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/... */ |
b4ffb190 GR |
39 | #include <linux/kernel.h> /* For printk/panic/... */ |
40 | #include <linux/kref.h> /* For data references */ | |
41 | #include <linux/miscdevice.h> /* For handling misc devices */ | |
42 | #include <linux/module.h> /* For module stuff/... */ | |
43 | #include <linux/mutex.h> /* For mutexes */ | |
44 | #include <linux/slab.h> /* For memory functions */ | |
45 | #include <linux/types.h> /* For standard types (like size_t) */ | |
46 | #include <linux/watchdog.h> /* For watchdog specific items */ | |
43316044 WVS |
47 | #include <linux/uaccess.h> /* For copy_to_user/put_user/... */ |
48 | ||
6cfb5aa8 | 49 | #include "watchdog_core.h" |
09a46e73 | 50 | |
b4ffb190 GR |
51 | /* |
52 | * struct watchdog_core_data - watchdog core internal data | |
53 | * @kref: Reference count. | |
54 | * @cdev: The watchdog's Character device. | |
55 | * @wdd: Pointer to watchdog device. | |
56 | * @lock: Lock for watchdog core. | |
57 | * @status: Watchdog core internal status bits. | |
58 | */ | |
59 | struct watchdog_core_data { | |
60 | struct kref kref; | |
61 | struct cdev cdev; | |
62 | struct watchdog_device *wdd; | |
63 | struct mutex lock; | |
64 | unsigned long status; /* Internal status bits */ | |
65 | #define _WDOG_DEV_OPEN 0 /* Opened ? */ | |
66 | #define _WDOG_ALLOW_RELEASE 1 /* Did we receive the magic char ? */ | |
67 | }; | |
68 | ||
45f5fed3 AC |
69 | /* the dev_t structure to store the dynamically allocated watchdog devices */ |
70 | static dev_t watchdog_devt; | |
b4ffb190 GR |
71 | /* Reference to watchdog device behind /dev/watchdog */ |
72 | static struct watchdog_core_data *old_wd_data; | |
43316044 WVS |
73 | |
74 | /* | |
75 | * watchdog_ping: ping the watchdog. | |
bc794ac3 | 76 | * @wdd: the watchdog device to ping |
43316044 | 77 | * |
b4ffb190 GR |
78 | * The caller must hold wd_data->lock. |
79 | * | |
43316044 WVS |
80 | * If the watchdog has no own ping operation then it needs to be |
81 | * restarted via the start operation. This wrapper function does | |
82 | * exactly that. | |
234445b4 | 83 | * We only ping when the watchdog device is running. |
43316044 WVS |
84 | */ |
85 | ||
bc794ac3 | 86 | static int watchdog_ping(struct watchdog_device *wdd) |
43316044 | 87 | { |
b4ffb190 | 88 | int err; |
e907df32 | 89 | |
bc794ac3 | 90 | if (!watchdog_active(wdd)) |
b4ffb190 | 91 | return 0; |
7a879824 | 92 | |
bc794ac3 GR |
93 | if (wdd->ops->ping) |
94 | err = wdd->ops->ping(wdd); /* ping the watchdog */ | |
7a879824 | 95 | else |
bc794ac3 | 96 | err = wdd->ops->start(wdd); /* restart watchdog */ |
7a879824 | 97 | |
7a879824 | 98 | return err; |
234445b4 WVS |
99 | } |
100 | ||
101 | /* | |
102 | * watchdog_start: wrapper to start the watchdog. | |
bc794ac3 | 103 | * @wdd: the watchdog device to start |
234445b4 | 104 | * |
b4ffb190 GR |
105 | * The caller must hold wd_data->lock. |
106 | * | |
234445b4 WVS |
107 | * Start the watchdog if it is not active and mark it active. |
108 | * This function returns zero on success or a negative errno code for | |
109 | * failure. | |
110 | */ | |
111 | ||
bc794ac3 | 112 | static int watchdog_start(struct watchdog_device *wdd) |
234445b4 | 113 | { |
b4ffb190 | 114 | int err; |
e907df32 | 115 | |
bc794ac3 | 116 | if (watchdog_active(wdd)) |
b4ffb190 | 117 | return 0; |
234445b4 | 118 | |
bc794ac3 | 119 | err = wdd->ops->start(wdd); |
7a879824 | 120 | if (err == 0) |
bc794ac3 | 121 | set_bit(WDOG_ACTIVE, &wdd->status); |
7a879824 | 122 | |
7a879824 | 123 | return err; |
234445b4 WVS |
124 | } |
125 | ||
126 | /* | |
127 | * watchdog_stop: wrapper to stop the watchdog. | |
bc794ac3 | 128 | * @wdd: the watchdog device to stop |
234445b4 | 129 | * |
b4ffb190 GR |
130 | * The caller must hold wd_data->lock. |
131 | * | |
234445b4 WVS |
132 | * Stop the watchdog if it is still active and unmark it active. |
133 | * This function returns zero on success or a negative errno code for | |
134 | * failure. | |
7e192b9c | 135 | * If the 'nowayout' feature was set, the watchdog cannot be stopped. |
234445b4 WVS |
136 | */ |
137 | ||
bc794ac3 | 138 | static int watchdog_stop(struct watchdog_device *wdd) |
234445b4 | 139 | { |
b4ffb190 | 140 | int err; |
e907df32 | 141 | |
bc794ac3 | 142 | if (!watchdog_active(wdd)) |
b4ffb190 | 143 | return 0; |
7e192b9c | 144 | |
bc794ac3 | 145 | if (test_bit(WDOG_NO_WAY_OUT, &wdd->status)) { |
0254e953 GR |
146 | pr_info("watchdog%d: nowayout prevents watchdog being stopped!\n", |
147 | wdd->id); | |
b4ffb190 | 148 | return -EBUSY; |
7e192b9c | 149 | } |
234445b4 | 150 | |
bc794ac3 | 151 | err = wdd->ops->stop(wdd); |
7a879824 | 152 | if (err == 0) |
bc794ac3 | 153 | clear_bit(WDOG_ACTIVE, &wdd->status); |
7a879824 | 154 | |
7a879824 HG |
155 | return err; |
156 | } | |
157 | ||
158 | /* | |
159 | * watchdog_get_status: wrapper to get the watchdog status | |
bc794ac3 | 160 | * @wdd: the watchdog device to get the status from |
b4ffb190 GR |
161 | * |
162 | * The caller must hold wd_data->lock. | |
7a879824 HG |
163 | * |
164 | * Get the watchdog's status flags. | |
165 | */ | |
166 | ||
b4ffb190 | 167 | static unsigned int watchdog_get_status(struct watchdog_device *wdd) |
7a879824 | 168 | { |
bc794ac3 | 169 | if (!wdd->ops->status) |
b4ffb190 | 170 | return 0; |
7a879824 | 171 | |
b4ffb190 | 172 | return wdd->ops->status(wdd); |
7a879824 HG |
173 | } |
174 | ||
175 | /* | |
176 | * watchdog_set_timeout: set the watchdog timer timeout | |
bc794ac3 | 177 | * @wdd: the watchdog device to set the timeout for |
7a879824 | 178 | * @timeout: timeout to set in seconds |
b4ffb190 GR |
179 | * |
180 | * The caller must hold wd_data->lock. | |
7a879824 HG |
181 | */ |
182 | ||
bc794ac3 | 183 | static int watchdog_set_timeout(struct watchdog_device *wdd, |
7a879824 HG |
184 | unsigned int timeout) |
185 | { | |
bc794ac3 | 186 | if (!wdd->ops->set_timeout || !(wdd->info->options & WDIOF_SETTIMEOUT)) |
7a879824 HG |
187 | return -EOPNOTSUPP; |
188 | ||
bc794ac3 | 189 | if (watchdog_timeout_invalid(wdd, timeout)) |
7a879824 HG |
190 | return -EINVAL; |
191 | ||
b4ffb190 | 192 | return wdd->ops->set_timeout(wdd, timeout); |
7a879824 HG |
193 | } |
194 | ||
195 | /* | |
196 | * watchdog_get_timeleft: wrapper to get the time left before a reboot | |
bc794ac3 | 197 | * @wdd: the watchdog device to get the remaining time from |
7a879824 HG |
198 | * @timeleft: the time that's left |
199 | * | |
b4ffb190 GR |
200 | * The caller must hold wd_data->lock. |
201 | * | |
7a879824 HG |
202 | * Get the time before a watchdog will reboot (if not pinged). |
203 | */ | |
204 | ||
bc794ac3 | 205 | static int watchdog_get_timeleft(struct watchdog_device *wdd, |
7a879824 HG |
206 | unsigned int *timeleft) |
207 | { | |
7a879824 | 208 | *timeleft = 0; |
b4ffb190 | 209 | |
bc794ac3 | 210 | if (!wdd->ops->get_timeleft) |
7a879824 HG |
211 | return -EOPNOTSUPP; |
212 | ||
bc794ac3 | 213 | *timeleft = wdd->ops->get_timeleft(wdd); |
7a879824 | 214 | |
b4ffb190 | 215 | return 0; |
7a879824 HG |
216 | } |
217 | ||
33b71126 PA |
218 | #ifdef CONFIG_WATCHDOG_SYSFS |
219 | static ssize_t nowayout_show(struct device *dev, struct device_attribute *attr, | |
220 | char *buf) | |
221 | { | |
222 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
223 | ||
224 | return sprintf(buf, "%d\n", !!test_bit(WDOG_NO_WAY_OUT, &wdd->status)); | |
225 | } | |
226 | static DEVICE_ATTR_RO(nowayout); | |
227 | ||
228 | static ssize_t status_show(struct device *dev, struct device_attribute *attr, | |
229 | char *buf) | |
230 | { | |
231 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
b4ffb190 GR |
232 | struct watchdog_core_data *wd_data = wdd->wd_data; |
233 | unsigned int status; | |
33b71126 | 234 | |
b4ffb190 GR |
235 | mutex_lock(&wd_data->lock); |
236 | status = watchdog_get_status(wdd); | |
237 | mutex_unlock(&wd_data->lock); | |
33b71126 | 238 | |
b4ffb190 | 239 | return sprintf(buf, "%u\n", status); |
33b71126 PA |
240 | } |
241 | static DEVICE_ATTR_RO(status); | |
242 | ||
243 | static ssize_t bootstatus_show(struct device *dev, | |
244 | struct device_attribute *attr, char *buf) | |
245 | { | |
246 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
247 | ||
248 | return sprintf(buf, "%u\n", wdd->bootstatus); | |
249 | } | |
250 | static DEVICE_ATTR_RO(bootstatus); | |
251 | ||
252 | static ssize_t timeleft_show(struct device *dev, struct device_attribute *attr, | |
253 | char *buf) | |
254 | { | |
255 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
b4ffb190 | 256 | struct watchdog_core_data *wd_data = wdd->wd_data; |
33b71126 PA |
257 | ssize_t status; |
258 | unsigned int val; | |
259 | ||
b4ffb190 | 260 | mutex_lock(&wd_data->lock); |
33b71126 | 261 | status = watchdog_get_timeleft(wdd, &val); |
b4ffb190 | 262 | mutex_unlock(&wd_data->lock); |
33b71126 PA |
263 | if (!status) |
264 | status = sprintf(buf, "%u\n", val); | |
265 | ||
266 | return status; | |
267 | } | |
268 | static DEVICE_ATTR_RO(timeleft); | |
269 | ||
270 | static ssize_t timeout_show(struct device *dev, struct device_attribute *attr, | |
271 | char *buf) | |
272 | { | |
273 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
274 | ||
275 | return sprintf(buf, "%u\n", wdd->timeout); | |
276 | } | |
277 | static DEVICE_ATTR_RO(timeout); | |
278 | ||
279 | static ssize_t identity_show(struct device *dev, struct device_attribute *attr, | |
280 | char *buf) | |
281 | { | |
282 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
283 | ||
284 | return sprintf(buf, "%s\n", wdd->info->identity); | |
285 | } | |
286 | static DEVICE_ATTR_RO(identity); | |
287 | ||
288 | static ssize_t state_show(struct device *dev, struct device_attribute *attr, | |
289 | char *buf) | |
290 | { | |
291 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
292 | ||
293 | if (watchdog_active(wdd)) | |
294 | return sprintf(buf, "active\n"); | |
295 | ||
296 | return sprintf(buf, "inactive\n"); | |
297 | } | |
298 | static DEVICE_ATTR_RO(state); | |
299 | ||
300 | static umode_t wdt_is_visible(struct kobject *kobj, struct attribute *attr, | |
301 | int n) | |
302 | { | |
303 | struct device *dev = container_of(kobj, struct device, kobj); | |
304 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
305 | umode_t mode = attr->mode; | |
306 | ||
307 | if (attr == &dev_attr_status.attr && !wdd->ops->status) | |
308 | mode = 0; | |
309 | else if (attr == &dev_attr_timeleft.attr && !wdd->ops->get_timeleft) | |
310 | mode = 0; | |
311 | ||
312 | return mode; | |
313 | } | |
314 | static struct attribute *wdt_attrs[] = { | |
315 | &dev_attr_state.attr, | |
316 | &dev_attr_identity.attr, | |
317 | &dev_attr_timeout.attr, | |
318 | &dev_attr_timeleft.attr, | |
319 | &dev_attr_bootstatus.attr, | |
320 | &dev_attr_status.attr, | |
321 | &dev_attr_nowayout.attr, | |
322 | NULL, | |
323 | }; | |
324 | ||
325 | static const struct attribute_group wdt_group = { | |
326 | .attrs = wdt_attrs, | |
327 | .is_visible = wdt_is_visible, | |
328 | }; | |
329 | __ATTRIBUTE_GROUPS(wdt); | |
330 | #else | |
331 | #define wdt_groups NULL | |
332 | #endif | |
333 | ||
7a879824 HG |
334 | /* |
335 | * watchdog_ioctl_op: call the watchdog drivers ioctl op if defined | |
bc794ac3 | 336 | * @wdd: the watchdog device to do the ioctl on |
7a879824 HG |
337 | * @cmd: watchdog command |
338 | * @arg: argument pointer | |
b4ffb190 GR |
339 | * |
340 | * The caller must hold wd_data->lock. | |
7a879824 HG |
341 | */ |
342 | ||
bc794ac3 | 343 | static int watchdog_ioctl_op(struct watchdog_device *wdd, unsigned int cmd, |
7a879824 HG |
344 | unsigned long arg) |
345 | { | |
bc794ac3 | 346 | if (!wdd->ops->ioctl) |
7a879824 HG |
347 | return -ENOIOCTLCMD; |
348 | ||
b4ffb190 | 349 | return wdd->ops->ioctl(wdd, cmd, arg); |
43316044 WVS |
350 | } |
351 | ||
352 | /* | |
353 | * watchdog_write: writes to the watchdog. | |
354 | * @file: file from VFS | |
355 | * @data: user address of data | |
356 | * @len: length of data | |
357 | * @ppos: pointer to the file offset | |
358 | * | |
359 | * A write to a watchdog device is defined as a keepalive ping. | |
017cf080 | 360 | * Writing the magic 'V' sequence allows the next close to turn |
7e192b9c | 361 | * off the watchdog (if 'nowayout' is not set). |
43316044 WVS |
362 | */ |
363 | ||
364 | static ssize_t watchdog_write(struct file *file, const char __user *data, | |
365 | size_t len, loff_t *ppos) | |
366 | { | |
b4ffb190 GR |
367 | struct watchdog_core_data *wd_data = file->private_data; |
368 | struct watchdog_device *wdd; | |
369 | int err; | |
43316044 WVS |
370 | size_t i; |
371 | char c; | |
372 | ||
373 | if (len == 0) | |
374 | return 0; | |
375 | ||
017cf080 WVS |
376 | /* |
377 | * Note: just in case someone wrote the magic character | |
378 | * five months ago... | |
379 | */ | |
b4ffb190 | 380 | clear_bit(_WDOG_ALLOW_RELEASE, &wd_data->status); |
017cf080 WVS |
381 | |
382 | /* scan to see whether or not we got the magic character */ | |
43316044 WVS |
383 | for (i = 0; i != len; i++) { |
384 | if (get_user(c, data + i)) | |
385 | return -EFAULT; | |
017cf080 | 386 | if (c == 'V') |
b4ffb190 | 387 | set_bit(_WDOG_ALLOW_RELEASE, &wd_data->status); |
43316044 WVS |
388 | } |
389 | ||
390 | /* someone wrote to us, so we send the watchdog a keepalive ping */ | |
b4ffb190 GR |
391 | |
392 | err = -ENODEV; | |
393 | mutex_lock(&wd_data->lock); | |
394 | wdd = wd_data->wdd; | |
395 | if (wdd) | |
396 | err = watchdog_ping(wdd); | |
397 | mutex_unlock(&wd_data->lock); | |
398 | ||
5ef79663 AU |
399 | if (err < 0) |
400 | return err; | |
43316044 WVS |
401 | |
402 | return len; | |
403 | } | |
404 | ||
2fa03560 WVS |
405 | /* |
406 | * watchdog_ioctl: handle the different ioctl's for the watchdog device. | |
407 | * @file: file handle to the device | |
408 | * @cmd: watchdog command | |
409 | * @arg: argument pointer | |
410 | * | |
411 | * The watchdog API defines a common set of functions for all watchdogs | |
412 | * according to their available features. | |
413 | */ | |
414 | ||
415 | static long watchdog_ioctl(struct file *file, unsigned int cmd, | |
416 | unsigned long arg) | |
417 | { | |
b4ffb190 | 418 | struct watchdog_core_data *wd_data = file->private_data; |
2fa03560 | 419 | void __user *argp = (void __user *)arg; |
b4ffb190 | 420 | struct watchdog_device *wdd; |
2fa03560 WVS |
421 | int __user *p = argp; |
422 | unsigned int val; | |
234445b4 | 423 | int err; |
2fa03560 | 424 | |
b4ffb190 GR |
425 | mutex_lock(&wd_data->lock); |
426 | ||
427 | wdd = wd_data->wdd; | |
428 | if (!wdd) { | |
429 | err = -ENODEV; | |
430 | goto out_ioctl; | |
431 | } | |
432 | ||
7a879824 HG |
433 | err = watchdog_ioctl_op(wdd, cmd, arg); |
434 | if (err != -ENOIOCTLCMD) | |
b4ffb190 | 435 | goto out_ioctl; |
78d88fc0 | 436 | |
2fa03560 WVS |
437 | switch (cmd) { |
438 | case WDIOC_GETSUPPORT: | |
b4ffb190 | 439 | err = copy_to_user(argp, wdd->info, |
2fa03560 | 440 | sizeof(struct watchdog_info)) ? -EFAULT : 0; |
b4ffb190 | 441 | break; |
2fa03560 | 442 | case WDIOC_GETSTATUS: |
b4ffb190 GR |
443 | val = watchdog_get_status(wdd); |
444 | err = put_user(val, p); | |
445 | break; | |
2fa03560 | 446 | case WDIOC_GETBOOTSTATUS: |
b4ffb190 GR |
447 | err = put_user(wdd->bootstatus, p); |
448 | break; | |
234445b4 | 449 | case WDIOC_SETOPTIONS: |
b4ffb190 GR |
450 | if (get_user(val, p)) { |
451 | err = -EFAULT; | |
452 | break; | |
453 | } | |
234445b4 WVS |
454 | if (val & WDIOS_DISABLECARD) { |
455 | err = watchdog_stop(wdd); | |
456 | if (err < 0) | |
b4ffb190 | 457 | break; |
234445b4 | 458 | } |
b4ffb190 | 459 | if (val & WDIOS_ENABLECARD) |
234445b4 | 460 | err = watchdog_start(wdd); |
b4ffb190 | 461 | break; |
c2dc00e4 | 462 | case WDIOC_KEEPALIVE: |
b4ffb190 GR |
463 | if (!(wdd->info->options & WDIOF_KEEPALIVEPING)) { |
464 | err = -EOPNOTSUPP; | |
465 | break; | |
466 | } | |
467 | err = watchdog_ping(wdd); | |
468 | break; | |
014d694e | 469 | case WDIOC_SETTIMEOUT: |
b4ffb190 GR |
470 | if (get_user(val, p)) { |
471 | err = -EFAULT; | |
472 | break; | |
473 | } | |
7a879824 | 474 | err = watchdog_set_timeout(wdd, val); |
014d694e | 475 | if (err < 0) |
b4ffb190 | 476 | break; |
014d694e WVS |
477 | /* If the watchdog is active then we send a keepalive ping |
478 | * to make sure that the watchdog keep's running (and if | |
479 | * possible that it takes the new timeout) */ | |
5ef79663 AU |
480 | err = watchdog_ping(wdd); |
481 | if (err < 0) | |
b4ffb190 | 482 | break; |
014d694e WVS |
483 | /* Fall */ |
484 | case WDIOC_GETTIMEOUT: | |
485 | /* timeout == 0 means that we don't know the timeout */ | |
b4ffb190 GR |
486 | if (wdd->timeout == 0) { |
487 | err = -EOPNOTSUPP; | |
488 | break; | |
489 | } | |
490 | err = put_user(wdd->timeout, p); | |
491 | break; | |
fd7b673c | 492 | case WDIOC_GETTIMELEFT: |
7a879824 | 493 | err = watchdog_get_timeleft(wdd, &val); |
b4ffb190 GR |
494 | if (err < 0) |
495 | break; | |
496 | err = put_user(val, p); | |
497 | break; | |
2fa03560 | 498 | default: |
b4ffb190 GR |
499 | err = -ENOTTY; |
500 | break; | |
2fa03560 | 501 | } |
b4ffb190 GR |
502 | |
503 | out_ioctl: | |
504 | mutex_unlock(&wd_data->lock); | |
505 | return err; | |
2fa03560 WVS |
506 | } |
507 | ||
43316044 | 508 | /* |
45f5fed3 | 509 | * watchdog_open: open the /dev/watchdog* devices. |
43316044 WVS |
510 | * @inode: inode of device |
511 | * @file: file handle to device | |
512 | * | |
45f5fed3 | 513 | * When the /dev/watchdog* device gets opened, we start the watchdog. |
43316044 WVS |
514 | * Watch out: the /dev/watchdog device is single open, so we make sure |
515 | * it can only be opened once. | |
516 | */ | |
517 | ||
518 | static int watchdog_open(struct inode *inode, struct file *file) | |
519 | { | |
b4ffb190 | 520 | struct watchdog_core_data *wd_data; |
45f5fed3 | 521 | struct watchdog_device *wdd; |
b4ffb190 | 522 | int err; |
45f5fed3 AC |
523 | |
524 | /* Get the corresponding watchdog device */ | |
525 | if (imajor(inode) == MISC_MAJOR) | |
b4ffb190 | 526 | wd_data = old_wd_data; |
45f5fed3 | 527 | else |
b4ffb190 GR |
528 | wd_data = container_of(inode->i_cdev, struct watchdog_core_data, |
529 | cdev); | |
43316044 WVS |
530 | |
531 | /* the watchdog is single open! */ | |
b4ffb190 | 532 | if (test_and_set_bit(_WDOG_DEV_OPEN, &wd_data->status)) |
43316044 WVS |
533 | return -EBUSY; |
534 | ||
b4ffb190 GR |
535 | wdd = wd_data->wdd; |
536 | ||
43316044 WVS |
537 | /* |
538 | * If the /dev/watchdog device is open, we don't want the module | |
539 | * to be unloaded. | |
540 | */ | |
b4ffb190 GR |
541 | if (!try_module_get(wdd->ops->owner)) { |
542 | err = -EBUSY; | |
543 | goto out_clear; | |
544 | } | |
43316044 | 545 | |
234445b4 | 546 | err = watchdog_start(wdd); |
43316044 WVS |
547 | if (err < 0) |
548 | goto out_mod; | |
549 | ||
b4ffb190 | 550 | file->private_data = wd_data; |
45f5fed3 | 551 | |
b4ffb190 | 552 | kref_get(&wd_data->kref); |
e907df32 | 553 | |
43316044 WVS |
554 | /* dev/watchdog is a virtual (and thus non-seekable) filesystem */ |
555 | return nonseekable_open(inode, file); | |
556 | ||
557 | out_mod: | |
b4ffb190 GR |
558 | module_put(wd_data->wdd->ops->owner); |
559 | out_clear: | |
560 | clear_bit(_WDOG_DEV_OPEN, &wd_data->status); | |
43316044 WVS |
561 | return err; |
562 | } | |
563 | ||
b4ffb190 GR |
564 | static void watchdog_core_data_release(struct kref *kref) |
565 | { | |
566 | struct watchdog_core_data *wd_data; | |
567 | ||
568 | wd_data = container_of(kref, struct watchdog_core_data, kref); | |
569 | ||
570 | kfree(wd_data); | |
571 | } | |
572 | ||
43316044 | 573 | /* |
45f5fed3 AC |
574 | * watchdog_release: release the watchdog device. |
575 | * @inode: inode of device | |
576 | * @file: file handle to device | |
43316044 | 577 | * |
017cf080 | 578 | * This is the code for when /dev/watchdog gets closed. We will only |
7e192b9c WVS |
579 | * stop the watchdog when we have received the magic char (and nowayout |
580 | * was not set), else the watchdog will keep running. | |
43316044 WVS |
581 | */ |
582 | ||
583 | static int watchdog_release(struct inode *inode, struct file *file) | |
584 | { | |
b4ffb190 GR |
585 | struct watchdog_core_data *wd_data = file->private_data; |
586 | struct watchdog_device *wdd; | |
017cf080 WVS |
587 | int err = -EBUSY; |
588 | ||
b4ffb190 GR |
589 | mutex_lock(&wd_data->lock); |
590 | ||
591 | wdd = wd_data->wdd; | |
592 | if (!wdd) | |
593 | goto done; | |
594 | ||
017cf080 WVS |
595 | /* |
596 | * We only stop the watchdog if we received the magic character | |
7e192b9c WVS |
597 | * or if WDIOF_MAGICCLOSE is not set. If nowayout was set then |
598 | * watchdog_stop will fail. | |
017cf080 | 599 | */ |
fcf95670 HP |
600 | if (!test_bit(WDOG_ACTIVE, &wdd->status)) |
601 | err = 0; | |
b4ffb190 | 602 | else if (test_and_clear_bit(_WDOG_ALLOW_RELEASE, &wd_data->status) || |
fcf95670 | 603 | !(wdd->info->options & WDIOF_MAGICCLOSE)) |
017cf080 | 604 | err = watchdog_stop(wdd); |
43316044 | 605 | |
017cf080 | 606 | /* If the watchdog was not stopped, send a keepalive ping */ |
234445b4 | 607 | if (err < 0) { |
0254e953 | 608 | pr_crit("watchdog%d: watchdog did not stop!\n", wdd->id); |
43316044 WVS |
609 | watchdog_ping(wdd); |
610 | } | |
611 | ||
43316044 | 612 | /* make sure that /dev/watchdog can be re-opened */ |
b4ffb190 | 613 | clear_bit(_WDOG_DEV_OPEN, &wd_data->status); |
e907df32 | 614 | |
b4ffb190 GR |
615 | done: |
616 | mutex_unlock(&wd_data->lock); | |
617 | /* Allow the owner module to be unloaded again */ | |
618 | module_put(wd_data->cdev.owner); | |
619 | kref_put(&wd_data->kref, watchdog_core_data_release); | |
43316044 WVS |
620 | return 0; |
621 | } | |
622 | ||
623 | static const struct file_operations watchdog_fops = { | |
624 | .owner = THIS_MODULE, | |
625 | .write = watchdog_write, | |
2fa03560 | 626 | .unlocked_ioctl = watchdog_ioctl, |
43316044 WVS |
627 | .open = watchdog_open, |
628 | .release = watchdog_release, | |
629 | }; | |
630 | ||
631 | static struct miscdevice watchdog_miscdev = { | |
632 | .minor = WATCHDOG_MINOR, | |
633 | .name = "watchdog", | |
634 | .fops = &watchdog_fops, | |
635 | }; | |
636 | ||
637 | /* | |
32ecc639 | 638 | * watchdog_cdev_register: register watchdog character device |
bc794ac3 | 639 | * @wdd: watchdog device |
32ecc639 | 640 | * @devno: character device number |
43316044 | 641 | * |
32ecc639 | 642 | * Register a watchdog character device including handling the legacy |
45f5fed3 AC |
643 | * /dev/watchdog node. /dev/watchdog is actually a miscdevice and |
644 | * thus we set it up like that. | |
43316044 WVS |
645 | */ |
646 | ||
32ecc639 | 647 | static int watchdog_cdev_register(struct watchdog_device *wdd, dev_t devno) |
43316044 | 648 | { |
b4ffb190 | 649 | struct watchdog_core_data *wd_data; |
32ecc639 | 650 | int err; |
45f5fed3 | 651 | |
b4ffb190 GR |
652 | wd_data = kzalloc(sizeof(struct watchdog_core_data), GFP_KERNEL); |
653 | if (!wd_data) | |
654 | return -ENOMEM; | |
655 | kref_init(&wd_data->kref); | |
656 | mutex_init(&wd_data->lock); | |
657 | ||
658 | wd_data->wdd = wdd; | |
659 | wdd->wd_data = wd_data; | |
660 | ||
bc794ac3 | 661 | if (wdd->id == 0) { |
b4ffb190 | 662 | old_wd_data = wd_data; |
bc794ac3 | 663 | watchdog_miscdev.parent = wdd->parent; |
45f5fed3 AC |
664 | err = misc_register(&watchdog_miscdev); |
665 | if (err != 0) { | |
666 | pr_err("%s: cannot register miscdev on minor=%d (err=%d).\n", | |
bc794ac3 | 667 | wdd->info->identity, WATCHDOG_MINOR, err); |
45f5fed3 AC |
668 | if (err == -EBUSY) |
669 | pr_err("%s: a legacy watchdog module is probably present.\n", | |
bc794ac3 | 670 | wdd->info->identity); |
b4ffb190 GR |
671 | old_wd_data = NULL; |
672 | kfree(wd_data); | |
45f5fed3 AC |
673 | return err; |
674 | } | |
43316044 WVS |
675 | } |
676 | ||
45f5fed3 | 677 | /* Fill in the data structures */ |
b4ffb190 GR |
678 | cdev_init(&wd_data->cdev, &watchdog_fops); |
679 | wd_data->cdev.owner = wdd->ops->owner; | |
45f5fed3 AC |
680 | |
681 | /* Add the device */ | |
b4ffb190 | 682 | err = cdev_add(&wd_data->cdev, devno, 1); |
45f5fed3 AC |
683 | if (err) { |
684 | pr_err("watchdog%d unable to add device %d:%d\n", | |
bc794ac3 GR |
685 | wdd->id, MAJOR(watchdog_devt), wdd->id); |
686 | if (wdd->id == 0) { | |
45f5fed3 | 687 | misc_deregister(&watchdog_miscdev); |
b4ffb190 GR |
688 | old_wd_data = NULL; |
689 | kref_put(&wd_data->kref, watchdog_core_data_release); | |
45f5fed3 | 690 | } |
43316044 | 691 | } |
43316044 WVS |
692 | return err; |
693 | } | |
694 | ||
695 | /* | |
32ecc639 | 696 | * watchdog_cdev_unregister: unregister watchdog character device |
43316044 WVS |
697 | * @watchdog: watchdog device |
698 | * | |
32ecc639 GR |
699 | * Unregister watchdog character device and if needed the legacy |
700 | * /dev/watchdog device. | |
43316044 WVS |
701 | */ |
702 | ||
32ecc639 | 703 | static void watchdog_cdev_unregister(struct watchdog_device *wdd) |
43316044 | 704 | { |
b4ffb190 | 705 | struct watchdog_core_data *wd_data = wdd->wd_data; |
e907df32 | 706 | |
b4ffb190 | 707 | cdev_del(&wd_data->cdev); |
bc794ac3 | 708 | if (wdd->id == 0) { |
45f5fed3 | 709 | misc_deregister(&watchdog_miscdev); |
b4ffb190 | 710 | old_wd_data = NULL; |
43316044 | 711 | } |
b4ffb190 GR |
712 | |
713 | mutex_lock(&wd_data->lock); | |
714 | wd_data->wdd = NULL; | |
715 | wdd->wd_data = NULL; | |
716 | mutex_unlock(&wd_data->lock); | |
717 | ||
718 | kref_put(&wd_data->kref, watchdog_core_data_release); | |
43316044 | 719 | } |
45f5fed3 | 720 | |
906d7a5c PA |
721 | static struct class watchdog_class = { |
722 | .name = "watchdog", | |
723 | .owner = THIS_MODULE, | |
33b71126 | 724 | .dev_groups = wdt_groups, |
906d7a5c PA |
725 | }; |
726 | ||
32ecc639 GR |
727 | /* |
728 | * watchdog_dev_register: register a watchdog device | |
729 | * @wdd: watchdog device | |
730 | * | |
731 | * Register a watchdog device including handling the legacy | |
732 | * /dev/watchdog node. /dev/watchdog is actually a miscdevice and | |
733 | * thus we set it up like that. | |
734 | */ | |
735 | ||
736 | int watchdog_dev_register(struct watchdog_device *wdd) | |
737 | { | |
738 | struct device *dev; | |
739 | dev_t devno; | |
740 | int ret; | |
741 | ||
742 | devno = MKDEV(MAJOR(watchdog_devt), wdd->id); | |
743 | ||
744 | ret = watchdog_cdev_register(wdd, devno); | |
745 | if (ret) | |
746 | return ret; | |
747 | ||
faa58475 GR |
748 | dev = device_create_with_groups(&watchdog_class, wdd->parent, |
749 | devno, wdd, wdd->groups, | |
750 | "watchdog%d", wdd->id); | |
32ecc639 GR |
751 | if (IS_ERR(dev)) { |
752 | watchdog_cdev_unregister(wdd); | |
753 | return PTR_ERR(dev); | |
754 | } | |
32ecc639 GR |
755 | |
756 | return ret; | |
757 | } | |
758 | ||
759 | /* | |
760 | * watchdog_dev_unregister: unregister a watchdog device | |
761 | * @watchdog: watchdog device | |
762 | * | |
763 | * Unregister watchdog device and if needed the legacy | |
764 | * /dev/watchdog device. | |
765 | */ | |
766 | ||
767 | void watchdog_dev_unregister(struct watchdog_device *wdd) | |
768 | { | |
0254e953 | 769 | device_destroy(&watchdog_class, wdd->wd_data->cdev.dev); |
b4ffb190 | 770 | watchdog_cdev_unregister(wdd); |
32ecc639 GR |
771 | } |
772 | ||
45f5fed3 AC |
773 | /* |
774 | * watchdog_dev_init: init dev part of watchdog core | |
775 | * | |
776 | * Allocate a range of chardev nodes to use for watchdog devices | |
777 | */ | |
778 | ||
32ecc639 | 779 | int __init watchdog_dev_init(void) |
45f5fed3 | 780 | { |
906d7a5c PA |
781 | int err; |
782 | ||
783 | err = class_register(&watchdog_class); | |
784 | if (err < 0) { | |
785 | pr_err("couldn't register class\n"); | |
32ecc639 | 786 | return err; |
906d7a5c PA |
787 | } |
788 | ||
789 | err = alloc_chrdev_region(&watchdog_devt, 0, MAX_DOGS, "watchdog"); | |
790 | if (err < 0) { | |
45f5fed3 | 791 | pr_err("watchdog: unable to allocate char dev region\n"); |
906d7a5c | 792 | class_unregister(&watchdog_class); |
32ecc639 | 793 | return err; |
906d7a5c PA |
794 | } |
795 | ||
32ecc639 | 796 | return 0; |
45f5fed3 AC |
797 | } |
798 | ||
799 | /* | |
800 | * watchdog_dev_exit: exit dev part of watchdog core | |
801 | * | |
802 | * Release the range of chardev nodes used for watchdog devices | |
803 | */ | |
804 | ||
805 | void __exit watchdog_dev_exit(void) | |
806 | { | |
807 | unregister_chrdev_region(watchdog_devt, MAX_DOGS); | |
906d7a5c | 808 | class_unregister(&watchdog_class); |
45f5fed3 | 809 | } |