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