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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/... */ |
a243cb93 | 38 | #include <linux/kstrtox.h> /* For kstrto* */ |
1ff68820 | 39 | #include <linux/kthread.h> /* For kthread_work */ |
b4ffb190 GR |
40 | #include <linux/miscdevice.h> /* For handling misc devices */ |
41 | #include <linux/module.h> /* For module stuff/... */ | |
42 | #include <linux/mutex.h> /* For mutexes */ | |
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 | ||
6cfb5aa8 | 48 | #include "watchdog_core.h" |
ff84136c | 49 | #include "watchdog_pretimeout.h" |
09a46e73 | 50 | |
e25b091b UKK |
51 | #include <trace/events/watchdog.h> |
52 | ||
45f5fed3 AC |
53 | /* the dev_t structure to store the dynamically allocated watchdog devices */ |
54 | static dev_t watchdog_devt; | |
b4ffb190 GR |
55 | /* Reference to watchdog device behind /dev/watchdog */ |
56 | static struct watchdog_core_data *old_wd_data; | |
43316044 | 57 | |
38a1222a | 58 | static struct kthread_worker *watchdog_kworker; |
664a3923 | 59 | |
2501b015 SR |
60 | static bool handle_boot_enabled = |
61 | IS_ENABLED(CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED); | |
62 | ||
487e4e08 | 63 | static unsigned open_timeout = CONFIG_WATCHDOG_OPEN_TIMEOUT; |
4d1c6a0e RV |
64 | |
65 | static bool watchdog_past_open_deadline(struct watchdog_core_data *data) | |
66 | { | |
67 | return ktime_after(ktime_get(), data->open_deadline); | |
68 | } | |
69 | ||
70 | static void watchdog_set_open_deadline(struct watchdog_core_data *data) | |
71 | { | |
72 | data->open_deadline = open_timeout ? | |
73 | ktime_get() + ktime_set(open_timeout, 0) : KTIME_MAX; | |
74 | } | |
75 | ||
664a3923 GR |
76 | static inline bool watchdog_need_worker(struct watchdog_device *wdd) |
77 | { | |
78 | /* All variables in milli-seconds */ | |
79 | unsigned int hm = wdd->max_hw_heartbeat_ms; | |
80 | unsigned int t = wdd->timeout * 1000; | |
81 | ||
82 | /* | |
83 | * A worker to generate heartbeat requests is needed if all of the | |
84 | * following conditions are true. | |
85 | * - Userspace activated the watchdog. | |
86 | * - The driver provided a value for the maximum hardware timeout, and | |
87 | * thus is aware that the framework supports generating heartbeat | |
88 | * requests. | |
89 | * - Userspace requests a longer timeout than the hardware can handle. | |
3fbfe926 RV |
90 | * |
91 | * Alternatively, if userspace has not opened the watchdog | |
92 | * device, we take care of feeding the watchdog if it is | |
93 | * running. | |
664a3923 | 94 | */ |
3fbfe926 RV |
95 | return (hm && watchdog_active(wdd) && t > hm) || |
96 | (t && !watchdog_active(wdd) && watchdog_hw_running(wdd)); | |
664a3923 GR |
97 | } |
98 | ||
1ff68820 | 99 | static ktime_t watchdog_next_keepalive(struct watchdog_device *wdd) |
664a3923 GR |
100 | { |
101 | struct watchdog_core_data *wd_data = wdd->wd_data; | |
102 | unsigned int timeout_ms = wdd->timeout * 1000; | |
1ff68820 CL |
103 | ktime_t keepalive_interval; |
104 | ktime_t last_heartbeat, latest_heartbeat; | |
105 | ktime_t virt_timeout; | |
664a3923 GR |
106 | unsigned int hw_heartbeat_ms; |
107 | ||
c2eac35b RV |
108 | if (watchdog_active(wdd)) |
109 | virt_timeout = ktime_add(wd_data->last_keepalive, | |
110 | ms_to_ktime(timeout_ms)); | |
111 | else | |
112 | virt_timeout = wd_data->open_deadline; | |
113 | ||
3fbfe926 | 114 | hw_heartbeat_ms = min_not_zero(timeout_ms, wdd->max_hw_heartbeat_ms); |
1ff68820 | 115 | keepalive_interval = ms_to_ktime(hw_heartbeat_ms / 2); |
664a3923 GR |
116 | |
117 | /* | |
118 | * To ensure that the watchdog times out wdd->timeout seconds | |
119 | * after the most recent ping from userspace, the last | |
120 | * worker ping has to come in hw_heartbeat_ms before this timeout. | |
121 | */ | |
1ff68820 CL |
122 | last_heartbeat = ktime_sub(virt_timeout, ms_to_ktime(hw_heartbeat_ms)); |
123 | latest_heartbeat = ktime_sub(last_heartbeat, ktime_get()); | |
124 | if (ktime_before(latest_heartbeat, keepalive_interval)) | |
125 | return latest_heartbeat; | |
126 | return keepalive_interval; | |
664a3923 GR |
127 | } |
128 | ||
129 | static inline void watchdog_update_worker(struct watchdog_device *wdd) | |
130 | { | |
131 | struct watchdog_core_data *wd_data = wdd->wd_data; | |
132 | ||
133 | if (watchdog_need_worker(wdd)) { | |
1ff68820 | 134 | ktime_t t = watchdog_next_keepalive(wdd); |
664a3923 GR |
135 | |
136 | if (t > 0) | |
a19f8933 JC |
137 | hrtimer_start(&wd_data->timer, t, |
138 | HRTIMER_MODE_REL_HARD); | |
664a3923 | 139 | } else { |
1ff68820 | 140 | hrtimer_cancel(&wd_data->timer); |
664a3923 GR |
141 | } |
142 | } | |
143 | ||
144 | static int __watchdog_ping(struct watchdog_device *wdd) | |
145 | { | |
15013ad8 | 146 | struct watchdog_core_data *wd_data = wdd->wd_data; |
1ff68820 | 147 | ktime_t earliest_keepalive, now; |
664a3923 GR |
148 | int err; |
149 | ||
1ff68820 CL |
150 | earliest_keepalive = ktime_add(wd_data->last_hw_keepalive, |
151 | ms_to_ktime(wdd->min_hw_heartbeat_ms)); | |
152 | now = ktime_get(); | |
153 | ||
154 | if (ktime_after(earliest_keepalive, now)) { | |
155 | hrtimer_start(&wd_data->timer, | |
156 | ktime_sub(earliest_keepalive, now), | |
a19f8933 | 157 | HRTIMER_MODE_REL_HARD); |
15013ad8 GR |
158 | return 0; |
159 | } | |
160 | ||
1ff68820 | 161 | wd_data->last_hw_keepalive = now; |
15013ad8 | 162 | |
e25b091b | 163 | if (wdd->ops->ping) { |
664a3923 | 164 | err = wdd->ops->ping(wdd); /* ping the watchdog */ |
e25b091b UKK |
165 | trace_watchdog_ping(wdd, err); |
166 | } else { | |
664a3923 | 167 | err = wdd->ops->start(wdd); /* restart watchdog */ |
e25b091b UKK |
168 | trace_watchdog_start(wdd, err); |
169 | } | |
664a3923 | 170 | |
7b7d2fdc CK |
171 | if (err == 0) |
172 | watchdog_hrtimer_pretimeout_start(wdd); | |
173 | ||
664a3923 GR |
174 | watchdog_update_worker(wdd); |
175 | ||
176 | return err; | |
177 | } | |
178 | ||
43316044 | 179 | /* |
ba6c89ab DBO |
180 | * watchdog_ping - ping the watchdog |
181 | * @wdd: The watchdog device to ping | |
43316044 | 182 | * |
ba6c89ab DBO |
183 | * If the watchdog has no own ping operation then it needs to be |
184 | * restarted via the start operation. This wrapper function does | |
185 | * exactly that. | |
186 | * We only ping when the watchdog device is running. | |
187 | * The caller must hold wd_data->lock. | |
b4ffb190 | 188 | * |
ba6c89ab | 189 | * Return: 0 on success, error otherwise. |
43316044 | 190 | */ |
bc794ac3 | 191 | static int watchdog_ping(struct watchdog_device *wdd) |
43316044 | 192 | { |
664a3923 | 193 | struct watchdog_core_data *wd_data = wdd->wd_data; |
e907df32 | 194 | |
ee142889 | 195 | if (!watchdog_active(wdd) && !watchdog_hw_running(wdd)) |
b4ffb190 | 196 | return 0; |
7a879824 | 197 | |
90b826f1 GR |
198 | set_bit(_WDOG_KEEPALIVE, &wd_data->status); |
199 | ||
1ff68820 | 200 | wd_data->last_keepalive = ktime_get(); |
664a3923 GR |
201 | return __watchdog_ping(wdd); |
202 | } | |
7a879824 | 203 | |
c013b65a RV |
204 | static bool watchdog_worker_should_ping(struct watchdog_core_data *wd_data) |
205 | { | |
206 | struct watchdog_device *wdd = wd_data->wdd; | |
207 | ||
4d1c6a0e RV |
208 | if (!wdd) |
209 | return false; | |
210 | ||
211 | if (watchdog_active(wdd)) | |
212 | return true; | |
213 | ||
214 | return watchdog_hw_running(wdd) && !watchdog_past_open_deadline(wd_data); | |
c013b65a RV |
215 | } |
216 | ||
38a1222a | 217 | static void watchdog_ping_work(struct kthread_work *work) |
664a3923 GR |
218 | { |
219 | struct watchdog_core_data *wd_data; | |
664a3923 | 220 | |
1ff68820 | 221 | wd_data = container_of(work, struct watchdog_core_data, work); |
664a3923 GR |
222 | |
223 | mutex_lock(&wd_data->lock); | |
c013b65a RV |
224 | if (watchdog_worker_should_ping(wd_data)) |
225 | __watchdog_ping(wd_data->wdd); | |
664a3923 | 226 | mutex_unlock(&wd_data->lock); |
234445b4 WVS |
227 | } |
228 | ||
1ff68820 CL |
229 | static enum hrtimer_restart watchdog_timer_expired(struct hrtimer *timer) |
230 | { | |
231 | struct watchdog_core_data *wd_data; | |
232 | ||
233 | wd_data = container_of(timer, struct watchdog_core_data, timer); | |
234 | ||
235 | kthread_queue_work(watchdog_kworker, &wd_data->work); | |
236 | return HRTIMER_NORESTART; | |
237 | } | |
238 | ||
234445b4 | 239 | /* |
ba6c89ab DBO |
240 | * watchdog_start - wrapper to start the watchdog |
241 | * @wdd: The watchdog device to start | |
234445b4 | 242 | * |
ba6c89ab DBO |
243 | * Start the watchdog if it is not active and mark it active. |
244 | * The caller must hold wd_data->lock. | |
b4ffb190 | 245 | * |
ba6c89ab | 246 | * Return: 0 on success or a negative errno code for failure. |
234445b4 | 247 | */ |
bc794ac3 | 248 | static int watchdog_start(struct watchdog_device *wdd) |
234445b4 | 249 | { |
664a3923 | 250 | struct watchdog_core_data *wd_data = wdd->wd_data; |
1ff68820 | 251 | ktime_t started_at; |
b4ffb190 | 252 | int err; |
e907df32 | 253 | |
bc794ac3 | 254 | if (watchdog_active(wdd)) |
b4ffb190 | 255 | return 0; |
234445b4 | 256 | |
90b826f1 GR |
257 | set_bit(_WDOG_KEEPALIVE, &wd_data->status); |
258 | ||
1ff68820 | 259 | started_at = ktime_get(); |
fbbe35df TK |
260 | if (watchdog_hw_running(wdd) && wdd->ops->ping) { |
261 | err = __watchdog_ping(wdd); | |
7b7d2fdc | 262 | if (err == 0) { |
fbbe35df | 263 | set_bit(WDOG_ACTIVE, &wdd->status); |
7b7d2fdc CK |
264 | watchdog_hrtimer_pretimeout_start(wdd); |
265 | } | |
fbbe35df | 266 | } else { |
ee142889 | 267 | err = wdd->ops->start(wdd); |
e25b091b | 268 | trace_watchdog_start(wdd, err); |
fbbe35df TK |
269 | if (err == 0) { |
270 | set_bit(WDOG_ACTIVE, &wdd->status); | |
271 | wd_data->last_keepalive = started_at; | |
272 | wd_data->last_hw_keepalive = started_at; | |
273 | watchdog_update_worker(wdd); | |
7b7d2fdc | 274 | watchdog_hrtimer_pretimeout_start(wdd); |
fbbe35df | 275 | } |
664a3923 | 276 | } |
7a879824 | 277 | |
7a879824 | 278 | return err; |
234445b4 WVS |
279 | } |
280 | ||
281 | /* | |
ba6c89ab DBO |
282 | * watchdog_stop - wrapper to stop the watchdog |
283 | * @wdd: The watchdog device to stop | |
234445b4 | 284 | * |
ba6c89ab DBO |
285 | * Stop the watchdog if it is still active and unmark it active. |
286 | * If the 'nowayout' feature was set, the watchdog cannot be stopped. | |
287 | * The caller must hold wd_data->lock. | |
b4ffb190 | 288 | * |
ba6c89ab | 289 | * Return: 0 on success or a negative errno code for failure. |
234445b4 | 290 | */ |
bc794ac3 | 291 | static int watchdog_stop(struct watchdog_device *wdd) |
234445b4 | 292 | { |
ee142889 | 293 | int err = 0; |
e907df32 | 294 | |
bc794ac3 | 295 | if (!watchdog_active(wdd)) |
b4ffb190 | 296 | return 0; |
7e192b9c | 297 | |
bc794ac3 | 298 | if (test_bit(WDOG_NO_WAY_OUT, &wdd->status)) { |
0254e953 GR |
299 | pr_info("watchdog%d: nowayout prevents watchdog being stopped!\n", |
300 | wdd->id); | |
b4ffb190 | 301 | return -EBUSY; |
7e192b9c | 302 | } |
234445b4 | 303 | |
3c10bbde GR |
304 | if (wdd->ops->stop) { |
305 | clear_bit(WDOG_HW_RUNNING, &wdd->status); | |
d0684c8a | 306 | err = wdd->ops->stop(wdd); |
e25b091b | 307 | trace_watchdog_stop(wdd, err); |
3c10bbde | 308 | } else { |
d0684c8a | 309 | set_bit(WDOG_HW_RUNNING, &wdd->status); |
3c10bbde | 310 | } |
d0684c8a | 311 | |
664a3923 | 312 | if (err == 0) { |
bc794ac3 | 313 | clear_bit(WDOG_ACTIVE, &wdd->status); |
ee142889 | 314 | watchdog_update_worker(wdd); |
7b7d2fdc | 315 | watchdog_hrtimer_pretimeout_stop(wdd); |
664a3923 | 316 | } |
7a879824 | 317 | |
7a879824 HG |
318 | return err; |
319 | } | |
320 | ||
321 | /* | |
ba6c89ab DBO |
322 | * watchdog_get_status - wrapper to get the watchdog status |
323 | * @wdd: The watchdog device to get the status from | |
b4ffb190 | 324 | * |
ba6c89ab DBO |
325 | * Get the watchdog's status flags. |
326 | * The caller must hold wd_data->lock. | |
7a879824 | 327 | * |
ba6c89ab | 328 | * Return: watchdog's status flags. |
7a879824 | 329 | */ |
b4ffb190 | 330 | static unsigned int watchdog_get_status(struct watchdog_device *wdd) |
7a879824 | 331 | { |
90b826f1 GR |
332 | struct watchdog_core_data *wd_data = wdd->wd_data; |
333 | unsigned int status; | |
7a879824 | 334 | |
90b826f1 GR |
335 | if (wdd->ops->status) |
336 | status = wdd->ops->status(wdd); | |
337 | else | |
338 | status = wdd->bootstatus & (WDIOF_CARDRESET | | |
339 | WDIOF_OVERHEAT | | |
340 | WDIOF_FANFAULT | | |
341 | WDIOF_EXTERN1 | | |
342 | WDIOF_EXTERN2 | | |
343 | WDIOF_POWERUNDER | | |
344 | WDIOF_POWEROVER); | |
345 | ||
346 | if (test_bit(_WDOG_ALLOW_RELEASE, &wd_data->status)) | |
347 | status |= WDIOF_MAGICCLOSE; | |
348 | ||
349 | if (test_and_clear_bit(_WDOG_KEEPALIVE, &wd_data->status)) | |
350 | status |= WDIOF_KEEPALIVEPING; | |
351 | ||
7b7d2fdc CK |
352 | if (IS_ENABLED(CONFIG_WATCHDOG_HRTIMER_PRETIMEOUT)) |
353 | status |= WDIOF_PRETIMEOUT; | |
354 | ||
90b826f1 | 355 | return status; |
7a879824 HG |
356 | } |
357 | ||
358 | /* | |
ba6c89ab DBO |
359 | * watchdog_set_timeout - set the watchdog timer timeout |
360 | * @wdd: The watchdog device to set the timeout for | |
361 | * @timeout: Timeout to set in seconds | |
362 | * | |
363 | * The caller must hold wd_data->lock. | |
b4ffb190 | 364 | * |
ba6c89ab | 365 | * Return: 0 if successful, error otherwise. |
7a879824 | 366 | */ |
bc794ac3 | 367 | static int watchdog_set_timeout(struct watchdog_device *wdd, |
7a879824 HG |
368 | unsigned int timeout) |
369 | { | |
fb32e9b9 GR |
370 | int err = 0; |
371 | ||
372 | if (!(wdd->info->options & WDIOF_SETTIMEOUT)) | |
7a879824 HG |
373 | return -EOPNOTSUPP; |
374 | ||
bc794ac3 | 375 | if (watchdog_timeout_invalid(wdd, timeout)) |
7a879824 HG |
376 | return -EINVAL; |
377 | ||
df044e02 | 378 | if (wdd->ops->set_timeout) { |
fb32e9b9 | 379 | err = wdd->ops->set_timeout(wdd, timeout); |
e25b091b | 380 | trace_watchdog_set_timeout(wdd, timeout, err); |
df044e02 | 381 | } else { |
fb32e9b9 | 382 | wdd->timeout = timeout; |
df044e02 WS |
383 | /* Disable pretimeout if it doesn't fit the new timeout */ |
384 | if (wdd->pretimeout >= wdd->timeout) | |
385 | wdd->pretimeout = 0; | |
386 | } | |
fb32e9b9 | 387 | |
664a3923 GR |
388 | watchdog_update_worker(wdd); |
389 | ||
fb32e9b9 | 390 | return err; |
7a879824 HG |
391 | } |
392 | ||
df044e02 | 393 | /* |
ba6c89ab DBO |
394 | * watchdog_set_pretimeout - set the watchdog timer pretimeout |
395 | * @wdd: The watchdog device to set the timeout for | |
396 | * @timeout: pretimeout to set in seconds | |
397 | * | |
398 | * Return: 0 if successful, error otherwise. | |
df044e02 | 399 | */ |
df044e02 WS |
400 | static int watchdog_set_pretimeout(struct watchdog_device *wdd, |
401 | unsigned int timeout) | |
402 | { | |
403 | int err = 0; | |
404 | ||
7b7d2fdc | 405 | if (!watchdog_have_pretimeout(wdd)) |
df044e02 WS |
406 | return -EOPNOTSUPP; |
407 | ||
408 | if (watchdog_pretimeout_invalid(wdd, timeout)) | |
409 | return -EINVAL; | |
410 | ||
cf6ea954 | 411 | if (wdd->ops->set_pretimeout && (wdd->info->options & WDIOF_PRETIMEOUT)) |
df044e02 WS |
412 | err = wdd->ops->set_pretimeout(wdd, timeout); |
413 | else | |
414 | wdd->pretimeout = timeout; | |
415 | ||
416 | return err; | |
417 | } | |
418 | ||
7a879824 | 419 | /* |
ba6c89ab DBO |
420 | * watchdog_get_timeleft - wrapper to get the time left before a reboot |
421 | * @wdd: The watchdog device to get the remaining time from | |
422 | * @timeleft: The time that's left | |
7a879824 | 423 | * |
ba6c89ab DBO |
424 | * Get the time before a watchdog will reboot (if not pinged). |
425 | * The caller must hold wd_data->lock. | |
b4ffb190 | 426 | * |
ba6c89ab | 427 | * Return: 0 if successful, error otherwise. |
7a879824 | 428 | */ |
bc794ac3 | 429 | static int watchdog_get_timeleft(struct watchdog_device *wdd, |
7a879824 HG |
430 | unsigned int *timeleft) |
431 | { | |
7a879824 | 432 | *timeleft = 0; |
b4ffb190 | 433 | |
bc794ac3 | 434 | if (!wdd->ops->get_timeleft) |
7a879824 HG |
435 | return -EOPNOTSUPP; |
436 | ||
bc794ac3 | 437 | *timeleft = wdd->ops->get_timeleft(wdd); |
7a879824 | 438 | |
b4ffb190 | 439 | return 0; |
7a879824 HG |
440 | } |
441 | ||
33b71126 PA |
442 | #ifdef CONFIG_WATCHDOG_SYSFS |
443 | static ssize_t nowayout_show(struct device *dev, struct device_attribute *attr, | |
444 | char *buf) | |
445 | { | |
446 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
447 | ||
3bb21781 JH |
448 | return sysfs_emit(buf, "%d\n", !!test_bit(WDOG_NO_WAY_OUT, |
449 | &wdd->status)); | |
33b71126 | 450 | } |
bc44fa73 RV |
451 | |
452 | static ssize_t nowayout_store(struct device *dev, struct device_attribute *attr, | |
453 | const char *buf, size_t len) | |
454 | { | |
455 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
456 | unsigned int value; | |
457 | int ret; | |
458 | ||
459 | ret = kstrtouint(buf, 0, &value); | |
460 | if (ret) | |
461 | return ret; | |
462 | if (value > 1) | |
463 | return -EINVAL; | |
464 | /* nowayout cannot be disabled once set */ | |
465 | if (test_bit(WDOG_NO_WAY_OUT, &wdd->status) && !value) | |
466 | return -EPERM; | |
467 | watchdog_set_nowayout(wdd, value); | |
468 | return len; | |
469 | } | |
470 | static DEVICE_ATTR_RW(nowayout); | |
33b71126 PA |
471 | |
472 | static ssize_t status_show(struct device *dev, struct device_attribute *attr, | |
473 | char *buf) | |
474 | { | |
475 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
b4ffb190 GR |
476 | struct watchdog_core_data *wd_data = wdd->wd_data; |
477 | unsigned int status; | |
33b71126 | 478 | |
b4ffb190 GR |
479 | mutex_lock(&wd_data->lock); |
480 | status = watchdog_get_status(wdd); | |
481 | mutex_unlock(&wd_data->lock); | |
33b71126 | 482 | |
3bb21781 | 483 | return sysfs_emit(buf, "0x%x\n", status); |
33b71126 PA |
484 | } |
485 | static DEVICE_ATTR_RO(status); | |
486 | ||
487 | static ssize_t bootstatus_show(struct device *dev, | |
488 | struct device_attribute *attr, char *buf) | |
489 | { | |
490 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
491 | ||
3bb21781 | 492 | return sysfs_emit(buf, "%u\n", wdd->bootstatus); |
33b71126 PA |
493 | } |
494 | static DEVICE_ATTR_RO(bootstatus); | |
495 | ||
496 | static ssize_t timeleft_show(struct device *dev, struct device_attribute *attr, | |
497 | char *buf) | |
498 | { | |
499 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
b4ffb190 | 500 | struct watchdog_core_data *wd_data = wdd->wd_data; |
33b71126 PA |
501 | ssize_t status; |
502 | unsigned int val; | |
503 | ||
b4ffb190 | 504 | mutex_lock(&wd_data->lock); |
33b71126 | 505 | status = watchdog_get_timeleft(wdd, &val); |
b4ffb190 | 506 | mutex_unlock(&wd_data->lock); |
33b71126 | 507 | if (!status) |
3bb21781 | 508 | status = sysfs_emit(buf, "%u\n", val); |
33b71126 PA |
509 | |
510 | return status; | |
511 | } | |
512 | static DEVICE_ATTR_RO(timeleft); | |
513 | ||
514 | static ssize_t timeout_show(struct device *dev, struct device_attribute *attr, | |
515 | char *buf) | |
516 | { | |
517 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
518 | ||
3bb21781 | 519 | return sysfs_emit(buf, "%u\n", wdd->timeout); |
33b71126 PA |
520 | } |
521 | static DEVICE_ATTR_RO(timeout); | |
522 | ||
6ddf5087 JH |
523 | static ssize_t min_timeout_show(struct device *dev, |
524 | struct device_attribute *attr, char *buf) | |
525 | { | |
526 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
527 | ||
528 | return sysfs_emit(buf, "%u\n", wdd->min_timeout); | |
529 | } | |
530 | static DEVICE_ATTR_RO(min_timeout); | |
531 | ||
532 | static ssize_t max_timeout_show(struct device *dev, | |
533 | struct device_attribute *attr, char *buf) | |
534 | { | |
535 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
536 | ||
537 | return sysfs_emit(buf, "%u\n", wdd->max_timeout); | |
538 | } | |
539 | static DEVICE_ATTR_RO(max_timeout); | |
540 | ||
df044e02 WS |
541 | static ssize_t pretimeout_show(struct device *dev, |
542 | struct device_attribute *attr, char *buf) | |
543 | { | |
544 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
545 | ||
3bb21781 | 546 | return sysfs_emit(buf, "%u\n", wdd->pretimeout); |
df044e02 WS |
547 | } |
548 | static DEVICE_ATTR_RO(pretimeout); | |
549 | ||
33b71126 PA |
550 | static ssize_t identity_show(struct device *dev, struct device_attribute *attr, |
551 | char *buf) | |
552 | { | |
553 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
554 | ||
3bb21781 | 555 | return sysfs_emit(buf, "%s\n", wdd->info->identity); |
33b71126 PA |
556 | } |
557 | static DEVICE_ATTR_RO(identity); | |
558 | ||
559 | static ssize_t state_show(struct device *dev, struct device_attribute *attr, | |
560 | char *buf) | |
561 | { | |
562 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
563 | ||
564 | if (watchdog_active(wdd)) | |
3bb21781 | 565 | return sysfs_emit(buf, "active\n"); |
33b71126 | 566 | |
3bb21781 | 567 | return sysfs_emit(buf, "inactive\n"); |
33b71126 PA |
568 | } |
569 | static DEVICE_ATTR_RO(state); | |
570 | ||
89873a71 VZ |
571 | static ssize_t pretimeout_available_governors_show(struct device *dev, |
572 | struct device_attribute *attr, char *buf) | |
573 | { | |
574 | return watchdog_pretimeout_available_governors_get(buf); | |
575 | } | |
576 | static DEVICE_ATTR_RO(pretimeout_available_governors); | |
577 | ||
ff84136c VZ |
578 | static ssize_t pretimeout_governor_show(struct device *dev, |
579 | struct device_attribute *attr, | |
580 | char *buf) | |
581 | { | |
582 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
583 | ||
584 | return watchdog_pretimeout_governor_get(wdd, buf); | |
585 | } | |
53f96cee VZ |
586 | |
587 | static ssize_t pretimeout_governor_store(struct device *dev, | |
588 | struct device_attribute *attr, | |
589 | const char *buf, size_t count) | |
590 | { | |
591 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
592 | int ret = watchdog_pretimeout_governor_set(wdd, buf); | |
593 | ||
594 | if (!ret) | |
595 | ret = count; | |
596 | ||
597 | return ret; | |
598 | } | |
599 | static DEVICE_ATTR_RW(pretimeout_governor); | |
ff84136c | 600 | |
33b71126 PA |
601 | static umode_t wdt_is_visible(struct kobject *kobj, struct attribute *attr, |
602 | int n) | |
603 | { | |
893c3d82 | 604 | struct device *dev = kobj_to_dev(kobj); |
33b71126 PA |
605 | struct watchdog_device *wdd = dev_get_drvdata(dev); |
606 | umode_t mode = attr->mode; | |
607 | ||
90b826f1 | 608 | if (attr == &dev_attr_timeleft.attr && !wdd->ops->get_timeleft) |
33b71126 | 609 | mode = 0; |
7b7d2fdc | 610 | else if (attr == &dev_attr_pretimeout.attr && !watchdog_have_pretimeout(wdd)) |
df044e02 | 611 | mode = 0; |
89873a71 VZ |
612 | else if ((attr == &dev_attr_pretimeout_governor.attr || |
613 | attr == &dev_attr_pretimeout_available_governors.attr) && | |
7b7d2fdc | 614 | (!watchdog_have_pretimeout(wdd) || !IS_ENABLED(CONFIG_WATCHDOG_PRETIMEOUT_GOV))) |
ff84136c | 615 | mode = 0; |
33b71126 PA |
616 | |
617 | return mode; | |
618 | } | |
619 | static struct attribute *wdt_attrs[] = { | |
620 | &dev_attr_state.attr, | |
621 | &dev_attr_identity.attr, | |
622 | &dev_attr_timeout.attr, | |
6ddf5087 JH |
623 | &dev_attr_min_timeout.attr, |
624 | &dev_attr_max_timeout.attr, | |
df044e02 | 625 | &dev_attr_pretimeout.attr, |
33b71126 PA |
626 | &dev_attr_timeleft.attr, |
627 | &dev_attr_bootstatus.attr, | |
628 | &dev_attr_status.attr, | |
629 | &dev_attr_nowayout.attr, | |
ff84136c | 630 | &dev_attr_pretimeout_governor.attr, |
89873a71 | 631 | &dev_attr_pretimeout_available_governors.attr, |
33b71126 PA |
632 | NULL, |
633 | }; | |
634 | ||
635 | static const struct attribute_group wdt_group = { | |
636 | .attrs = wdt_attrs, | |
637 | .is_visible = wdt_is_visible, | |
638 | }; | |
639 | __ATTRIBUTE_GROUPS(wdt); | |
640 | #else | |
641 | #define wdt_groups NULL | |
642 | #endif | |
643 | ||
7a879824 | 644 | /* |
ba6c89ab DBO |
645 | * watchdog_ioctl_op - call the watchdog drivers ioctl op if defined |
646 | * @wdd: The watchdog device to do the ioctl on | |
647 | * @cmd: Watchdog command | |
648 | * @arg: Argument pointer | |
b4ffb190 | 649 | * |
ba6c89ab DBO |
650 | * The caller must hold wd_data->lock. |
651 | * | |
652 | * Return: 0 if successful, error otherwise. | |
7a879824 | 653 | */ |
bc794ac3 | 654 | static int watchdog_ioctl_op(struct watchdog_device *wdd, unsigned int cmd, |
7a879824 HG |
655 | unsigned long arg) |
656 | { | |
bc794ac3 | 657 | if (!wdd->ops->ioctl) |
7a879824 HG |
658 | return -ENOIOCTLCMD; |
659 | ||
b4ffb190 | 660 | return wdd->ops->ioctl(wdd, cmd, arg); |
43316044 WVS |
661 | } |
662 | ||
663 | /* | |
ba6c89ab DBO |
664 | * watchdog_write - writes to the watchdog |
665 | * @file: File from VFS | |
666 | * @data: User address of data | |
667 | * @len: Length of data | |
668 | * @ppos: Pointer to the file offset | |
43316044 | 669 | * |
ba6c89ab DBO |
670 | * A write to a watchdog device is defined as a keepalive ping. |
671 | * Writing the magic 'V' sequence allows the next close to turn | |
672 | * off the watchdog (if 'nowayout' is not set). | |
673 | * | |
674 | * Return: @len if successful, error otherwise. | |
43316044 | 675 | */ |
43316044 WVS |
676 | static ssize_t watchdog_write(struct file *file, const char __user *data, |
677 | size_t len, loff_t *ppos) | |
678 | { | |
b4ffb190 GR |
679 | struct watchdog_core_data *wd_data = file->private_data; |
680 | struct watchdog_device *wdd; | |
681 | int err; | |
43316044 WVS |
682 | size_t i; |
683 | char c; | |
684 | ||
685 | if (len == 0) | |
686 | return 0; | |
687 | ||
017cf080 WVS |
688 | /* |
689 | * Note: just in case someone wrote the magic character | |
690 | * five months ago... | |
691 | */ | |
b4ffb190 | 692 | clear_bit(_WDOG_ALLOW_RELEASE, &wd_data->status); |
017cf080 WVS |
693 | |
694 | /* scan to see whether or not we got the magic character */ | |
43316044 WVS |
695 | for (i = 0; i != len; i++) { |
696 | if (get_user(c, data + i)) | |
697 | return -EFAULT; | |
017cf080 | 698 | if (c == 'V') |
b4ffb190 | 699 | set_bit(_WDOG_ALLOW_RELEASE, &wd_data->status); |
43316044 WVS |
700 | } |
701 | ||
702 | /* someone wrote to us, so we send the watchdog a keepalive ping */ | |
b4ffb190 GR |
703 | |
704 | err = -ENODEV; | |
705 | mutex_lock(&wd_data->lock); | |
706 | wdd = wd_data->wdd; | |
707 | if (wdd) | |
708 | err = watchdog_ping(wdd); | |
709 | mutex_unlock(&wd_data->lock); | |
710 | ||
5ef79663 AU |
711 | if (err < 0) |
712 | return err; | |
43316044 WVS |
713 | |
714 | return len; | |
715 | } | |
716 | ||
2fa03560 | 717 | /* |
ba6c89ab DBO |
718 | * watchdog_ioctl - handle the different ioctl's for the watchdog device |
719 | * @file: File handle to the device | |
720 | * @cmd: Watchdog command | |
721 | * @arg: Argument pointer | |
2fa03560 | 722 | * |
ba6c89ab DBO |
723 | * The watchdog API defines a common set of functions for all watchdogs |
724 | * according to their available features. | |
725 | * | |
726 | * Return: 0 if successful, error otherwise. | |
2fa03560 WVS |
727 | */ |
728 | ||
729 | static long watchdog_ioctl(struct file *file, unsigned int cmd, | |
730 | unsigned long arg) | |
731 | { | |
b4ffb190 | 732 | struct watchdog_core_data *wd_data = file->private_data; |
2fa03560 | 733 | void __user *argp = (void __user *)arg; |
b4ffb190 | 734 | struct watchdog_device *wdd; |
2fa03560 WVS |
735 | int __user *p = argp; |
736 | unsigned int val; | |
234445b4 | 737 | int err; |
2fa03560 | 738 | |
b4ffb190 GR |
739 | mutex_lock(&wd_data->lock); |
740 | ||
741 | wdd = wd_data->wdd; | |
742 | if (!wdd) { | |
743 | err = -ENODEV; | |
744 | goto out_ioctl; | |
745 | } | |
746 | ||
7a879824 HG |
747 | err = watchdog_ioctl_op(wdd, cmd, arg); |
748 | if (err != -ENOIOCTLCMD) | |
b4ffb190 | 749 | goto out_ioctl; |
78d88fc0 | 750 | |
2fa03560 WVS |
751 | switch (cmd) { |
752 | case WDIOC_GETSUPPORT: | |
b4ffb190 | 753 | err = copy_to_user(argp, wdd->info, |
2fa03560 | 754 | sizeof(struct watchdog_info)) ? -EFAULT : 0; |
b4ffb190 | 755 | break; |
2fa03560 | 756 | case WDIOC_GETSTATUS: |
b4ffb190 GR |
757 | val = watchdog_get_status(wdd); |
758 | err = put_user(val, p); | |
759 | break; | |
2fa03560 | 760 | case WDIOC_GETBOOTSTATUS: |
b4ffb190 GR |
761 | err = put_user(wdd->bootstatus, p); |
762 | break; | |
234445b4 | 763 | case WDIOC_SETOPTIONS: |
b4ffb190 GR |
764 | if (get_user(val, p)) { |
765 | err = -EFAULT; | |
766 | break; | |
767 | } | |
234445b4 WVS |
768 | if (val & WDIOS_DISABLECARD) { |
769 | err = watchdog_stop(wdd); | |
770 | if (err < 0) | |
b4ffb190 | 771 | break; |
234445b4 | 772 | } |
b4ffb190 | 773 | if (val & WDIOS_ENABLECARD) |
234445b4 | 774 | err = watchdog_start(wdd); |
b4ffb190 | 775 | break; |
c2dc00e4 | 776 | case WDIOC_KEEPALIVE: |
b4ffb190 GR |
777 | if (!(wdd->info->options & WDIOF_KEEPALIVEPING)) { |
778 | err = -EOPNOTSUPP; | |
779 | break; | |
780 | } | |
781 | err = watchdog_ping(wdd); | |
782 | break; | |
014d694e | 783 | case WDIOC_SETTIMEOUT: |
b4ffb190 GR |
784 | if (get_user(val, p)) { |
785 | err = -EFAULT; | |
786 | break; | |
787 | } | |
7a879824 | 788 | err = watchdog_set_timeout(wdd, val); |
014d694e | 789 | if (err < 0) |
b4ffb190 | 790 | break; |
014d694e WVS |
791 | /* If the watchdog is active then we send a keepalive ping |
792 | * to make sure that the watchdog keep's running (and if | |
793 | * possible that it takes the new timeout) */ | |
5ef79663 AU |
794 | err = watchdog_ping(wdd); |
795 | if (err < 0) | |
b4ffb190 | 796 | break; |
bd490f82 | 797 | fallthrough; |
014d694e WVS |
798 | case WDIOC_GETTIMEOUT: |
799 | /* timeout == 0 means that we don't know the timeout */ | |
b4ffb190 GR |
800 | if (wdd->timeout == 0) { |
801 | err = -EOPNOTSUPP; | |
802 | break; | |
803 | } | |
804 | err = put_user(wdd->timeout, p); | |
805 | break; | |
fd7b673c | 806 | case WDIOC_GETTIMELEFT: |
7a879824 | 807 | err = watchdog_get_timeleft(wdd, &val); |
b4ffb190 GR |
808 | if (err < 0) |
809 | break; | |
810 | err = put_user(val, p); | |
811 | break; | |
df044e02 WS |
812 | case WDIOC_SETPRETIMEOUT: |
813 | if (get_user(val, p)) { | |
814 | err = -EFAULT; | |
815 | break; | |
816 | } | |
817 | err = watchdog_set_pretimeout(wdd, val); | |
818 | break; | |
819 | case WDIOC_GETPRETIMEOUT: | |
820 | err = put_user(wdd->pretimeout, p); | |
821 | break; | |
2fa03560 | 822 | default: |
b4ffb190 GR |
823 | err = -ENOTTY; |
824 | break; | |
2fa03560 | 825 | } |
b4ffb190 GR |
826 | |
827 | out_ioctl: | |
828 | mutex_unlock(&wd_data->lock); | |
829 | return err; | |
2fa03560 WVS |
830 | } |
831 | ||
43316044 | 832 | /* |
ba6c89ab DBO |
833 | * watchdog_open - open the /dev/watchdog* devices |
834 | * @inode: Inode of device | |
835 | * @file: File handle to device | |
836 | * | |
837 | * When the /dev/watchdog* device gets opened, we start the watchdog. | |
838 | * Watch out: the /dev/watchdog device is single open, so we make sure | |
839 | * it can only be opened once. | |
43316044 | 840 | * |
ba6c89ab | 841 | * Return: 0 if successful, error otherwise. |
43316044 | 842 | */ |
43316044 WVS |
843 | static int watchdog_open(struct inode *inode, struct file *file) |
844 | { | |
b4ffb190 | 845 | struct watchdog_core_data *wd_data; |
45f5fed3 | 846 | struct watchdog_device *wdd; |
4bcd615f | 847 | bool hw_running; |
b4ffb190 | 848 | int err; |
45f5fed3 AC |
849 | |
850 | /* Get the corresponding watchdog device */ | |
851 | if (imajor(inode) == MISC_MAJOR) | |
b4ffb190 | 852 | wd_data = old_wd_data; |
45f5fed3 | 853 | else |
b4ffb190 GR |
854 | wd_data = container_of(inode->i_cdev, struct watchdog_core_data, |
855 | cdev); | |
43316044 WVS |
856 | |
857 | /* the watchdog is single open! */ | |
b4ffb190 | 858 | if (test_and_set_bit(_WDOG_DEV_OPEN, &wd_data->status)) |
43316044 WVS |
859 | return -EBUSY; |
860 | ||
b4ffb190 GR |
861 | wdd = wd_data->wdd; |
862 | ||
43316044 WVS |
863 | /* |
864 | * If the /dev/watchdog device is open, we don't want the module | |
865 | * to be unloaded. | |
866 | */ | |
4bcd615f GR |
867 | hw_running = watchdog_hw_running(wdd); |
868 | if (!hw_running && !try_module_get(wdd->ops->owner)) { | |
b4ffb190 GR |
869 | err = -EBUSY; |
870 | goto out_clear; | |
871 | } | |
43316044 | 872 | |
234445b4 | 873 | err = watchdog_start(wdd); |
43316044 WVS |
874 | if (err < 0) |
875 | goto out_mod; | |
876 | ||
b4ffb190 | 877 | file->private_data = wd_data; |
45f5fed3 | 878 | |
4bcd615f | 879 | if (!hw_running) |
72139dfa | 880 | get_device(&wd_data->dev); |
e907df32 | 881 | |
4d1c6a0e RV |
882 | /* |
883 | * open_timeout only applies for the first open from | |
884 | * userspace. Set open_deadline to infinity so that the kernel | |
885 | * will take care of an always-running hardware watchdog in | |
886 | * case the device gets magic-closed or WDIOS_DISABLECARD is | |
887 | * applied. | |
888 | */ | |
889 | wd_data->open_deadline = KTIME_MAX; | |
890 | ||
43316044 | 891 | /* dev/watchdog is a virtual (and thus non-seekable) filesystem */ |
c5bf68fe | 892 | return stream_open(inode, file); |
43316044 WVS |
893 | |
894 | out_mod: | |
b4ffb190 GR |
895 | module_put(wd_data->wdd->ops->owner); |
896 | out_clear: | |
897 | clear_bit(_WDOG_DEV_OPEN, &wd_data->status); | |
43316044 WVS |
898 | return err; |
899 | } | |
900 | ||
72139dfa | 901 | static void watchdog_core_data_release(struct device *dev) |
b4ffb190 GR |
902 | { |
903 | struct watchdog_core_data *wd_data; | |
904 | ||
72139dfa | 905 | wd_data = container_of(dev, struct watchdog_core_data, dev); |
b4ffb190 GR |
906 | |
907 | kfree(wd_data); | |
908 | } | |
909 | ||
43316044 | 910 | /* |
ba6c89ab DBO |
911 | * watchdog_release - release the watchdog device |
912 | * @inode: Inode of device | |
913 | * @file: File handle to device | |
914 | * | |
915 | * This is the code for when /dev/watchdog gets closed. We will only | |
916 | * stop the watchdog when we have received the magic char (and nowayout | |
917 | * was not set), else the watchdog will keep running. | |
43316044 | 918 | * |
ba6c89ab | 919 | * Always returns 0. |
43316044 | 920 | */ |
43316044 WVS |
921 | static int watchdog_release(struct inode *inode, struct file *file) |
922 | { | |
b4ffb190 GR |
923 | struct watchdog_core_data *wd_data = file->private_data; |
924 | struct watchdog_device *wdd; | |
017cf080 | 925 | int err = -EBUSY; |
d1ed3ba4 | 926 | bool running; |
017cf080 | 927 | |
b4ffb190 GR |
928 | mutex_lock(&wd_data->lock); |
929 | ||
930 | wdd = wd_data->wdd; | |
931 | if (!wdd) | |
932 | goto done; | |
933 | ||
017cf080 WVS |
934 | /* |
935 | * We only stop the watchdog if we received the magic character | |
7e192b9c WVS |
936 | * or if WDIOF_MAGICCLOSE is not set. If nowayout was set then |
937 | * watchdog_stop will fail. | |
017cf080 | 938 | */ |
0be01476 | 939 | if (!watchdog_active(wdd)) |
fcf95670 | 940 | err = 0; |
b4ffb190 | 941 | else if (test_and_clear_bit(_WDOG_ALLOW_RELEASE, &wd_data->status) || |
fcf95670 | 942 | !(wdd->info->options & WDIOF_MAGICCLOSE)) |
017cf080 | 943 | err = watchdog_stop(wdd); |
43316044 | 944 | |
017cf080 | 945 | /* If the watchdog was not stopped, send a keepalive ping */ |
234445b4 | 946 | if (err < 0) { |
0254e953 | 947 | pr_crit("watchdog%d: watchdog did not stop!\n", wdd->id); |
43316044 WVS |
948 | watchdog_ping(wdd); |
949 | } | |
950 | ||
ee142889 | 951 | watchdog_update_worker(wdd); |
664a3923 | 952 | |
43316044 | 953 | /* make sure that /dev/watchdog can be re-opened */ |
b4ffb190 | 954 | clear_bit(_WDOG_DEV_OPEN, &wd_data->status); |
e907df32 | 955 | |
b4ffb190 | 956 | done: |
d1ed3ba4 | 957 | running = wdd && watchdog_hw_running(wdd); |
b4ffb190 | 958 | mutex_unlock(&wd_data->lock); |
ee142889 GR |
959 | /* |
960 | * Allow the owner module to be unloaded again unless the watchdog | |
961 | * is still running. If the watchdog is still running, it can not | |
962 | * be stopped, and its driver must not be unloaded. | |
963 | */ | |
d1ed3ba4 GR |
964 | if (!running) { |
965 | module_put(wd_data->cdev.owner); | |
72139dfa | 966 | put_device(&wd_data->dev); |
ee142889 | 967 | } |
43316044 WVS |
968 | return 0; |
969 | } | |
970 | ||
971 | static const struct file_operations watchdog_fops = { | |
972 | .owner = THIS_MODULE, | |
973 | .write = watchdog_write, | |
2fa03560 | 974 | .unlocked_ioctl = watchdog_ioctl, |
b6dfb247 | 975 | .compat_ioctl = compat_ptr_ioctl, |
43316044 WVS |
976 | .open = watchdog_open, |
977 | .release = watchdog_release, | |
978 | }; | |
979 | ||
980 | static struct miscdevice watchdog_miscdev = { | |
981 | .minor = WATCHDOG_MINOR, | |
982 | .name = "watchdog", | |
983 | .fops = &watchdog_fops, | |
984 | }; | |
985 | ||
72139dfa KH |
986 | static struct class watchdog_class = { |
987 | .name = "watchdog", | |
988 | .owner = THIS_MODULE, | |
989 | .dev_groups = wdt_groups, | |
990 | }; | |
991 | ||
43316044 | 992 | /* |
ba6c89ab DBO |
993 | * watchdog_cdev_register - register watchdog character device |
994 | * @wdd: Watchdog device | |
995 | * | |
996 | * Register a watchdog character device including handling the legacy | |
997 | * /dev/watchdog node. /dev/watchdog is actually a miscdevice and | |
998 | * thus we set it up like that. | |
43316044 | 999 | * |
ba6c89ab | 1000 | * Return: 0 if successful, error otherwise. |
43316044 | 1001 | */ |
72139dfa | 1002 | static int watchdog_cdev_register(struct watchdog_device *wdd) |
43316044 | 1003 | { |
b4ffb190 | 1004 | struct watchdog_core_data *wd_data; |
32ecc639 | 1005 | int err; |
45f5fed3 | 1006 | |
b4ffb190 GR |
1007 | wd_data = kzalloc(sizeof(struct watchdog_core_data), GFP_KERNEL); |
1008 | if (!wd_data) | |
1009 | return -ENOMEM; | |
b4ffb190 GR |
1010 | mutex_init(&wd_data->lock); |
1011 | ||
1012 | wd_data->wdd = wdd; | |
1013 | wdd->wd_data = wd_data; | |
1014 | ||
5afb6d20 DL |
1015 | if (IS_ERR_OR_NULL(watchdog_kworker)) { |
1016 | kfree(wd_data); | |
664a3923 | 1017 | return -ENODEV; |
5afb6d20 | 1018 | } |
664a3923 | 1019 | |
cb36e29b KS |
1020 | device_initialize(&wd_data->dev); |
1021 | wd_data->dev.devt = MKDEV(MAJOR(watchdog_devt), wdd->id); | |
1022 | wd_data->dev.class = &watchdog_class; | |
1023 | wd_data->dev.parent = wdd->parent; | |
1024 | wd_data->dev.groups = wdd->groups; | |
1025 | wd_data->dev.release = watchdog_core_data_release; | |
1026 | dev_set_drvdata(&wd_data->dev, wdd); | |
0e012972 BL |
1027 | err = dev_set_name(&wd_data->dev, "watchdog%d", wdd->id); |
1028 | if (err) { | |
1029 | put_device(&wd_data->dev); | |
1030 | return err; | |
1031 | } | |
cb36e29b | 1032 | |
1ff68820 | 1033 | kthread_init_work(&wd_data->work, watchdog_ping_work); |
a19f8933 | 1034 | hrtimer_init(&wd_data->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD); |
1ff68820 | 1035 | wd_data->timer.function = watchdog_timer_expired; |
7b7d2fdc | 1036 | watchdog_hrtimer_pretimeout_init(wdd); |
664a3923 | 1037 | |
bc794ac3 | 1038 | if (wdd->id == 0) { |
b4ffb190 | 1039 | old_wd_data = wd_data; |
bc794ac3 | 1040 | watchdog_miscdev.parent = wdd->parent; |
45f5fed3 AC |
1041 | err = misc_register(&watchdog_miscdev); |
1042 | if (err != 0) { | |
1043 | pr_err("%s: cannot register miscdev on minor=%d (err=%d).\n", | |
bc794ac3 | 1044 | wdd->info->identity, WATCHDOG_MINOR, err); |
45f5fed3 AC |
1045 | if (err == -EBUSY) |
1046 | pr_err("%s: a legacy watchdog module is probably present.\n", | |
bc794ac3 | 1047 | wdd->info->identity); |
b4ffb190 | 1048 | old_wd_data = NULL; |
937425d4 | 1049 | put_device(&wd_data->dev); |
45f5fed3 AC |
1050 | return err; |
1051 | } | |
43316044 WVS |
1052 | } |
1053 | ||
45f5fed3 | 1054 | /* Fill in the data structures */ |
b4ffb190 | 1055 | cdev_init(&wd_data->cdev, &watchdog_fops); |
45f5fed3 AC |
1056 | |
1057 | /* Add the device */ | |
72139dfa | 1058 | err = cdev_device_add(&wd_data->cdev, &wd_data->dev); |
45f5fed3 AC |
1059 | if (err) { |
1060 | pr_err("watchdog%d unable to add device %d:%d\n", | |
bc794ac3 GR |
1061 | wdd->id, MAJOR(watchdog_devt), wdd->id); |
1062 | if (wdd->id == 0) { | |
45f5fed3 | 1063 | misc_deregister(&watchdog_miscdev); |
b4ffb190 | 1064 | old_wd_data = NULL; |
45f5fed3 | 1065 | } |
13721a2a | 1066 | put_device(&wd_data->dev); |
ee142889 | 1067 | return err; |
43316044 | 1068 | } |
ee142889 | 1069 | |
72139dfa KH |
1070 | wd_data->cdev.owner = wdd->ops->owner; |
1071 | ||
15013ad8 | 1072 | /* Record time of most recent heartbeat as 'just before now'. */ |
1ff68820 | 1073 | wd_data->last_hw_keepalive = ktime_sub(ktime_get(), 1); |
4d1c6a0e | 1074 | watchdog_set_open_deadline(wd_data); |
15013ad8 | 1075 | |
ee142889 GR |
1076 | /* |
1077 | * If the watchdog is running, prevent its driver from being unloaded, | |
1078 | * and schedule an immediate ping. | |
1079 | */ | |
1080 | if (watchdog_hw_running(wdd)) { | |
914d65f3 | 1081 | __module_get(wdd->ops->owner); |
72139dfa | 1082 | get_device(&wd_data->dev); |
914d65f3 | 1083 | if (handle_boot_enabled) |
a19f8933 JC |
1084 | hrtimer_start(&wd_data->timer, 0, |
1085 | HRTIMER_MODE_REL_HARD); | |
914d65f3 | 1086 | else |
2501b015 | 1087 | pr_info("watchdog%d running and kernel based pre-userspace handler disabled\n", |
914d65f3 | 1088 | wdd->id); |
ee142889 GR |
1089 | } |
1090 | ||
1091 | return 0; | |
43316044 WVS |
1092 | } |
1093 | ||
1094 | /* | |
ba6c89ab DBO |
1095 | * watchdog_cdev_unregister - unregister watchdog character device |
1096 | * @wdd: Watchdog device | |
43316044 | 1097 | * |
ba6c89ab DBO |
1098 | * Unregister watchdog character device and if needed the legacy |
1099 | * /dev/watchdog device. | |
43316044 | 1100 | */ |
32ecc639 | 1101 | static void watchdog_cdev_unregister(struct watchdog_device *wdd) |
43316044 | 1102 | { |
b4ffb190 | 1103 | struct watchdog_core_data *wd_data = wdd->wd_data; |
e907df32 | 1104 | |
72139dfa | 1105 | cdev_device_del(&wd_data->cdev, &wd_data->dev); |
bc794ac3 | 1106 | if (wdd->id == 0) { |
45f5fed3 | 1107 | misc_deregister(&watchdog_miscdev); |
b4ffb190 | 1108 | old_wd_data = NULL; |
43316044 | 1109 | } |
b4ffb190 | 1110 | |
bb292ac1 GR |
1111 | if (watchdog_active(wdd) && |
1112 | test_bit(WDOG_STOP_ON_UNREGISTER, &wdd->status)) { | |
1113 | watchdog_stop(wdd); | |
1114 | } | |
1115 | ||
c7b178da CK |
1116 | watchdog_hrtimer_pretimeout_stop(wdd); |
1117 | ||
953b9dd7 WS |
1118 | mutex_lock(&wd_data->lock); |
1119 | wd_data->wdd = NULL; | |
1120 | wdd->wd_data = NULL; | |
1121 | mutex_unlock(&wd_data->lock); | |
1122 | ||
1ff68820 CL |
1123 | hrtimer_cancel(&wd_data->timer); |
1124 | kthread_cancel_work_sync(&wd_data->work); | |
664a3923 | 1125 | |
72139dfa | 1126 | put_device(&wd_data->dev); |
43316044 | 1127 | } |
45f5fed3 | 1128 | |
ba6c89ab DBO |
1129 | /** |
1130 | * watchdog_dev_register - register a watchdog device | |
1131 | * @wdd: Watchdog device | |
1132 | * | |
1133 | * Register a watchdog device including handling the legacy | |
1134 | * /dev/watchdog node. /dev/watchdog is actually a miscdevice and | |
1135 | * thus we set it up like that. | |
32ecc639 | 1136 | * |
ba6c89ab | 1137 | * Return: 0 if successful, error otherwise. |
32ecc639 | 1138 | */ |
32ecc639 GR |
1139 | int watchdog_dev_register(struct watchdog_device *wdd) |
1140 | { | |
32ecc639 GR |
1141 | int ret; |
1142 | ||
72139dfa | 1143 | ret = watchdog_cdev_register(wdd); |
32ecc639 GR |
1144 | if (ret) |
1145 | return ret; | |
1146 | ||
ff84136c | 1147 | ret = watchdog_register_pretimeout(wdd); |
69503e58 | 1148 | if (ret) |
ff84136c | 1149 | watchdog_cdev_unregister(wdd); |
ff84136c | 1150 | |
32ecc639 GR |
1151 | return ret; |
1152 | } | |
1153 | ||
ba6c89ab DBO |
1154 | /** |
1155 | * watchdog_dev_unregister - unregister a watchdog device | |
1156 | * @wdd: watchdog device | |
32ecc639 | 1157 | * |
ba6c89ab DBO |
1158 | * Unregister watchdog device and if needed the legacy |
1159 | * /dev/watchdog device. | |
32ecc639 | 1160 | */ |
32ecc639 GR |
1161 | void watchdog_dev_unregister(struct watchdog_device *wdd) |
1162 | { | |
ff84136c | 1163 | watchdog_unregister_pretimeout(wdd); |
b4ffb190 | 1164 | watchdog_cdev_unregister(wdd); |
32ecc639 GR |
1165 | } |
1166 | ||
ba6c89ab DBO |
1167 | /** |
1168 | * watchdog_set_last_hw_keepalive - set last HW keepalive time for watchdog | |
1169 | * @wdd: Watchdog device | |
1170 | * @last_ping_ms: Time since last HW heartbeat | |
cef9572e | 1171 | * |
ba6c89ab DBO |
1172 | * Adjusts the last known HW keepalive time for a watchdog timer. |
1173 | * This is needed if the watchdog is already running when the probe | |
1174 | * function is called, and it can't be pinged immediately. This | |
1175 | * function must be called immediately after watchdog registration, | |
1176 | * and min_hw_heartbeat_ms must be set for this to be useful. | |
1177 | * | |
1178 | * Return: 0 if successful, error otherwise. | |
cef9572e TK |
1179 | */ |
1180 | int watchdog_set_last_hw_keepalive(struct watchdog_device *wdd, | |
1181 | unsigned int last_ping_ms) | |
1182 | { | |
1183 | struct watchdog_core_data *wd_data; | |
1184 | ktime_t now; | |
1185 | ||
1186 | if (!wdd) | |
1187 | return -EINVAL; | |
1188 | ||
1189 | wd_data = wdd->wd_data; | |
1190 | ||
1191 | now = ktime_get(); | |
1192 | ||
1193 | wd_data->last_hw_keepalive = ktime_sub(now, ms_to_ktime(last_ping_ms)); | |
1194 | ||
dbe80cf4 JK |
1195 | if (watchdog_hw_running(wdd) && handle_boot_enabled) |
1196 | return __watchdog_ping(wdd); | |
1197 | ||
1198 | return 0; | |
cef9572e TK |
1199 | } |
1200 | EXPORT_SYMBOL_GPL(watchdog_set_last_hw_keepalive); | |
1201 | ||
ba6c89ab DBO |
1202 | /** |
1203 | * watchdog_dev_init - init dev part of watchdog core | |
45f5fed3 | 1204 | * |
ba6c89ab DBO |
1205 | * Allocate a range of chardev nodes to use for watchdog devices. |
1206 | * | |
1207 | * Return: 0 if successful, error otherwise. | |
45f5fed3 | 1208 | */ |
32ecc639 | 1209 | int __init watchdog_dev_init(void) |
45f5fed3 | 1210 | { |
906d7a5c PA |
1211 | int err; |
1212 | ||
38a1222a CL |
1213 | watchdog_kworker = kthread_create_worker(0, "watchdogd"); |
1214 | if (IS_ERR(watchdog_kworker)) { | |
1215 | pr_err("Failed to create watchdog kworker\n"); | |
1216 | return PTR_ERR(watchdog_kworker); | |
664a3923 | 1217 | } |
94beddac | 1218 | sched_set_fifo(watchdog_kworker->task); |
664a3923 | 1219 | |
906d7a5c PA |
1220 | err = class_register(&watchdog_class); |
1221 | if (err < 0) { | |
1222 | pr_err("couldn't register class\n"); | |
138913cb | 1223 | goto err_register; |
906d7a5c PA |
1224 | } |
1225 | ||
1226 | err = alloc_chrdev_region(&watchdog_devt, 0, MAX_DOGS, "watchdog"); | |
1227 | if (err < 0) { | |
45f5fed3 | 1228 | pr_err("watchdog: unable to allocate char dev region\n"); |
138913cb | 1229 | goto err_alloc; |
906d7a5c PA |
1230 | } |
1231 | ||
32ecc639 | 1232 | return 0; |
138913cb WY |
1233 | |
1234 | err_alloc: | |
1235 | class_unregister(&watchdog_class); | |
1236 | err_register: | |
38a1222a | 1237 | kthread_destroy_worker(watchdog_kworker); |
138913cb | 1238 | return err; |
45f5fed3 AC |
1239 | } |
1240 | ||
ba6c89ab DBO |
1241 | /** |
1242 | * watchdog_dev_exit - exit dev part of watchdog core | |
45f5fed3 | 1243 | * |
ba6c89ab | 1244 | * Release the range of chardev nodes used for watchdog devices. |
45f5fed3 | 1245 | */ |
45f5fed3 AC |
1246 | void __exit watchdog_dev_exit(void) |
1247 | { | |
1248 | unregister_chrdev_region(watchdog_devt, MAX_DOGS); | |
906d7a5c | 1249 | class_unregister(&watchdog_class); |
38a1222a | 1250 | kthread_destroy_worker(watchdog_kworker); |
45f5fed3 | 1251 | } |
2501b015 | 1252 | |
60bcd91a GJ |
1253 | int watchdog_dev_suspend(struct watchdog_device *wdd) |
1254 | { | |
1255 | struct watchdog_core_data *wd_data = wdd->wd_data; | |
1256 | int ret = 0; | |
1257 | ||
1258 | if (!wdd->wd_data) | |
1259 | return -ENODEV; | |
1260 | ||
1261 | /* ping for the last time before suspend */ | |
1262 | mutex_lock(&wd_data->lock); | |
1263 | if (watchdog_worker_should_ping(wd_data)) | |
1264 | ret = __watchdog_ping(wd_data->wdd); | |
1265 | mutex_unlock(&wd_data->lock); | |
1266 | ||
1267 | if (ret) | |
1268 | return ret; | |
1269 | ||
1270 | /* | |
1271 | * make sure that watchdog worker will not kick in when the wdog is | |
1272 | * suspended | |
1273 | */ | |
1274 | hrtimer_cancel(&wd_data->timer); | |
1275 | kthread_cancel_work_sync(&wd_data->work); | |
1276 | ||
1277 | return 0; | |
1278 | } | |
1279 | ||
1280 | int watchdog_dev_resume(struct watchdog_device *wdd) | |
1281 | { | |
1282 | struct watchdog_core_data *wd_data = wdd->wd_data; | |
1283 | int ret = 0; | |
1284 | ||
1285 | if (!wdd->wd_data) | |
1286 | return -ENODEV; | |
1287 | ||
1288 | /* | |
1289 | * __watchdog_ping will also retrigger hrtimer and therefore restore the | |
1290 | * ping worker if needed. | |
1291 | */ | |
1292 | mutex_lock(&wd_data->lock); | |
1293 | if (watchdog_worker_should_ping(wd_data)) | |
1294 | ret = __watchdog_ping(wd_data->wdd); | |
1295 | mutex_unlock(&wd_data->lock); | |
1296 | ||
1297 | return ret; | |
1298 | } | |
1299 | ||
2501b015 SR |
1300 | module_param(handle_boot_enabled, bool, 0444); |
1301 | MODULE_PARM_DESC(handle_boot_enabled, | |
1302 | "Watchdog core auto-updates boot enabled watchdogs before userspace takes over (default=" | |
1303 | __MODULE_STRING(IS_ENABLED(CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED)) ")"); | |
4d1c6a0e RV |
1304 | |
1305 | module_param(open_timeout, uint, 0644); | |
1306 | MODULE_PARM_DESC(open_timeout, | |
487e4e08 RV |
1307 | "Maximum time (in seconds, 0 means infinity) for userspace to take over a running watchdog (default=" |
1308 | __MODULE_STRING(CONFIG_WATCHDOG_OPEN_TIMEOUT) ")"); |