2 * Generic watchdog defines. Derived from..
4 * Berkshire PC Watchdog Defines
5 * by Ken Hollis <khollis@bitgate.com>
8 #ifndef _LINUX_WATCHDOG_H
9 #define _LINUX_WATCHDOG_H
12 #include <linux/bitops.h>
13 #include <linux/cdev.h>
14 #include <linux/device.h>
15 #include <linux/kernel.h>
16 #include <linux/notifier.h>
17 #include <uapi/linux/watchdog.h>
20 struct watchdog_device;
21 struct watchdog_core_data;
23 /** struct watchdog_ops - The watchdog-devices operations
25 * @owner: The module owner.
26 * @start: The routine for starting the watchdog device.
27 * @stop: The routine for stopping the watchdog device.
28 * @ping: The routine that sends a keepalive ping to the watchdog device.
29 * @status: The routine that shows the status of the watchdog device.
30 * @set_timeout:The routine for setting the watchdog devices timeout value (in seconds).
31 * @set_pretimeout:The routine for setting the watchdog devices pretimeout.
32 * @get_timeleft:The routine that gets the time left before a reset (in seconds).
33 * @restart: The routine for restarting the machine.
34 * @ioctl: The routines that handles extra ioctl calls.
36 * The watchdog_ops structure contains a list of low-level operations
37 * that control a watchdog device. It also contains the module that owns
38 * these operations. The start and stop function are mandatory, all other
39 * functions are optional.
43 /* mandatory operations */
44 int (*start)(struct watchdog_device *);
45 int (*stop)(struct watchdog_device *);
46 /* optional operations */
47 int (*ping)(struct watchdog_device *);
48 unsigned int (*status)(struct watchdog_device *);
49 int (*set_timeout)(struct watchdog_device *, unsigned int);
50 int (*set_pretimeout)(struct watchdog_device *, unsigned int);
51 unsigned int (*get_timeleft)(struct watchdog_device *);
52 int (*restart)(struct watchdog_device *, unsigned long, void *);
53 long (*ioctl)(struct watchdog_device *, unsigned int, unsigned long);
56 /** struct watchdog_device - The structure that defines a watchdog device
58 * @id: The watchdog's ID. (Allocated by watchdog_register_device)
59 * @parent: The parent bus device
60 * @groups: List of sysfs attribute groups to create when creating the
62 * @info: Pointer to a watchdog_info structure.
63 * @ops: Pointer to the list of watchdog operations.
64 * @bootstatus: Status of the watchdog device at boot.
65 * @timeout: The watchdog devices timeout value (in seconds).
66 * @pretimeout: The watchdog devices pre_timeout value.
67 * @min_timeout:The watchdog devices minimum timeout value (in seconds).
68 * @max_timeout:The watchdog devices maximum timeout value (in seconds)
69 * as configurable from user space. Only relevant if
70 * max_hw_heartbeat_ms is not provided.
71 * @min_hw_heartbeat_ms:
72 * Hardware limit for minimum time between heartbeats,
74 * @max_hw_heartbeat_ms:
75 * Hardware limit for maximum timeout, in milli-seconds.
76 * Replaces max_timeout if specified.
77 * @reboot_nb: The notifier block to stop watchdog on reboot.
78 * @restart_nb: The notifier block to register a restart function.
79 * @driver_data:Pointer to the drivers private data.
80 * @wd_data: Pointer to watchdog core internal data.
81 * @status: Field that contains the devices internal status bits.
82 * @deferred: Entry in wtd_deferred_reg_list which is used to
83 * register early initialized watchdogs.
85 * The watchdog_device structure contains all information about a
86 * watchdog timer device.
88 * The driver-data field may not be accessed directly. It must be accessed
89 * via the watchdog_set_drvdata and watchdog_get_drvdata helpers.
91 * The lock field is for watchdog core internal use only and should not be
94 struct watchdog_device {
96 struct device *parent;
97 const struct attribute_group **groups;
98 const struct watchdog_info *info;
99 const struct watchdog_ops *ops;
100 unsigned int bootstatus;
101 unsigned int timeout;
102 unsigned int pretimeout;
103 unsigned int min_timeout;
104 unsigned int max_timeout;
105 unsigned int min_hw_heartbeat_ms;
106 unsigned int max_hw_heartbeat_ms;
107 struct notifier_block reboot_nb;
108 struct notifier_block restart_nb;
110 struct watchdog_core_data *wd_data;
111 unsigned long status;
112 /* Bit numbers for status flags */
113 #define WDOG_ACTIVE 0 /* Is the watchdog running/active */
114 #define WDOG_NO_WAY_OUT 1 /* Is 'nowayout' feature set ? */
115 #define WDOG_STOP_ON_REBOOT 2 /* Should be stopped on reboot */
116 #define WDOG_HW_RUNNING 3 /* True if HW watchdog running */
117 struct list_head deferred;
120 #define WATCHDOG_NOWAYOUT IS_BUILTIN(CONFIG_WATCHDOG_NOWAYOUT)
121 #define WATCHDOG_NOWAYOUT_INIT_STATUS (WATCHDOG_NOWAYOUT << WDOG_NO_WAY_OUT)
123 /* Use the following function to check whether or not the watchdog is active */
124 static inline bool watchdog_active(struct watchdog_device *wdd)
126 return test_bit(WDOG_ACTIVE, &wdd->status);
130 * Use the following function to check whether or not the hardware watchdog
133 static inline bool watchdog_hw_running(struct watchdog_device *wdd)
135 return test_bit(WDOG_HW_RUNNING, &wdd->status);
138 /* Use the following function to set the nowayout feature */
139 static inline void watchdog_set_nowayout(struct watchdog_device *wdd, bool nowayout)
142 set_bit(WDOG_NO_WAY_OUT, &wdd->status);
145 /* Use the following function to stop the watchdog on reboot */
146 static inline void watchdog_stop_on_reboot(struct watchdog_device *wdd)
148 set_bit(WDOG_STOP_ON_REBOOT, &wdd->status);
151 /* Use the following function to check if a timeout value is invalid */
152 static inline bool watchdog_timeout_invalid(struct watchdog_device *wdd, unsigned int t)
155 * The timeout is invalid if
156 * - the requested value is larger than UINT_MAX / 1000
157 * (since internal calculations are done in milli-seconds),
159 * - the requested value is smaller than the configured minimum timeout,
161 * - a maximum hardware timeout is not configured, a maximum timeout
162 * is configured, and the requested value is larger than the
163 * configured maximum timeout.
165 return t > UINT_MAX / 1000 || t < wdd->min_timeout ||
166 (!wdd->max_hw_heartbeat_ms && wdd->max_timeout &&
167 t > wdd->max_timeout);
170 /* Use the following function to check if a pretimeout value is invalid */
171 static inline bool watchdog_pretimeout_invalid(struct watchdog_device *wdd,
174 return t && wdd->timeout && t >= wdd->timeout;
177 /* Use the following functions to manipulate watchdog driver specific data */
178 static inline void watchdog_set_drvdata(struct watchdog_device *wdd, void *data)
180 wdd->driver_data = data;
183 static inline void *watchdog_get_drvdata(struct watchdog_device *wdd)
185 return wdd->driver_data;
188 /* drivers/watchdog/watchdog_core.c */
189 void watchdog_set_restart_priority(struct watchdog_device *wdd, int priority);
190 extern int watchdog_init_timeout(struct watchdog_device *wdd,
191 unsigned int timeout_parm, struct device *dev);
192 extern int watchdog_register_device(struct watchdog_device *);
193 extern void watchdog_unregister_device(struct watchdog_device *);
195 /* devres register variant */
196 int devm_watchdog_register_device(struct device *dev, struct watchdog_device *);
198 #endif /* ifndef _LINUX_WATCHDOG_H */