Commit | Line | Data |
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43316044 WVS |
1 | /* |
2 | * watchdog_dev.c | |
3 | * | |
4 | * (c) Copyright 2008-2011 Alan Cox <alan@lxorguk.ukuu.org.uk>, | |
5 | * All Rights Reserved. | |
6 | * | |
7 | * (c) Copyright 2008-2011 Wim Van Sebroeck <wim@iguana.be>. | |
8 | * | |
9 | * | |
10 | * This source code is part of the generic code that can be used | |
11 | * by all the watchdog timer drivers. | |
12 | * | |
13 | * This part of the generic code takes care of the following | |
14 | * misc device: /dev/watchdog. | |
15 | * | |
16 | * Based on source code of the following authors: | |
17 | * Matt Domsch <Matt_Domsch@dell.com>, | |
18 | * Rob Radez <rob@osinvestor.com>, | |
19 | * Rusty Lynch <rusty@linux.co.intel.com> | |
20 | * Satyam Sharma <satyam@infradead.org> | |
21 | * Randy Dunlap <randy.dunlap@oracle.com> | |
22 | * | |
23 | * This program is free software; you can redistribute it and/or | |
24 | * modify it under the terms of the GNU General Public License | |
25 | * as published by the Free Software Foundation; either version | |
26 | * 2 of the License, or (at your option) any later version. | |
27 | * | |
28 | * Neither Alan Cox, CymruNet Ltd., Wim Van Sebroeck nor Iguana vzw. | |
29 | * admit liability nor provide warranty for any of this software. | |
30 | * This material is provided "AS-IS" and at no charge. | |
31 | */ | |
32 | ||
33 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
34 | ||
b4ffb190 | 35 | #include <linux/cdev.h> /* For character device */ |
43316044 | 36 | #include <linux/errno.h> /* For the -ENODEV/... values */ |
43316044 | 37 | #include <linux/fs.h> /* For file operations */ |
43316044 | 38 | #include <linux/init.h> /* For __init/__exit/... */ |
664a3923 | 39 | #include <linux/jiffies.h> /* For timeout functions */ |
b4ffb190 GR |
40 | #include <linux/kernel.h> /* For printk/panic/... */ |
41 | #include <linux/kref.h> /* For data references */ | |
42 | #include <linux/miscdevice.h> /* For handling misc devices */ | |
43 | #include <linux/module.h> /* For module stuff/... */ | |
44 | #include <linux/mutex.h> /* For mutexes */ | |
45 | #include <linux/slab.h> /* For memory functions */ | |
46 | #include <linux/types.h> /* For standard types (like size_t) */ | |
47 | #include <linux/watchdog.h> /* For watchdog specific items */ | |
664a3923 | 48 | #include <linux/workqueue.h> /* For workqueue */ |
43316044 WVS |
49 | #include <linux/uaccess.h> /* For copy_to_user/put_user/... */ |
50 | ||
6cfb5aa8 | 51 | #include "watchdog_core.h" |
09a46e73 | 52 | |
b4ffb190 GR |
53 | /* |
54 | * struct watchdog_core_data - watchdog core internal data | |
55 | * @kref: Reference count. | |
56 | * @cdev: The watchdog's Character device. | |
57 | * @wdd: Pointer to watchdog device. | |
58 | * @lock: Lock for watchdog core. | |
59 | * @status: Watchdog core internal status bits. | |
60 | */ | |
61 | struct watchdog_core_data { | |
62 | struct kref kref; | |
63 | struct cdev cdev; | |
64 | struct watchdog_device *wdd; | |
65 | struct mutex lock; | |
664a3923 | 66 | unsigned long last_keepalive; |
15013ad8 | 67 | unsigned long last_hw_keepalive; |
664a3923 | 68 | struct delayed_work work; |
b4ffb190 GR |
69 | unsigned long status; /* Internal status bits */ |
70 | #define _WDOG_DEV_OPEN 0 /* Opened ? */ | |
71 | #define _WDOG_ALLOW_RELEASE 1 /* Did we receive the magic char ? */ | |
90b826f1 | 72 | #define _WDOG_KEEPALIVE 2 /* Did we receive a keepalive ? */ |
b4ffb190 GR |
73 | }; |
74 | ||
45f5fed3 AC |
75 | /* the dev_t structure to store the dynamically allocated watchdog devices */ |
76 | static dev_t watchdog_devt; | |
b4ffb190 GR |
77 | /* Reference to watchdog device behind /dev/watchdog */ |
78 | static struct watchdog_core_data *old_wd_data; | |
43316044 | 79 | |
664a3923 GR |
80 | static struct workqueue_struct *watchdog_wq; |
81 | ||
82 | static inline bool watchdog_need_worker(struct watchdog_device *wdd) | |
83 | { | |
84 | /* All variables in milli-seconds */ | |
85 | unsigned int hm = wdd->max_hw_heartbeat_ms; | |
86 | unsigned int t = wdd->timeout * 1000; | |
87 | ||
88 | /* | |
89 | * A worker to generate heartbeat requests is needed if all of the | |
90 | * following conditions are true. | |
91 | * - Userspace activated the watchdog. | |
92 | * - The driver provided a value for the maximum hardware timeout, and | |
93 | * thus is aware that the framework supports generating heartbeat | |
94 | * requests. | |
95 | * - Userspace requests a longer timeout than the hardware can handle. | |
3fbfe926 RV |
96 | * |
97 | * Alternatively, if userspace has not opened the watchdog | |
98 | * device, we take care of feeding the watchdog if it is | |
99 | * running. | |
664a3923 | 100 | */ |
3fbfe926 RV |
101 | return (hm && watchdog_active(wdd) && t > hm) || |
102 | (t && !watchdog_active(wdd) && watchdog_hw_running(wdd)); | |
664a3923 GR |
103 | } |
104 | ||
105 | static long watchdog_next_keepalive(struct watchdog_device *wdd) | |
106 | { | |
107 | struct watchdog_core_data *wd_data = wdd->wd_data; | |
108 | unsigned int timeout_ms = wdd->timeout * 1000; | |
109 | unsigned long keepalive_interval; | |
110 | unsigned long last_heartbeat; | |
111 | unsigned long virt_timeout; | |
112 | unsigned int hw_heartbeat_ms; | |
113 | ||
114 | virt_timeout = wd_data->last_keepalive + msecs_to_jiffies(timeout_ms); | |
3fbfe926 | 115 | hw_heartbeat_ms = min_not_zero(timeout_ms, wdd->max_hw_heartbeat_ms); |
664a3923 GR |
116 | keepalive_interval = msecs_to_jiffies(hw_heartbeat_ms / 2); |
117 | ||
ee142889 GR |
118 | if (!watchdog_active(wdd)) |
119 | return keepalive_interval; | |
120 | ||
664a3923 GR |
121 | /* |
122 | * To ensure that the watchdog times out wdd->timeout seconds | |
123 | * after the most recent ping from userspace, the last | |
124 | * worker ping has to come in hw_heartbeat_ms before this timeout. | |
125 | */ | |
126 | last_heartbeat = virt_timeout - msecs_to_jiffies(hw_heartbeat_ms); | |
127 | return min_t(long, last_heartbeat - jiffies, keepalive_interval); | |
128 | } | |
129 | ||
130 | static inline void watchdog_update_worker(struct watchdog_device *wdd) | |
131 | { | |
132 | struct watchdog_core_data *wd_data = wdd->wd_data; | |
133 | ||
134 | if (watchdog_need_worker(wdd)) { | |
135 | long t = watchdog_next_keepalive(wdd); | |
136 | ||
137 | if (t > 0) | |
138 | mod_delayed_work(watchdog_wq, &wd_data->work, t); | |
139 | } else { | |
140 | cancel_delayed_work(&wd_data->work); | |
141 | } | |
142 | } | |
143 | ||
144 | static int __watchdog_ping(struct watchdog_device *wdd) | |
145 | { | |
15013ad8 GR |
146 | struct watchdog_core_data *wd_data = wdd->wd_data; |
147 | unsigned long earliest_keepalive = wd_data->last_hw_keepalive + | |
148 | msecs_to_jiffies(wdd->min_hw_heartbeat_ms); | |
664a3923 GR |
149 | int err; |
150 | ||
15013ad8 GR |
151 | if (time_is_after_jiffies(earliest_keepalive)) { |
152 | mod_delayed_work(watchdog_wq, &wd_data->work, | |
153 | earliest_keepalive - jiffies); | |
154 | return 0; | |
155 | } | |
156 | ||
157 | wd_data->last_hw_keepalive = jiffies; | |
158 | ||
664a3923 GR |
159 | if (wdd->ops->ping) |
160 | err = wdd->ops->ping(wdd); /* ping the watchdog */ | |
161 | else | |
162 | err = wdd->ops->start(wdd); /* restart watchdog */ | |
163 | ||
164 | watchdog_update_worker(wdd); | |
165 | ||
166 | return err; | |
167 | } | |
168 | ||
43316044 WVS |
169 | /* |
170 | * watchdog_ping: ping the watchdog. | |
bc794ac3 | 171 | * @wdd: the watchdog device to ping |
43316044 | 172 | * |
b4ffb190 GR |
173 | * The caller must hold wd_data->lock. |
174 | * | |
43316044 WVS |
175 | * If the watchdog has no own ping operation then it needs to be |
176 | * restarted via the start operation. This wrapper function does | |
177 | * exactly that. | |
234445b4 | 178 | * We only ping when the watchdog device is running. |
43316044 WVS |
179 | */ |
180 | ||
bc794ac3 | 181 | static int watchdog_ping(struct watchdog_device *wdd) |
43316044 | 182 | { |
664a3923 | 183 | struct watchdog_core_data *wd_data = wdd->wd_data; |
e907df32 | 184 | |
ee142889 | 185 | if (!watchdog_active(wdd) && !watchdog_hw_running(wdd)) |
b4ffb190 | 186 | return 0; |
7a879824 | 187 | |
90b826f1 GR |
188 | set_bit(_WDOG_KEEPALIVE, &wd_data->status); |
189 | ||
664a3923 GR |
190 | wd_data->last_keepalive = jiffies; |
191 | return __watchdog_ping(wdd); | |
192 | } | |
7a879824 | 193 | |
664a3923 GR |
194 | static void watchdog_ping_work(struct work_struct *work) |
195 | { | |
196 | struct watchdog_core_data *wd_data; | |
197 | struct watchdog_device *wdd; | |
198 | ||
199 | wd_data = container_of(to_delayed_work(work), struct watchdog_core_data, | |
200 | work); | |
201 | ||
202 | mutex_lock(&wd_data->lock); | |
203 | wdd = wd_data->wdd; | |
ee142889 | 204 | if (wdd && (watchdog_active(wdd) || watchdog_hw_running(wdd))) |
664a3923 GR |
205 | __watchdog_ping(wdd); |
206 | mutex_unlock(&wd_data->lock); | |
234445b4 WVS |
207 | } |
208 | ||
209 | /* | |
210 | * watchdog_start: wrapper to start the watchdog. | |
bc794ac3 | 211 | * @wdd: the watchdog device to start |
234445b4 | 212 | * |
b4ffb190 GR |
213 | * The caller must hold wd_data->lock. |
214 | * | |
234445b4 WVS |
215 | * Start the watchdog if it is not active and mark it active. |
216 | * This function returns zero on success or a negative errno code for | |
217 | * failure. | |
218 | */ | |
219 | ||
bc794ac3 | 220 | static int watchdog_start(struct watchdog_device *wdd) |
234445b4 | 221 | { |
664a3923 GR |
222 | struct watchdog_core_data *wd_data = wdd->wd_data; |
223 | unsigned long started_at; | |
b4ffb190 | 224 | int err; |
e907df32 | 225 | |
bc794ac3 | 226 | if (watchdog_active(wdd)) |
b4ffb190 | 227 | return 0; |
234445b4 | 228 | |
90b826f1 GR |
229 | set_bit(_WDOG_KEEPALIVE, &wd_data->status); |
230 | ||
664a3923 | 231 | started_at = jiffies; |
ee142889 GR |
232 | if (watchdog_hw_running(wdd) && wdd->ops->ping) |
233 | err = wdd->ops->ping(wdd); | |
234 | else | |
235 | err = wdd->ops->start(wdd); | |
664a3923 | 236 | if (err == 0) { |
bc794ac3 | 237 | set_bit(WDOG_ACTIVE, &wdd->status); |
664a3923 GR |
238 | wd_data->last_keepalive = started_at; |
239 | watchdog_update_worker(wdd); | |
240 | } | |
7a879824 | 241 | |
7a879824 | 242 | return err; |
234445b4 WVS |
243 | } |
244 | ||
245 | /* | |
246 | * watchdog_stop: wrapper to stop the watchdog. | |
bc794ac3 | 247 | * @wdd: the watchdog device to stop |
234445b4 | 248 | * |
b4ffb190 GR |
249 | * The caller must hold wd_data->lock. |
250 | * | |
234445b4 WVS |
251 | * Stop the watchdog if it is still active and unmark it active. |
252 | * This function returns zero on success or a negative errno code for | |
253 | * failure. | |
7e192b9c | 254 | * If the 'nowayout' feature was set, the watchdog cannot be stopped. |
234445b4 WVS |
255 | */ |
256 | ||
bc794ac3 | 257 | static int watchdog_stop(struct watchdog_device *wdd) |
234445b4 | 258 | { |
ee142889 | 259 | int err = 0; |
e907df32 | 260 | |
bc794ac3 | 261 | if (!watchdog_active(wdd)) |
b4ffb190 | 262 | return 0; |
7e192b9c | 263 | |
bc794ac3 | 264 | if (test_bit(WDOG_NO_WAY_OUT, &wdd->status)) { |
0254e953 GR |
265 | pr_info("watchdog%d: nowayout prevents watchdog being stopped!\n", |
266 | wdd->id); | |
b4ffb190 | 267 | return -EBUSY; |
7e192b9c | 268 | } |
234445b4 | 269 | |
3c10bbde GR |
270 | if (wdd->ops->stop) { |
271 | clear_bit(WDOG_HW_RUNNING, &wdd->status); | |
d0684c8a | 272 | err = wdd->ops->stop(wdd); |
3c10bbde | 273 | } else { |
d0684c8a | 274 | set_bit(WDOG_HW_RUNNING, &wdd->status); |
3c10bbde | 275 | } |
d0684c8a | 276 | |
664a3923 | 277 | if (err == 0) { |
bc794ac3 | 278 | clear_bit(WDOG_ACTIVE, &wdd->status); |
ee142889 | 279 | watchdog_update_worker(wdd); |
664a3923 | 280 | } |
7a879824 | 281 | |
7a879824 HG |
282 | return err; |
283 | } | |
284 | ||
285 | /* | |
286 | * watchdog_get_status: wrapper to get the watchdog status | |
bc794ac3 | 287 | * @wdd: the watchdog device to get the status from |
b4ffb190 GR |
288 | * |
289 | * The caller must hold wd_data->lock. | |
7a879824 HG |
290 | * |
291 | * Get the watchdog's status flags. | |
292 | */ | |
293 | ||
b4ffb190 | 294 | static unsigned int watchdog_get_status(struct watchdog_device *wdd) |
7a879824 | 295 | { |
90b826f1 GR |
296 | struct watchdog_core_data *wd_data = wdd->wd_data; |
297 | unsigned int status; | |
7a879824 | 298 | |
90b826f1 GR |
299 | if (wdd->ops->status) |
300 | status = wdd->ops->status(wdd); | |
301 | else | |
302 | status = wdd->bootstatus & (WDIOF_CARDRESET | | |
303 | WDIOF_OVERHEAT | | |
304 | WDIOF_FANFAULT | | |
305 | WDIOF_EXTERN1 | | |
306 | WDIOF_EXTERN2 | | |
307 | WDIOF_POWERUNDER | | |
308 | WDIOF_POWEROVER); | |
309 | ||
310 | if (test_bit(_WDOG_ALLOW_RELEASE, &wd_data->status)) | |
311 | status |= WDIOF_MAGICCLOSE; | |
312 | ||
313 | if (test_and_clear_bit(_WDOG_KEEPALIVE, &wd_data->status)) | |
314 | status |= WDIOF_KEEPALIVEPING; | |
315 | ||
316 | return status; | |
7a879824 HG |
317 | } |
318 | ||
319 | /* | |
320 | * watchdog_set_timeout: set the watchdog timer timeout | |
bc794ac3 | 321 | * @wdd: the watchdog device to set the timeout for |
7a879824 | 322 | * @timeout: timeout to set in seconds |
b4ffb190 GR |
323 | * |
324 | * The caller must hold wd_data->lock. | |
7a879824 HG |
325 | */ |
326 | ||
bc794ac3 | 327 | static int watchdog_set_timeout(struct watchdog_device *wdd, |
7a879824 HG |
328 | unsigned int timeout) |
329 | { | |
fb32e9b9 GR |
330 | int err = 0; |
331 | ||
332 | if (!(wdd->info->options & WDIOF_SETTIMEOUT)) | |
7a879824 HG |
333 | return -EOPNOTSUPP; |
334 | ||
bc794ac3 | 335 | if (watchdog_timeout_invalid(wdd, timeout)) |
7a879824 HG |
336 | return -EINVAL; |
337 | ||
fb32e9b9 GR |
338 | if (wdd->ops->set_timeout) |
339 | err = wdd->ops->set_timeout(wdd, timeout); | |
340 | else | |
341 | wdd->timeout = timeout; | |
342 | ||
664a3923 GR |
343 | watchdog_update_worker(wdd); |
344 | ||
fb32e9b9 | 345 | return err; |
7a879824 HG |
346 | } |
347 | ||
348 | /* | |
349 | * watchdog_get_timeleft: wrapper to get the time left before a reboot | |
bc794ac3 | 350 | * @wdd: the watchdog device to get the remaining time from |
7a879824 HG |
351 | * @timeleft: the time that's left |
352 | * | |
b4ffb190 GR |
353 | * The caller must hold wd_data->lock. |
354 | * | |
7a879824 HG |
355 | * Get the time before a watchdog will reboot (if not pinged). |
356 | */ | |
357 | ||
bc794ac3 | 358 | static int watchdog_get_timeleft(struct watchdog_device *wdd, |
7a879824 HG |
359 | unsigned int *timeleft) |
360 | { | |
7a879824 | 361 | *timeleft = 0; |
b4ffb190 | 362 | |
bc794ac3 | 363 | if (!wdd->ops->get_timeleft) |
7a879824 HG |
364 | return -EOPNOTSUPP; |
365 | ||
bc794ac3 | 366 | *timeleft = wdd->ops->get_timeleft(wdd); |
7a879824 | 367 | |
b4ffb190 | 368 | return 0; |
7a879824 HG |
369 | } |
370 | ||
33b71126 PA |
371 | #ifdef CONFIG_WATCHDOG_SYSFS |
372 | static ssize_t nowayout_show(struct device *dev, struct device_attribute *attr, | |
373 | char *buf) | |
374 | { | |
375 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
376 | ||
377 | return sprintf(buf, "%d\n", !!test_bit(WDOG_NO_WAY_OUT, &wdd->status)); | |
378 | } | |
379 | static DEVICE_ATTR_RO(nowayout); | |
380 | ||
381 | static ssize_t status_show(struct device *dev, struct device_attribute *attr, | |
382 | char *buf) | |
383 | { | |
384 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
b4ffb190 GR |
385 | struct watchdog_core_data *wd_data = wdd->wd_data; |
386 | unsigned int status; | |
33b71126 | 387 | |
b4ffb190 GR |
388 | mutex_lock(&wd_data->lock); |
389 | status = watchdog_get_status(wdd); | |
390 | mutex_unlock(&wd_data->lock); | |
33b71126 | 391 | |
90b826f1 | 392 | return sprintf(buf, "0x%x\n", status); |
33b71126 PA |
393 | } |
394 | static DEVICE_ATTR_RO(status); | |
395 | ||
396 | static ssize_t bootstatus_show(struct device *dev, | |
397 | struct device_attribute *attr, char *buf) | |
398 | { | |
399 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
400 | ||
401 | return sprintf(buf, "%u\n", wdd->bootstatus); | |
402 | } | |
403 | static DEVICE_ATTR_RO(bootstatus); | |
404 | ||
405 | static ssize_t timeleft_show(struct device *dev, struct device_attribute *attr, | |
406 | char *buf) | |
407 | { | |
408 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
b4ffb190 | 409 | struct watchdog_core_data *wd_data = wdd->wd_data; |
33b71126 PA |
410 | ssize_t status; |
411 | unsigned int val; | |
412 | ||
b4ffb190 | 413 | mutex_lock(&wd_data->lock); |
33b71126 | 414 | status = watchdog_get_timeleft(wdd, &val); |
b4ffb190 | 415 | mutex_unlock(&wd_data->lock); |
33b71126 PA |
416 | if (!status) |
417 | status = sprintf(buf, "%u\n", val); | |
418 | ||
419 | return status; | |
420 | } | |
421 | static DEVICE_ATTR_RO(timeleft); | |
422 | ||
423 | static ssize_t timeout_show(struct device *dev, struct device_attribute *attr, | |
424 | char *buf) | |
425 | { | |
426 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
427 | ||
428 | return sprintf(buf, "%u\n", wdd->timeout); | |
429 | } | |
430 | static DEVICE_ATTR_RO(timeout); | |
431 | ||
432 | static ssize_t identity_show(struct device *dev, struct device_attribute *attr, | |
433 | char *buf) | |
434 | { | |
435 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
436 | ||
437 | return sprintf(buf, "%s\n", wdd->info->identity); | |
438 | } | |
439 | static DEVICE_ATTR_RO(identity); | |
440 | ||
441 | static ssize_t state_show(struct device *dev, struct device_attribute *attr, | |
442 | char *buf) | |
443 | { | |
444 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
445 | ||
446 | if (watchdog_active(wdd)) | |
447 | return sprintf(buf, "active\n"); | |
448 | ||
449 | return sprintf(buf, "inactive\n"); | |
450 | } | |
451 | static DEVICE_ATTR_RO(state); | |
452 | ||
453 | static umode_t wdt_is_visible(struct kobject *kobj, struct attribute *attr, | |
454 | int n) | |
455 | { | |
456 | struct device *dev = container_of(kobj, struct device, kobj); | |
457 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
458 | umode_t mode = attr->mode; | |
459 | ||
90b826f1 | 460 | if (attr == &dev_attr_timeleft.attr && !wdd->ops->get_timeleft) |
33b71126 PA |
461 | mode = 0; |
462 | ||
463 | return mode; | |
464 | } | |
465 | static struct attribute *wdt_attrs[] = { | |
466 | &dev_attr_state.attr, | |
467 | &dev_attr_identity.attr, | |
468 | &dev_attr_timeout.attr, | |
469 | &dev_attr_timeleft.attr, | |
470 | &dev_attr_bootstatus.attr, | |
471 | &dev_attr_status.attr, | |
472 | &dev_attr_nowayout.attr, | |
473 | NULL, | |
474 | }; | |
475 | ||
476 | static const struct attribute_group wdt_group = { | |
477 | .attrs = wdt_attrs, | |
478 | .is_visible = wdt_is_visible, | |
479 | }; | |
480 | __ATTRIBUTE_GROUPS(wdt); | |
481 | #else | |
482 | #define wdt_groups NULL | |
483 | #endif | |
484 | ||
7a879824 HG |
485 | /* |
486 | * watchdog_ioctl_op: call the watchdog drivers ioctl op if defined | |
bc794ac3 | 487 | * @wdd: the watchdog device to do the ioctl on |
7a879824 HG |
488 | * @cmd: watchdog command |
489 | * @arg: argument pointer | |
b4ffb190 GR |
490 | * |
491 | * The caller must hold wd_data->lock. | |
7a879824 HG |
492 | */ |
493 | ||
bc794ac3 | 494 | static int watchdog_ioctl_op(struct watchdog_device *wdd, unsigned int cmd, |
7a879824 HG |
495 | unsigned long arg) |
496 | { | |
bc794ac3 | 497 | if (!wdd->ops->ioctl) |
7a879824 HG |
498 | return -ENOIOCTLCMD; |
499 | ||
b4ffb190 | 500 | return wdd->ops->ioctl(wdd, cmd, arg); |
43316044 WVS |
501 | } |
502 | ||
503 | /* | |
504 | * watchdog_write: writes to the watchdog. | |
505 | * @file: file from VFS | |
506 | * @data: user address of data | |
507 | * @len: length of data | |
508 | * @ppos: pointer to the file offset | |
509 | * | |
510 | * A write to a watchdog device is defined as a keepalive ping. | |
017cf080 | 511 | * Writing the magic 'V' sequence allows the next close to turn |
7e192b9c | 512 | * off the watchdog (if 'nowayout' is not set). |
43316044 WVS |
513 | */ |
514 | ||
515 | static ssize_t watchdog_write(struct file *file, const char __user *data, | |
516 | size_t len, loff_t *ppos) | |
517 | { | |
b4ffb190 GR |
518 | struct watchdog_core_data *wd_data = file->private_data; |
519 | struct watchdog_device *wdd; | |
520 | int err; | |
43316044 WVS |
521 | size_t i; |
522 | char c; | |
523 | ||
524 | if (len == 0) | |
525 | return 0; | |
526 | ||
017cf080 WVS |
527 | /* |
528 | * Note: just in case someone wrote the magic character | |
529 | * five months ago... | |
530 | */ | |
b4ffb190 | 531 | clear_bit(_WDOG_ALLOW_RELEASE, &wd_data->status); |
017cf080 WVS |
532 | |
533 | /* scan to see whether or not we got the magic character */ | |
43316044 WVS |
534 | for (i = 0; i != len; i++) { |
535 | if (get_user(c, data + i)) | |
536 | return -EFAULT; | |
017cf080 | 537 | if (c == 'V') |
b4ffb190 | 538 | set_bit(_WDOG_ALLOW_RELEASE, &wd_data->status); |
43316044 WVS |
539 | } |
540 | ||
541 | /* someone wrote to us, so we send the watchdog a keepalive ping */ | |
b4ffb190 GR |
542 | |
543 | err = -ENODEV; | |
544 | mutex_lock(&wd_data->lock); | |
545 | wdd = wd_data->wdd; | |
546 | if (wdd) | |
547 | err = watchdog_ping(wdd); | |
548 | mutex_unlock(&wd_data->lock); | |
549 | ||
5ef79663 AU |
550 | if (err < 0) |
551 | return err; | |
43316044 WVS |
552 | |
553 | return len; | |
554 | } | |
555 | ||
2fa03560 WVS |
556 | /* |
557 | * watchdog_ioctl: handle the different ioctl's for the watchdog device. | |
558 | * @file: file handle to the device | |
559 | * @cmd: watchdog command | |
560 | * @arg: argument pointer | |
561 | * | |
562 | * The watchdog API defines a common set of functions for all watchdogs | |
563 | * according to their available features. | |
564 | */ | |
565 | ||
566 | static long watchdog_ioctl(struct file *file, unsigned int cmd, | |
567 | unsigned long arg) | |
568 | { | |
b4ffb190 | 569 | struct watchdog_core_data *wd_data = file->private_data; |
2fa03560 | 570 | void __user *argp = (void __user *)arg; |
b4ffb190 | 571 | struct watchdog_device *wdd; |
2fa03560 WVS |
572 | int __user *p = argp; |
573 | unsigned int val; | |
234445b4 | 574 | int err; |
2fa03560 | 575 | |
b4ffb190 GR |
576 | mutex_lock(&wd_data->lock); |
577 | ||
578 | wdd = wd_data->wdd; | |
579 | if (!wdd) { | |
580 | err = -ENODEV; | |
581 | goto out_ioctl; | |
582 | } | |
583 | ||
7a879824 HG |
584 | err = watchdog_ioctl_op(wdd, cmd, arg); |
585 | if (err != -ENOIOCTLCMD) | |
b4ffb190 | 586 | goto out_ioctl; |
78d88fc0 | 587 | |
2fa03560 WVS |
588 | switch (cmd) { |
589 | case WDIOC_GETSUPPORT: | |
b4ffb190 | 590 | err = copy_to_user(argp, wdd->info, |
2fa03560 | 591 | sizeof(struct watchdog_info)) ? -EFAULT : 0; |
b4ffb190 | 592 | break; |
2fa03560 | 593 | case WDIOC_GETSTATUS: |
b4ffb190 GR |
594 | val = watchdog_get_status(wdd); |
595 | err = put_user(val, p); | |
596 | break; | |
2fa03560 | 597 | case WDIOC_GETBOOTSTATUS: |
b4ffb190 GR |
598 | err = put_user(wdd->bootstatus, p); |
599 | break; | |
234445b4 | 600 | case WDIOC_SETOPTIONS: |
b4ffb190 GR |
601 | if (get_user(val, p)) { |
602 | err = -EFAULT; | |
603 | break; | |
604 | } | |
234445b4 WVS |
605 | if (val & WDIOS_DISABLECARD) { |
606 | err = watchdog_stop(wdd); | |
607 | if (err < 0) | |
b4ffb190 | 608 | break; |
234445b4 | 609 | } |
b4ffb190 | 610 | if (val & WDIOS_ENABLECARD) |
234445b4 | 611 | err = watchdog_start(wdd); |
b4ffb190 | 612 | break; |
c2dc00e4 | 613 | case WDIOC_KEEPALIVE: |
b4ffb190 GR |
614 | if (!(wdd->info->options & WDIOF_KEEPALIVEPING)) { |
615 | err = -EOPNOTSUPP; | |
616 | break; | |
617 | } | |
618 | err = watchdog_ping(wdd); | |
619 | break; | |
014d694e | 620 | case WDIOC_SETTIMEOUT: |
b4ffb190 GR |
621 | if (get_user(val, p)) { |
622 | err = -EFAULT; | |
623 | break; | |
624 | } | |
7a879824 | 625 | err = watchdog_set_timeout(wdd, val); |
014d694e | 626 | if (err < 0) |
b4ffb190 | 627 | break; |
014d694e WVS |
628 | /* If the watchdog is active then we send a keepalive ping |
629 | * to make sure that the watchdog keep's running (and if | |
630 | * possible that it takes the new timeout) */ | |
5ef79663 AU |
631 | err = watchdog_ping(wdd); |
632 | if (err < 0) | |
b4ffb190 | 633 | break; |
014d694e WVS |
634 | /* Fall */ |
635 | case WDIOC_GETTIMEOUT: | |
636 | /* timeout == 0 means that we don't know the timeout */ | |
b4ffb190 GR |
637 | if (wdd->timeout == 0) { |
638 | err = -EOPNOTSUPP; | |
639 | break; | |
640 | } | |
641 | err = put_user(wdd->timeout, p); | |
642 | break; | |
fd7b673c | 643 | case WDIOC_GETTIMELEFT: |
7a879824 | 644 | err = watchdog_get_timeleft(wdd, &val); |
b4ffb190 GR |
645 | if (err < 0) |
646 | break; | |
647 | err = put_user(val, p); | |
648 | break; | |
2fa03560 | 649 | default: |
b4ffb190 GR |
650 | err = -ENOTTY; |
651 | break; | |
2fa03560 | 652 | } |
b4ffb190 GR |
653 | |
654 | out_ioctl: | |
655 | mutex_unlock(&wd_data->lock); | |
656 | return err; | |
2fa03560 WVS |
657 | } |
658 | ||
43316044 | 659 | /* |
45f5fed3 | 660 | * watchdog_open: open the /dev/watchdog* devices. |
43316044 WVS |
661 | * @inode: inode of device |
662 | * @file: file handle to device | |
663 | * | |
45f5fed3 | 664 | * When the /dev/watchdog* device gets opened, we start the watchdog. |
43316044 WVS |
665 | * Watch out: the /dev/watchdog device is single open, so we make sure |
666 | * it can only be opened once. | |
667 | */ | |
668 | ||
669 | static int watchdog_open(struct inode *inode, struct file *file) | |
670 | { | |
b4ffb190 | 671 | struct watchdog_core_data *wd_data; |
45f5fed3 | 672 | struct watchdog_device *wdd; |
b4ffb190 | 673 | int err; |
45f5fed3 AC |
674 | |
675 | /* Get the corresponding watchdog device */ | |
676 | if (imajor(inode) == MISC_MAJOR) | |
b4ffb190 | 677 | wd_data = old_wd_data; |
45f5fed3 | 678 | else |
b4ffb190 GR |
679 | wd_data = container_of(inode->i_cdev, struct watchdog_core_data, |
680 | cdev); | |
43316044 WVS |
681 | |
682 | /* the watchdog is single open! */ | |
b4ffb190 | 683 | if (test_and_set_bit(_WDOG_DEV_OPEN, &wd_data->status)) |
43316044 WVS |
684 | return -EBUSY; |
685 | ||
b4ffb190 GR |
686 | wdd = wd_data->wdd; |
687 | ||
43316044 WVS |
688 | /* |
689 | * If the /dev/watchdog device is open, we don't want the module | |
690 | * to be unloaded. | |
691 | */ | |
ee142889 | 692 | if (!watchdog_hw_running(wdd) && !try_module_get(wdd->ops->owner)) { |
b4ffb190 GR |
693 | err = -EBUSY; |
694 | goto out_clear; | |
695 | } | |
43316044 | 696 | |
234445b4 | 697 | err = watchdog_start(wdd); |
43316044 WVS |
698 | if (err < 0) |
699 | goto out_mod; | |
700 | ||
b4ffb190 | 701 | file->private_data = wd_data; |
45f5fed3 | 702 | |
ee142889 GR |
703 | if (!watchdog_hw_running(wdd)) |
704 | kref_get(&wd_data->kref); | |
e907df32 | 705 | |
43316044 WVS |
706 | /* dev/watchdog is a virtual (and thus non-seekable) filesystem */ |
707 | return nonseekable_open(inode, file); | |
708 | ||
709 | out_mod: | |
b4ffb190 GR |
710 | module_put(wd_data->wdd->ops->owner); |
711 | out_clear: | |
712 | clear_bit(_WDOG_DEV_OPEN, &wd_data->status); | |
43316044 WVS |
713 | return err; |
714 | } | |
715 | ||
b4ffb190 GR |
716 | static void watchdog_core_data_release(struct kref *kref) |
717 | { | |
718 | struct watchdog_core_data *wd_data; | |
719 | ||
720 | wd_data = container_of(kref, struct watchdog_core_data, kref); | |
721 | ||
722 | kfree(wd_data); | |
723 | } | |
724 | ||
43316044 | 725 | /* |
45f5fed3 AC |
726 | * watchdog_release: release the watchdog device. |
727 | * @inode: inode of device | |
728 | * @file: file handle to device | |
43316044 | 729 | * |
017cf080 | 730 | * This is the code for when /dev/watchdog gets closed. We will only |
7e192b9c WVS |
731 | * stop the watchdog when we have received the magic char (and nowayout |
732 | * was not set), else the watchdog will keep running. | |
43316044 WVS |
733 | */ |
734 | ||
735 | static int watchdog_release(struct inode *inode, struct file *file) | |
736 | { | |
b4ffb190 GR |
737 | struct watchdog_core_data *wd_data = file->private_data; |
738 | struct watchdog_device *wdd; | |
017cf080 | 739 | int err = -EBUSY; |
d1ed3ba4 | 740 | bool running; |
017cf080 | 741 | |
b4ffb190 GR |
742 | mutex_lock(&wd_data->lock); |
743 | ||
744 | wdd = wd_data->wdd; | |
745 | if (!wdd) | |
746 | goto done; | |
747 | ||
017cf080 WVS |
748 | /* |
749 | * We only stop the watchdog if we received the magic character | |
7e192b9c WVS |
750 | * or if WDIOF_MAGICCLOSE is not set. If nowayout was set then |
751 | * watchdog_stop will fail. | |
017cf080 | 752 | */ |
fcf95670 HP |
753 | if (!test_bit(WDOG_ACTIVE, &wdd->status)) |
754 | err = 0; | |
b4ffb190 | 755 | else if (test_and_clear_bit(_WDOG_ALLOW_RELEASE, &wd_data->status) || |
fcf95670 | 756 | !(wdd->info->options & WDIOF_MAGICCLOSE)) |
017cf080 | 757 | err = watchdog_stop(wdd); |
43316044 | 758 | |
017cf080 | 759 | /* If the watchdog was not stopped, send a keepalive ping */ |
234445b4 | 760 | if (err < 0) { |
0254e953 | 761 | pr_crit("watchdog%d: watchdog did not stop!\n", wdd->id); |
43316044 WVS |
762 | watchdog_ping(wdd); |
763 | } | |
764 | ||
ee142889 | 765 | watchdog_update_worker(wdd); |
664a3923 | 766 | |
43316044 | 767 | /* make sure that /dev/watchdog can be re-opened */ |
b4ffb190 | 768 | clear_bit(_WDOG_DEV_OPEN, &wd_data->status); |
e907df32 | 769 | |
b4ffb190 | 770 | done: |
d1ed3ba4 | 771 | running = wdd && watchdog_hw_running(wdd); |
b4ffb190 | 772 | mutex_unlock(&wd_data->lock); |
ee142889 GR |
773 | /* |
774 | * Allow the owner module to be unloaded again unless the watchdog | |
775 | * is still running. If the watchdog is still running, it can not | |
776 | * be stopped, and its driver must not be unloaded. | |
777 | */ | |
d1ed3ba4 GR |
778 | if (!running) { |
779 | module_put(wd_data->cdev.owner); | |
ee142889 GR |
780 | kref_put(&wd_data->kref, watchdog_core_data_release); |
781 | } | |
43316044 WVS |
782 | return 0; |
783 | } | |
784 | ||
785 | static const struct file_operations watchdog_fops = { | |
786 | .owner = THIS_MODULE, | |
787 | .write = watchdog_write, | |
2fa03560 | 788 | .unlocked_ioctl = watchdog_ioctl, |
43316044 WVS |
789 | .open = watchdog_open, |
790 | .release = watchdog_release, | |
791 | }; | |
792 | ||
793 | static struct miscdevice watchdog_miscdev = { | |
794 | .minor = WATCHDOG_MINOR, | |
795 | .name = "watchdog", | |
796 | .fops = &watchdog_fops, | |
797 | }; | |
798 | ||
799 | /* | |
32ecc639 | 800 | * watchdog_cdev_register: register watchdog character device |
bc794ac3 | 801 | * @wdd: watchdog device |
32ecc639 | 802 | * @devno: character device number |
43316044 | 803 | * |
32ecc639 | 804 | * Register a watchdog character device including handling the legacy |
45f5fed3 AC |
805 | * /dev/watchdog node. /dev/watchdog is actually a miscdevice and |
806 | * thus we set it up like that. | |
43316044 WVS |
807 | */ |
808 | ||
32ecc639 | 809 | static int watchdog_cdev_register(struct watchdog_device *wdd, dev_t devno) |
43316044 | 810 | { |
b4ffb190 | 811 | struct watchdog_core_data *wd_data; |
32ecc639 | 812 | int err; |
45f5fed3 | 813 | |
b4ffb190 GR |
814 | wd_data = kzalloc(sizeof(struct watchdog_core_data), GFP_KERNEL); |
815 | if (!wd_data) | |
816 | return -ENOMEM; | |
817 | kref_init(&wd_data->kref); | |
818 | mutex_init(&wd_data->lock); | |
819 | ||
820 | wd_data->wdd = wdd; | |
821 | wdd->wd_data = wd_data; | |
822 | ||
664a3923 GR |
823 | if (!watchdog_wq) |
824 | return -ENODEV; | |
825 | ||
826 | INIT_DELAYED_WORK(&wd_data->work, watchdog_ping_work); | |
827 | ||
bc794ac3 | 828 | if (wdd->id == 0) { |
b4ffb190 | 829 | old_wd_data = wd_data; |
bc794ac3 | 830 | watchdog_miscdev.parent = wdd->parent; |
45f5fed3 AC |
831 | err = misc_register(&watchdog_miscdev); |
832 | if (err != 0) { | |
833 | pr_err("%s: cannot register miscdev on minor=%d (err=%d).\n", | |
bc794ac3 | 834 | wdd->info->identity, WATCHDOG_MINOR, err); |
45f5fed3 AC |
835 | if (err == -EBUSY) |
836 | pr_err("%s: a legacy watchdog module is probably present.\n", | |
bc794ac3 | 837 | wdd->info->identity); |
b4ffb190 GR |
838 | old_wd_data = NULL; |
839 | kfree(wd_data); | |
45f5fed3 AC |
840 | return err; |
841 | } | |
43316044 WVS |
842 | } |
843 | ||
45f5fed3 | 844 | /* Fill in the data structures */ |
b4ffb190 GR |
845 | cdev_init(&wd_data->cdev, &watchdog_fops); |
846 | wd_data->cdev.owner = wdd->ops->owner; | |
45f5fed3 AC |
847 | |
848 | /* Add the device */ | |
b4ffb190 | 849 | err = cdev_add(&wd_data->cdev, devno, 1); |
45f5fed3 AC |
850 | if (err) { |
851 | pr_err("watchdog%d unable to add device %d:%d\n", | |
bc794ac3 GR |
852 | wdd->id, MAJOR(watchdog_devt), wdd->id); |
853 | if (wdd->id == 0) { | |
45f5fed3 | 854 | misc_deregister(&watchdog_miscdev); |
b4ffb190 GR |
855 | old_wd_data = NULL; |
856 | kref_put(&wd_data->kref, watchdog_core_data_release); | |
45f5fed3 | 857 | } |
ee142889 | 858 | return err; |
43316044 | 859 | } |
ee142889 | 860 | |
15013ad8 GR |
861 | /* Record time of most recent heartbeat as 'just before now'. */ |
862 | wd_data->last_hw_keepalive = jiffies - 1; | |
863 | ||
ee142889 GR |
864 | /* |
865 | * If the watchdog is running, prevent its driver from being unloaded, | |
866 | * and schedule an immediate ping. | |
867 | */ | |
868 | if (watchdog_hw_running(wdd)) { | |
869 | __module_get(wdd->ops->owner); | |
870 | kref_get(&wd_data->kref); | |
871 | queue_delayed_work(watchdog_wq, &wd_data->work, 0); | |
872 | } | |
873 | ||
874 | return 0; | |
43316044 WVS |
875 | } |
876 | ||
877 | /* | |
32ecc639 | 878 | * watchdog_cdev_unregister: unregister watchdog character device |
43316044 WVS |
879 | * @watchdog: watchdog device |
880 | * | |
32ecc639 GR |
881 | * Unregister watchdog character device and if needed the legacy |
882 | * /dev/watchdog device. | |
43316044 WVS |
883 | */ |
884 | ||
32ecc639 | 885 | static void watchdog_cdev_unregister(struct watchdog_device *wdd) |
43316044 | 886 | { |
b4ffb190 | 887 | struct watchdog_core_data *wd_data = wdd->wd_data; |
e907df32 | 888 | |
b4ffb190 | 889 | cdev_del(&wd_data->cdev); |
bc794ac3 | 890 | if (wdd->id == 0) { |
45f5fed3 | 891 | misc_deregister(&watchdog_miscdev); |
b4ffb190 | 892 | old_wd_data = NULL; |
43316044 | 893 | } |
b4ffb190 GR |
894 | |
895 | mutex_lock(&wd_data->lock); | |
896 | wd_data->wdd = NULL; | |
897 | wdd->wd_data = NULL; | |
898 | mutex_unlock(&wd_data->lock); | |
899 | ||
664a3923 GR |
900 | cancel_delayed_work_sync(&wd_data->work); |
901 | ||
b4ffb190 | 902 | kref_put(&wd_data->kref, watchdog_core_data_release); |
43316044 | 903 | } |
45f5fed3 | 904 | |
906d7a5c PA |
905 | static struct class watchdog_class = { |
906 | .name = "watchdog", | |
907 | .owner = THIS_MODULE, | |
33b71126 | 908 | .dev_groups = wdt_groups, |
906d7a5c PA |
909 | }; |
910 | ||
32ecc639 GR |
911 | /* |
912 | * watchdog_dev_register: register a watchdog device | |
913 | * @wdd: watchdog device | |
914 | * | |
915 | * Register a watchdog device including handling the legacy | |
916 | * /dev/watchdog node. /dev/watchdog is actually a miscdevice and | |
917 | * thus we set it up like that. | |
918 | */ | |
919 | ||
920 | int watchdog_dev_register(struct watchdog_device *wdd) | |
921 | { | |
922 | struct device *dev; | |
923 | dev_t devno; | |
924 | int ret; | |
925 | ||
926 | devno = MKDEV(MAJOR(watchdog_devt), wdd->id); | |
927 | ||
928 | ret = watchdog_cdev_register(wdd, devno); | |
929 | if (ret) | |
930 | return ret; | |
931 | ||
faa58475 GR |
932 | dev = device_create_with_groups(&watchdog_class, wdd->parent, |
933 | devno, wdd, wdd->groups, | |
934 | "watchdog%d", wdd->id); | |
32ecc639 GR |
935 | if (IS_ERR(dev)) { |
936 | watchdog_cdev_unregister(wdd); | |
937 | return PTR_ERR(dev); | |
938 | } | |
32ecc639 GR |
939 | |
940 | return ret; | |
941 | } | |
942 | ||
943 | /* | |
944 | * watchdog_dev_unregister: unregister a watchdog device | |
945 | * @watchdog: watchdog device | |
946 | * | |
947 | * Unregister watchdog device and if needed the legacy | |
948 | * /dev/watchdog device. | |
949 | */ | |
950 | ||
951 | void watchdog_dev_unregister(struct watchdog_device *wdd) | |
952 | { | |
0254e953 | 953 | device_destroy(&watchdog_class, wdd->wd_data->cdev.dev); |
b4ffb190 | 954 | watchdog_cdev_unregister(wdd); |
32ecc639 GR |
955 | } |
956 | ||
45f5fed3 AC |
957 | /* |
958 | * watchdog_dev_init: init dev part of watchdog core | |
959 | * | |
960 | * Allocate a range of chardev nodes to use for watchdog devices | |
961 | */ | |
962 | ||
32ecc639 | 963 | int __init watchdog_dev_init(void) |
45f5fed3 | 964 | { |
906d7a5c PA |
965 | int err; |
966 | ||
664a3923 GR |
967 | watchdog_wq = alloc_workqueue("watchdogd", |
968 | WQ_HIGHPRI | WQ_MEM_RECLAIM, 0); | |
969 | if (!watchdog_wq) { | |
970 | pr_err("Failed to create watchdog workqueue\n"); | |
971 | return -ENOMEM; | |
972 | } | |
973 | ||
906d7a5c PA |
974 | err = class_register(&watchdog_class); |
975 | if (err < 0) { | |
976 | pr_err("couldn't register class\n"); | |
138913cb | 977 | goto err_register; |
906d7a5c PA |
978 | } |
979 | ||
980 | err = alloc_chrdev_region(&watchdog_devt, 0, MAX_DOGS, "watchdog"); | |
981 | if (err < 0) { | |
45f5fed3 | 982 | pr_err("watchdog: unable to allocate char dev region\n"); |
138913cb | 983 | goto err_alloc; |
906d7a5c PA |
984 | } |
985 | ||
32ecc639 | 986 | return 0; |
138913cb WY |
987 | |
988 | err_alloc: | |
989 | class_unregister(&watchdog_class); | |
990 | err_register: | |
991 | destroy_workqueue(watchdog_wq); | |
992 | return err; | |
45f5fed3 AC |
993 | } |
994 | ||
995 | /* | |
996 | * watchdog_dev_exit: exit dev part of watchdog core | |
997 | * | |
998 | * Release the range of chardev nodes used for watchdog devices | |
999 | */ | |
1000 | ||
1001 | void __exit watchdog_dev_exit(void) | |
1002 | { | |
1003 | unregister_chrdev_region(watchdog_devt, MAX_DOGS); | |
906d7a5c | 1004 | class_unregister(&watchdog_class); |
664a3923 | 1005 | destroy_workqueue(watchdog_wq); |
45f5fed3 | 1006 | } |