projects/linux·blob v3.13 · refs

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1/*
2 * Generic watchdog defines. Derived from..
3 *
4 * Berkshire PC Watchdog Defines
5 * by Ken Hollis <[email protected]>
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 <uapi/linux/watchdog.h>
16
17struct watchdog_ops;
18struct watchdog_device;
19
20/** struct watchdog_ops - The watchdog-devices operations
21 *
22 * @owner: The module owner.
23 * @start: The routine for starting the watchdog device.
24 * @stop: The routine for stopping the watchdog device.
25 * @ping: The routine that sends a keepalive ping to the watchdog device.
26 * @status: The routine that shows the status of the watchdog device.
27 * @set_timeout:The routine for setting the watchdog devices timeout value.
28 * @get_timeleft:The routine that get's the time that's left before a reset.
29 * @ref: The ref operation for dyn. allocated watchdog_device structs
30 * @unref: The unref operation for dyn. allocated watchdog_device structs
31 * @ioctl: The routines that handles extra ioctl calls.
32 *
33 * The watchdog_ops structure contains a list of low-level operations
34 * that control a watchdog device. It also contains the module that owns
35 * these operations. The start and stop function are mandatory, all other
36 * functions are optonal.
37 */
38struct watchdog_ops {
39 struct module *owner;
40 /* mandatory operations */
41 int (*start)(struct watchdog_device *);
42 int (*stop)(struct watchdog_device *);
43 /* optional operations */
44 int (*ping)(struct watchdog_device *);
45 unsigned int (*status)(struct watchdog_device *);
46 int (*set_timeout)(struct watchdog_device *, unsigned int);
47 unsigned int (*get_timeleft)(struct watchdog_device *);
48 void (*ref)(struct watchdog_device *);
49 void (*unref)(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 * @cdev: The watchdog's Character device.
57 * @dev: The device for our watchdog
58 * @parent: The parent bus 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.
63 * @min_timeout:The watchdog devices minimum timeout value.
64 * @max_timeout:The watchdog devices maximum timeout value.
65 * @driver-data:Pointer to the drivers private data.
66 * @lock: Lock for watchdog core internal use only.
67 * @status: Field that contains the devices internal status bits.
68 *
69 * The watchdog_device structure contains all information about a
70 * watchdog timer device.
71 *
72 * The driver-data field may not be accessed directly. It must be accessed
73 * via the watchdog_set_drvdata and watchdog_get_drvdata helpers.
74 *
75 * The lock field is for watchdog core internal use only and should not be
76 * touched.
77 */
78struct watchdog_device {
79 int id;
80 struct cdev cdev;
81 struct device *dev;
82 struct device *parent;
83 const struct watchdog_info *info;
84 const struct watchdog_ops *ops;
85 unsigned int bootstatus;
86 unsigned int timeout;
87 unsigned int min_timeout;
88 unsigned int max_timeout;
89 void *driver_data;
90 struct mutex lock;
91 unsigned long status;
92/* Bit numbers for status flags */
93#define WDOG_ACTIVE 0 /* Is the watchdog running/active */
94#define WDOG_DEV_OPEN 1 /* Opened via /dev/watchdog ? */
95#define WDOG_ALLOW_RELEASE 2 /* Did we receive the magic char ? */
96#define WDOG_NO_WAY_OUT 3 /* Is 'nowayout' feature set ? */
97#define WDOG_UNREGISTERED 4 /* Has the device been unregistered */
98};
99
100#ifdef CONFIG_WATCHDOG_NOWAYOUT
101#define WATCHDOG_NOWAYOUT 1
102#define WATCHDOG_NOWAYOUT_INIT_STATUS (1 << WDOG_NO_WAY_OUT)
103#else
104#define WATCHDOG_NOWAYOUT 0
105#define WATCHDOG_NOWAYOUT_INIT_STATUS 0
106#endif
107
108/* Use the following function to check whether or not the watchdog is active */
109static inline bool watchdog_active(struct watchdog_device *wdd)
110{
111 return test_bit(WDOG_ACTIVE, &wdd->status);
112}
113
114/* Use the following function to set the nowayout feature */
115static inline void watchdog_set_nowayout(struct watchdog_device *wdd, bool nowayout)
116{
117 if (nowayout)
118 set_bit(WDOG_NO_WAY_OUT, &wdd->status);
119}
120
121/* Use the following function to check if a timeout value is invalid */
122static inline bool watchdog_timeout_invalid(struct watchdog_device *wdd, unsigned int t)
123{
124 return ((wdd->max_timeout != 0) &&
125 (t < wdd->min_timeout || t > wdd->max_timeout));
126}
127
128/* Use the following functions to manipulate watchdog driver specific data */
129static inline void watchdog_set_drvdata(struct watchdog_device *wdd, void *data)
130{
131 wdd->driver_data = data;
132}
133
134static inline void *watchdog_get_drvdata(struct watchdog_device *wdd)
135{
136 return wdd->driver_data;
137}
138
139/* drivers/watchdog/watchdog_core.c */
140extern int watchdog_init_timeout(struct watchdog_device *wdd,
141 unsigned int timeout_parm, struct device *dev);
142extern int watchdog_register_device(struct watchdog_device *);
143extern void watchdog_unregister_device(struct watchdog_device *);
144
145#endif /* ifndef _LINUX_WATCHDOG_H */