | |
33b71126 | 463 | |
b4ffb190 GR |
464 | mutex_lock(&wd_data->lock); |
465 | status = watchdog_get_status(wdd); | |
466 | mutex_unlock(&wd_data->lock); | |
33b71126 | 467 | |
90b826f1 | 468 | return sprintf(buf, "0x%x\n", status); |
33b71126 PA |
469 | } |
470 | static DEVICE_ATTR_RO(status); | |
471 | ||
472 | static ssize_t bootstatus_show(struct device *dev, | |
473 | struct device_attribute *attr, char *buf) | |
474 | { | |
475 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
476 | ||
477 | return sprintf(buf, "%u\n", wdd->bootstatus); | |
478 | } | |
479 | static DEVICE_ATTR_RO(bootstatus); | |
480 | ||
481 | static ssize_t timeleft_show(struct device *dev, struct device_attribute *attr, | |
482 | char *buf) | |
483 | { | |
484 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
b4ffb190 | 485 | struct watchdog_core_data *wd_data = wdd->wd_data; |
33b71126 PA |
486 | ssize_t status; |
487 | unsigned int val; | |
488 | ||
b4ffb190 | 489 | mutex_lock(&wd_data->lock); |
33b71126 | 490 | status = watchdog_get_timeleft(wdd, &val); |
b4ffb190 | 491 | mutex_unlock(&wd_data->lock); |
33b71126 PA |
492 | if (!status) |
493 | status = sprintf(buf, "%u\n", val); | |
494 | ||
495 | return status; | |
496 | } | |
497 | static DEVICE_ATTR_RO(timeleft); | |
498 | ||
499 | static ssize_t timeout_show(struct device *dev, struct device_attribute *attr, | |
500 | char *buf) | |
501 | { | |
502 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
503 | ||
504 | return sprintf(buf, "%u\n", wdd->timeout); | |
505 | } | |
506 | static DEVICE_ATTR_RO(timeout); | |
507 | ||
df044e02 WS |
508 | static ssize_t pretimeout_show(struct device *dev, |
509 | struct device_attribute *attr, char *buf) | |
510 | { | |
511 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
512 | ||
513 | return sprintf(buf, "%u\n", wdd->pretimeout); | |
514 | } | |
515 | static DEVICE_ATTR_RO(pretimeout); | |
516 | ||
33b71126 PA |
517 | static ssize_t identity_show(struct device *dev, struct device_attribute *attr, |
518 | char *buf) | |
519 | { | |
520 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
521 | ||
522 | return sprintf(buf, "%s\n", wdd->info->identity); | |
523 | } | |
524 | static DEVICE_ATTR_RO(identity); | |
525 | ||
526 | static ssize_t state_show(struct device *dev, struct device_attribute *attr, | |
527 | char *buf) | |
528 | { | |
529 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
530 | ||
531 | if (watchdog_active(wdd)) | |
532 | return sprintf(buf, "active\n"); | |
533 | ||
534 | return sprintf(buf, "inactive\n"); | |
535 | } | |
536 | static DEVICE_ATTR_RO(state); | |
537 | ||
89873a71 VZ |
538 | static ssize_t pretimeout_available_governors_show(struct device *dev, |
539 | struct device_attribute *attr, char *buf) | |
540 | { | |
541 | return watchdog_pretimeout_available_governors_get(buf); | |
542 | } | |
543 | static DEVICE_ATTR_RO(pretimeout_available_governors); | |
544 | ||
ff84136c VZ |
545 | static ssize_t pretimeout_governor_show(struct device *dev, |
546 | struct device_attribute *attr, | |
547 | char *buf) | |
548 | { | |
549 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
550 | ||
551 | return watchdog_pretimeout_governor_get(wdd, buf); | |
552 | } | |
53f96cee VZ |
553 | |
554 | static ssize_t pretimeout_governor_store(struct device *dev, | |
555 | struct device_attribute *attr, | |
556 | const char *buf, size_t count) | |
557 | { | |
558 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
559 | int ret = watchdog_pretimeout_governor_set(wdd, buf); | |
560 | ||
561 | if (!ret) | |
562 | ret = count; | |
563 | ||
564 | return ret; | |
565 | } | |
566 | static DEVICE_ATTR_RW(pretimeout_governor); | |
ff84136c | 567 | |
33b71126 PA |
568 | static umode_t wdt_is_visible(struct kobject *kobj, struct attribute *attr, |
569 | int n) | |
570 | { | |
571 | struct device *dev = container_of(kobj, struct device, kobj); | |
572 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
573 | umode_t mode = attr->mode; | |
574 | ||
90b826f1 | 575 | if (attr == &dev_attr_timeleft.attr && !wdd->ops->get_timeleft) |
33b71126 | 576 | mode = 0; |
df044e02 WS |
577 | else if (attr == &dev_attr_pretimeout.attr && |
578 | !(wdd->info->options & WDIOF_PRETIMEOUT)) | |
579 | mode = 0; | |
89873a71 VZ |
580 | else if ((attr == &dev_attr_pretimeout_governor.attr || |
581 | attr == &dev_attr_pretimeout_available_governors.attr) && | |
ff84136c VZ |
582 | (!(wdd->info->options & WDIOF_PRETIMEOUT) || |
583 | !IS_ENABLED(CONFIG_WATCHDOG_PRETIMEOUT_GOV))) | |
584 | mode = 0; | |
33b71126 PA |
585 | |
586 | return mode; | |
587 | } | |
588 | static struct attribute *wdt_attrs[] = { | |
589 | &dev_attr_state.attr, | |
590 | &dev_attr_identity.attr, | |
591 | &dev_attr_timeout.attr, | |
df044e02 | 592 | &dev_attr_pretimeout.attr, |
33b71126 PA |
593 | &dev_attr_timeleft.attr, |
594 | &dev_attr_bootstatus.attr, | |
595 | &dev_attr_status.attr, | |
596 | &dev_attr_nowayout.attr, | |
ff84136c | 597 | &dev_attr_pretimeout_governor.attr, |
89873a71 | 598 | &dev_attr_pretimeout_available_governors.attr, |
33b71126 PA |
599 | NULL, |
600 | }; | |
601 | ||
602 | static const struct attribute_group wdt_group = { | |
603 | .attrs = wdt_attrs, | |
604 | .is_visible = wdt_is_visible, | |
605 | }; | |
606 | __ATTRIBUTE_GROUPS(wdt); | |
607 | #else | |
608 | #define wdt_groups NULL | |
609 | #endif | |
610 | ||
7a879824 HG |
611 | /* |
612 | * watchdog_ioctl_op: call the watchdog drivers ioctl op if defined | |
bc794ac3 | 613 | * @wdd: the watchdog device to do the ioctl on |
7a879824 HG |
614 | * @cmd: watchdog command |
615 | * @arg: argument pointer | |
b4ffb190 GR |
616 | * |
617 | * The caller must hold wd_data->lock. | |
7a879824 HG |
618 | */ |
619 | ||
bc794ac3 | 620 | static int watchdog_ioctl_op(struct watchdog_device *wdd, unsigned int cmd, |
7a879824 HG |
621 | unsigned long arg) |
622 | { | |
bc794ac3 | 623 | if (!wdd->ops->ioctl) |
7a879824 HG |
624 | return -ENOIOCTLCMD; |
625 | ||
b4ffb190 | 626 | return wdd->ops->ioctl(wdd, cmd, arg); |
43316044 WVS |
627 | } |
628 | ||
629 | /* | |
630 | * watchdog_write: writes to the watchdog. | |
631 | * @file: file from VFS | |
632 | * @data: user address of data | |
633 | * @len: length of data | |
634 | * @ppos: pointer to the file offset | |
635 | * | |
636 | * A write to a watchdog device is defined as a keepalive ping. | |
017cf080 | 637 | * Writing the magic 'V' sequence allows the next close to turn |
7e192b9c | 638 | * off the watchdog (if 'nowayout' is not set). |
43316044 WVS |
639 | */ |
640 | ||
641 | static ssize_t watchdog_write(struct file *file, const char __user *data, | |
642 | size_t len, loff_t *ppos) | |
643 | { | |
b4ffb190 GR |
644 | struct watchdog_core_data *wd_data = file->private_data; |
645 | struct watchdog_device *wdd; | |
646 | int err; | |
43316044 WVS |
647 | size_t i; |
648 | char c; | |
649 | ||
650 | if (len == 0) | |
651 | return 0; | |
652 | ||
017cf080 WVS |
653 | /* |
654 | * Note: just in case someone wrote the magic character | |
655 | * five months ago... | |
656 | */ | |
b4ffb190 | 657 | clear_bit(_WDOG_ALLOW_RELEASE, &wd_data->status); |
017cf080 WVS |
658 | |
659 | /* scan to see whether or not we got the magic character */ | |
43316044 WVS |
660 | for (i = 0; i != len; i++) { |
661 | if (get_user(c, data + i)) | |
662 | return -EFAULT; | |
017cf080 | 663 | if (c == 'V') |
b4ffb190 | 664 | set_bit(_WDOG_ALLOW_RELEASE, &wd_data->status); |
43316044 WVS |
665 | } |
666 | ||
667 | /* someone wrote to us, so we send the watchdog a keepalive ping */ | |
b4ffb190 GR |
668 | |
669 | err = -ENODEV; | |
670 | mutex_lock(&wd_data->lock); | |
671 | wdd = wd_data->wdd; | |
672 | if (wdd) | |
673 | err = watchdog_ping(wdd); | |
674 | mutex_unlock(&wd_data->lock); | |
675 | ||
5ef79663 AU |
676 | if (err < 0) |
677 | return err; | |
43316044 WVS |
678 | |
679 | return len; | |
680 | } | |
681 | ||
2fa03560 WVS |
682 | /* |
683 | * watchdog_ioctl: handle the different ioctl's for the watchdog device. | |
684 | * @file: file handle to the device | |
685 | * @cmd: watchdog command | |
686 | * @arg: argument pointer | |
687 | * | |
688 | * The watchdog API defines a common set of functions for all watchdogs | |
689 | * according to their available features. | |
690 | */ | |
691 | ||
692 | static long watchdog_ioctl(struct file *file, unsigned int cmd, | |
693 | unsigned long arg) | |
694 | { | |
b4ffb190 | 695 | struct watchdog_core_data *wd_data = file->private_data; |
2fa03560 | 696 | void __user *argp = (void __user *)arg; |
b4ffb190 | 697 | struct watchdog_device *wdd; |
2fa03560 WVS |
698 | int __user *p = argp; |
699 | unsigned int val; | |
234445b4 | 700 | int err; |
2fa03560 | 701 | |
b4ffb190 GR |
702 | mutex_lock(&wd_data->lock); |
703 | ||
704 | wdd = wd_data->wdd; | |
705 | if (!wdd) { | |
706 | err = -ENODEV; | |
707 | goto out_ioctl; | |
708 | } | |
709 | ||
7a879824 HG |
710 | err = watchdog_ioctl_op(wdd, cmd, arg); |
711 | if (err != -ENOIOCTLCMD) | |
b4ffb190 | 712 | goto out_ioctl; |
78d88fc0 | 713 | |
2fa03560 WVS |
714 | switch (cmd) { |
715 | case WDIOC_GETSUPPORT: | |
b4ffb190 | 716 | err = copy_to_user(argp, wdd->info, |
2fa03560 | 717 | sizeof(struct watchdog_info)) ? -EFAULT : 0; |
b4ffb190 | 718 | break; |
2fa03560 | 719 | case WDIOC_GETSTATUS: |
b4ffb190 GR |
720 | val = watchdog_get_status(wdd); |
721 | err = put_user(val, p); | |
722 | break; | |
2fa03560 | 723 | case WDIOC_GETBOOTSTATUS: |
b4ffb190 GR |
724 | err = put_user(wdd->bootstatus, p); |
725 | break; | |
234445b4 | 726 | case WDIOC_SETOPTIONS: |
b4ffb190 GR |
727 | if (get_user(val, p)) { |
728 | err = -EFAULT; | |
729 | break; | |
730 | } | |
234445b4 WVS |
731 | if (val & WDIOS_DISABLECARD) { |
732 | err = watchdog_stop(wdd); | |
733 | if (err < 0) | |
b4ffb190 | 734 | break; |
234445b4 | 735 | } |
b4ffb190 | 736 | if (val & WDIOS_ENABLECARD) |
234445b4 | 737 | err = watchdog_start(wdd); |
b4ffb190 | 738 | break; |
c2dc00e4 | 739 | case WDIOC_KEEPALIVE: |
b4ffb190 GR |
740 | if (!(wdd->info->options & WDIOF_KEEPALIVEPING)) { |
741 | err = -EOPNOTSUPP; | |
742 | break; | |
743 | } | |
744 | err = watchdog_ping(wdd); | |
745 | break; | |
014d694e | 746 | case WDIOC_SETTIMEOUT: |
b4ffb190 GR |
747 | if (get_user(val, p)) { |
748 | err = -EFAULT; | |
749 | break; | |
750 | } | |
7a879824 | 751 | err = watchdog_set_timeout(wdd, val); |
014d694e | 752 | if (err < 0) |
b4ffb190 | 753 | break; |
014d694e WVS |
754 | /* If the watchdog is active then we send a keepalive ping |
755 | * to make sure that the watchdog keep's running (and if | |
756 | * possible that it takes the new timeout) */ | |
5ef79663 AU |
757 | err = watchdog_ping(wdd); |
758 | if (err < 0) | |
b4ffb190 | 759 | break; |
e2af3092 | 760 | /* fall through */ |
014d694e WVS |
761 | case WDIOC_GETTIMEOUT: |
762 | /* timeout == 0 means that we don't know the timeout */ | |
b4ffb190 GR |
763 | if (wdd->timeout == 0) { |
764 | err = -EOPNOTSUPP; | |
765 | break; | |
766 | } | |
767 | err = put_user(wdd->timeout, p); | |
768 | break; | |
fd7b673c | 769 | case WDIOC_GETTIMELEFT: |
7a879824 | 770 | err = watchdog_get_timeleft(wdd, &val); |
b4ffb190 GR |
771 | if (err < 0) |
772 | break; | |
773 | err = put_user(val, p); | |
774 | break; | |
df044e02 WS |
775 | case WDIOC_SETPRETIMEOUT: |
776 | if (get_user(val, p)) { | |
777 | err = -EFAULT; | |
778 | break; | |
779 | } | |
780 | err = watchdog_set_pretimeout(wdd, val); | |
781 | break; | |
782 | case WDIOC_GETPRETIMEOUT: | |
783 | err = put_user(wdd->pretimeout, p); | |
784 | break; | |
2fa03560 | 785 | default: |
b4ffb190 GR |
786 | err = -ENOTTY; |
787 | break; | |
2fa03560 | 788 | } |
b4ffb190 GR |
789 | |
790 | out_ioctl: | |
791 | mutex_unlock(&wd_data->lock); | |
792 | return err; | |
2fa03560 WVS |
793 | } |
794 | ||
43316044 | 795 | /* |
45f5fed3 | 796 | * watchdog_open: open the /dev/watchdog* devices. |
43316044 WVS |
797 | * @inode: inode of device |
798 | * @file: file handle to device | |
799 | * | |
45f5fed3 | 800 | * When the /dev/watchdog* device gets opened, we start the watchdog. |
43316044 WVS |
801 | * Watch out: the /dev/watchdog device is single open, so we make sure |
802 | * it can only be opened once. | |
803 | */ | |
804 | ||
805 | static int watchdog_open(struct inode *inode, struct file *file) | |
806 | { | |
b4ffb190 | 807 | struct watchdog_core_data *wd_data; |
45f5fed3 | 808 | struct watchdog_device *wdd; |
4bcd615f | 809 | bool hw_running; |
b4ffb190 | 810 | int err; |
45f5fed3 AC |
811 | |
812 | /* Get the corresponding watchdog device */ | |
813 | if (imajor(inode) == MISC_MAJOR) | |
b4ffb190 | 814 | wd_data = old_wd_data; |
45f5fed3 | 815 | else |
b4ffb190 GR |
816 | wd_data = container_of(inode->i_cdev, struct watchdog_core_data, |
817 | cdev); | |
43316044 WVS |
818 | |
819 | /* the watchdog is single open! */ | |
b4ffb190 | 820 | if (test_and_set_bit(_WDOG_DEV_OPEN, &wd_data->status)) |
43316044 WVS |
821 | return -EBUSY; |
822 | ||
b4ffb190 GR |
823 | wdd = wd_data->wdd; |
824 | ||
43316044 WVS |
825 | /* |
826 | * If the /dev/watchdog device is open, we don't want the module | |
827 | * to be unloaded. | |
828 | */ | |
4bcd615f GR |
829 | hw_running = watchdog_hw_running(wdd); |
830 | if (!hw_running && !try_module_get(wdd->ops->owner)) { | |
b4ffb190 GR |
831 | err = -EBUSY; |
832 | goto out_clear; | |
833 | } | |
43316044 | 834 | |
234445b4 | 835 | err = watchdog_start(wdd); |
43316044 WVS |
836 | if (err < 0) |
837 | goto out_mod; | |
838 | ||
b4ffb190 | 839 | file->private_data = wd_data; |
45f5fed3 | 840 | |
4bcd615f | 841 | if (!hw_running) |
ee142889 | 842 | kref_get(&wd_data->kref); |
e907df32 | 843 | |
4d1c6a0e RV |
844 | /* |
845 | * open_timeout only applies for the first open from | |
846 | * userspace. Set open_deadline to infinity so that the kernel | |
847 | * will take care of an always-running hardware watchdog in | |
848 | * case the device gets magic-closed or WDIOS_DISABLECARD is | |
849 | * applied. | |
850 | */ | |
851 | wd_data->open_deadline = KTIME_MAX; | |
852 | ||
43316044 | 853 | /* dev/watchdog is a virtual (and thus non-seekable) filesystem */ |
c5bf68fe | 854 | return stream_open(inode, file); |
43316044 WVS |
855 | |
856 | out_mod: | |
b4ffb190 GR |
857 | module_put(wd_data->wdd->ops->owner); |
858 | out_clear: | |
859 | clear_bit(_WDOG_DEV_OPEN, &wd_data->status); | |
43316044 WVS |
860 | return err; |
861 | } | |
862 | ||
b4ffb190 GR |
863 | static void watchdog_core_data_release(struct kref *kref) |
864 | { | |
865 | struct watchdog_core_data *wd_data; | |
866 | ||
867 | wd_data = container_of(kref, struct watchdog_core_data, kref); | |
868 | ||
869 | kfree(wd_data); | |
870 | } | |
871 | ||
43316044 | 872 | /* |
45f5fed3 AC |
873 | * watchdog_release: release the watchdog device. |
874 | * @inode: inode of device | |
875 | * @file: file handle to device | |
43316044 | 876 | * |
017cf080 | 877 | * This is the code for when /dev/watchdog gets closed. We will only |
7e192b9c WVS |
878 | * stop the watchdog when we have received the magic char (and nowayout |
879 | * was not set), else the watchdog will keep running. | |
43316044 WVS |
880 | */ |
881 | ||
882 | static int watchdog_release(struct inode *inode, struct file *file) | |
883 | { | |
b4ffb190 GR |
884 | struct watchdog_core_data *wd_data = file->private_data; |
885 | struct watchdog_device *wdd; | |
017cf080 | 886 | int err = -EBUSY; |
d1ed3ba4 | 887 | bool running; |
017cf080 | 888 | |
b4ffb190 GR |
889 | mutex_lock(&wd_data->lock); |
890 | ||
891 | wdd = wd_data->wdd; | |
892 | if (!wdd) | |
893 | goto done; | |
894 | ||
017cf080 WVS |
895 | /* |
896 | * We only stop the watchdog if we received the magic character | |
7e192b9c WVS |
897 | * or if WDIOF_MAGICCLOSE is not set. If nowayout was set then |
898 | * watchdog_stop will fail. | |
017cf080 | 899 | */ |
fcf95670 HP |
900 | if (!test_bit(WDOG_ACTIVE, &wdd->status)) |
901 | err = 0; | |
b4ffb190 | 902 | else if (test_and_clear_bit(_WDOG_ALLOW_RELEASE, &wd_data->status) || |
fcf95670 | 903 | !(wdd->info->options & WDIOF_MAGICCLOSE)) |
017cf080 | 904 | err = watchdog_stop(wdd); |
43316044 | 905 | |
017cf080 | 906 | /* If the watchdog was not stopped, send a keepalive ping */ |
234445b4 | 907 | if (err < 0) { |
0254e953 | 908 | pr_crit("watchdog%d: watchdog did not stop!\n", wdd->id); |
43316044 WVS |
909 | watchdog_ping(wdd); |
910 | } | |
911 | ||
ee142889 | 912 | watchdog_update_worker(wdd); |
664a3923 | 913 | |
43316044 | 914 | /* make sure that /dev/watchdog can be re-opened */ |
b4ffb190 | 915 | clear_bit(_WDOG_DEV_OPEN, &wd_data->status); |
e907df32 | 916 | |
b4ffb190 | 917 | done: |
d1ed3ba4 | 918 | running = wdd && watchdog_hw_running(wdd); |
b4ffb190 | 919 | mutex_unlock(&wd_data->lock); |
ee142889 GR |
920 | /* |
921 | * Allow the owner module to be unloaded again unless the watchdog | |
922 | * is still running. If the watchdog is still running, it can not | |
923 | * be stopped, and its driver must not be unloaded. | |
924 | */ | |
d1ed3ba4 GR |
925 | if (!running) { |
926 | module_put(wd_data->cdev.owner); | |
ee142889 GR |
927 | kref_put(&wd_data->kref, watchdog_core_data_release); |
928 | } | |
43316044 WVS |
929 | return 0; |
930 | } | |
931 | ||
932 | static const struct file_operations watchdog_fops = { | |
933 | .owner = THIS_MODULE, | |
934 | .write = watchdog_write, | |
2fa03560 | 935 | .unlocked_ioctl = watchdog_ioctl, |
43316044 WVS |
936 | .open = watchdog_open, |
937 | .release = watchdog_release, | |
938 | }; | |
939 | ||
940 | static struct miscdevice watchdog_miscdev = { | |
941 | .minor = WATCHDOG_MINOR, | |
942 | .name = "watchdog", | |
943 | .fops = &watchdog_fops, | |
944 | }; | |
945 | ||
946 | /* | |
32ecc639 | 947 | * watchdog_cdev_register: register watchdog character device |
bc794ac3 | 948 | * @wdd: watchdog device |
32ecc639 | 949 | * @devno: character device number |
43316044 | 950 | * |
32ecc639 | 951 | * Register a watchdog character device including handling the legacy |
45f5fed3 AC |
952 | * /dev/watchdog node. /dev/watchdog is actually a miscdevice and |
953 | * thus we set it up like that. | |
43316044 WVS |
954 | */ |
955 | ||
32ecc639 | 956 | static int watchdog_cdev_register(struct watchdog_device *wdd, dev_t devno) |
43316044 | 957 | { |
b4ffb190 | 958 | struct watchdog_core_data *wd_data; |
32ecc639 | 959 | int err; |
45f5fed3 | 960 | |
b4ffb190 GR |
961 | wd_data = kzalloc(sizeof(struct watchdog_core_data), GFP_KERNEL); |
962 | if (!wd_data) | |
963 | return -ENOMEM; | |
964 | kref_init(&wd_data->kref); | |
965 | mutex_init(&wd_data->lock); | |
966 | ||
967 | wd_data->wdd = wdd; | |
968 | wdd->wd_data = wd_data; | |
969 | ||
38a1222a | 970 | if (IS_ERR_OR_NULL(watchdog_kworker)) |
664a3923 GR |
971 | return -ENODEV; |
972 | ||
1ff68820 CL |
973 | kthread_init_work(&wd_data->work, watchdog_ping_work); |
974 | hrtimer_init(&wd_data->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); | |
975 | wd_data->timer.function = watchdog_timer_expired; | |
664a3923 | 976 | |
bc794ac3 | 977 | if (wdd->id == 0) { |
b4ffb190 | 978 | old_wd_data = wd_data; |
bc794ac3 | 979 | watchdog_miscdev.parent = wdd->parent; |
45f5fed3 AC |
980 | err = misc_register(&watchdog_miscdev); |
981 | if (err != 0) { | |
982 | pr_err("%s: cannot register miscdev on minor=%d (err=%d).\n", | |
bc794ac3 | 983 | wdd->info->identity, WATCHDOG_MINOR, err); |
45f5fed3 AC |
984 | if (err == -EBUSY) |
985 | pr_err("%s: a legacy watchdog module is probably present.\n", | |
bc794ac3 | 986 | wdd->info->identity); |
b4ffb190 GR |
987 | old_wd_data = NULL; |
988 | kfree(wd_data); | |
45f5fed3 AC |
989 | return err; |
990 | } | |
43316044 WVS |
991 | } |
992 | ||
45f5fed3 | 993 | /* Fill in the data structures */ |
b4ffb190 GR |
994 | cdev_init(&wd_data->cdev, &watchdog_fops); |
995 | wd_data->cdev.owner = wdd->ops->owner; | |
45f5fed3 AC |
996 | |
997 | /* Add the device */ | |
b4ffb190 | 998 | err = cdev_add(&wd_data->cdev, devno, 1); |
45f5fed3 AC |
999 | if (err) { |
1000 | pr_err("watchdog%d unable to add device %d:%d\n", | |
bc794ac3 GR |
1001 | wdd->id, MAJOR(watchdog_devt), wdd->id); |
1002 | if (wdd->id == 0) { | |
45f5fed3 | 1003 | misc_deregister(&watchdog_miscdev); |
b4ffb190 GR |
1004 | old_wd_data = NULL; |
1005 | kref_put(&wd_data->kref, watchdog_core_data_release); | |
45f5fed3 | 1006 | } |
ee142889 | 1007 | return err; |
43316044 | 1008 | } |
ee142889 | 1009 | |
15013ad8 | 1010 | /* Record time of most recent heartbeat as 'just before now'. */ |
1ff68820 | 1011 | wd_data->last_hw_keepalive = ktime_sub(ktime_get(), 1); |
4d1c6a0e | 1012 | watchdog_set_open_deadline(wd_data); |
15013ad8 | 1013 | |
ee142889 GR |
1014 | /* |
1015 | * If the watchdog is running, prevent its driver from being unloaded, | |
1016 | * and schedule an immediate ping. | |
1017 | */ | |
1018 | if (watchdog_hw_running(wdd)) { | |
914d65f3 GR |
1019 | __module_get(wdd->ops->owner); |
1020 | kref_get(&wd_data->kref); | |
1021 | if (handle_boot_enabled) | |
1ff68820 | 1022 | hrtimer_start(&wd_data->timer, 0, HRTIMER_MODE_REL); |
914d65f3 | 1023 | else |
2501b015 | 1024 | pr_info("watchdog%d running and kernel based pre-userspace handler disabled\n", |
914d65f3 | 1025 | wdd->id); |
ee142889 GR |
1026 | } |
1027 | ||
1028 | return 0; | |
43316044 WVS |
1029 | } |
1030 | ||
1031 | /* | |
32ecc639 | 1032 | * watchdog_cdev_unregister: unregister watchdog character device |
43316044 WVS |
1033 | * @watchdog: watchdog device |
1034 | * | |
32ecc639 GR |
1035 | * Unregister watchdog character device and if needed the legacy |
1036 | * /dev/watchdog device. | |
43316044 WVS |
1037 | */ |
1038 | ||
32ecc639 | 1039 | static void watchdog_cdev_unregister(struct watchdog_device *wdd) |
43316044 | 1040 | { |
b4ffb190 | 1041 | struct watchdog_core_data *wd_data = wdd->wd_data; |
e907df32 | 1042 | |
b4ffb190 | 1043 | cdev_del(&wd_data->cdev); |
bc794ac3 | 1044 | if (wdd->id == 0) { |
45f5fed3 | 1045 | misc_deregister(&watchdog_miscdev); |
b4ffb190 | 1046 | old_wd_data = NULL; |
43316044 | 1047 | } |
b4ffb190 | 1048 | |
bb292ac1 GR |
1049 | if (watchdog_active(wdd) && |
1050 | test_bit(WDOG_STOP_ON_UNREGISTER, &wdd->status)) { | |
1051 | watchdog_stop(wdd); | |
1052 | } | |
1053 | ||
953b9dd7 WS |
1054 | mutex_lock(&wd_data->lock); |
1055 | wd_data->wdd = NULL; | |
1056 | wdd->wd_data = NULL; | |
1057 | mutex_unlock(&wd_data->lock); | |
1058 | ||
1ff68820 CL |
1059 | hrtimer_cancel(&wd_data->timer); |
1060 | kthread_cancel_work_sync(&wd_data->work); | |
664a3923 | 1061 | |
b4ffb190 | 1062 | kref_put(&wd_data->kref, watchdog_core_data_release); |
43316044 | 1063 | } |
45f5fed3 | 1064 | |
906d7a5c PA |
1065 | static struct class watchdog_class = { |
1066 | .name = "watchdog", | |
1067 | .owner = THIS_MODULE, | |
33b71126 | 1068 | .dev_groups = wdt_groups, |
906d7a5c PA |
1069 | }; |
1070 | ||
44ea3942 AS |
1071 | static int watchdog_reboot_notifier(struct notifier_block *nb, |
1072 | unsigned long code, void *data) | |
1073 | { | |
1074 | struct watchdog_device *wdd; | |
1075 | ||
1076 | wdd = container_of(nb, struct watchdog_device, reboot_nb); | |
1077 | if (code == SYS_DOWN || code == SYS_HALT) { | |
1078 | if (watchdog_active(wdd)) { | |
1079 | int ret; | |
1080 | ||
1081 | ret = wdd->ops->stop(wdd); | |
1082 | if (ret) | |
1083 | return NOTIFY_BAD; | |
1084 | } | |
1085 | } | |
1086 | ||
1087 | return NOTIFY_DONE; | |
1088 | } | |
1089 | ||
32ecc639 GR |
1090 | /* |
1091 | * watchdog_dev_register: register a watchdog device | |
1092 | * @wdd: watchdog device | |
1093 | * | |
1094 | * Register a watchdog device including handling the legacy | |
1095 | * /dev/watchdog node. /dev/watchdog is actually a miscdevice and | |
1096 | * thus we set it up like that. | |
1097 | */ | |
1098 | ||
1099 | int watchdog_dev_register(struct watchdog_device *wdd) | |
1100 | { | |
1101 | struct device *dev; | |
1102 | dev_t devno; | |
1103 | int ret; | |
1104 | ||
1105 | devno = MKDEV(MAJOR(watchdog_devt), wdd->id); | |
1106 | ||
1107 | ret = watchdog_cdev_register(wdd, devno); | |
1108 | if (ret) | |
1109 | return ret; | |
1110 | ||
faa58475 GR |
1111 | dev = device_create_with_groups(&watchdog_class, wdd->parent, |
1112 | devno, wdd, wdd->groups, | |
1113 | "watchdog%d", wdd->id); | |
32ecc639 GR |
1114 | if (IS_ERR(dev)) { |
1115 | watchdog_cdev_unregister(wdd); | |
1116 | return PTR_ERR(dev); | |
1117 | } | |
32ecc639 | 1118 | |
ff84136c VZ |
1119 | ret = watchdog_register_pretimeout(wdd); |
1120 | if (ret) { | |
1121 | device_destroy(&watchdog_class, devno); | |
1122 | watchdog_cdev_unregister(wdd); | |
44ea3942 AS |
1123 | return ret; |
1124 | } | |
1125 | ||
1126 | if (test_bit(WDOG_STOP_ON_REBOOT, &wdd->status)) { | |
1127 | wdd->reboot_nb.notifier_call = watchdog_reboot_notifier; | |
1128 | ||
1129 | ret = devm_register_reboot_notifier(dev, &wdd->reboot_nb); | |
1130 | if (ret) { | |
1131 | pr_err("watchdog%d: Cannot register reboot notifier (%d)\n", | |
1132 | wdd->id, ret); | |
1133 | watchdog_dev_unregister(wdd); | |
1134 | } | |
ff84136c VZ |
1135 | } |
1136 | ||
32ecc639 GR |
1137 | return ret; |
1138 | } | |
1139 | ||
1140 | /* | |
1141 | * watchdog_dev_unregister: unregister a watchdog device | |
1142 | * @watchdog: watchdog device | |
1143 | * | |
1144 | * Unregister watchdog device and if needed the legacy | |
1145 | * /dev/watchdog device. | |
1146 | */ | |
1147 | ||
1148 | void watchdog_dev_unregister(struct watchdog_device *wdd) | |
1149 | { | |
ff84136c | 1150 | watchdog_unregister_pretimeout(wdd); |
0254e953 | 1151 | device_destroy(&watchdog_class, wdd->wd_data->cdev.dev); |
b4ffb190 | 1152 | watchdog_cdev_unregister(wdd); |
32ecc639 GR |
1153 | } |
1154 | ||
45f5fed3 AC |
1155 | /* |
1156 | * watchdog_dev_init: init dev part of watchdog core | |
1157 | * | |
1158 | * Allocate a range of chardev nodes to use for watchdog devices | |
1159 | */ | |
1160 | ||
32ecc639 | 1161 | int __init watchdog_dev_init(void) |
45f5fed3 | 1162 | { |
906d7a5c | 1163 | int err; |
38a1222a | 1164 | struct sched_param param = {.sched_priority = MAX_RT_PRIO - 1,}; |
906d7a5c | 1165 | |
38a1222a CL |
1166 | watchdog_kworker = kthread_create_worker(0, "watchdogd"); |
1167 | if (IS_ERR(watchdog_kworker)) { | |
1168 | pr_err("Failed to create watchdog kworker\n"); | |
1169 | return PTR_ERR(watchdog_kworker); | |
664a3923 | 1170 | } |
38a1222a | 1171 | sched_setscheduler(watchdog_kworker->task, SCHED_FIFO, ¶m); |
664a3923 | 1172 | |
906d7a5c PA |
1173 | err = class_register(&watchdog_class); |
1174 | if (err < 0) { | |
1175 | pr_err("couldn't register class\n"); | |
138913cb | 1176 | goto err_register; |
906d7a5c PA |
1177 | } |
1178 | ||
1179 | err = alloc_chrdev_region(&watchdog_devt, 0, MAX_DOGS, "watchdog"); | |
1180 | if (err < 0) { | |
45f5fed3 | 1181 | pr_err("watchdog: unable to allocate char dev region\n"); |
138913cb | 1182 | goto err_alloc; |
906d7a5c PA |
1183 | } |
1184 | ||
32ecc639 | 1185 | return 0; |
138913cb WY |
1186 | |
1187 | err_alloc: | |
1188 | class_unregister(&watchdog_class); | |
1189 | err_register: | |
38a1222a | 1190 | kthread_destroy_worker(watchdog_kworker); |
138913cb | 1191 | return err; |
45f5fed3 AC |
1192 | } |
1193 | ||
1194 | /* | |
1195 | * watchdog_dev_exit: exit dev part of watchdog core | |
1196 | * | |
1197 | * Release the range of chardev nodes used for watchdog devices | |
1198 | */ | |
1199 | ||
1200 | void __exit watchdog_dev_exit(void) | |
1201 | { | |
1202 | unregister_chrdev_region(watchdog_devt, MAX_DOGS); | |
906d7a5c | 1203 | class_unregister(&watchdog_class); |
38a1222a | 1204 | kthread_destroy_worker(watchdog_kworker); |
45f5fed3 | 1205 | } |
2501b015 SR |
1206 | |
1207 | module_param(handle_boot_enabled, bool, 0444); | |
1208 | MODULE_PARM_DESC(handle_boot_enabled, | |
1209 | "Watchdog core auto-updates boot enabled watchdogs before userspace takes over (default=" | |
1210 | __MODULE_STRING(IS_ENABLED(CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED)) ")"); | |
4d1c6a0e RV |
1211 | |
1212 | module_param(open_timeout, uint, 0644); | |
1213 | MODULE_PARM_DESC(open_timeout, | |
487e4e08 RV |
1214 | "Maximum time (in seconds, 0 means infinity) for userspace to take over a running watchdog (default=" |
1215 | __MODULE_STRING(CONFIG_WATCHDOG_OPEN_TIMEOUT) ")"); |