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1/*
2 * Generic watchdog defines. Derived from..
3 *
4 * Berkshire PC Watchdog Defines
5 * by Ken Hollis <khollis@bitgate.com>
6 *
7 */
8#ifndef _LINUX_WATCHDOG_H
9#define _LINUX_WATCHDOG_H
10
11
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>
17
18struct watchdog_ops;
19struct watchdog_device;
20struct watchdog_core_data;
21
22/** struct watchdog_ops - The watchdog-devices operations
23 *
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.
33 *
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.
38 */
39struct watchdog_ops {
40 struct module *owner;
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);
51};
52
53/** struct watchdog_device - The structure that defines a watchdog device
54 *
55 * @id: The watchdog's ID. (Allocated by watchdog_register_device)
56 * @parent: The parent bus device
57 * @groups: List of sysfs attribute groups to create when creating the
58 * watchdog device.
59 * @info: Pointer to a watchdog_info structure.
60 * @ops: Pointer to the list of watchdog operations.
61 * @bootstatus: Status of the watchdog device at boot.
62 * @timeout: The watchdog devices timeout value (in seconds).
63 * @min_timeout:The watchdog devices minimum timeout value (in seconds).
64 * @max_timeout:The watchdog devices maximum timeout value (in seconds).
65 * @reboot_nb: The notifier block to stop watchdog on reboot.
66 * @restart_nb: The notifier block to register a restart function.
67 * @driver_data:Pointer to the drivers private data.
68 * @wd_data: Pointer to watchdog core internal data.
69 * @status: Field that contains the devices internal status bits.
70 * @deferred: entry in wtd_deferred_reg_list which is used to
71 * register early initialized watchdogs.
72 *
73 * The watchdog_device structure contains all information about a
74 * watchdog timer device.
75 *
76 * The driver-data field may not be accessed directly. It must be accessed
77 * via the watchdog_set_drvdata and watchdog_get_drvdata helpers.
78 *
79 * The lock field is for watchdog core internal use only and should not be
80 * touched.
81 */
82struct watchdog_device {
83 int id;
84 struct device *parent;
85 const struct attribute_group **groups;
86 const struct watchdog_info *info;
87 const struct watchdog_ops *ops;
88 unsigned int bootstatus;
89 unsigned int timeout;
90 unsigned int min_timeout;
91 unsigned int max_timeout;
92 struct notifier_block reboot_nb;
93 struct notifier_block restart_nb;
94 void *driver_data;
95 struct watchdog_core_data *wd_data;
96 unsigned long status;
97/* Bit numbers for status flags */
98#define WDOG_ACTIVE 0 /* Is the watchdog running/active */
99#define WDOG_NO_WAY_OUT 1 /* Is 'nowayout' feature set ? */
100#define WDOG_STOP_ON_REBOOT 2 /* Should be stopped on reboot */
101 struct list_head deferred;
102};
103
104#define WATCHDOG_NOWAYOUT IS_BUILTIN(CONFIG_WATCHDOG_NOWAYOUT)
105#define WATCHDOG_NOWAYOUT_INIT_STATUS (WATCHDOG_NOWAYOUT << WDOG_NO_WAY_OUT)
106
107/* Use the following function to check whether or not the watchdog is active */
108static inline bool watchdog_active(struct watchdog_device *wdd)
109{
110 return test_bit(WDOG_ACTIVE, &wdd->status);
111}
112
113/* Use the following function to set the nowayout feature */
114static inline void watchdog_set_nowayout(struct watchdog_device *wdd, bool nowayout)
115{
116 if (nowayout)
117 set_bit(WDOG_NO_WAY_OUT, &wdd->status);
118}
119
120/* Use the following function to stop the watchdog on reboot */
121static inline void watchdog_stop_on_reboot(struct watchdog_device *wdd)
122{
123 set_bit(WDOG_STOP_ON_REBOOT, &wdd->status);
124}
125
126/* Use the following function to check if a timeout value is invalid */
127static inline bool watchdog_timeout_invalid(struct watchdog_device *wdd, unsigned int t)
128{
129 /*
130 * The timeout is invalid if
131 * - the requested value is smaller than the configured minimum timeout,
132 * or
133 * - a maximum timeout is configured, and the requested value is larger
134 * than the maximum timeout.
135 */
136 return t < wdd->min_timeout ||
137 (wdd->max_timeout && t > wdd->max_timeout);
138}
139
140/* Use the following functions to manipulate watchdog driver specific data */
141static inline void watchdog_set_drvdata(struct watchdog_device *wdd, void *data)
142{
143 wdd->driver_data = data;
144}
145
146static inline void *watchdog_get_drvdata(struct watchdog_device *wdd)
147{
148 return wdd->driver_data;
149}
150
151/* drivers/watchdog/watchdog_core.c */
152void watchdog_set_restart_priority(struct watchdog_device *wdd, int priority);
153extern int watchdog_init_timeout(struct watchdog_device *wdd,
154 unsigned int timeout_parm, struct device *dev);
155extern int watchdog_register_device(struct watchdog_device *);
156extern void watchdog_unregister_device(struct watchdog_device *);
157
158#endif /* ifndef _LINUX_WATCHDOG_H */