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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 | * | |
7b7d2fdc | 10 | * (c) Copyright 2021 Hewlett Packard Enterprise Development LP. |
43316044 WVS |
11 | * |
12 | * This source code is part of the generic code that can be used | |
13 | * by all the watchdog timer drivers. | |
14 | * | |
15 | * This part of the generic code takes care of the following | |
16 | * misc device: /dev/watchdog. | |
17 | * | |
18 | * Based on source code of the following authors: | |
19 | * Matt Domsch <Matt_Domsch@dell.com>, | |
20 | * Rob Radez <rob@osinvestor.com>, | |
21 | * Rusty Lynch <rusty@linux.co.intel.com> | |
22 | * Satyam Sharma <satyam@infradead.org> | |
23 | * Randy Dunlap <randy.dunlap@oracle.com> | |
24 | * | |
43316044 WVS |
25 | * Neither Alan Cox, CymruNet Ltd., Wim Van Sebroeck nor Iguana vzw. |
26 | * admit liability nor provide warranty for any of this software. | |
27 | * This material is provided "AS-IS" and at no charge. | |
28 | */ | |
29 | ||
30 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
31 | ||
b4ffb190 | 32 | #include <linux/cdev.h> /* For character device */ |
43316044 | 33 | #include <linux/errno.h> /* For the -ENODEV/... values */ |
43316044 | 34 | #include <linux/fs.h> /* For file operations */ |
43316044 | 35 | #include <linux/init.h> /* For __init/__exit/... */ |
1ff68820 | 36 | #include <linux/hrtimer.h> /* For hrtimers */ |
b4ffb190 | 37 | #include <linux/kernel.h> /* For printk/panic/... */ |
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 */ | |
42 | #include <linux/slab.h> /* For memory functions */ | |
43 | #include <linux/types.h> /* For standard types (like size_t) */ | |
44 | #include <linux/watchdog.h> /* For watchdog specific items */ | |
43316044 WVS |
45 | #include <linux/uaccess.h> /* For copy_to_user/put_user/... */ |
46 | ||
6cfb5aa8 | 47 | #include "watchdog_core.h" |
ff84136c | 48 | #include "watchdog_pretimeout.h" |
09a46e73 | 49 | |
e25b091b UKK |
50 | #include <trace/events/watchdog.h> |
51 | ||
45f5fed3 AC |
52 | /* the dev_t structure to store the dynamically allocated watchdog devices */ |
53 | static dev_t watchdog_devt; | |
b4ffb190 GR |
54 | /* Reference to watchdog device behind /dev/watchdog */ |
55 | static struct watchdog_core_data *old_wd_data; | |
43316044 | 56 | |
38a1222a | 57 | static struct kthread_worker *watchdog_kworker; |
664a3923 | 58 | |
2501b015 SR |
59 | static bool handle_boot_enabled = |
60 | IS_ENABLED(CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED); | |
61 | ||
487e4e08 | 62 | static unsigned open_timeout = CONFIG_WATCHDOG_OPEN_TIMEOUT; |
4d1c6a0e RV |
63 | |
64 | static bool watchdog_past_open_deadline(struct watchdog_core_data *data) | |
65 | { | |
66 | return ktime_after(ktime_get(), data->open_deadline); | |
67 | } | |
68 | ||
69 | static void watchdog_set_open_deadline(struct watchdog_core_data *data) | |
70 | { | |
71 | data->open_deadline = open_timeout ? | |
72 | ktime_get() + ktime_set(open_timeout, 0) : KTIME_MAX; | |
73 | } | |
74 | ||
664a3923 GR |
75 | static inline bool watchdog_need_worker(struct watchdog_device *wdd) |
76 | { | |
77 | /* All variables in milli-seconds */ | |
78 | unsigned int hm = wdd->max_hw_heartbeat_ms; | |
79 | unsigned int t = wdd->timeout * 1000; | |
80 | ||
81 | /* | |
82 | * A worker to generate heartbeat requests is needed if all of the | |
83 | * following conditions are true. | |
84 | * - Userspace activated the watchdog. | |
85 | * - The driver provided a value for the maximum hardware timeout, and | |
86 | * thus is aware that the framework supports generating heartbeat | |
87 | * requests. | |
88 | * - Userspace requests a longer timeout than the hardware can handle. | |
3fbfe926 RV |
89 | * |
90 | * Alternatively, if userspace has not opened the watchdog | |
91 | * device, we take care of feeding the watchdog if it is | |
92 | * running. | |
664a3923 | 93 | */ |
3fbfe926 RV |
94 | return (hm && watchdog_active(wdd) && t > hm) || |
95 | (t && !watchdog_active(wdd) && watchdog_hw_running(wdd)); | |
664a3923 GR |
96 | } |
97 | ||
1ff68820 | 98 | static ktime_t watchdog_next_keepalive(struct watchdog_device *wdd) |
664a3923 GR |
99 | { |
100 | struct watchdog_core_data *wd_data = wdd->wd_data; | |
101 | unsigned int timeout_ms = wdd->timeout * 1000; | |
1ff68820 CL |
102 | ktime_t keepalive_interval; |
103 | ktime_t last_heartbeat, latest_heartbeat; | |
104 | ktime_t virt_timeout; | |
664a3923 GR |
105 | unsigned int hw_heartbeat_ms; |
106 | ||
c2eac35b RV |
107 | if (watchdog_active(wdd)) |
108 | virt_timeout = ktime_add(wd_data->last_keepalive, | |
109 | ms_to_ktime(timeout_ms)); | |
110 | else | |
111 | virt_timeout = wd_data->open_deadline; | |
112 | ||
3fbfe926 | 113 | hw_heartbeat_ms = min_not_zero(timeout_ms, wdd->max_hw_heartbeat_ms); |
1ff68820 | 114 | keepalive_interval = ms_to_ktime(hw_heartbeat_ms / 2); |
664a3923 GR |
115 | |
116 | /* | |
117 | * To ensure that the watchdog times out wdd->timeout seconds | |
118 | * after the most recent ping from userspace, the last | |
119 | * worker ping has to come in hw_heartbeat_ms before this timeout. | |
120 | */ | |
1ff68820 CL |
121 | last_heartbeat = ktime_sub(virt_timeout, ms_to_ktime(hw_heartbeat_ms)); |
122 | latest_heartbeat = ktime_sub(last_heartbeat, ktime_get()); | |
123 | if (ktime_before(latest_heartbeat, keepalive_interval)) | |
124 | return latest_heartbeat; | |
125 | return keepalive_interval; | |
664a3923 GR |
126 | } |
127 | ||
128 | static inline void watchdog_update_worker(struct watchdog_device *wdd) | |
129 | { | |
130 | struct watchdog_core_data *wd_data = wdd->wd_data; | |
131 | ||
132 | if (watchdog_need_worker(wdd)) { | |
1ff68820 | 133 | ktime_t t = watchdog_next_keepalive(wdd); |
664a3923 GR |
134 | |
135 | if (t > 0) | |
a19f8933 JC |
136 | hrtimer_start(&wd_data->timer, t, |
137 | HRTIMER_MODE_REL_HARD); | |
664a3923 | 138 | } else { |
1ff68820 | 139 | hrtimer_cancel(&wd_data->timer); |
664a3923 GR |
140 | } |
141 | } | |
142 | ||
143 | static int __watchdog_ping(struct watchdog_device *wdd) | |
144 | { | |
15013ad8 | 145 | struct watchdog_core_data *wd_data = wdd->wd_data; |
1ff68820 | 146 | ktime_t earliest_keepalive, now; |
664a3923 GR |
147 | int err; |
148 | ||
1ff68820 CL |
149 | earliest_keepalive = ktime_add(wd_data->last_hw_keepalive, |
150 | ms_to_ktime(wdd->min_hw_heartbeat_ms)); | |
151 | now = ktime_get(); | |
152 | ||
153 | if (ktime_after(earliest_keepalive, now)) { | |
154 | hrtimer_start(&wd_data->timer, | |
155 | ktime_sub(earliest_keepalive, now), | |
a19f8933 | 156 | HRTIMER_MODE_REL_HARD); |
15013ad8 GR |
157 | return 0; |
158 | } | |
159 | ||
1ff68820 | 160 | wd_data->last_hw_keepalive = now; |
15013ad8 | 161 | |
e25b091b | 162 | if (wdd->ops->ping) { |
664a3923 | 163 | err = wdd->ops->ping(wdd); /* ping the watchdog */ |
e25b091b UKK |
164 | trace_watchdog_ping(wdd, err); |
165 | } else { | |
664a3923 | 166 | err = wdd->ops->start(wdd); /* restart watchdog */ |
e25b091b UKK |
167 | trace_watchdog_start(wdd, err); |
168 | } | |
664a3923 | 169 | |
7b7d2fdc CK |
170 | if (err == 0) |
171 | watchdog_hrtimer_pretimeout_start(wdd); | |
172 | ||
664a3923 GR |
173 | watchdog_update_worker(wdd); |
174 | ||
175 | return err; | |
176 | } | |
177 | ||
43316044 | 178 | /* |
ba6c89ab DBO |
179 | * watchdog_ping - ping the watchdog |
180 | * @wdd: The watchdog device to ping | |
43316044 | 181 | * |
ba6c89ab DBO |
182 | * If the watchdog has no own ping operation then it needs to be |
183 | * restarted via the start operation. This wrapper function does | |
184 | * exactly that. | |
185 | * We only ping when the watchdog device is running. | |
186 | * The caller must hold wd_data->lock. | |
b4ffb190 | 187 | * |
ba6c89ab | 188 | * Return: 0 on success, error otherwise. |
43316044 | 189 | */ |
bc794ac3 | 190 | static int watchdog_ping(struct watchdog_device *wdd) |
43316044 | 191 | { |
664a3923 | 192 | struct watchdog_core_data *wd_data = wdd->wd_data; |
e907df32 | 193 | |
ee142889 | 194 | if (!watchdog_active(wdd) && !watchdog_hw_running(wdd)) |
b4ffb190 | 195 | return 0; |
7a879824 | 196 | |
90b826f1 GR |
197 | set_bit(_WDOG_KEEPALIVE, &wd_data->status); |
198 | ||
1ff68820 | 199 | wd_data->last_keepalive = ktime_get(); |
664a3923 GR |
200 | return __watchdog_ping(wdd); |
201 | } | |
7a879824 | 202 | |
c013b65a RV |
203 | static bool watchdog_worker_should_ping(struct watchdog_core_data *wd_data) |
204 | { | |
205 | struct watchdog_device *wdd = wd_data->wdd; | |
206 | ||
4d1c6a0e RV |
207 | if (!wdd) |
208 | return false; | |
209 | ||
210 | if (watchdog_active(wdd)) | |
211 | return true; | |
212 | ||
213 | return watchdog_hw_running(wdd) && !watchdog_past_open_deadline(wd_data); | |
c013b65a RV |
214 | } |
215 | ||
38a1222a | 216 | static void watchdog_ping_work(struct kthread_work *work) |
664a3923 GR |
217 | { |
218 | struct watchdog_core_data *wd_data; | |
664a3923 | 219 | |
1ff68820 | 220 | wd_data = container_of(work, struct watchdog_core_data, work); |
664a3923 GR |
221 | |
222 | mutex_lock(&wd_data->lock); | |
c013b65a RV |
223 | if (watchdog_worker_should_ping(wd_data)) |
224 | __watchdog_ping(wd_data->wdd); | |
664a3923 | 225 | mutex_unlock(&wd_data->lock); |
234445b4 WVS |
226 | } |
227 | ||
1ff68820 CL |
228 | static enum hrtimer_restart watchdog_timer_expired(struct hrtimer *timer) |
229 | { | |
230 | struct watchdog_core_data *wd_data; | |
231 | ||
232 | wd_data = container_of(timer, struct watchdog_core_data, timer); | |
233 | ||
234 | kthread_queue_work(watchdog_kworker, &wd_data->work); | |
235 | return HRTIMER_NORESTART; | |
236 | } | |
237 | ||
234445b4 | 238 | /* |
ba6c89ab DBO |
239 | * watchdog_start - wrapper to start the watchdog |
240 | * @wdd: The watchdog device to start | |
234445b4 | 241 | * |
ba6c89ab DBO |
242 | * Start the watchdog if it is not active and mark it active. |
243 | * The caller must hold wd_data->lock. | |
b4ffb190 | 244 | * |
ba6c89ab | 245 | * Return: 0 on success or a negative errno code for failure. |
234445b4 | 246 | */ |
bc794ac3 | 247 | static int watchdog_start(struct watchdog_device *wdd) |
234445b4 | 248 | { |
664a3923 | 249 | struct watchdog_core_data *wd_data = wdd->wd_data; |
1ff68820 | 250 | ktime_t started_at; |
b4ffb190 | 251 | int err; |
e907df32 | 252 | |
bc794ac3 | 253 | if (watchdog_active(wdd)) |
b4ffb190 | 254 | return 0; |
234445b4 | 255 | |
90b826f1 GR |
256 | set_bit(_WDOG_KEEPALIVE, &wd_data->status); |
257 | ||
1ff68820 | 258 | started_at = ktime_get(); |
fbbe35df TK |
259 | if (watchdog_hw_running(wdd) && wdd->ops->ping) { |
260 | err = __watchdog_ping(wdd); | |
7b7d2fdc | 261 | if (err == 0) { |
fbbe35df | 262 | set_bit(WDOG_ACTIVE, &wdd->status); |
7b7d2fdc CK |
263 | watchdog_hrtimer_pretimeout_start(wdd); |
264 | } | |
fbbe35df | 265 | } else { |
ee142889 | 266 | err = wdd->ops->start(wdd); |
e25b091b | 267 | trace_watchdog_start(wdd, err); |
fbbe35df TK |
268 | if (err == 0) { |
269 | set_bit(WDOG_ACTIVE, &wdd->status); | |
270 | wd_data->last_keepalive = started_at; | |
271 | wd_data->last_hw_keepalive = started_at; | |
272 | watchdog_update_worker(wdd); | |
7b7d2fdc | 273 | watchdog_hrtimer_pretimeout_start(wdd); |
fbbe35df | 274 | } |
664a3923 | 275 | } |
7a879824 | 276 | |
7a879824 | 277 | return err; |
234445b4 WVS |
278 | } |
279 | ||
280 | /* | |
ba6c89ab DBO |
281 | * watchdog_stop - wrapper to stop the watchdog |
282 | * @wdd: The watchdog device to stop | |
234445b4 | 283 | * |
ba6c89ab DBO |
284 | * Stop the watchdog if it is still active and unmark it active. |
285 | * If the 'nowayout' feature was set, the watchdog cannot be stopped. | |
286 | * The caller must hold wd_data->lock. | |
b4ffb190 | 287 | * |
ba6c89ab | 288 | * Return: 0 on success or a negative errno code for failure. |
234445b4 | 289 | */ |
bc794ac3 | 290 | static int watchdog_stop(struct watchdog_device *wdd) |
234445b4 | 291 | { |
ee142889 | 292 | int err = 0; |
e907df32 | 293 | |
bc794ac3 | 294 | if (!watchdog_active(wdd)) |
b4ffb190 | 295 | return 0; |
7e192b9c | 296 | |
bc794ac3 | 297 | if (test_bit(WDOG_NO_WAY_OUT, &wdd->status)) { |
0254e953 GR |
298 | pr_info("watchdog%d: nowayout prevents watchdog being stopped!\n", |
299 | wdd->id); | |
b4ffb190 | 300 | return -EBUSY; |
7e192b9c | 301 | } |
234445b4 | 302 | |
3c10bbde GR |
303 | if (wdd->ops->stop) { |
304 | clear_bit(WDOG_HW_RUNNING, &wdd->status); | |
d0684c8a | 305 | err = wdd->ops->stop(wdd); |
e25b091b | 306 | trace_watchdog_stop(wdd, err); |
3c10bbde | 307 | } else { |
d0684c8a | 308 | set_bit(WDOG_HW_RUNNING, &wdd->status); |
3c10bbde | 309 | } |
d0684c8a | 310 | |
664a3923 | 311 | if (err == 0) { |
bc794ac3 | 312 | clear_bit(WDOG_ACTIVE, &wdd->status); |
ee142889 | 313 | watchdog_update_worker(wdd); |
7b7d2fdc | 314 | watchdog_hrtimer_pretimeout_stop(wdd); |
664a3923 | 315 | } |
7a879824 | 316 | |
7a879824 HG |
317 | return err; |
318 | } | |
319 | ||
320 | /* | |
ba6c89ab DBO |
321 | * watchdog_get_status - wrapper to get the watchdog status |
322 | * @wdd: The watchdog device to get the status from | |
b4ffb190 | 323 | * |
ba6c89ab DBO |
324 | * Get the watchdog's status flags. |
325 | * The caller must hold wd_data->lock. | |
7a879824 | 326 | * |
ba6c89ab | 327 | * Return: watchdog's status flags. |
7a879824 | 328 | */ |
b4ffb190 | 329 | static unsigned int watchdog_get_status(struct watchdog_device *wdd) |
7a879824 | 330 | { |
90b826f1 GR |
331 | struct watchdog_core_data *wd_data = wdd->wd_data; |
332 | unsigned int status; | |
7a879824 | 333 | |
90b826f1 GR |
334 | if (wdd->ops->status) |
335 | status = wdd->ops->status(wdd); | |
336 | else | |
337 | status = wdd->bootstatus & (WDIOF_CARDRESET | | |
338 | WDIOF_OVERHEAT | | |
339 | WDIOF_FANFAULT | | |
340 | WDIOF_EXTERN1 | | |
341 | WDIOF_EXTERN2 | | |
342 | WDIOF_POWERUNDER | | |
343 | WDIOF_POWEROVER); | |
344 | ||
345 | if (test_bit(_WDOG_ALLOW_RELEASE, &wd_data->status)) | |
346 | status |= WDIOF_MAGICCLOSE; | |
347 | ||
348 | if (test_and_clear_bit(_WDOG_KEEPALIVE, &wd_data->status)) | |
349 | status |= WDIOF_KEEPALIVEPING; | |
350 | ||
7b7d2fdc CK |
351 | if (IS_ENABLED(CONFIG_WATCHDOG_HRTIMER_PRETIMEOUT)) |
352 | status |= WDIOF_PRETIMEOUT; | |
353 | ||
90b826f1 | 354 | return status; |
7a879824 HG |
355 | } |
356 | ||
357 | /* | |
ba6c89ab DBO |
358 | * watchdog_set_timeout - set the watchdog timer timeout |
359 | * @wdd: The watchdog device to set the timeout for | |
360 | * @timeout: Timeout to set in seconds | |
361 | * | |
362 | * The caller must hold wd_data->lock. | |
b4ffb190 | 363 | * |
ba6c89ab | 364 | * Return: 0 if successful, error otherwise. |
7a879824 | 365 | */ |
bc794ac3 | 366 | static int watchdog_set_timeout(struct watchdog_device *wdd, |
7a879824 HG |
367 | unsigned int timeout) |
368 | { | |
fb32e9b9 GR |
369 | int err = 0; |
370 | ||
371 | if (!(wdd->info->options & WDIOF_SETTIMEOUT)) | |
7a879824 HG |
372 | return -EOPNOTSUPP; |
373 | ||
bc794ac3 | 374 | if (watchdog_timeout_invalid(wdd, timeout)) |
7a879824 HG |
375 | return -EINVAL; |
376 | ||
df044e02 | 377 | if (wdd->ops->set_timeout) { |
fb32e9b9 | 378 | err = wdd->ops->set_timeout(wdd, timeout); |
e25b091b | 379 | trace_watchdog_set_timeout(wdd, timeout, err); |
df044e02 | 380 | } else { |
fb32e9b9 | 381 | wdd->timeout = timeout; |
df044e02 WS |
382 | /* Disable pretimeout if it doesn't fit the new timeout */ |
383 | if (wdd->pretimeout >= wdd->timeout) | |
384 | wdd->pretimeout = 0; | |
385 | } | |
fb32e9b9 | 386 | |
664a3923 GR |
387 | watchdog_update_worker(wdd); |
388 | ||
fb32e9b9 | 389 | return err; |
7a879824 HG |
390 | } |
391 | ||
df044e02 | 392 | /* |
ba6c89ab DBO |
393 | * watchdog_set_pretimeout - set the watchdog timer pretimeout |
394 | * @wdd: The watchdog device to set the timeout for | |
395 | * @timeout: pretimeout to set in seconds | |
396 | * | |
397 | * Return: 0 if successful, error otherwise. | |
df044e02 | 398 | */ |
df044e02 WS |
399 | static int watchdog_set_pretimeout(struct watchdog_device *wdd, |
400 | unsigned int timeout) | |
401 | { | |
402 | int err = 0; | |
403 | ||
7b7d2fdc | 404 | if (!watchdog_have_pretimeout(wdd)) |
df044e02 WS |
405 | return -EOPNOTSUPP; |
406 | ||
407 | if (watchdog_pretimeout_invalid(wdd, timeout)) | |
408 | return -EINVAL; | |
409 | ||
cf6ea954 | 410 | if (wdd->ops->set_pretimeout && (wdd->info->options & WDIOF_PRETIMEOUT)) |
df044e02 WS |
411 | err = wdd->ops->set_pretimeout(wdd, timeout); |
412 | else | |
413 | wdd->pretimeout = timeout; | |
414 | ||
415 | return err; | |
416 | } | |
417 | ||
7a879824 | 418 | /* |
ba6c89ab DBO |
419 | * watchdog_get_timeleft - wrapper to get the time left before a reboot |
420 | * @wdd: The watchdog device to get the remaining time from | |
421 | * @timeleft: The time that's left | |
7a879824 | 422 | * |
ba6c89ab DBO |
423 | * Get the time before a watchdog will reboot (if not pinged). |
424 | * The caller must hold wd_data->lock. | |
b4ffb190 | 425 | * |
ba6c89ab | 426 | * Return: 0 if successful, error otherwise. |
7a879824 | 427 | */ |
bc794ac3 | 428 | static int watchdog_get_timeleft(struct watchdog_device *wdd, |
7a879824 HG |
429 | unsigned int *timeleft) |
430 | { | |
7a879824 | 431 | *timeleft = 0; |
b4ffb190 | 432 | |
bc794ac3 | 433 | if (!wdd->ops->get_timeleft) |
7a879824 HG |
434 | return -EOPNOTSUPP; |
435 | ||
bc794ac3 | 436 | *timeleft = wdd->ops->get_timeleft(wdd); |
7a879824 | 437 | |
b4ffb190 | 438 | return 0; |
7a879824 HG |
439 | } |
440 | ||
33b71126 PA |
441 | #ifdef CONFIG_WATCHDOG_SYSFS |
442 | static ssize_t nowayout_show(struct device *dev, struct device_attribute *attr, | |
443 | char *buf) | |
444 | { | |
445 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
446 | ||
3bb21781 JH |
447 | return sysfs_emit(buf, "%d\n", !!test_bit(WDOG_NO_WAY_OUT, |
448 | &wdd->status)); | |
33b71126 | 449 | } |
bc44fa73 RV |
450 | |
451 | static ssize_t nowayout_store(struct device *dev, struct device_attribute *attr, | |
452 | const char *buf, size_t len) | |
453 | { | |
454 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
455 | unsigned int value; | |
456 | int ret; | |
457 | ||
458 | ret = kstrtouint(buf, 0, &value); | |
459 | if (ret) | |
460 | return ret; | |
461 | if (value > 1) | |
462 | return -EINVAL; | |
463 | /* nowayout cannot be disabled once set */ | |
464 | if (test_bit(WDOG_NO_WAY_OUT, &wdd->status) && !value) | |
465 | return -EPERM; | |
466 | watchdog_set_nowayout(wdd, value); | |
467 | return len; | |
468 | } | |
469 | static DEVICE_ATTR_RW(nowayout); | |
33b71126 PA |
470 | |
471 | static ssize_t status_show(struct device *dev, struct device_attribute *attr, | |
472 | char *buf) | |
473 | { | |
474 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
b4ffb190 GR |
475 | struct watchdog_core_data *wd_data = wdd->wd_data; |
476 | unsigned int status; | |
33b71126 | 477 | |
b4ffb190 GR |
478 | mutex_lock(&wd_data->lock); |
479 | status = watchdog_get_status(wdd); | |
480 | mutex_unlock(&wd_data->lock); | |
33b71126 | 481 | |
3bb21781 | 482 | return sysfs_emit(buf, "0x%x\n", status); |
33b71126 PA |
483 | } |
484 | static DEVICE_ATTR_RO(status); | |
485 | ||
486 | static ssize_t bootstatus_show(struct device *dev, | |
487 | struct device_attribute *attr, char *buf) | |
488 | { | |
489 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
490 | ||
3bb21781 | 491 | return sysfs_emit(buf, "%u\n", wdd->bootstatus); |
33b71126 PA |
492 | } |
493 | static DEVICE_ATTR_RO(bootstatus); | |
494 | ||
495 | static ssize_t timeleft_show(struct device *dev, struct device_attribute *attr, | |
496 | char *buf) | |
497 | { | |
498 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
b4ffb190 | 499 | struct watchdog_core_data *wd_data = wdd->wd_data; |
33b71126 PA |
500 | ssize_t status; |
501 | unsigned int val; | |
502 | ||
b4ffb190 | 503 | mutex_lock(&wd_data->lock); |
33b71126 | 504 | status = watchdog_get_timeleft(wdd, &val); |
b4ffb190 | 505 | mutex_unlock(&wd_data->lock); |
33b71126 | 506 | if (!status) |
3bb21781 | 507 | status = sysfs_emit(buf, "%u\n", val); |
33b71126 PA |
508 | |
509 | return status; | |
510 | } | |
511 | static DEVICE_ATTR_RO(timeleft); | |
512 | ||
513 | static ssize_t timeout_show(struct device *dev, struct device_attribute *attr, | |
514 | char *buf) | |
515 | { | |
516 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
517 | ||
3bb21781 | 518 | return sysfs_emit(buf, "%u\n", wdd->timeout); |
33b71126 PA |
519 | } |
520 | static DEVICE_ATTR_RO(timeout); | |
521 | ||
6ddf5087 JH |
522 | static ssize_t min_timeout_show(struct device *dev, |
523 | struct device_attribute *attr, char *buf) | |
524 | { | |
525 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
526 | ||
527 | return sysfs_emit(buf, "%u\n", wdd->min_timeout); | |
528 | } | |
529 | static DEVICE_ATTR_RO(min_timeout); | |
530 | ||
531 | static ssize_t max_timeout_show(struct device *dev, | |
532 | struct device_attribute *attr, char *buf) | |
533 | { | |
534 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
535 | ||
536 | return sysfs_emit(buf, "%u\n", wdd->max_timeout); | |
537 | } | |
538 | static DEVICE_ATTR_RO(max_timeout); | |
539 | ||
df044e02 WS |
540 | static ssize_t pretimeout_show(struct device *dev, |
541 | struct device_attribute *attr, char *buf) | |
542 | { | |
543 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
544 | ||
3bb21781 | 545 | return sysfs_emit(buf, "%u\n", wdd->pretimeout); |
df044e02 WS |
546 | } |
547 | static DEVICE_ATTR_RO(pretimeout); | |
548 | ||
33b71126 PA |
549 | static ssize_t identity_show(struct device *dev, struct device_attribute *attr, |
550 | char *buf) | |
551 | { | |
552 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
553 | ||
3bb21781 | 554 | return sysfs_emit(buf, "%s\n", wdd->info->identity); |
33b71126 PA |
555 | } |
556 | static DEVICE_ATTR_RO(identity); | |
557 | ||
558 | static ssize_t state_show(struct device *dev, struct device_attribute *attr, | |
559 | char *buf) | |
560 | { | |
561 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
562 | ||
563 | if (watchdog_active(wdd)) | |
3bb21781 | 564 | return sysfs_emit(buf, "active\n"); |
33b71126 | 565 | |
3bb21781 | 566 | return sysfs_emit(buf, "inactive\n"); |
33b71126 PA |
567 | } |
568 | static DEVICE_ATTR_RO(state); | |
569 | ||
89873a71 VZ |
570 | static ssize_t pretimeout_available_governors_show(struct device *dev, |
571 | struct device_attribute *attr, char *buf) | |
572 | { | |
573 | return watchdog_pretimeout_available_governors_get(buf); | |
574 | } | |
575 | static DEVICE_ATTR_RO(pretimeout_available_governors); | |
576 | ||
ff84136c VZ |
577 | static ssize_t pretimeout_governor_show(struct device *dev, |
578 | struct device_attribute *attr, | |
579 | char *buf) | |
580 | { | |
581 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
582 | ||
583 | return watchdog_pretimeout_governor_get(wdd, buf); | |
584 | } | |
53f96cee VZ |
585 | |
586 | static ssize_t pretimeout_governor_store(struct device *dev, | |
587 | struct device_attribute *attr, | |
588 | const char *buf, size_t count) | |
589 | { | |
590 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
591 | int ret = watchdog_pretimeout_governor_set(wdd, buf); | |
592 | ||
593 | if (!ret) | |
594 | ret = count; | |
595 | ||
596 | return ret; | |
597 | } | |
598 | static DEVICE_ATTR_RW(pretimeout_governor); | |
ff84136c | 599 | |
33b71126 PA |
600 | static umode_t wdt_is_visible(struct kobject *kobj, struct attribute *attr, |
601 | int n) | |
602 | { | |
893c3d82 | 603 | struct device *dev = kobj_to_dev(kobj); |
33b71126 PA |
604 | struct watchdog_device *wdd = dev_get_drvdata(dev); |
605 | umode_t mode = attr->mode; | |
606 | ||
90b826f1 | 607 | if (attr == &dev_attr_timeleft.attr && !wdd->ops->get_timeleft) |
33b71126 | 608 | mode = 0; |
7b7d2fdc | 609 | else if (attr == &dev_attr_pretimeout.attr && !watchdog_have_pretimeout(wdd)) |
df044e02 | 610 | mode = 0; |
89873a71 VZ |
611 | else if ((attr == &dev_attr_pretimeout_governor.attr || |
612 | attr == &dev_attr_pretimeout_available_governors.attr) && | |
7b7d2fdc | 613 | (!watchdog_have_pretimeout(wdd) || !IS_ENABLED(CONFIG_WATCHDOG_PRETIMEOUT_GOV))) |
ff84136c | 614 | mode = 0; |
33b71126 PA |
615 | |
616 | return mode; | |
617 | } | |
618 | static struct attribute *wdt_attrs[] = { | |
619 | &dev_attr_state.attr, | |
620 | &dev_attr_identity.attr, | |
621 | &dev_attr_timeout.attr, | |
6ddf5087 JH |
622 | &dev_attr_min_timeout.attr, |
623 | &dev_attr_max_timeout.attr, | |
df044e02 | 624 | &dev_attr_pretimeout.attr, |
33b71126 PA |
625 | &dev_attr_timeleft.attr, |
626 | &dev_attr_bootstatus.attr, | |
627 | &dev_attr_status.attr, | |
628 | &dev_attr_nowayout.attr, | |
ff84136c | 629 | &dev_attr_pretimeout_governor.attr, |
89873a71 | 630 | &dev_attr_pretimeout_available_governors.attr, |
33b71126 PA |
631 | NULL, |
632 | }; | |
633 | ||
634 | static const struct attribute_group wdt_group = { | |
635 | .attrs = wdt_attrs, | |
636 | .is_visible = wdt_is_visible, | |
637 | }; | |
638 | __ATTRIBUTE_GROUPS(wdt); | |
639 | #else | |
640 | #define wdt_groups NULL | |
641 | #endif | |
642 | ||
7a879824 | 643 | /* |
ba6c89ab DBO |
644 | * watchdog_ioctl_op - call the watchdog drivers ioctl op if defined |
645 | * @wdd: The watchdog device to do the ioctl on | |
646 | * @cmd: Watchdog command | |
647 | * @arg: Argument pointer | |
b4ffb190 | 648 | * |
ba6c89ab DBO |
649 | * The caller must hold wd_data->lock. |
650 | * | |
651 | * Return: 0 if successful, error otherwise. | |
7a879824 | 652 | */ |
bc794ac3 | 653 | static int watchdog_ioctl_op(struct watchdog_device *wdd, unsigned int cmd, |
7a879824 HG |
654 | unsigned long arg) |
655 | { | |
bc794ac3 | 656 | if (!wdd->ops->ioctl) |
7a879824 HG |
657 | return -ENOIOCTLCMD; |
658 | ||
b4ffb190 | 659 | return wdd->ops->ioctl(wdd, cmd, arg); |
43316044 WVS |
660 | } |
661 | ||
662 | /* | |
ba6c89ab DBO |
663 | * watchdog_write - writes to the watchdog |
664 | * @file: File from VFS | |
665 | * @data: User address of data | |
666 | * @len: Length of data | |
667 | * @ppos: Pointer to the file offset | |
43316044 | 668 | * |
ba6c89ab DBO |
669 | * A write to a watchdog device is defined as a keepalive ping. |
670 | * Writing the magic 'V' sequence allows the next close to turn | |
671 | * off the watchdog (if 'nowayout' is not set). | |
672 | * | |
673 | * Return: @len if successful, error otherwise. | |
43316044 | 674 | */ |
43316044 WVS |
675 | static ssize_t watchdog_write(struct file *file, const char __user *data, |
676 | size_t len, loff_t *ppos) | |
677 | { | |
b4ffb190 GR |
678 | struct watchdog_core_data *wd_data = file->private_data; |
679 | struct watchdog_device *wdd; | |
680 | int err; | |
43316044 WVS |
681 | size_t i; |
682 | char c; | |
683 | ||
684 | if (len == 0) | |
685 | return 0; | |
686 | ||
017cf080 WVS |
687 | /* |
688 | * Note: just in case someone wrote the magic character | |
689 | * five months ago... | |
690 | */ | |
b4ffb190 | 691 | clear_bit(_WDOG_ALLOW_RELEASE, &wd_data->status); |
017cf080 WVS |
692 | |
693 | /* scan to see whether or not we got the magic character */ | |
43316044 WVS |
694 | for (i = 0; i != len; i++) { |
695 | if (get_user(c, data + i)) | |
696 | return -EFAULT; | |
017cf080 | 697 | if (c == 'V') |
b4ffb190 | 698 | set_bit(_WDOG_ALLOW_RELEASE, &wd_data->status); |
43316044 WVS |
699 | } |
700 | ||
701 | /* someone wrote to us, so we send the watchdog a keepalive ping */ | |
b4ffb190 GR |
702 | |
703 | err = -ENODEV; | |
704 | mutex_lock(&wd_data->lock); | |
705 | wdd = wd_data->wdd; | |
706 | if (wdd) | |
707 | err = watchdog_ping(wdd); | |
708 | mutex_unlock(&wd_data->lock); | |
709 | ||
5ef79663 AU |
710 | if (err < 0) |
711 | return err; | |
43316044 WVS |
712 | |
713 | return len; | |
714 | } | |
715 | ||
2fa03560 | 716 | /* |
ba6c89ab DBO |
717 | * watchdog_ioctl - handle the different ioctl's for the watchdog device |
718 | * @file: File handle to the device | |
719 | * @cmd: Watchdog command | |
720 | * @arg: Argument pointer | |
2fa03560 | 721 | * |
ba6c89ab DBO |
722 | * The watchdog API defines a common set of functions for all watchdogs |
723 | * according to their available features. | |
724 | * | |
725 | * Return: 0 if successful, error otherwise. | |
2fa03560 WVS |
726 | */ |
727 | ||
728 | static long watchdog_ioctl(struct file *file, unsigned int cmd, | |
729 | unsigned long arg) | |
730 | { | |
b4ffb190 | 731 | struct watchdog_core_data *wd_data = file->private_data; |
2fa03560 | 732 | void __user *argp = (void __user *)arg; |
b4ffb190 | 733 | struct watchdog_device *wdd; |
2fa03560 WVS |
734 | int __user *p = argp; |
735 | unsigned int val; | |
234445b4 | 736 | int err; |
2fa03560 | 737 | |
b4ffb190 GR |
738 | mutex_lock(&wd_data->lock); |
739 | ||
740 | wdd = wd_data->wdd; | |
741 | if (!wdd) { | |
742 | err = -ENODEV; | |
743 | goto out_ioctl; | |
744 | } | |
745 | ||
7a879824 HG |
746 | err = watchdog_ioctl_op(wdd, cmd, arg); |
747 | if (err != -ENOIOCTLCMD) | |
b4ffb190 | 748 | goto out_ioctl; |
78d88fc0 | 749 | |
2fa03560 WVS |
750 | switch (cmd) { |
751 | case WDIOC_GETSUPPORT: | |
b4ffb190 | 752 | err = copy_to_user(argp, wdd->info, |
2fa03560 | 753 | sizeof(struct watchdog_info)) ? -EFAULT : 0; |
b4ffb190 | 754 | break; |
2fa03560 | 755 | case WDIOC_GETSTATUS: |
b4ffb190 GR |
756 | val = watchdog_get_status(wdd); |
757 | err = put_user(val, p); | |
758 | break; | |
2fa03560 | 759 | case WDIOC_GETBOOTSTATUS: |
b4ffb190 GR |
760 | err = put_user(wdd->bootstatus, p); |
761 | break; | |
234445b4 | 762 | case WDIOC_SETOPTIONS: |
b4ffb190 GR |
763 | if (get_user(val, p)) { |
764 | err = -EFAULT; | |
765 | break; | |
766 | } | |
234445b4 WVS |
767 | if (val & WDIOS_DISABLECARD) { |
768 | err = watchdog_stop(wdd); | |
769 | if (err < 0) | |
b4ffb190 | 770 | break; |
234445b4 | 771 | } |
b4ffb190 | 772 | if (val & WDIOS_ENABLECARD) |
234445b4 | 773 | err = watchdog_start(wdd); |
b4ffb190 | 774 | break; |
c2dc00e4 | 775 | case WDIOC_KEEPALIVE: |
b4ffb190 GR |
776 | if (!(wdd->info->options & WDIOF_KEEPALIVEPING)) { |
777 | err = -EOPNOTSUPP; | |
778 | break; | |
779 | } | |
780 | err = watchdog_ping(wdd); | |
781 | break; | |
014d694e | 782 | case WDIOC_SETTIMEOUT: |
b4ffb190 GR |
783 | if (get_user(val, p)) { |
784 | err = -EFAULT; | |
785 | break; | |
786 | } | |
7a879824 | 787 | err = watchdog_set_timeout(wdd, val); |
014d694e | 788 | if (err < 0) |
b4ffb190 | 789 | break; |
014d694e WVS |
790 | /* If the watchdog is active then we send a keepalive ping |
791 | * to make sure that the watchdog keep's running (and if | |
792 | * possible that it takes the new timeout) */ | |
5ef79663 AU |
793 | err = watchdog_ping(wdd); |
794 | if (err < 0) | |
b4ffb190 | 795 | break; |
bd490f82 | 796 | fallthrough; |
014d694e WVS |
797 | case WDIOC_GETTIMEOUT: |
798 | /* timeout == 0 means that we don't know the timeout */ | |
b4ffb190 GR |
799 | if (wdd->timeout == 0) { |
800 | err = -EOPNOTSUPP; | |
801 | break; | |
802 | } | |
803 | err = put_user(wdd->timeout, p); | |
804 | break; | |
fd7b673c | 805 | case WDIOC_GETTIMELEFT: |
7a879824 | 806 | err = watchdog_get_timeleft(wdd, &val); |
b4ffb190 GR |
807 | if (err < 0) |
808 | break; | |
809 | err = put_user(val, p); | |
810 | break; | |
df044e02 WS |
811 | case WDIOC_SETPRETIMEOUT: |
812 | if (get_user(val, p)) { | |
813 | err = -EFAULT; | |
814 | break; | |
815 | } | |
816 | err = watchdog_set_pretimeout(wdd, val); | |
817 | break; | |
818 | case WDIOC_GETPRETIMEOUT: | |
819 | err = put_user(wdd->pretimeout, p); | |
820 | break; | |
2fa03560 | 821 | default: |
b4ffb190 GR |
822 | err = -ENOTTY; |
823 | break; | |
2fa03560 | 824 | } |
b4ffb190 GR |
825 | |
826 | out_ioctl: | |
827 | mutex_unlock(&wd_data->lock); | |
828 | return err; | |
2fa03560 WVS |
829 | } |
830 | ||
43316044 | 831 | /* |
ba6c89ab DBO |
832 | * watchdog_open - open the /dev/watchdog* devices |
833 | * @inode: Inode of device | |
834 | * @file: File handle to device | |
835 | * | |
836 | * When the /dev/watchdog* device gets opened, we start the watchdog. | |
837 | * Watch out: the /dev/watchdog device is single open, so we make sure | |
838 | * it can only be opened once. | |
43316044 | 839 | * |
ba6c89ab | 840 | * Return: 0 if successful, error otherwise. |
43316044 | 841 | */ |
43316044 WVS |
842 | static int watchdog_open(struct inode *inode, struct file *file) |
843 | { | |
b4ffb190 | 844 | struct watchdog_core_data *wd_data; |
45f5fed3 | 845 | struct watchdog_device *wdd; |
4bcd615f | 846 | bool hw_running; |
b4ffb190 | 847 | int err; |
45f5fed3 AC |
848 | |
849 | /* Get the corresponding watchdog device */ | |
850 | if (imajor(inode) == MISC_MAJOR) | |
b4ffb190 | 851 | wd_data = old_wd_data; |
45f5fed3 | 852 | else |
b4ffb190 GR |
853 | wd_data = container_of(inode->i_cdev, struct watchdog_core_data, |
854 | cdev); | |
43316044 WVS |
855 | |
856 | /* the watchdog is single open! */ | |
b4ffb190 | 857 | if (test_and_set_bit(_WDOG_DEV_OPEN, &wd_data->status)) |
43316044 WVS |
858 | return -EBUSY; |
859 | ||
b4ffb190 GR |
860 | wdd = wd_data->wdd; |
861 | ||
43316044 WVS |
862 | /* |
863 | * If the /dev/watchdog device is open, we don't want the module | |
864 | * to be unloaded. | |
865 | */ | |
4bcd615f GR |
866 | hw_running = watchdog_hw_running(wdd); |
867 | if (!hw_running && !try_module_get(wdd->ops->owner)) { | |
b4ffb190 GR |
868 | err = -EBUSY; |
869 | goto out_clear; | |
870 | } | |
43316044 | 871 | |
234445b4 | 872 | err = watchdog_start(wdd); |
43316044 WVS |
873 | if (err < 0) |
874 | goto out_mod; | |
875 | ||
b4ffb190 | 876 | file->private_data = wd_data; |
45f5fed3 | 877 | |
4bcd615f | 878 | if (!hw_running) |
72139dfa | 879 | get_device(&wd_data->dev); |
e907df32 | 880 | |
4d1c6a0e RV |
881 | /* |
882 | * open_timeout only applies for the first open from | |
883 | * userspace. Set open_deadline to infinity so that the kernel | |
884 | * will take care of an always-running hardware watchdog in | |
885 | * case the device gets magic-closed or WDIOS_DISABLECARD is | |
886 | * applied. | |
887 | */ | |
888 | wd_data->open_deadline = KTIME_MAX; | |
889 | ||
43316044 | 890 | /* dev/watchdog is a virtual (and thus non-seekable) filesystem */ |
c5bf68fe | 891 | return stream_open(inode, file); |
43316044 WVS |
892 | |
893 | out_mod: | |
b4ffb190 GR |
894 | module_put(wd_data->wdd->ops->owner); |
895 | out_clear: | |
896 | clear_bit(_WDOG_DEV_OPEN, &wd_data->status); | |
43316044 WVS |
897 | return err; |
898 | } | |
899 | ||
72139dfa | 900 | static void watchdog_core_data_release(struct device *dev) |
b4ffb190 GR |
901 | { |
902 | struct watchdog_core_data *wd_data; | |
903 | ||
72139dfa | 904 | wd_data = container_of(dev, struct watchdog_core_data, dev); |
b4ffb190 GR |
905 | |
906 | kfree(wd_data); | |
907 | } | |
908 | ||
43316044 | 909 | /* |
ba6c89ab DBO |
910 | * watchdog_release - release the watchdog device |
911 | * @inode: Inode of device | |
912 | * @file: File handle to device | |
913 | * | |
914 | * This is the code for when /dev/watchdog gets closed. We will only | |
915 | * stop the watchdog when we have received the magic char (and nowayout | |
916 | * was not set), else the watchdog will keep running. | |
43316044 | 917 | * |
ba6c89ab | 918 | * Always returns 0. |
43316044 | 919 | */ |
43316044 WVS |
920 | static int watchdog_release(struct inode *inode, struct file *file) |
921 | { | |
b4ffb190 GR |
922 | struct watchdog_core_data *wd_data = file->private_data; |
923 | struct watchdog_device *wdd; | |
017cf080 | 924 | int err = -EBUSY; |
d1ed3ba4 | 925 | bool running; |
017cf080 | 926 | |
b4ffb190 GR |
927 | mutex_lock(&wd_data->lock); |
928 | ||
929 | wdd = wd_data->wdd; | |
930 | if (!wdd) | |
931 | goto done; | |
932 | ||
017cf080 WVS |
933 | /* |
934 | * We only stop the watchdog if we received the magic character | |
7e192b9c WVS |
935 | * or if WDIOF_MAGICCLOSE is not set. If nowayout was set then |
936 | * watchdog_stop will fail. | |
017cf080 | 937 | */ |
0be01476 | 938 | if (!watchdog_active(wdd)) |
fcf95670 | 939 | err = 0; |
b4ffb190 | 940 | else if (test_and_clear_bit(_WDOG_ALLOW_RELEASE, &wd_data->status) || |
fcf95670 | 941 | !(wdd->info->options & WDIOF_MAGICCLOSE)) |
017cf080 | 942 | err = watchdog_stop(wdd); |
43316044 | 943 | |
017cf080 | 944 | /* If the watchdog was not stopped, send a keepalive ping */ |
234445b4 | 945 | if (err < 0) { |
0254e953 | 946 | pr_crit("watchdog%d: watchdog did not stop!\n", wdd->id); |
43316044 WVS |
947 | watchdog_ping(wdd); |
948 | } | |
949 | ||
ee142889 | 950 | watchdog_update_worker(wdd); |
664a3923 | 951 | |
43316044 | 952 | /* make sure that /dev/watchdog can be re-opened */ |
b4ffb190 | 953 | clear_bit(_WDOG_DEV_OPEN, &wd_data->status); |
e907df32 | 954 | |
b4ffb190 | 955 | done: |
d1ed3ba4 | 956 | running = wdd && watchdog_hw_running(wdd); |
b4ffb190 | 957 | mutex_unlock(&wd_data->lock); |
ee142889 GR |
958 | /* |
959 | * Allow the owner module to be unloaded again unless the watchdog | |
960 | * is still running. If the watchdog is still running, it can not | |
961 | * be stopped, and its driver must not be unloaded. | |
962 | */ | |
d1ed3ba4 GR |
963 | if (!running) { |
964 | module_put(wd_data->cdev.owner); | |
72139dfa | 965 | put_device(&wd_data->dev); |
ee142889 | 966 | } |
43316044 WVS |
967 | return 0; |
968 | } | |
969 | ||
970 | static const struct file_operations watchdog_fops = { | |
971 | .owner = THIS_MODULE, | |
972 | .write = watchdog_write, | |
2fa03560 | 973 | .unlocked_ioctl = watchdog_ioctl, |
b6dfb247 | 974 | .compat_ioctl = compat_ptr_ioctl, |
43316044 WVS |
975 | .open = watchdog_open, |
976 | .release = watchdog_release, | |
977 | }; | |
978 | ||
979 | static struct miscdevice watchdog_miscdev = { | |
980 | .minor = WATCHDOG_MINOR, | |
981 | .name = "watchdog", | |
982 | .fops = &watchdog_fops, | |
983 | }; | |
984 | ||
72139dfa KH |
985 | static struct class watchdog_class = { |
986 | .name = "watchdog", | |
987 | .owner = THIS_MODULE, | |
988 | .dev_groups = wdt_groups, | |
989 | }; | |
990 | ||
43316044 | 991 | /* |
ba6c89ab DBO |
992 | * watchdog_cdev_register - register watchdog character device |
993 | * @wdd: Watchdog device | |
994 | * | |
995 | * Register a watchdog character device including handling the legacy | |
996 | * /dev/watchdog node. /dev/watchdog is actually a miscdevice and | |
997 | * thus we set it up like that. | |
43316044 | 998 | * |
ba6c89ab | 999 | * Return: 0 if successful, error otherwise. |
43316044 | 1000 | */ |
72139dfa | 1001 | static int watchdog_cdev_register(struct watchdog_device *wdd) |
43316044 | 1002 | { |
b4ffb190 | 1003 | struct watchdog_core_data *wd_data; |
32ecc639 | 1004 | int err; |
45f5fed3 | 1005 | |
b4ffb190 GR |
1006 | wd_data = kzalloc(sizeof(struct watchdog_core_data), GFP_KERNEL); |
1007 | if (!wd_data) | |
1008 | return -ENOMEM; | |
b4ffb190 GR |
1009 | mutex_init(&wd_data->lock); |
1010 | ||
1011 | wd_data->wdd = wdd; | |
1012 | wdd->wd_data = wd_data; | |
1013 | ||
5afb6d20 DL |
1014 | if (IS_ERR_OR_NULL(watchdog_kworker)) { |
1015 | kfree(wd_data); | |
664a3923 | 1016 | return -ENODEV; |
5afb6d20 | 1017 | } |
664a3923 | 1018 | |
cb36e29b KS |
1019 | device_initialize(&wd_data->dev); |
1020 | wd_data->dev.devt = MKDEV(MAJOR(watchdog_devt), wdd->id); | |
1021 | wd_data->dev.class = &watchdog_class; | |
1022 | wd_data->dev.parent = wdd->parent; | |
1023 | wd_data->dev.groups = wdd->groups; | |
1024 | wd_data->dev.release = watchdog_core_data_release; | |
1025 | dev_set_drvdata(&wd_data->dev, wdd); | |
0e012972 BL |
1026 | err = dev_set_name(&wd_data->dev, "watchdog%d", wdd->id); |
1027 | if (err) { | |
1028 | put_device(&wd_data->dev); | |
1029 | return err; | |
1030 | } | |
cb36e29b | 1031 | |
1ff68820 | 1032 | kthread_init_work(&wd_data->work, watchdog_ping_work); |
a19f8933 | 1033 | hrtimer_init(&wd_data->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD); |
1ff68820 | 1034 | wd_data->timer.function = watchdog_timer_expired; |
7b7d2fdc | 1035 | watchdog_hrtimer_pretimeout_init(wdd); |
664a3923 | 1036 | |
bc794ac3 | 1037 | if (wdd->id == 0) { |
b4ffb190 | 1038 | old_wd_data = wd_data; |
bc794ac3 | 1039 | watchdog_miscdev.parent = wdd->parent; |
45f5fed3 AC |
1040 | err = misc_register(&watchdog_miscdev); |
1041 | if (err != 0) { | |
1042 | pr_err("%s: cannot register miscdev on minor=%d (err=%d).\n", | |
bc794ac3 | 1043 | wdd->info->identity, WATCHDOG_MINOR, err); |
45f5fed3 AC |
1044 | if (err == -EBUSY) |
1045 | pr_err("%s: a legacy watchdog module is probably present.\n", | |
bc794ac3 | 1046 | wdd->info->identity); |
b4ffb190 | 1047 | old_wd_data = NULL; |
937425d4 | 1048 | put_device(&wd_data->dev); |
45f5fed3 AC |
1049 | return err; |
1050 | } | |
43316044 WVS |
1051 | } |
1052 | ||
45f5fed3 | 1053 | /* Fill in the data structures */ |
b4ffb190 | 1054 | cdev_init(&wd_data->cdev, &watchdog_fops); |
45f5fed3 AC |
1055 | |
1056 | /* Add the device */ | |
72139dfa | 1057 | err = cdev_device_add(&wd_data->cdev, &wd_data->dev); |
45f5fed3 AC |
1058 | if (err) { |
1059 | pr_err("watchdog%d unable to add device %d:%d\n", | |
bc794ac3 GR |
1060 | wdd->id, MAJOR(watchdog_devt), wdd->id); |
1061 | if (wdd->id == 0) { | |
45f5fed3 | 1062 | misc_deregister(&watchdog_miscdev); |
b4ffb190 | 1063 | old_wd_data = NULL; |
72139dfa | 1064 | put_device(&wd_data->dev); |
45f5fed3 | 1065 | } |
ee142889 | 1066 | return err; |
43316044 | 1067 | } |
ee142889 | 1068 | |
72139dfa KH |
1069 | wd_data->cdev.owner = wdd->ops->owner; |
1070 | ||
15013ad8 | 1071 | /* Record time of most recent heartbeat as 'just before now'. */ |
1ff68820 | 1072 | wd_data->last_hw_keepalive = ktime_sub(ktime_get(), 1); |
4d1c6a0e | 1073 | watchdog_set_open_deadline(wd_data); |
15013ad8 | 1074 | |
ee142889 GR |
1075 | /* |
1076 | * If the watchdog is running, prevent its driver from being unloaded, | |
1077 | * and schedule an immediate ping. | |
1078 | */ | |
1079 | if (watchdog_hw_running(wdd)) { | |
914d65f3 | 1080 | __module_get(wdd->ops->owner); |
72139dfa | 1081 | get_device(&wd_data->dev); |
914d65f3 | 1082 | if (handle_boot_enabled) |
a19f8933 JC |
1083 | hrtimer_start(&wd_data->timer, 0, |
1084 | HRTIMER_MODE_REL_HARD); | |
914d65f3 | 1085 | else |
2501b015 | 1086 | pr_info("watchdog%d running and kernel based pre-userspace handler disabled\n", |
914d65f3 | 1087 | wdd->id); |
ee142889 GR |
1088 | } |
1089 | ||
1090 | return 0; | |
43316044 WVS |
1091 | } |
1092 | ||
1093 | /* | |
ba6c89ab DBO |
1094 | * watchdog_cdev_unregister - unregister watchdog character device |
1095 | * @wdd: Watchdog device | |
43316044 | 1096 | * |
ba6c89ab DBO |
1097 | * Unregister watchdog character device and if needed the legacy |
1098 | * /dev/watchdog device. | |
43316044 | 1099 | */ |
32ecc639 | 1100 | static void watchdog_cdev_unregister(struct watchdog_device *wdd) |
43316044 | 1101 | { |
b4ffb190 | 1102 | struct watchdog_core_data *wd_data = wdd->wd_data; |
e907df32 | 1103 | |
72139dfa | 1104 | cdev_device_del(&wd_data->cdev, &wd_data->dev); |
bc794ac3 | 1105 | if (wdd->id == 0) { |
45f5fed3 | 1106 | misc_deregister(&watchdog_miscdev); |
b4ffb190 | 1107 | old_wd_data = NULL; |
43316044 | 1108 | } |
b4ffb190 | 1109 | |
bb292ac1 GR |
1110 | if (watchdog_active(wdd) && |
1111 | test_bit(WDOG_STOP_ON_UNREGISTER, &wdd->status)) { | |
1112 | watchdog_stop(wdd); | |
1113 | } | |
1114 | ||
c7b178da CK |
1115 | watchdog_hrtimer_pretimeout_stop(wdd); |
1116 | ||
953b9dd7 WS |
1117 | mutex_lock(&wd_data->lock); |
1118 | wd_data->wdd = NULL; | |
1119 | wdd->wd_data = NULL; | |
1120 | mutex_unlock(&wd_data->lock); | |
1121 | ||
1ff68820 CL |
1122 | hrtimer_cancel(&wd_data->timer); |
1123 | kthread_cancel_work_sync(&wd_data->work); | |
664a3923 | 1124 | |
72139dfa | 1125 | put_device(&wd_data->dev); |
43316044 | 1126 | } |
45f5fed3 | 1127 | |
ba6c89ab DBO |
1128 | /** |
1129 | * watchdog_dev_register - register a watchdog device | |
1130 | * @wdd: Watchdog device | |
1131 | * | |
1132 | * Register a watchdog device including handling the legacy | |
1133 | * /dev/watchdog node. /dev/watchdog is actually a miscdevice and | |
1134 | * thus we set it up like that. | |
32ecc639 | 1135 | * |
ba6c89ab | 1136 | * Return: 0 if successful, error otherwise. |
32ecc639 | 1137 | */ |
32ecc639 GR |
1138 | int watchdog_dev_register(struct watchdog_device *wdd) |
1139 | { | |
32ecc639 GR |
1140 | int ret; |
1141 | ||
72139dfa | 1142 | ret = watchdog_cdev_register(wdd); |
32ecc639 GR |
1143 | if (ret) |
1144 | return ret; | |
1145 | ||
ff84136c | 1146 | ret = watchdog_register_pretimeout(wdd); |
69503e58 | 1147 | if (ret) |
ff84136c | 1148 | watchdog_cdev_unregister(wdd); |
ff84136c | 1149 | |
32ecc639 GR |
1150 | return ret; |
1151 | } | |
1152 | ||
ba6c89ab DBO |
1153 | /** |
1154 | * watchdog_dev_unregister - unregister a watchdog device | |
1155 | * @wdd: watchdog device | |
32ecc639 | 1156 | * |
ba6c89ab DBO |
1157 | * Unregister watchdog device and if needed the legacy |
1158 | * /dev/watchdog device. | |
32ecc639 | 1159 | */ |
32ecc639 GR |
1160 | void watchdog_dev_unregister(struct watchdog_device *wdd) |
1161 | { | |
ff84136c | 1162 | watchdog_unregister_pretimeout(wdd); |
b4ffb190 | 1163 | watchdog_cdev_unregister(wdd); |
32ecc639 GR |
1164 | } |
1165 | ||
ba6c89ab DBO |
1166 | /** |
1167 | * watchdog_set_last_hw_keepalive - set last HW keepalive time for watchdog | |
1168 | * @wdd: Watchdog device | |
1169 | * @last_ping_ms: Time since last HW heartbeat | |
cef9572e | 1170 | * |
ba6c89ab DBO |
1171 | * Adjusts the last known HW keepalive time for a watchdog timer. |
1172 | * This is needed if the watchdog is already running when the probe | |
1173 | * function is called, and it can't be pinged immediately. This | |
1174 | * function must be called immediately after watchdog registration, | |
1175 | * and min_hw_heartbeat_ms must be set for this to be useful. | |
1176 | * | |
1177 | * Return: 0 if successful, error otherwise. | |
cef9572e TK |
1178 | */ |
1179 | int watchdog_set_last_hw_keepalive(struct watchdog_device *wdd, | |
1180 | unsigned int last_ping_ms) | |
1181 | { | |
1182 | struct watchdog_core_data *wd_data; | |
1183 | ktime_t now; | |
1184 | ||
1185 | if (!wdd) | |
1186 | return -EINVAL; | |
1187 | ||
1188 | wd_data = wdd->wd_data; | |
1189 | ||
1190 | now = ktime_get(); | |
1191 | ||
1192 | wd_data->last_hw_keepalive = ktime_sub(now, ms_to_ktime(last_ping_ms)); | |
1193 | ||
dbe80cf4 JK |
1194 | if (watchdog_hw_running(wdd) && handle_boot_enabled) |
1195 | return __watchdog_ping(wdd); | |
1196 | ||
1197 | return 0; | |
cef9572e TK |
1198 | } |
1199 | EXPORT_SYMBOL_GPL(watchdog_set_last_hw_keepalive); | |
1200 | ||
ba6c89ab DBO |
1201 | /** |
1202 | * watchdog_dev_init - init dev part of watchdog core | |
45f5fed3 | 1203 | * |
ba6c89ab DBO |
1204 | * Allocate a range of chardev nodes to use for watchdog devices. |
1205 | * | |
1206 | * Return: 0 if successful, error otherwise. | |
45f5fed3 | 1207 | */ |
32ecc639 | 1208 | int __init watchdog_dev_init(void) |
45f5fed3 | 1209 | { |
906d7a5c PA |
1210 | int err; |
1211 | ||
38a1222a CL |
1212 | watchdog_kworker = kthread_create_worker(0, "watchdogd"); |
1213 | if (IS_ERR(watchdog_kworker)) { | |
1214 | pr_err("Failed to create watchdog kworker\n"); | |
1215 | return PTR_ERR(watchdog_kworker); | |
664a3923 | 1216 | } |
94beddac | 1217 | sched_set_fifo(watchdog_kworker->task); |
664a3923 | 1218 | |
906d7a5c PA |
1219 | err = class_register(&watchdog_class); |
1220 | if (err < 0) { | |
1221 | pr_err("couldn't register class\n"); | |
138913cb | 1222 | goto err_register; |
906d7a5c PA |
1223 | } |
1224 | ||
1225 | err = alloc_chrdev_region(&watchdog_devt, 0, MAX_DOGS, "watchdog"); | |
1226 | if (err < 0) { | |
45f5fed3 | 1227 | pr_err("watchdog: unable to allocate char dev region\n"); |
138913cb | 1228 | goto err_alloc; |
906d7a5c PA |
1229 | } |
1230 | ||
32ecc639 | 1231 | return 0; |
138913cb WY |
1232 | |
1233 | err_alloc: | |
1234 | class_unregister(&watchdog_class); | |
1235 | err_register: | |
38a1222a | 1236 | kthread_destroy_worker(watchdog_kworker); |
138913cb | 1237 | return err; |
45f5fed3 AC |
1238 | } |
1239 | ||
ba6c89ab DBO |
1240 | /** |
1241 | * watchdog_dev_exit - exit dev part of watchdog core | |
45f5fed3 | 1242 | * |
ba6c89ab | 1243 | * Release the range of chardev nodes used for watchdog devices. |
45f5fed3 | 1244 | */ |
45f5fed3 AC |
1245 | void __exit watchdog_dev_exit(void) |
1246 | { | |
1247 | unregister_chrdev_region(watchdog_devt, MAX_DOGS); | |
906d7a5c | 1248 | class_unregister(&watchdog_class); |
38a1222a | 1249 | kthread_destroy_worker(watchdog_kworker); |
45f5fed3 | 1250 | } |
2501b015 | 1251 | |
60bcd91a GJ |
1252 | int watchdog_dev_suspend(struct watchdog_device *wdd) |
1253 | { | |
1254 | struct watchdog_core_data *wd_data = wdd->wd_data; | |
1255 | int ret = 0; | |
1256 | ||
1257 | if (!wdd->wd_data) | |
1258 | return -ENODEV; | |
1259 | ||
1260 | /* ping for the last time before suspend */ | |
1261 | mutex_lock(&wd_data->lock); | |
1262 | if (watchdog_worker_should_ping(wd_data)) | |
1263 | ret = __watchdog_ping(wd_data->wdd); | |
1264 | mutex_unlock(&wd_data->lock); | |
1265 | ||
1266 | if (ret) | |
1267 | return ret; | |
1268 | ||
1269 | /* | |
1270 | * make sure that watchdog worker will not kick in when the wdog is | |
1271 | * suspended | |
1272 | */ | |
1273 | hrtimer_cancel(&wd_data->timer); | |
1274 | kthread_cancel_work_sync(&wd_data->work); | |
1275 | ||
1276 | return 0; | |
1277 | } | |
1278 | ||
1279 | int watchdog_dev_resume(struct watchdog_device *wdd) | |
1280 | { | |
1281 | struct watchdog_core_data *wd_data = wdd->wd_data; | |
1282 | int ret = 0; | |
1283 | ||
1284 | if (!wdd->wd_data) | |
1285 | return -ENODEV; | |
1286 | ||
1287 | /* | |
1288 | * __watchdog_ping will also retrigger hrtimer and therefore restore the | |
1289 | * ping worker if needed. | |
1290 | */ | |
1291 | mutex_lock(&wd_data->lock); | |
1292 | if (watchdog_worker_should_ping(wd_data)) | |
1293 | ret = __watchdog_ping(wd_data->wdd); | |
1294 | mutex_unlock(&wd_data->lock); | |
1295 | ||
1296 | return ret; | |
1297 | } | |
1298 | ||
2501b015 SR |
1299 | module_param(handle_boot_enabled, bool, 0444); |
1300 | MODULE_PARM_DESC(handle_boot_enabled, | |
1301 | "Watchdog core auto-updates boot enabled watchdogs before userspace takes over (default=" | |
1302 | __MODULE_STRING(IS_ENABLED(CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED)) ")"); | |
4d1c6a0e RV |
1303 | |
1304 | module_param(open_timeout, uint, 0644); | |
1305 | MODULE_PARM_DESC(open_timeout, | |
487e4e08 RV |
1306 | "Maximum time (in seconds, 0 means infinity) for userspace to take over a running watchdog (default=" |
1307 | __MODULE_STRING(CONFIG_WATCHDOG_OPEN_TIMEOUT) ")"); |