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25#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
26
27#include <linux/module.h>
28#include <linux/types.h>
29#include <linux/errno.h>
30#include <linux/kernel.h>
31#include <linux/reboot.h>
32#include <linux/watchdog.h>
33#include <linux/init.h>
34#include <linux/idr.h>
35#include <linux/err.h>
36#include <linux/of.h>
37#include <linux/suspend.h>
38
39#include "watchdog_core.h"
40
41static DEFINE_IDA(watchdog_ida);
42
43static int stop_on_reboot = -1;
44module_param(stop_on_reboot, int, 0444);
45MODULE_PARM_DESC(stop_on_reboot, "Stop watchdogs on reboot (0=keep watching, 1=stop)");
46
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59
60static DEFINE_MUTEX(wtd_deferred_reg_mutex);
61static LIST_HEAD(wtd_deferred_reg_list);
62static bool wtd_deferred_reg_done;
63
64static void watchdog_deferred_registration_add(struct watchdog_device *wdd)
65{
66 list_add_tail(&wdd->deferred,
67 &wtd_deferred_reg_list);
68}
69
70static void watchdog_deferred_registration_del(struct watchdog_device *wdd)
71{
72 struct list_head *p, *n;
73 struct watchdog_device *wdd_tmp;
74
75 list_for_each_safe(p, n, &wtd_deferred_reg_list) {
76 wdd_tmp = list_entry(p, struct watchdog_device,
77 deferred);
78 if (wdd_tmp == wdd) {
79 list_del(&wdd_tmp->deferred);
80 break;
81 }
82 }
83}
84
85static void watchdog_check_min_max_timeout(struct watchdog_device *wdd)
86{
87
88
89
90
91 if (!wdd->max_hw_heartbeat_ms && wdd->min_timeout > wdd->max_timeout) {
92 pr_info("Invalid min and max timeout values, resetting to 0!\n");
93 wdd->min_timeout = 0;
94 wdd->max_timeout = 0;
95 }
96}
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114
115int watchdog_init_timeout(struct watchdog_device *wdd,
116 unsigned int timeout_parm, struct device *dev)
117{
118 const char *dev_str = wdd->parent ? dev_name(wdd->parent) :
119 (const char *)wdd->info->identity;
120 unsigned int t = 0;
121 int ret = 0;
122
123 watchdog_check_min_max_timeout(wdd);
124
125
126 if (timeout_parm) {
127 if (!watchdog_timeout_invalid(wdd, timeout_parm)) {
128 wdd->timeout = timeout_parm;
129 return 0;
130 }
131 pr_err("%s: driver supplied timeout (%u) out of range\n",
132 dev_str, timeout_parm);
133 ret = -EINVAL;
134 }
135
136
137 if (dev && dev->of_node &&
138 of_property_read_u32(dev->of_node, "timeout-sec", &t) == 0) {
139 if (t && !watchdog_timeout_invalid(wdd, t)) {
140 wdd->timeout = t;
141 return 0;
142 }
143 pr_err("%s: DT supplied timeout (%u) out of range\n", dev_str, t);
144 ret = -EINVAL;
145 }
146
147 if (ret < 0 && wdd->timeout)
148 pr_warn("%s: falling back to default timeout (%u)\n", dev_str,
149 wdd->timeout);
150
151 return ret;
152}
153EXPORT_SYMBOL_GPL(watchdog_init_timeout);
154
155static int watchdog_reboot_notifier(struct notifier_block *nb,
156 unsigned long code, void *data)
157{
158 struct watchdog_device *wdd;
159
160 wdd = container_of(nb, struct watchdog_device, reboot_nb);
161 if (code == SYS_DOWN || code == SYS_HALT) {
162 if (watchdog_active(wdd) || watchdog_hw_running(wdd)) {
163 int ret;
164
165 ret = wdd->ops->stop(wdd);
166 if (ret)
167 return NOTIFY_BAD;
168 }
169 }
170
171 return NOTIFY_DONE;
172}
173
174static int watchdog_restart_notifier(struct notifier_block *nb,
175 unsigned long action, void *data)
176{
177 struct watchdog_device *wdd = container_of(nb, struct watchdog_device,
178 restart_nb);
179
180 int ret;
181
182 ret = wdd->ops->restart(wdd, action, data);
183 if (ret)
184 return NOTIFY_BAD;
185
186 return NOTIFY_DONE;
187}
188
189static int watchdog_pm_notifier(struct notifier_block *nb, unsigned long mode,
190 void *data)
191{
192 struct watchdog_device *wdd;
193 int ret = 0;
194
195 wdd = container_of(nb, struct watchdog_device, pm_nb);
196
197 switch (mode) {
198 case PM_HIBERNATION_PREPARE:
199 case PM_RESTORE_PREPARE:
200 case PM_SUSPEND_PREPARE:
201 ret = watchdog_dev_suspend(wdd);
202 break;
203 case PM_POST_HIBERNATION:
204 case PM_POST_RESTORE:
205 case PM_POST_SUSPEND:
206 ret = watchdog_dev_resume(wdd);
207 break;
208 }
209
210 if (ret)
211 return NOTIFY_BAD;
212
213 return NOTIFY_DONE;
214}
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229
230void watchdog_set_restart_priority(struct watchdog_device *wdd, int priority)
231{
232 wdd->restart_nb.priority = priority;
233}
234EXPORT_SYMBOL_GPL(watchdog_set_restart_priority);
235
236static int __watchdog_register_device(struct watchdog_device *wdd)
237{
238 int ret, id = -1;
239
240 if (wdd == NULL || wdd->info == NULL || wdd->ops == NULL)
241 return -EINVAL;
242
243
244 if (!wdd->ops->start || (!wdd->ops->stop && !wdd->max_hw_heartbeat_ms))
245 return -EINVAL;
246
247 watchdog_check_min_max_timeout(wdd);
248
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255
256 if (wdd->parent) {
257 ret = of_alias_get_id(wdd->parent->of_node, "watchdog");
258 if (ret >= 0)
259 id = ida_simple_get(&watchdog_ida, ret,
260 ret + 1, GFP_KERNEL);
261 }
262
263 if (id < 0)
264 id = ida_simple_get(&watchdog_ida, 0, MAX_DOGS, GFP_KERNEL);
265
266 if (id < 0)
267 return id;
268 wdd->id = id;
269
270 ret = watchdog_dev_register(wdd);
271 if (ret) {
272 ida_simple_remove(&watchdog_ida, id);
273 if (!(id == 0 && ret == -EBUSY))
274 return ret;
275
276
277 id = ida_simple_get(&watchdog_ida, 1, MAX_DOGS, GFP_KERNEL);
278 if (id < 0)
279 return id;
280 wdd->id = id;
281
282 ret = watchdog_dev_register(wdd);
283 if (ret) {
284 ida_simple_remove(&watchdog_ida, id);
285 return ret;
286 }
287 }
288
289
290 if (stop_on_reboot != -1) {
291 if (stop_on_reboot)
292 set_bit(WDOG_STOP_ON_REBOOT, &wdd->status);
293 else
294 clear_bit(WDOG_STOP_ON_REBOOT, &wdd->status);
295 }
296
297 if (test_bit(WDOG_STOP_ON_REBOOT, &wdd->status)) {
298 if (!wdd->ops->stop)
299 pr_warn("watchdog%d: stop_on_reboot not supported\n", wdd->id);
300 else {
301 wdd->reboot_nb.notifier_call = watchdog_reboot_notifier;
302
303 ret = register_reboot_notifier(&wdd->reboot_nb);
304 if (ret) {
305 pr_err("watchdog%d: Cannot register reboot notifier (%d)\n",
306 wdd->id, ret);
307 watchdog_dev_unregister(wdd);
308 ida_simple_remove(&watchdog_ida, id);
309 return ret;
310 }
311 }
312 }
313
314 if (wdd->ops->restart) {
315 wdd->restart_nb.notifier_call = watchdog_restart_notifier;
316
317 ret = register_restart_handler(&wdd->restart_nb);
318 if (ret)
319 pr_warn("watchdog%d: Cannot register restart handler (%d)\n",
320 wdd->id, ret);
321 }
322
323 if (test_bit(WDOG_NO_PING_ON_SUSPEND, &wdd->status)) {
324 wdd->pm_nb.notifier_call = watchdog_pm_notifier;
325
326 ret = register_pm_notifier(&wdd->pm_nb);
327 if (ret)
328 pr_warn("watchdog%d: Cannot register pm handler (%d)\n",
329 wdd->id, ret);
330 }
331
332 return 0;
333}
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346int watchdog_register_device(struct watchdog_device *wdd)
347{
348 const char *dev_str;
349 int ret = 0;
350
351 mutex_lock(&wtd_deferred_reg_mutex);
352 if (wtd_deferred_reg_done)
353 ret = __watchdog_register_device(wdd);
354 else
355 watchdog_deferred_registration_add(wdd);
356 mutex_unlock(&wtd_deferred_reg_mutex);
357
358 if (ret) {
359 dev_str = wdd->parent ? dev_name(wdd->parent) :
360 (const char *)wdd->info->identity;
361 pr_err("%s: failed to register watchdog device (err = %d)\n",
362 dev_str, ret);
363 }
364
365 return ret;
366}
367EXPORT_SYMBOL_GPL(watchdog_register_device);
368
369static void __watchdog_unregister_device(struct watchdog_device *wdd)
370{
371 if (wdd == NULL)
372 return;
373
374 if (wdd->ops->restart)
375 unregister_restart_handler(&wdd->restart_nb);
376
377 if (test_bit(WDOG_STOP_ON_REBOOT, &wdd->status))
378 unregister_reboot_notifier(&wdd->reboot_nb);
379
380 watchdog_dev_unregister(wdd);
381 ida_simple_remove(&watchdog_ida, wdd->id);
382}
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392void watchdog_unregister_device(struct watchdog_device *wdd)
393{
394 mutex_lock(&wtd_deferred_reg_mutex);
395 if (wtd_deferred_reg_done)
396 __watchdog_unregister_device(wdd);
397 else
398 watchdog_deferred_registration_del(wdd);
399 mutex_unlock(&wtd_deferred_reg_mutex);
400}
401
402EXPORT_SYMBOL_GPL(watchdog_unregister_device);
403
404static void devm_watchdog_unregister_device(struct device *dev, void *res)
405{
406 watchdog_unregister_device(*(struct watchdog_device **)res);
407}
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418int devm_watchdog_register_device(struct device *dev,
419 struct watchdog_device *wdd)
420{
421 struct watchdog_device **rcwdd;
422 int ret;
423
424 rcwdd = devres_alloc(devm_watchdog_unregister_device, sizeof(*rcwdd),
425 GFP_KERNEL);
426 if (!rcwdd)
427 return -ENOMEM;
428
429 ret = watchdog_register_device(wdd);
430 if (!ret) {
431 *rcwdd = wdd;
432 devres_add(dev, rcwdd);
433 } else {
434 devres_free(rcwdd);
435 }
436
437 return ret;
438}
439EXPORT_SYMBOL_GPL(devm_watchdog_register_device);
440
441static int __init watchdog_deferred_registration(void)
442{
443 mutex_lock(&wtd_deferred_reg_mutex);
444 wtd_deferred_reg_done = true;
445 while (!list_empty(&wtd_deferred_reg_list)) {
446 struct watchdog_device *wdd;
447
448 wdd = list_first_entry(&wtd_deferred_reg_list,
449 struct watchdog_device, deferred);
450 list_del(&wdd->deferred);
451 __watchdog_register_device(wdd);
452 }
453 mutex_unlock(&wtd_deferred_reg_mutex);
454 return 0;
455}
456
457static int __init watchdog_init(void)
458{
459 int err;
460
461 err = watchdog_dev_init();
462 if (err < 0)
463 return err;
464
465 watchdog_deferred_registration();
466 return 0;
467}
468
469static void __exit watchdog_exit(void)
470{
471 watchdog_dev_exit();
472 ida_destroy(&watchdog_ida);
473}
474
475subsys_initcall_sync(watchdog_init);
476module_exit(watchdog_exit);
477
478MODULE_AUTHOR("Alan Cox <alan@lxorguk.ukuu.org.uk>");
479MODULE_AUTHOR("Wim Van Sebroeck <wim@iguana.be>");
480MODULE_DESCRIPTION("WatchDog Timer Driver Core");
481MODULE_LICENSE("GPL");
482