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/device.h>
14 #include <linux/cdev.h>
15 #include <linux/notifier.h>
16 #include <uapi/linux/watchdog.h>
19 struct watchdog_device;
20 struct watchdog_core_data;
22 /** struct watchdog_ops - The watchdog-devices operations
24 * @owner: The module owner.
25 * @start: The routine for starting the watchdog device.
26 * @stop: The routine for stopping the watchdog device.
27 * @ping: The routine that sends a keepalive ping to the watchdog device.
28 * @status: The routine that shows the status of the watchdog device.
29 * @set_timeout:The routine for setting the watchdog devices timeout value (in seconds).
30 * @get_timeleft:The routine that gets the time left before a reset (in seconds).
31 * @restart: The routine for restarting the machine.
32 * @ioctl: The routines that handles extra ioctl calls.
34 * The watchdog_ops structure contains a list of low-level operations
35 * that control a watchdog device. It also contains the module that owns
36 * these operations. The start and stop function are mandatory, all other
37 * functions are optional.
41 /* mandatory operations */
42 int (*start)(struct watchdog_device *);
43 int (*stop)(struct watchdog_device *);
44 /* optional operations */
45 int (*ping)(struct watchdog_device *);
46 unsigned int (*status)(struct watchdog_device *);
47 int (*set_timeout)(struct watchdog_device *, unsigned int);
48 unsigned int (*get_timeleft)(struct watchdog_device *);
49 int (*restart)(struct watchdog_device *);
50 long (*ioctl)(struct watchdog_device *, unsigned int, unsigned long);
53 /** struct watchdog_device - The structure that defines a watchdog device
55 * @id: The watchdog's ID. (Allocated by watchdog_register_device)
56 * @dev: The device for our watchdog
57 * @parent: The parent bus device
58 * @groups: List of sysfs attribute groups to create when creating the
60 * @info: Pointer to a watchdog_info structure.
61 * @ops: Pointer to the list of watchdog operations.
62 * @bootstatus: Status of the watchdog device at boot.
63 * @timeout: The watchdog devices timeout value (in seconds).
64 * @min_timeout:The watchdog devices minimum timeout value (in seconds).
65 * @max_timeout:The watchdog devices maximum timeout value (in seconds).
66 * @reboot_nb: The notifier block to stop watchdog on reboot.
67 * @restart_nb: The notifier block to register a restart function.
68 * @driver_data:Pointer to the drivers private data.
69 * @wd_data: Pointer to watchdog core internal data.
70 * @status: Field that contains the devices internal status bits.
71 * @deferred: entry in wtd_deferred_reg_list which is used to
72 * register early initialized watchdogs.
74 * The watchdog_device structure contains all information about a
75 * watchdog timer device.
77 * The driver-data field may not be accessed directly. It must be accessed
78 * via the watchdog_set_drvdata and watchdog_get_drvdata helpers.
80 * The lock field is for watchdog core internal use only and should not be
83 struct watchdog_device {
86 struct device *parent;
87 const struct attribute_group **groups;
88 const struct watchdog_info *info;
89 const struct watchdog_ops *ops;
90 unsigned int bootstatus;
92 unsigned int min_timeout;
93 unsigned int max_timeout;
94 struct notifier_block reboot_nb;
95 struct notifier_block restart_nb;
97 struct watchdog_core_data *wd_data;
99 /* Bit numbers for status flags */
100 #define WDOG_ACTIVE 0 /* Is the watchdog running/active */
101 #define WDOG_NO_WAY_OUT 1 /* Is 'nowayout' feature set ? */
102 #define WDOG_STOP_ON_REBOOT 2 /* Should be stopped on reboot */
103 struct list_head deferred;
106 #define WATCHDOG_NOWAYOUT IS_BUILTIN(CONFIG_WATCHDOG_NOWAYOUT)
107 #define WATCHDOG_NOWAYOUT_INIT_STATUS (WATCHDOG_NOWAYOUT << WDOG_NO_WAY_OUT)
109 /* Use the following function to check whether or not the watchdog is active */
110 static inline bool watchdog_active(struct watchdog_device *wdd)
112 return test_bit(WDOG_ACTIVE, &wdd->status);
115 /* Use the following function to set the nowayout feature */
116 static inline void watchdog_set_nowayout(struct watchdog_device *wdd, bool nowayout)
119 set_bit(WDOG_NO_WAY_OUT, &wdd->status);
122 /* Use the following function to stop the watchdog on reboot */
123 static inline void watchdog_stop_on_reboot(struct watchdog_device *wdd)
125 set_bit(WDOG_STOP_ON_REBOOT, &wdd->status);
128 /* Use the following function to check if a timeout value is invalid */
129 static inline bool watchdog_timeout_invalid(struct watchdog_device *wdd, unsigned int t)
132 * The timeout is invalid if
133 * - the requested value is smaller than the configured minimum timeout,
135 * - a maximum timeout is configured, and the requested value is larger
136 * than the maximum timeout.
138 return t < wdd->min_timeout ||
139 (wdd->max_timeout && t > wdd->max_timeout);
142 /* Use the following functions to manipulate watchdog driver specific data */
143 static inline void watchdog_set_drvdata(struct watchdog_device *wdd, void *data)
145 wdd->driver_data = data;
148 static inline void *watchdog_get_drvdata(struct watchdog_device *wdd)
150 return wdd->driver_data;
153 /* drivers/watchdog/watchdog_core.c */
154 void watchdog_set_restart_priority(struct watchdog_device *wdd, int priority);
155 extern int watchdog_init_timeout(struct watchdog_device *wdd,
156 unsigned int timeout_parm, struct device *dev);
157 extern int watchdog_register_device(struct watchdog_device *);
158 extern void watchdog_unregister_device(struct watchdog_device *);
160 #endif /* ifndef _LINUX_WATCHDOG_H */