blob: 32930a073a12744b6d6cf1bcc0b154effea431ab [file] [log] [blame]
Wim Van Sebroeck43316042011-07-22 18:55:18 +00001/*
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
Guenter Roeckb4ffb192015-12-25 16:01:42 -080035#include <linux/cdev.h> /* For character device */
Wim Van Sebroeck43316042011-07-22 18:55:18 +000036#include <linux/errno.h> /* For the -ENODEV/... values */
Wim Van Sebroeck43316042011-07-22 18:55:18 +000037#include <linux/fs.h> /* For file operations */
Wim Van Sebroeck43316042011-07-22 18:55:18 +000038#include <linux/init.h> /* For __init/__exit/... */
Guenter Roeck664a3922016-02-28 13:12:15 -080039#include <linux/jiffies.h> /* For timeout functions */
Guenter Roeckb4ffb192015-12-25 16:01:42 -080040#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 */
Guenter Roeck664a3922016-02-28 13:12:15 -080048#include <linux/workqueue.h> /* For workqueue */
Wim Van Sebroeck43316042011-07-22 18:55:18 +000049#include <linux/uaccess.h> /* For copy_to_user/put_user/... */
50
Wim Van Sebroeck6cfb5aa2012-05-21 15:31:06 +020051#include "watchdog_core.h"
Vladimir Zapolskiyff841362016-10-07 15:39:54 +030052#include "watchdog_pretimeout.h"
H Hartley Sweeten09a46e72012-04-20 13:28:24 -070053
Guenter Roeckb4ffb192015-12-25 16:01:42 -080054/*
55 * struct watchdog_core_data - watchdog core internal data
56 * @kref: Reference count.
57 * @cdev: The watchdog's Character device.
58 * @wdd: Pointer to watchdog device.
59 * @lock: Lock for watchdog core.
60 * @status: Watchdog core internal status bits.
61 */
62struct watchdog_core_data {
63 struct kref kref;
64 struct cdev cdev;
65 struct watchdog_device *wdd;
66 struct mutex lock;
Guenter Roeck664a3922016-02-28 13:12:15 -080067 unsigned long last_keepalive;
Guenter Roeck15013ad2016-02-28 13:12:18 -080068 unsigned long last_hw_keepalive;
Guenter Roeck664a3922016-02-28 13:12:15 -080069 struct delayed_work work;
Guenter Roeckb4ffb192015-12-25 16:01:42 -080070 unsigned long status; /* Internal status bits */
71#define _WDOG_DEV_OPEN 0 /* Opened ? */
72#define _WDOG_ALLOW_RELEASE 1 /* Did we receive the magic char ? */
Guenter Roeck90b826f2016-07-17 15:04:11 -070073#define _WDOG_KEEPALIVE 2 /* Did we receive a keepalive ? */
Guenter Roeckb4ffb192015-12-25 16:01:42 -080074};
75
Alan Cox45f5fed2012-05-10 21:48:59 +020076/* the dev_t structure to store the dynamically allocated watchdog devices */
77static dev_t watchdog_devt;
Guenter Roeckb4ffb192015-12-25 16:01:42 -080078/* Reference to watchdog device behind /dev/watchdog */
79static struct watchdog_core_data *old_wd_data;
Wim Van Sebroeck43316042011-07-22 18:55:18 +000080
Guenter Roeck664a3922016-02-28 13:12:15 -080081static struct workqueue_struct *watchdog_wq;
82
83static inline bool watchdog_need_worker(struct watchdog_device *wdd)
84{
85 /* All variables in milli-seconds */
86 unsigned int hm = wdd->max_hw_heartbeat_ms;
87 unsigned int t = wdd->timeout * 1000;
88
89 /*
90 * A worker to generate heartbeat requests is needed if all of the
91 * following conditions are true.
92 * - Userspace activated the watchdog.
93 * - The driver provided a value for the maximum hardware timeout, and
94 * thus is aware that the framework supports generating heartbeat
95 * requests.
96 * - Userspace requests a longer timeout than the hardware can handle.
Rasmus Villemoes3fbfe922016-07-14 11:16:26 +020097 *
98 * Alternatively, if userspace has not opened the watchdog
99 * device, we take care of feeding the watchdog if it is
100 * running.
Guenter Roeck664a3922016-02-28 13:12:15 -0800101 */
Rasmus Villemoes3fbfe922016-07-14 11:16:26 +0200102 return (hm && watchdog_active(wdd) && t > hm) ||
103 (t && !watchdog_active(wdd) && watchdog_hw_running(wdd));
Guenter Roeck664a3922016-02-28 13:12:15 -0800104}
105
106static long watchdog_next_keepalive(struct watchdog_device *wdd)
107{
108 struct watchdog_core_data *wd_data = wdd->wd_data;
109 unsigned int timeout_ms = wdd->timeout * 1000;
110 unsigned long keepalive_interval;
111 unsigned long last_heartbeat;
112 unsigned long virt_timeout;
113 unsigned int hw_heartbeat_ms;
114
115 virt_timeout = wd_data->last_keepalive + msecs_to_jiffies(timeout_ms);
Rasmus Villemoes3fbfe922016-07-14 11:16:26 +0200116 hw_heartbeat_ms = min_not_zero(timeout_ms, wdd->max_hw_heartbeat_ms);
Guenter Roeck664a3922016-02-28 13:12:15 -0800117 keepalive_interval = msecs_to_jiffies(hw_heartbeat_ms / 2);
118
Guenter Roeckee142882016-02-28 13:12:16 -0800119 if (!watchdog_active(wdd))
120 return keepalive_interval;
121
Guenter Roeck664a3922016-02-28 13:12:15 -0800122 /*
123 * To ensure that the watchdog times out wdd->timeout seconds
124 * after the most recent ping from userspace, the last
125 * worker ping has to come in hw_heartbeat_ms before this timeout.
126 */
127 last_heartbeat = virt_timeout - msecs_to_jiffies(hw_heartbeat_ms);
128 return min_t(long, last_heartbeat - jiffies, keepalive_interval);
129}
130
131static inline void watchdog_update_worker(struct watchdog_device *wdd)
132{
133 struct watchdog_core_data *wd_data = wdd->wd_data;
134
135 if (watchdog_need_worker(wdd)) {
136 long t = watchdog_next_keepalive(wdd);
137
138 if (t > 0)
139 mod_delayed_work(watchdog_wq, &wd_data->work, t);
140 } else {
141 cancel_delayed_work(&wd_data->work);
142 }
143}
144
145static int __watchdog_ping(struct watchdog_device *wdd)
146{
Guenter Roeck15013ad2016-02-28 13:12:18 -0800147 struct watchdog_core_data *wd_data = wdd->wd_data;
148 unsigned long earliest_keepalive = wd_data->last_hw_keepalive +
149 msecs_to_jiffies(wdd->min_hw_heartbeat_ms);
Guenter Roeck664a3922016-02-28 13:12:15 -0800150 int err;
151
Guenter Roeck15013ad2016-02-28 13:12:18 -0800152 if (time_is_after_jiffies(earliest_keepalive)) {
153 mod_delayed_work(watchdog_wq, &wd_data->work,
154 earliest_keepalive - jiffies);
155 return 0;
156 }
157
158 wd_data->last_hw_keepalive = jiffies;
159
Guenter Roeck664a3922016-02-28 13:12:15 -0800160 if (wdd->ops->ping)
161 err = wdd->ops->ping(wdd); /* ping the watchdog */
162 else
163 err = wdd->ops->start(wdd); /* restart watchdog */
164
165 watchdog_update_worker(wdd);
166
167 return err;
168}
169
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000170/*
171 * watchdog_ping: ping the watchdog.
Guenter Roeckbc794ac2015-09-29 01:27:25 -0700172 * @wdd: the watchdog device to ping
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000173 *
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800174 * The caller must hold wd_data->lock.
175 *
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000176 * If the watchdog has no own ping operation then it needs to be
177 * restarted via the start operation. This wrapper function does
178 * exactly that.
Wim Van Sebroeck234445b2011-07-22 18:57:55 +0000179 * We only ping when the watchdog device is running.
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000180 */
181
Guenter Roeckbc794ac2015-09-29 01:27:25 -0700182static int watchdog_ping(struct watchdog_device *wdd)
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000183{
Guenter Roeck664a3922016-02-28 13:12:15 -0800184 struct watchdog_core_data *wd_data = wdd->wd_data;
Hans de Goedee907df32012-05-22 11:40:26 +0200185
Guenter Roeckee142882016-02-28 13:12:16 -0800186 if (!watchdog_active(wdd) && !watchdog_hw_running(wdd))
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800187 return 0;
Hans de Goede7a879822012-05-22 11:40:26 +0200188
Guenter Roeck90b826f2016-07-17 15:04:11 -0700189 set_bit(_WDOG_KEEPALIVE, &wd_data->status);
190
Guenter Roeck664a3922016-02-28 13:12:15 -0800191 wd_data->last_keepalive = jiffies;
192 return __watchdog_ping(wdd);
193}
Hans de Goede7a879822012-05-22 11:40:26 +0200194
Guenter Roeck664a3922016-02-28 13:12:15 -0800195static void watchdog_ping_work(struct work_struct *work)
196{
197 struct watchdog_core_data *wd_data;
198 struct watchdog_device *wdd;
199
200 wd_data = container_of(to_delayed_work(work), struct watchdog_core_data,
201 work);
202
203 mutex_lock(&wd_data->lock);
204 wdd = wd_data->wdd;
Guenter Roeckee142882016-02-28 13:12:16 -0800205 if (wdd && (watchdog_active(wdd) || watchdog_hw_running(wdd)))
Guenter Roeck664a3922016-02-28 13:12:15 -0800206 __watchdog_ping(wdd);
207 mutex_unlock(&wd_data->lock);
Wim Van Sebroeck234445b2011-07-22 18:57:55 +0000208}
209
210/*
211 * watchdog_start: wrapper to start the watchdog.
Guenter Roeckbc794ac2015-09-29 01:27:25 -0700212 * @wdd: the watchdog device to start
Wim Van Sebroeck234445b2011-07-22 18:57:55 +0000213 *
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800214 * The caller must hold wd_data->lock.
215 *
Wim Van Sebroeck234445b2011-07-22 18:57:55 +0000216 * Start the watchdog if it is not active and mark it active.
217 * This function returns zero on success or a negative errno code for
218 * failure.
219 */
220
Guenter Roeckbc794ac2015-09-29 01:27:25 -0700221static int watchdog_start(struct watchdog_device *wdd)
Wim Van Sebroeck234445b2011-07-22 18:57:55 +0000222{
Guenter Roeck664a3922016-02-28 13:12:15 -0800223 struct watchdog_core_data *wd_data = wdd->wd_data;
224 unsigned long started_at;
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800225 int err;
Hans de Goedee907df32012-05-22 11:40:26 +0200226
Guenter Roeckbc794ac2015-09-29 01:27:25 -0700227 if (watchdog_active(wdd))
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800228 return 0;
Wim Van Sebroeck234445b2011-07-22 18:57:55 +0000229
Guenter Roeck90b826f2016-07-17 15:04:11 -0700230 set_bit(_WDOG_KEEPALIVE, &wd_data->status);
231
Guenter Roeck664a3922016-02-28 13:12:15 -0800232 started_at = jiffies;
Guenter Roeckee142882016-02-28 13:12:16 -0800233 if (watchdog_hw_running(wdd) && wdd->ops->ping)
234 err = wdd->ops->ping(wdd);
235 else
236 err = wdd->ops->start(wdd);
Guenter Roeck664a3922016-02-28 13:12:15 -0800237 if (err == 0) {
Guenter Roeckbc794ac2015-09-29 01:27:25 -0700238 set_bit(WDOG_ACTIVE, &wdd->status);
Guenter Roeck664a3922016-02-28 13:12:15 -0800239 wd_data->last_keepalive = started_at;
240 watchdog_update_worker(wdd);
241 }
Hans de Goede7a879822012-05-22 11:40:26 +0200242
Hans de Goede7a879822012-05-22 11:40:26 +0200243 return err;
Wim Van Sebroeck234445b2011-07-22 18:57:55 +0000244}
245
246/*
247 * watchdog_stop: wrapper to stop the watchdog.
Guenter Roeckbc794ac2015-09-29 01:27:25 -0700248 * @wdd: the watchdog device to stop
Wim Van Sebroeck234445b2011-07-22 18:57:55 +0000249 *
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800250 * The caller must hold wd_data->lock.
251 *
Wim Van Sebroeck234445b2011-07-22 18:57:55 +0000252 * Stop the watchdog if it is still active and unmark it active.
253 * This function returns zero on success or a negative errno code for
254 * failure.
Wim Van Sebroeck7e192b92011-07-22 18:59:17 +0000255 * If the 'nowayout' feature was set, the watchdog cannot be stopped.
Wim Van Sebroeck234445b2011-07-22 18:57:55 +0000256 */
257
Guenter Roeckbc794ac2015-09-29 01:27:25 -0700258static int watchdog_stop(struct watchdog_device *wdd)
Wim Van Sebroeck234445b2011-07-22 18:57:55 +0000259{
Guenter Roeckee142882016-02-28 13:12:16 -0800260 int err = 0;
Hans de Goedee907df32012-05-22 11:40:26 +0200261
Guenter Roeckbc794ac2015-09-29 01:27:25 -0700262 if (!watchdog_active(wdd))
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800263 return 0;
Wim Van Sebroeck7e192b92011-07-22 18:59:17 +0000264
Guenter Roeckbc794ac2015-09-29 01:27:25 -0700265 if (test_bit(WDOG_NO_WAY_OUT, &wdd->status)) {
Guenter Roeck0254e952016-01-03 15:11:58 -0800266 pr_info("watchdog%d: nowayout prevents watchdog being stopped!\n",
267 wdd->id);
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800268 return -EBUSY;
Wim Van Sebroeck7e192b92011-07-22 18:59:17 +0000269 }
Wim Van Sebroeck234445b2011-07-22 18:57:55 +0000270
Guenter Roeck3c10bbd2016-07-21 14:21:56 -0700271 if (wdd->ops->stop) {
272 clear_bit(WDOG_HW_RUNNING, &wdd->status);
Guenter Roeckd0684c82016-02-28 13:12:17 -0800273 err = wdd->ops->stop(wdd);
Guenter Roeck3c10bbd2016-07-21 14:21:56 -0700274 } else {
Guenter Roeckd0684c82016-02-28 13:12:17 -0800275 set_bit(WDOG_HW_RUNNING, &wdd->status);
Guenter Roeck3c10bbd2016-07-21 14:21:56 -0700276 }
Guenter Roeckd0684c82016-02-28 13:12:17 -0800277
Guenter Roeck664a3922016-02-28 13:12:15 -0800278 if (err == 0) {
Guenter Roeckbc794ac2015-09-29 01:27:25 -0700279 clear_bit(WDOG_ACTIVE, &wdd->status);
Guenter Roeckee142882016-02-28 13:12:16 -0800280 watchdog_update_worker(wdd);
Guenter Roeck664a3922016-02-28 13:12:15 -0800281 }
Hans de Goede7a879822012-05-22 11:40:26 +0200282
Hans de Goede7a879822012-05-22 11:40:26 +0200283 return err;
284}
285
286/*
287 * watchdog_get_status: wrapper to get the watchdog status
Guenter Roeckbc794ac2015-09-29 01:27:25 -0700288 * @wdd: the watchdog device to get the status from
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800289 *
290 * The caller must hold wd_data->lock.
Hans de Goede7a879822012-05-22 11:40:26 +0200291 *
292 * Get the watchdog's status flags.
293 */
294
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800295static unsigned int watchdog_get_status(struct watchdog_device *wdd)
Hans de Goede7a879822012-05-22 11:40:26 +0200296{
Guenter Roeck90b826f2016-07-17 15:04:11 -0700297 struct watchdog_core_data *wd_data = wdd->wd_data;
298 unsigned int status;
Hans de Goede7a879822012-05-22 11:40:26 +0200299
Guenter Roeck90b826f2016-07-17 15:04:11 -0700300 if (wdd->ops->status)
301 status = wdd->ops->status(wdd);
302 else
303 status = wdd->bootstatus & (WDIOF_CARDRESET |
304 WDIOF_OVERHEAT |
305 WDIOF_FANFAULT |
306 WDIOF_EXTERN1 |
307 WDIOF_EXTERN2 |
308 WDIOF_POWERUNDER |
309 WDIOF_POWEROVER);
310
311 if (test_bit(_WDOG_ALLOW_RELEASE, &wd_data->status))
312 status |= WDIOF_MAGICCLOSE;
313
314 if (test_and_clear_bit(_WDOG_KEEPALIVE, &wd_data->status))
315 status |= WDIOF_KEEPALIVEPING;
316
317 return status;
Hans de Goede7a879822012-05-22 11:40:26 +0200318}
319
320/*
321 * watchdog_set_timeout: set the watchdog timer timeout
Guenter Roeckbc794ac2015-09-29 01:27:25 -0700322 * @wdd: the watchdog device to set the timeout for
Hans de Goede7a879822012-05-22 11:40:26 +0200323 * @timeout: timeout to set in seconds
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800324 *
325 * The caller must hold wd_data->lock.
Hans de Goede7a879822012-05-22 11:40:26 +0200326 */
327
Guenter Roeckbc794ac2015-09-29 01:27:25 -0700328static int watchdog_set_timeout(struct watchdog_device *wdd,
Hans de Goede7a879822012-05-22 11:40:26 +0200329 unsigned int timeout)
330{
Guenter Roeckfb32e9b2016-02-28 13:12:14 -0800331 int err = 0;
332
333 if (!(wdd->info->options & WDIOF_SETTIMEOUT))
Hans de Goede7a879822012-05-22 11:40:26 +0200334 return -EOPNOTSUPP;
335
Guenter Roeckbc794ac2015-09-29 01:27:25 -0700336 if (watchdog_timeout_invalid(wdd, timeout))
Hans de Goede7a879822012-05-22 11:40:26 +0200337 return -EINVAL;
338
Wolfram Sangdf044e02016-08-31 14:52:41 +0300339 if (wdd->ops->set_timeout) {
Guenter Roeckfb32e9b2016-02-28 13:12:14 -0800340 err = wdd->ops->set_timeout(wdd, timeout);
Wolfram Sangdf044e02016-08-31 14:52:41 +0300341 } else {
Guenter Roeckfb32e9b2016-02-28 13:12:14 -0800342 wdd->timeout = timeout;
Wolfram Sangdf044e02016-08-31 14:52:41 +0300343 /* Disable pretimeout if it doesn't fit the new timeout */
344 if (wdd->pretimeout >= wdd->timeout)
345 wdd->pretimeout = 0;
346 }
Guenter Roeckfb32e9b2016-02-28 13:12:14 -0800347
Guenter Roeck664a3922016-02-28 13:12:15 -0800348 watchdog_update_worker(wdd);
349
Guenter Roeckfb32e9b2016-02-28 13:12:14 -0800350 return err;
Hans de Goede7a879822012-05-22 11:40:26 +0200351}
352
353/*
Wolfram Sangdf044e02016-08-31 14:52:41 +0300354 * watchdog_set_pretimeout: set the watchdog timer pretimeout
355 * @wdd: the watchdog device to set the timeout for
356 * @timeout: pretimeout to set in seconds
357 */
358
359static int watchdog_set_pretimeout(struct watchdog_device *wdd,
360 unsigned int timeout)
361{
362 int err = 0;
363
364 if (!(wdd->info->options & WDIOF_PRETIMEOUT))
365 return -EOPNOTSUPP;
366
367 if (watchdog_pretimeout_invalid(wdd, timeout))
368 return -EINVAL;
369
370 if (wdd->ops->set_pretimeout)
371 err = wdd->ops->set_pretimeout(wdd, timeout);
372 else
373 wdd->pretimeout = timeout;
374
375 return err;
376}
377
378/*
Hans de Goede7a879822012-05-22 11:40:26 +0200379 * watchdog_get_timeleft: wrapper to get the time left before a reboot
Guenter Roeckbc794ac2015-09-29 01:27:25 -0700380 * @wdd: the watchdog device to get the remaining time from
Hans de Goede7a879822012-05-22 11:40:26 +0200381 * @timeleft: the time that's left
382 *
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800383 * The caller must hold wd_data->lock.
384 *
Hans de Goede7a879822012-05-22 11:40:26 +0200385 * Get the time before a watchdog will reboot (if not pinged).
386 */
387
Guenter Roeckbc794ac2015-09-29 01:27:25 -0700388static int watchdog_get_timeleft(struct watchdog_device *wdd,
Hans de Goede7a879822012-05-22 11:40:26 +0200389 unsigned int *timeleft)
390{
Hans de Goede7a879822012-05-22 11:40:26 +0200391 *timeleft = 0;
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800392
Guenter Roeckbc794ac2015-09-29 01:27:25 -0700393 if (!wdd->ops->get_timeleft)
Hans de Goede7a879822012-05-22 11:40:26 +0200394 return -EOPNOTSUPP;
395
Guenter Roeckbc794ac2015-09-29 01:27:25 -0700396 *timeleft = wdd->ops->get_timeleft(wdd);
Hans de Goede7a879822012-05-22 11:40:26 +0200397
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800398 return 0;
Hans de Goede7a879822012-05-22 11:40:26 +0200399}
400
Pratyush Anand33b71122015-12-17 17:53:59 +0530401#ifdef CONFIG_WATCHDOG_SYSFS
402static ssize_t nowayout_show(struct device *dev, struct device_attribute *attr,
403 char *buf)
404{
405 struct watchdog_device *wdd = dev_get_drvdata(dev);
406
407 return sprintf(buf, "%d\n", !!test_bit(WDOG_NO_WAY_OUT, &wdd->status));
408}
409static DEVICE_ATTR_RO(nowayout);
410
411static ssize_t status_show(struct device *dev, struct device_attribute *attr,
412 char *buf)
413{
414 struct watchdog_device *wdd = dev_get_drvdata(dev);
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800415 struct watchdog_core_data *wd_data = wdd->wd_data;
416 unsigned int status;
Pratyush Anand33b71122015-12-17 17:53:59 +0530417
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800418 mutex_lock(&wd_data->lock);
419 status = watchdog_get_status(wdd);
420 mutex_unlock(&wd_data->lock);
Pratyush Anand33b71122015-12-17 17:53:59 +0530421
Guenter Roeck90b826f2016-07-17 15:04:11 -0700422 return sprintf(buf, "0x%x\n", status);
Pratyush Anand33b71122015-12-17 17:53:59 +0530423}
424static DEVICE_ATTR_RO(status);
425
426static ssize_t bootstatus_show(struct device *dev,
427 struct device_attribute *attr, char *buf)
428{
429 struct watchdog_device *wdd = dev_get_drvdata(dev);
430
431 return sprintf(buf, "%u\n", wdd->bootstatus);
432}
433static DEVICE_ATTR_RO(bootstatus);
434
435static ssize_t timeleft_show(struct device *dev, struct device_attribute *attr,
436 char *buf)
437{
438 struct watchdog_device *wdd = dev_get_drvdata(dev);
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800439 struct watchdog_core_data *wd_data = wdd->wd_data;
Pratyush Anand33b71122015-12-17 17:53:59 +0530440 ssize_t status;
441 unsigned int val;
442
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800443 mutex_lock(&wd_data->lock);
Pratyush Anand33b71122015-12-17 17:53:59 +0530444 status = watchdog_get_timeleft(wdd, &val);
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800445 mutex_unlock(&wd_data->lock);
Pratyush Anand33b71122015-12-17 17:53:59 +0530446 if (!status)
447 status = sprintf(buf, "%u\n", val);
448
449 return status;
450}
451static DEVICE_ATTR_RO(timeleft);
452
453static ssize_t timeout_show(struct device *dev, struct device_attribute *attr,
454 char *buf)
455{
456 struct watchdog_device *wdd = dev_get_drvdata(dev);
457
458 return sprintf(buf, "%u\n", wdd->timeout);
459}
460static DEVICE_ATTR_RO(timeout);
461
Wolfram Sangdf044e02016-08-31 14:52:41 +0300462static ssize_t pretimeout_show(struct device *dev,
463 struct device_attribute *attr, char *buf)
464{
465 struct watchdog_device *wdd = dev_get_drvdata(dev);
466
467 return sprintf(buf, "%u\n", wdd->pretimeout);
468}
469static DEVICE_ATTR_RO(pretimeout);
470
Pratyush Anand33b71122015-12-17 17:53:59 +0530471static ssize_t identity_show(struct device *dev, struct device_attribute *attr,
472 char *buf)
473{
474 struct watchdog_device *wdd = dev_get_drvdata(dev);
475
476 return sprintf(buf, "%s\n", wdd->info->identity);
477}
478static DEVICE_ATTR_RO(identity);
479
480static ssize_t state_show(struct device *dev, struct device_attribute *attr,
481 char *buf)
482{
483 struct watchdog_device *wdd = dev_get_drvdata(dev);
484
485 if (watchdog_active(wdd))
486 return sprintf(buf, "active\n");
487
488 return sprintf(buf, "inactive\n");
489}
490static DEVICE_ATTR_RO(state);
491
Vladimir Zapolskiy89873a72016-10-07 15:39:57 +0300492static ssize_t pretimeout_available_governors_show(struct device *dev,
493 struct device_attribute *attr, char *buf)
494{
495 return watchdog_pretimeout_available_governors_get(buf);
496}
497static DEVICE_ATTR_RO(pretimeout_available_governors);
498
Vladimir Zapolskiyff841362016-10-07 15:39:54 +0300499static ssize_t pretimeout_governor_show(struct device *dev,
500 struct device_attribute *attr,
501 char *buf)
502{
503 struct watchdog_device *wdd = dev_get_drvdata(dev);
504
505 return watchdog_pretimeout_governor_get(wdd, buf);
506}
Vladimir Zapolskiy53f96ce2016-10-07 15:37:00 +0300507
508static ssize_t pretimeout_governor_store(struct device *dev,
509 struct device_attribute *attr,
510 const char *buf, size_t count)
511{
512 struct watchdog_device *wdd = dev_get_drvdata(dev);
513 int ret = watchdog_pretimeout_governor_set(wdd, buf);
514
515 if (!ret)
516 ret = count;
517
518 return ret;
519}
520static DEVICE_ATTR_RW(pretimeout_governor);
Vladimir Zapolskiyff841362016-10-07 15:39:54 +0300521
Pratyush Anand33b71122015-12-17 17:53:59 +0530522static umode_t wdt_is_visible(struct kobject *kobj, struct attribute *attr,
523 int n)
524{
525 struct device *dev = container_of(kobj, struct device, kobj);
526 struct watchdog_device *wdd = dev_get_drvdata(dev);
527 umode_t mode = attr->mode;
528
Guenter Roeck90b826f2016-07-17 15:04:11 -0700529 if (attr == &dev_attr_timeleft.attr && !wdd->ops->get_timeleft)
Pratyush Anand33b71122015-12-17 17:53:59 +0530530 mode = 0;
Wolfram Sangdf044e02016-08-31 14:52:41 +0300531 else if (attr == &dev_attr_pretimeout.attr &&
532 !(wdd->info->options & WDIOF_PRETIMEOUT))
533 mode = 0;
Vladimir Zapolskiy89873a72016-10-07 15:39:57 +0300534 else if ((attr == &dev_attr_pretimeout_governor.attr ||
535 attr == &dev_attr_pretimeout_available_governors.attr) &&
Vladimir Zapolskiyff841362016-10-07 15:39:54 +0300536 (!(wdd->info->options & WDIOF_PRETIMEOUT) ||
537 !IS_ENABLED(CONFIG_WATCHDOG_PRETIMEOUT_GOV)))
538 mode = 0;
Pratyush Anand33b71122015-12-17 17:53:59 +0530539
540 return mode;
541}
542static struct attribute *wdt_attrs[] = {
543 &dev_attr_state.attr,
544 &dev_attr_identity.attr,
545 &dev_attr_timeout.attr,
Wolfram Sangdf044e02016-08-31 14:52:41 +0300546 &dev_attr_pretimeout.attr,
Pratyush Anand33b71122015-12-17 17:53:59 +0530547 &dev_attr_timeleft.attr,
548 &dev_attr_bootstatus.attr,
549 &dev_attr_status.attr,
550 &dev_attr_nowayout.attr,
Vladimir Zapolskiyff841362016-10-07 15:39:54 +0300551 &dev_attr_pretimeout_governor.attr,
Vladimir Zapolskiy89873a72016-10-07 15:39:57 +0300552 &dev_attr_pretimeout_available_governors.attr,
Pratyush Anand33b71122015-12-17 17:53:59 +0530553 NULL,
554};
555
556static const struct attribute_group wdt_group = {
557 .attrs = wdt_attrs,
558 .is_visible = wdt_is_visible,
559};
560__ATTRIBUTE_GROUPS(wdt);
561#else
562#define wdt_groups NULL
563#endif
564
Hans de Goede7a879822012-05-22 11:40:26 +0200565/*
566 * watchdog_ioctl_op: call the watchdog drivers ioctl op if defined
Guenter Roeckbc794ac2015-09-29 01:27:25 -0700567 * @wdd: the watchdog device to do the ioctl on
Hans de Goede7a879822012-05-22 11:40:26 +0200568 * @cmd: watchdog command
569 * @arg: argument pointer
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800570 *
571 * The caller must hold wd_data->lock.
Hans de Goede7a879822012-05-22 11:40:26 +0200572 */
573
Guenter Roeckbc794ac2015-09-29 01:27:25 -0700574static int watchdog_ioctl_op(struct watchdog_device *wdd, unsigned int cmd,
Hans de Goede7a879822012-05-22 11:40:26 +0200575 unsigned long arg)
576{
Guenter Roeckbc794ac2015-09-29 01:27:25 -0700577 if (!wdd->ops->ioctl)
Hans de Goede7a879822012-05-22 11:40:26 +0200578 return -ENOIOCTLCMD;
579
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800580 return wdd->ops->ioctl(wdd, cmd, arg);
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000581}
582
583/*
584 * watchdog_write: writes to the watchdog.
585 * @file: file from VFS
586 * @data: user address of data
587 * @len: length of data
588 * @ppos: pointer to the file offset
589 *
590 * A write to a watchdog device is defined as a keepalive ping.
Wim Van Sebroeck017cf082011-07-22 18:58:54 +0000591 * Writing the magic 'V' sequence allows the next close to turn
Wim Van Sebroeck7e192b92011-07-22 18:59:17 +0000592 * off the watchdog (if 'nowayout' is not set).
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000593 */
594
595static ssize_t watchdog_write(struct file *file, const char __user *data,
596 size_t len, loff_t *ppos)
597{
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800598 struct watchdog_core_data *wd_data = file->private_data;
599 struct watchdog_device *wdd;
600 int err;
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000601 size_t i;
602 char c;
603
604 if (len == 0)
605 return 0;
606
Wim Van Sebroeck017cf082011-07-22 18:58:54 +0000607 /*
608 * Note: just in case someone wrote the magic character
609 * five months ago...
610 */
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800611 clear_bit(_WDOG_ALLOW_RELEASE, &wd_data->status);
Wim Van Sebroeck017cf082011-07-22 18:58:54 +0000612
613 /* scan to see whether or not we got the magic character */
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000614 for (i = 0; i != len; i++) {
615 if (get_user(c, data + i))
616 return -EFAULT;
Wim Van Sebroeck017cf082011-07-22 18:58:54 +0000617 if (c == 'V')
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800618 set_bit(_WDOG_ALLOW_RELEASE, &wd_data->status);
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000619 }
620
621 /* someone wrote to us, so we send the watchdog a keepalive ping */
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800622
623 err = -ENODEV;
624 mutex_lock(&wd_data->lock);
625 wdd = wd_data->wdd;
626 if (wdd)
627 err = watchdog_ping(wdd);
628 mutex_unlock(&wd_data->lock);
629
Alexander Usyskin5ef79662015-10-26 14:07:58 +0200630 if (err < 0)
631 return err;
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000632
633 return len;
634}
635
636/*
Wim Van Sebroeck2fa03562011-07-22 18:56:38 +0000637 * watchdog_ioctl: handle the different ioctl's for the watchdog device.
638 * @file: file handle to the device
639 * @cmd: watchdog command
640 * @arg: argument pointer
641 *
642 * The watchdog API defines a common set of functions for all watchdogs
643 * according to their available features.
644 */
645
646static long watchdog_ioctl(struct file *file, unsigned int cmd,
647 unsigned long arg)
648{
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800649 struct watchdog_core_data *wd_data = file->private_data;
Wim Van Sebroeck2fa03562011-07-22 18:56:38 +0000650 void __user *argp = (void __user *)arg;
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800651 struct watchdog_device *wdd;
Wim Van Sebroeck2fa03562011-07-22 18:56:38 +0000652 int __user *p = argp;
653 unsigned int val;
Wim Van Sebroeck234445b2011-07-22 18:57:55 +0000654 int err;
Wim Van Sebroeck2fa03562011-07-22 18:56:38 +0000655
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800656 mutex_lock(&wd_data->lock);
657
658 wdd = wd_data->wdd;
659 if (!wdd) {
660 err = -ENODEV;
661 goto out_ioctl;
662 }
663
Hans de Goede7a879822012-05-22 11:40:26 +0200664 err = watchdog_ioctl_op(wdd, cmd, arg);
665 if (err != -ENOIOCTLCMD)
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800666 goto out_ioctl;
Wim Van Sebroeck78d88fc2011-07-22 18:59:49 +0000667
Wim Van Sebroeck2fa03562011-07-22 18:56:38 +0000668 switch (cmd) {
669 case WDIOC_GETSUPPORT:
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800670 err = copy_to_user(argp, wdd->info,
Wim Van Sebroeck2fa03562011-07-22 18:56:38 +0000671 sizeof(struct watchdog_info)) ? -EFAULT : 0;
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800672 break;
Wim Van Sebroeck2fa03562011-07-22 18:56:38 +0000673 case WDIOC_GETSTATUS:
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800674 val = watchdog_get_status(wdd);
675 err = put_user(val, p);
676 break;
Wim Van Sebroeck2fa03562011-07-22 18:56:38 +0000677 case WDIOC_GETBOOTSTATUS:
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800678 err = put_user(wdd->bootstatus, p);
679 break;
Wim Van Sebroeck234445b2011-07-22 18:57:55 +0000680 case WDIOC_SETOPTIONS:
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800681 if (get_user(val, p)) {
682 err = -EFAULT;
683 break;
684 }
Wim Van Sebroeck234445b2011-07-22 18:57:55 +0000685 if (val & WDIOS_DISABLECARD) {
686 err = watchdog_stop(wdd);
687 if (err < 0)
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800688 break;
Wim Van Sebroeck234445b2011-07-22 18:57:55 +0000689 }
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800690 if (val & WDIOS_ENABLECARD)
Wim Van Sebroeck234445b2011-07-22 18:57:55 +0000691 err = watchdog_start(wdd);
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800692 break;
Wim Van Sebroeckc2dc00e2011-07-22 18:57:23 +0000693 case WDIOC_KEEPALIVE:
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800694 if (!(wdd->info->options & WDIOF_KEEPALIVEPING)) {
695 err = -EOPNOTSUPP;
696 break;
697 }
698 err = watchdog_ping(wdd);
699 break;
Wim Van Sebroeck014d6942011-07-22 18:58:21 +0000700 case WDIOC_SETTIMEOUT:
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800701 if (get_user(val, p)) {
702 err = -EFAULT;
703 break;
704 }
Hans de Goede7a879822012-05-22 11:40:26 +0200705 err = watchdog_set_timeout(wdd, val);
Wim Van Sebroeck014d6942011-07-22 18:58:21 +0000706 if (err < 0)
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800707 break;
Wim Van Sebroeck014d6942011-07-22 18:58:21 +0000708 /* If the watchdog is active then we send a keepalive ping
709 * to make sure that the watchdog keep's running (and if
710 * possible that it takes the new timeout) */
Alexander Usyskin5ef79662015-10-26 14:07:58 +0200711 err = watchdog_ping(wdd);
712 if (err < 0)
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800713 break;
Wim Van Sebroeck014d6942011-07-22 18:58:21 +0000714 /* Fall */
715 case WDIOC_GETTIMEOUT:
716 /* timeout == 0 means that we don't know the timeout */
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800717 if (wdd->timeout == 0) {
718 err = -EOPNOTSUPP;
719 break;
720 }
721 err = put_user(wdd->timeout, p);
722 break;
Viresh Kumarfd7b6732012-03-16 09:14:00 +0100723 case WDIOC_GETTIMELEFT:
Hans de Goede7a879822012-05-22 11:40:26 +0200724 err = watchdog_get_timeleft(wdd, &val);
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800725 if (err < 0)
726 break;
727 err = put_user(val, p);
728 break;
Wolfram Sangdf044e02016-08-31 14:52:41 +0300729 case WDIOC_SETPRETIMEOUT:
730 if (get_user(val, p)) {
731 err = -EFAULT;
732 break;
733 }
734 err = watchdog_set_pretimeout(wdd, val);
735 break;
736 case WDIOC_GETPRETIMEOUT:
737 err = put_user(wdd->pretimeout, p);
738 break;
Wim Van Sebroeck2fa03562011-07-22 18:56:38 +0000739 default:
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800740 err = -ENOTTY;
741 break;
Wim Van Sebroeck2fa03562011-07-22 18:56:38 +0000742 }
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800743
744out_ioctl:
745 mutex_unlock(&wd_data->lock);
746 return err;
Wim Van Sebroeck2fa03562011-07-22 18:56:38 +0000747}
748
749/*
Alan Cox45f5fed2012-05-10 21:48:59 +0200750 * watchdog_open: open the /dev/watchdog* devices.
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000751 * @inode: inode of device
752 * @file: file handle to device
753 *
Alan Cox45f5fed2012-05-10 21:48:59 +0200754 * When the /dev/watchdog* device gets opened, we start the watchdog.
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000755 * Watch out: the /dev/watchdog device is single open, so we make sure
756 * it can only be opened once.
757 */
758
759static int watchdog_open(struct inode *inode, struct file *file)
760{
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800761 struct watchdog_core_data *wd_data;
Alan Cox45f5fed2012-05-10 21:48:59 +0200762 struct watchdog_device *wdd;
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800763 int err;
Alan Cox45f5fed2012-05-10 21:48:59 +0200764
765 /* Get the corresponding watchdog device */
766 if (imajor(inode) == MISC_MAJOR)
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800767 wd_data = old_wd_data;
Alan Cox45f5fed2012-05-10 21:48:59 +0200768 else
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800769 wd_data = container_of(inode->i_cdev, struct watchdog_core_data,
770 cdev);
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000771
772 /* the watchdog is single open! */
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800773 if (test_and_set_bit(_WDOG_DEV_OPEN, &wd_data->status))
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000774 return -EBUSY;
775
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800776 wdd = wd_data->wdd;
777
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000778 /*
779 * If the /dev/watchdog device is open, we don't want the module
780 * to be unloaded.
781 */
Guenter Roeckee142882016-02-28 13:12:16 -0800782 if (!watchdog_hw_running(wdd) && !try_module_get(wdd->ops->owner)) {
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800783 err = -EBUSY;
784 goto out_clear;
785 }
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000786
Wim Van Sebroeck234445b2011-07-22 18:57:55 +0000787 err = watchdog_start(wdd);
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000788 if (err < 0)
789 goto out_mod;
790
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800791 file->private_data = wd_data;
Alan Cox45f5fed2012-05-10 21:48:59 +0200792
Guenter Roeckee142882016-02-28 13:12:16 -0800793 if (!watchdog_hw_running(wdd))
794 kref_get(&wd_data->kref);
Hans de Goedee907df32012-05-22 11:40:26 +0200795
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000796 /* dev/watchdog is a virtual (and thus non-seekable) filesystem */
797 return nonseekable_open(inode, file);
798
799out_mod:
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800800 module_put(wd_data->wdd->ops->owner);
801out_clear:
802 clear_bit(_WDOG_DEV_OPEN, &wd_data->status);
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000803 return err;
804}
805
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800806static void watchdog_core_data_release(struct kref *kref)
807{
808 struct watchdog_core_data *wd_data;
809
810 wd_data = container_of(kref, struct watchdog_core_data, kref);
811
812 kfree(wd_data);
813}
814
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000815/*
Alan Cox45f5fed2012-05-10 21:48:59 +0200816 * watchdog_release: release the watchdog device.
817 * @inode: inode of device
818 * @file: file handle to device
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000819 *
Wim Van Sebroeck017cf082011-07-22 18:58:54 +0000820 * This is the code for when /dev/watchdog gets closed. We will only
Wim Van Sebroeck7e192b92011-07-22 18:59:17 +0000821 * stop the watchdog when we have received the magic char (and nowayout
822 * was not set), else the watchdog will keep running.
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000823 */
824
825static int watchdog_release(struct inode *inode, struct file *file)
826{
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800827 struct watchdog_core_data *wd_data = file->private_data;
828 struct watchdog_device *wdd;
Wim Van Sebroeck017cf082011-07-22 18:58:54 +0000829 int err = -EBUSY;
Guenter Roeckd1ed3ba2016-03-08 18:46:13 -0800830 bool running;
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000831
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800832 mutex_lock(&wd_data->lock);
833
834 wdd = wd_data->wdd;
835 if (!wdd)
836 goto done;
837
Wim Van Sebroeck017cf082011-07-22 18:58:54 +0000838 /*
839 * We only stop the watchdog if we received the magic character
Wim Van Sebroeck7e192b92011-07-22 18:59:17 +0000840 * or if WDIOF_MAGICCLOSE is not set. If nowayout was set then
841 * watchdog_stop will fail.
Wim Van Sebroeck017cf082011-07-22 18:58:54 +0000842 */
Hector Palaciosfcf95672013-04-08 17:06:32 +0200843 if (!test_bit(WDOG_ACTIVE, &wdd->status))
844 err = 0;
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800845 else if (test_and_clear_bit(_WDOG_ALLOW_RELEASE, &wd_data->status) ||
Hector Palaciosfcf95672013-04-08 17:06:32 +0200846 !(wdd->info->options & WDIOF_MAGICCLOSE))
Wim Van Sebroeck017cf082011-07-22 18:58:54 +0000847 err = watchdog_stop(wdd);
848
849 /* If the watchdog was not stopped, send a keepalive ping */
Wim Van Sebroeck234445b2011-07-22 18:57:55 +0000850 if (err < 0) {
Guenter Roeck0254e952016-01-03 15:11:58 -0800851 pr_crit("watchdog%d: watchdog did not stop!\n", wdd->id);
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000852 watchdog_ping(wdd);
853 }
854
Guenter Roeckee142882016-02-28 13:12:16 -0800855 watchdog_update_worker(wdd);
Guenter Roeck664a3922016-02-28 13:12:15 -0800856
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000857 /* make sure that /dev/watchdog can be re-opened */
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800858 clear_bit(_WDOG_DEV_OPEN, &wd_data->status);
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000859
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800860done:
Guenter Roeckd1ed3ba2016-03-08 18:46:13 -0800861 running = wdd && watchdog_hw_running(wdd);
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800862 mutex_unlock(&wd_data->lock);
Guenter Roeckee142882016-02-28 13:12:16 -0800863 /*
864 * Allow the owner module to be unloaded again unless the watchdog
865 * is still running. If the watchdog is still running, it can not
866 * be stopped, and its driver must not be unloaded.
867 */
Guenter Roeckd1ed3ba2016-03-08 18:46:13 -0800868 if (!running) {
869 module_put(wd_data->cdev.owner);
Guenter Roeckee142882016-02-28 13:12:16 -0800870 kref_put(&wd_data->kref, watchdog_core_data_release);
871 }
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000872 return 0;
873}
874
875static const struct file_operations watchdog_fops = {
876 .owner = THIS_MODULE,
877 .write = watchdog_write,
Wim Van Sebroeck2fa03562011-07-22 18:56:38 +0000878 .unlocked_ioctl = watchdog_ioctl,
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000879 .open = watchdog_open,
880 .release = watchdog_release,
881};
882
883static struct miscdevice watchdog_miscdev = {
884 .minor = WATCHDOG_MINOR,
885 .name = "watchdog",
886 .fops = &watchdog_fops,
887};
888
889/*
Guenter Roeck32ecc632015-12-25 16:01:40 -0800890 * watchdog_cdev_register: register watchdog character device
Guenter Roeckbc794ac2015-09-29 01:27:25 -0700891 * @wdd: watchdog device
Guenter Roeck32ecc632015-12-25 16:01:40 -0800892 * @devno: character device number
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000893 *
Guenter Roeck32ecc632015-12-25 16:01:40 -0800894 * Register a watchdog character device including handling the legacy
Alan Cox45f5fed2012-05-10 21:48:59 +0200895 * /dev/watchdog node. /dev/watchdog is actually a miscdevice and
896 * thus we set it up like that.
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000897 */
898
Guenter Roeck32ecc632015-12-25 16:01:40 -0800899static int watchdog_cdev_register(struct watchdog_device *wdd, dev_t devno)
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000900{
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800901 struct watchdog_core_data *wd_data;
Guenter Roeck32ecc632015-12-25 16:01:40 -0800902 int err;
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000903
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800904 wd_data = kzalloc(sizeof(struct watchdog_core_data), GFP_KERNEL);
905 if (!wd_data)
906 return -ENOMEM;
907 kref_init(&wd_data->kref);
908 mutex_init(&wd_data->lock);
909
910 wd_data->wdd = wdd;
911 wdd->wd_data = wd_data;
912
Guenter Roeck664a3922016-02-28 13:12:15 -0800913 if (!watchdog_wq)
914 return -ENODEV;
915
916 INIT_DELAYED_WORK(&wd_data->work, watchdog_ping_work);
917
Guenter Roeckbc794ac2015-09-29 01:27:25 -0700918 if (wdd->id == 0) {
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800919 old_wd_data = wd_data;
Guenter Roeckbc794ac2015-09-29 01:27:25 -0700920 watchdog_miscdev.parent = wdd->parent;
Alan Cox45f5fed2012-05-10 21:48:59 +0200921 err = misc_register(&watchdog_miscdev);
922 if (err != 0) {
923 pr_err("%s: cannot register miscdev on minor=%d (err=%d).\n",
Guenter Roeckbc794ac2015-09-29 01:27:25 -0700924 wdd->info->identity, WATCHDOG_MINOR, err);
Alan Cox45f5fed2012-05-10 21:48:59 +0200925 if (err == -EBUSY)
926 pr_err("%s: a legacy watchdog module is probably present.\n",
Guenter Roeckbc794ac2015-09-29 01:27:25 -0700927 wdd->info->identity);
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800928 old_wd_data = NULL;
929 kfree(wd_data);
Alan Cox45f5fed2012-05-10 21:48:59 +0200930 return err;
931 }
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000932 }
933
Alan Cox45f5fed2012-05-10 21:48:59 +0200934 /* Fill in the data structures */
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800935 cdev_init(&wd_data->cdev, &watchdog_fops);
936 wd_data->cdev.owner = wdd->ops->owner;
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000937
Alan Cox45f5fed2012-05-10 21:48:59 +0200938 /* Add the device */
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800939 err = cdev_add(&wd_data->cdev, devno, 1);
Alan Cox45f5fed2012-05-10 21:48:59 +0200940 if (err) {
941 pr_err("watchdog%d unable to add device %d:%d\n",
Guenter Roeckbc794ac2015-09-29 01:27:25 -0700942 wdd->id, MAJOR(watchdog_devt), wdd->id);
943 if (wdd->id == 0) {
Alan Cox45f5fed2012-05-10 21:48:59 +0200944 misc_deregister(&watchdog_miscdev);
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800945 old_wd_data = NULL;
946 kref_put(&wd_data->kref, watchdog_core_data_release);
Alan Cox45f5fed2012-05-10 21:48:59 +0200947 }
Guenter Roeckee142882016-02-28 13:12:16 -0800948 return err;
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000949 }
Guenter Roeckee142882016-02-28 13:12:16 -0800950
Guenter Roeck15013ad2016-02-28 13:12:18 -0800951 /* Record time of most recent heartbeat as 'just before now'. */
952 wd_data->last_hw_keepalive = jiffies - 1;
953
Guenter Roeckee142882016-02-28 13:12:16 -0800954 /*
955 * If the watchdog is running, prevent its driver from being unloaded,
956 * and schedule an immediate ping.
957 */
958 if (watchdog_hw_running(wdd)) {
959 __module_get(wdd->ops->owner);
960 kref_get(&wd_data->kref);
961 queue_delayed_work(watchdog_wq, &wd_data->work, 0);
962 }
963
964 return 0;
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000965}
966
967/*
Guenter Roeck32ecc632015-12-25 16:01:40 -0800968 * watchdog_cdev_unregister: unregister watchdog character device
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000969 * @watchdog: watchdog device
970 *
Guenter Roeck32ecc632015-12-25 16:01:40 -0800971 * Unregister watchdog character device and if needed the legacy
972 * /dev/watchdog device.
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000973 */
974
Guenter Roeck32ecc632015-12-25 16:01:40 -0800975static void watchdog_cdev_unregister(struct watchdog_device *wdd)
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000976{
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800977 struct watchdog_core_data *wd_data = wdd->wd_data;
Hans de Goedee907df32012-05-22 11:40:26 +0200978
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800979 cdev_del(&wd_data->cdev);
Guenter Roeckbc794ac2015-09-29 01:27:25 -0700980 if (wdd->id == 0) {
Alan Cox45f5fed2012-05-10 21:48:59 +0200981 misc_deregister(&watchdog_miscdev);
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800982 old_wd_data = NULL;
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000983 }
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800984
985 mutex_lock(&wd_data->lock);
986 wd_data->wdd = NULL;
987 wdd->wd_data = NULL;
988 mutex_unlock(&wd_data->lock);
989
Guenter Roeck664a3922016-02-28 13:12:15 -0800990 cancel_delayed_work_sync(&wd_data->work);
991
Guenter Roeckb4ffb192015-12-25 16:01:42 -0800992 kref_put(&wd_data->kref, watchdog_core_data_release);
Wim Van Sebroeck43316042011-07-22 18:55:18 +0000993}
Alan Cox45f5fed2012-05-10 21:48:59 +0200994
Pratyush Anand906d7a52015-12-17 17:53:58 +0530995static struct class watchdog_class = {
996 .name = "watchdog",
997 .owner = THIS_MODULE,
Pratyush Anand33b71122015-12-17 17:53:59 +0530998 .dev_groups = wdt_groups,
Pratyush Anand906d7a52015-12-17 17:53:58 +0530999};
1000
Alan Cox45f5fed2012-05-10 21:48:59 +02001001/*
Guenter Roeck32ecc632015-12-25 16:01:40 -08001002 * watchdog_dev_register: register a watchdog device
1003 * @wdd: watchdog device
1004 *
1005 * Register a watchdog device including handling the legacy
1006 * /dev/watchdog node. /dev/watchdog is actually a miscdevice and
1007 * thus we set it up like that.
1008 */
1009
1010int watchdog_dev_register(struct watchdog_device *wdd)
1011{
1012 struct device *dev;
1013 dev_t devno;
1014 int ret;
1015
1016 devno = MKDEV(MAJOR(watchdog_devt), wdd->id);
1017
1018 ret = watchdog_cdev_register(wdd, devno);
1019 if (ret)
1020 return ret;
1021
Guenter Roeckfaa58472016-01-03 15:11:56 -08001022 dev = device_create_with_groups(&watchdog_class, wdd->parent,
1023 devno, wdd, wdd->groups,
1024 "watchdog%d", wdd->id);
Guenter Roeck32ecc632015-12-25 16:01:40 -08001025 if (IS_ERR(dev)) {
1026 watchdog_cdev_unregister(wdd);
1027 return PTR_ERR(dev);
1028 }
Guenter Roeck32ecc632015-12-25 16:01:40 -08001029
Vladimir Zapolskiyff841362016-10-07 15:39:54 +03001030 ret = watchdog_register_pretimeout(wdd);
1031 if (ret) {
1032 device_destroy(&watchdog_class, devno);
1033 watchdog_cdev_unregister(wdd);
1034 }
1035
Guenter Roeck32ecc632015-12-25 16:01:40 -08001036 return ret;
1037}
1038
1039/*
1040 * watchdog_dev_unregister: unregister a watchdog device
1041 * @watchdog: watchdog device
1042 *
1043 * Unregister watchdog device and if needed the legacy
1044 * /dev/watchdog device.
1045 */
1046
1047void watchdog_dev_unregister(struct watchdog_device *wdd)
1048{
Vladimir Zapolskiyff841362016-10-07 15:39:54 +03001049 watchdog_unregister_pretimeout(wdd);
Guenter Roeck0254e952016-01-03 15:11:58 -08001050 device_destroy(&watchdog_class, wdd->wd_data->cdev.dev);
Guenter Roeckb4ffb192015-12-25 16:01:42 -08001051 watchdog_cdev_unregister(wdd);
Guenter Roeck32ecc632015-12-25 16:01:40 -08001052}
1053
1054/*
Alan Cox45f5fed2012-05-10 21:48:59 +02001055 * watchdog_dev_init: init dev part of watchdog core
1056 *
1057 * Allocate a range of chardev nodes to use for watchdog devices
1058 */
1059
Guenter Roeck32ecc632015-12-25 16:01:40 -08001060int __init watchdog_dev_init(void)
Alan Cox45f5fed2012-05-10 21:48:59 +02001061{
Pratyush Anand906d7a52015-12-17 17:53:58 +05301062 int err;
1063
Guenter Roeck664a3922016-02-28 13:12:15 -08001064 watchdog_wq = alloc_workqueue("watchdogd",
1065 WQ_HIGHPRI | WQ_MEM_RECLAIM, 0);
1066 if (!watchdog_wq) {
1067 pr_err("Failed to create watchdog workqueue\n");
1068 return -ENOMEM;
1069 }
1070
Pratyush Anand906d7a52015-12-17 17:53:58 +05301071 err = class_register(&watchdog_class);
1072 if (err < 0) {
1073 pr_err("couldn't register class\n");
Wei Yongjun138913c2016-07-19 11:22:34 +00001074 goto err_register;
Pratyush Anand906d7a52015-12-17 17:53:58 +05301075 }
1076
1077 err = alloc_chrdev_region(&watchdog_devt, 0, MAX_DOGS, "watchdog");
1078 if (err < 0) {
Alan Cox45f5fed2012-05-10 21:48:59 +02001079 pr_err("watchdog: unable to allocate char dev region\n");
Wei Yongjun138913c2016-07-19 11:22:34 +00001080 goto err_alloc;
Pratyush Anand906d7a52015-12-17 17:53:58 +05301081 }
1082
Guenter Roeck32ecc632015-12-25 16:01:40 -08001083 return 0;
Wei Yongjun138913c2016-07-19 11:22:34 +00001084
1085err_alloc:
1086 class_unregister(&watchdog_class);
1087err_register:
1088 destroy_workqueue(watchdog_wq);
1089 return err;
Alan Cox45f5fed2012-05-10 21:48:59 +02001090}
1091
1092/*
1093 * watchdog_dev_exit: exit dev part of watchdog core
1094 *
1095 * Release the range of chardev nodes used for watchdog devices
1096 */
1097
1098void __exit watchdog_dev_exit(void)
1099{
1100 unregister_chrdev_region(watchdog_devt, MAX_DOGS);
Pratyush Anand906d7a52015-12-17 17:53:58 +05301101 class_unregister(&watchdog_class);
Guenter Roeck664a3922016-02-28 13:12:15 -08001102 destroy_workqueue(watchdog_wq);
Alan Cox45f5fed2012-05-10 21:48:59 +02001103}