1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * Generic watchdog defines. Derived from..
4 *
5 * Berkshire PC Watchdog Defines
6 * by Ken Hollis <khollis@bitgate.com>
7 *
8 */
9 #ifndef _LINUX_WATCHDOG_H
10 #define _LINUX_WATCHDOG_H
11
12 #include <linux/bitops.h>
13 #include <linux/limits.h>
14 #include <linux/notifier.h>
15 #include <linux/printk.h>
16 #include <linux/types.h>
17
18 #include <uapi/linux/watchdog.h>
19
20 struct attribute_group;
21 struct device;
22 struct module;
23
24 struct watchdog_ops;
25 struct watchdog_device;
26 struct watchdog_core_data;
27 struct watchdog_governor;
28
29 /** struct watchdog_ops - The watchdog-devices operations
30 *
31 * @owner: The module owner.
32 * @start: The routine for starting the watchdog device.
33 * @stop: The routine for stopping the watchdog device.
34 * @ping: The routine that sends a keepalive ping to the watchdog device.
35 * @status: The routine that shows the status of the watchdog device.
36 * @set_timeout:The routine for setting the watchdog devices timeout value (in seconds).
37 * @set_pretimeout:The routine for setting the watchdog devices pretimeout.
38 * @get_timeleft:The routine that gets the time left before a reset (in seconds).
39 * @restart: The routine for restarting the machine.
40 * @ioctl: The routines that handles extra ioctl calls.
41 *
42 * The watchdog_ops structure contains a list of low-level operations
43 * that control a watchdog device. It also contains the module that owns
44 * these operations. The start function is mandatory, all other
45 * functions are optional.
46 */
47 struct watchdog_ops {
48 struct module *owner;
49 /* mandatory operations */
50 int (*start)(struct watchdog_device *);
51 /* optional operations */
52 int (*stop)(struct watchdog_device *);
53 int (*ping)(struct watchdog_device *);
54 unsigned int (*status)(struct watchdog_device *);
55 int (*set_timeout)(struct watchdog_device *, unsigned int);
56 int (*set_pretimeout)(struct watchdog_device *, unsigned int);
57 unsigned int (*get_timeleft)(struct watchdog_device *);
58 int (*restart)(struct watchdog_device *, unsigned long, void *);
59 long (*ioctl)(struct watchdog_device *, unsigned int, unsigned long);
60 };
61
62 /** struct watchdog_device - The structure that defines a watchdog device
63 *
64 * @id: The watchdog's ID. (Allocated by watchdog_register_device)
65 * @parent: The parent bus device
66 * @groups: List of sysfs attribute groups to create when creating the
67 * watchdog device.
68 * @info: Pointer to a watchdog_info structure.
69 * @ops: Pointer to the list of watchdog operations.
70 * @gov: Pointer to watchdog pretimeout governor.
71 * @bootstatus: Status of the watchdog device at boot.
72 * @timeout: The watchdog devices timeout value (in seconds).
73 * @pretimeout: The watchdog devices pre_timeout value.
74 * @min_timeout:The watchdog devices minimum timeout value (in seconds).
75 * @max_timeout:The watchdog devices maximum timeout value (in seconds)
76 * as configurable from user space. Only relevant if
77 * max_hw_heartbeat_ms is not provided.
78 * @min_hw_heartbeat_ms:
79 * Hardware limit for minimum time between heartbeats,
80 * in milli-seconds.
81 * @max_hw_heartbeat_ms:
82 * Hardware limit for maximum timeout, in milli-seconds.
83 * Replaces max_timeout if specified.
84 * @reboot_nb: The notifier block to stop watchdog on reboot.
85 * @restart_nb: The notifier block to register a restart function.
86 * @driver_data:Pointer to the drivers private data.
87 * @wd_data: Pointer to watchdog core internal data.
88 * @status: Field that contains the devices internal status bits.
89 * @deferred: Entry in wtd_deferred_reg_list which is used to
90 * register early initialized watchdogs.
91 *
92 * The watchdog_device structure contains all information about a
93 * watchdog timer device.
94 *
95 * The driver-data field may not be accessed directly. It must be accessed
96 * via the watchdog_set_drvdata and watchdog_get_drvdata helpers.
97 */
98 struct watchdog_device {
99 int id;
100 struct device *parent;
101 const struct attribute_group **groups;
102 const struct watchdog_info *info;
103 const struct watchdog_ops *ops;
104 const struct watchdog_governor *gov;
105 unsigned int bootstatus;
106 unsigned int timeout;
107 unsigned int pretimeout;
108 unsigned int min_timeout;
109 unsigned int max_timeout;
110 unsigned int min_hw_heartbeat_ms;
111 unsigned int max_hw_heartbeat_ms;
112 struct notifier_block reboot_nb;
113 struct notifier_block restart_nb;
114 struct notifier_block pm_nb;
115 void *driver_data;
116 struct watchdog_core_data *wd_data;
117 unsigned long status;
118 /* Bit numbers for status flags */
119 #define WDOG_ACTIVE 0 /* Is the watchdog running/active */
120 #define WDOG_NO_WAY_OUT 1 /* Is 'nowayout' feature set ? */
121 #define WDOG_STOP_ON_REBOOT 2 /* Should be stopped on reboot */
122 #define WDOG_HW_RUNNING 3 /* True if HW watchdog running */
123 #define WDOG_STOP_ON_UNREGISTER 4 /* Should be stopped on unregister */
124 #define WDOG_NO_PING_ON_SUSPEND 5 /* Ping worker should be stopped on suspend */
125 struct list_head deferred;
126 };
127
128 #define WATCHDOG_NOWAYOUT IS_BUILTIN(CONFIG_WATCHDOG_NOWAYOUT)
129 #define WATCHDOG_NOWAYOUT_INIT_STATUS (WATCHDOG_NOWAYOUT << WDOG_NO_WAY_OUT)
130
131 /* Use the following function to check whether or not the watchdog is active */
watchdog_active(struct watchdog_device * wdd)132 static inline bool watchdog_active(struct watchdog_device *wdd)
133 {
134 return test_bit(WDOG_ACTIVE, &wdd->status);
135 }
136
137 /*
138 * Use the following function to check whether or not the hardware watchdog
139 * is running
140 */
watchdog_hw_running(struct watchdog_device * wdd)141 static inline bool watchdog_hw_running(struct watchdog_device *wdd)
142 {
143 return test_bit(WDOG_HW_RUNNING, &wdd->status);
144 }
145
146 /* Use the following function to set the nowayout feature */
watchdog_set_nowayout(struct watchdog_device * wdd,bool nowayout)147 static inline void watchdog_set_nowayout(struct watchdog_device *wdd, bool nowayout)
148 {
149 if (nowayout)
150 set_bit(WDOG_NO_WAY_OUT, &wdd->status);
151 }
152
153 /* Use the following function to stop the watchdog on reboot */
watchdog_stop_on_reboot(struct watchdog_device * wdd)154 static inline void watchdog_stop_on_reboot(struct watchdog_device *wdd)
155 {
156 set_bit(WDOG_STOP_ON_REBOOT, &wdd->status);
157 }
158
159 /* Use the following function to stop the watchdog when unregistering it */
watchdog_stop_on_unregister(struct watchdog_device * wdd)160 static inline void watchdog_stop_on_unregister(struct watchdog_device *wdd)
161 {
162 set_bit(WDOG_STOP_ON_UNREGISTER, &wdd->status);
163 }
164
165 /* Use the following function to stop the wdog ping worker when suspending */
watchdog_stop_ping_on_suspend(struct watchdog_device * wdd)166 static inline void watchdog_stop_ping_on_suspend(struct watchdog_device *wdd)
167 {
168 set_bit(WDOG_NO_PING_ON_SUSPEND, &wdd->status);
169 }
170
171 /* Use the following function to check if a timeout value is invalid */
watchdog_timeout_invalid(struct watchdog_device * wdd,unsigned int t)172 static inline bool watchdog_timeout_invalid(struct watchdog_device *wdd, unsigned int t)
173 {
174 /*
175 * The timeout is invalid if
176 * - the requested value is larger than UINT_MAX / 1000
177 * (since internal calculations are done in milli-seconds),
178 * or
179 * - the requested value is smaller than the configured minimum timeout,
180 * or
181 * - a maximum hardware timeout is not configured, a maximum timeout
182 * is configured, and the requested value is larger than the
183 * configured maximum timeout.
184 */
185 return t > UINT_MAX / 1000 || t < wdd->min_timeout ||
186 (!wdd->max_hw_heartbeat_ms && wdd->max_timeout &&
187 t > wdd->max_timeout);
188 }
189
190 /* Use the following function to check if a pretimeout value is invalid */
watchdog_pretimeout_invalid(struct watchdog_device * wdd,unsigned int t)191 static inline bool watchdog_pretimeout_invalid(struct watchdog_device *wdd,
192 unsigned int t)
193 {
194 return t && wdd->timeout && t >= wdd->timeout;
195 }
196
197 /* Use the following functions to manipulate watchdog driver specific data */
watchdog_set_drvdata(struct watchdog_device * wdd,void * data)198 static inline void watchdog_set_drvdata(struct watchdog_device *wdd, void *data)
199 {
200 wdd->driver_data = data;
201 }
202
watchdog_get_drvdata(struct watchdog_device * wdd)203 static inline void *watchdog_get_drvdata(struct watchdog_device *wdd)
204 {
205 return wdd->driver_data;
206 }
207
208 /* Use the following functions to report watchdog pretimeout event */
209 #if IS_ENABLED(CONFIG_WATCHDOG_PRETIMEOUT_GOV)
210 void watchdog_notify_pretimeout(struct watchdog_device *wdd);
211 #else
watchdog_notify_pretimeout(struct watchdog_device * wdd)212 static inline void watchdog_notify_pretimeout(struct watchdog_device *wdd)
213 {
214 pr_alert("watchdog%d: pretimeout event\n", wdd->id);
215 }
216 #endif
217
218 /* drivers/watchdog/watchdog_core.c */
219 void watchdog_set_restart_priority(struct watchdog_device *wdd, int priority);
220 extern int watchdog_init_timeout(struct watchdog_device *wdd,
221 unsigned int timeout_parm, struct device *dev);
222 extern int watchdog_register_device(struct watchdog_device *);
223 extern void watchdog_unregister_device(struct watchdog_device *);
224 int watchdog_dev_suspend(struct watchdog_device *wdd);
225 int watchdog_dev_resume(struct watchdog_device *wdd);
226
227 int watchdog_set_last_hw_keepalive(struct watchdog_device *, unsigned int);
228
229 /* devres register variant */
230 int devm_watchdog_register_device(struct device *dev, struct watchdog_device *);
231
232 #endif /* ifndef _LINUX_WATCHDOG_H */
233