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