aboutsummaryrefslogtreecommitdiffstats
path: root/include/linux/watchdog.h
blob: 87490ac4bd87c72909aa8171e12ec8381af54f8c (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
/*
 *	Generic watchdog defines. Derived from..
 *
 * Berkshire PC Watchdog Defines
 * by Ken Hollis <khollis@bitgate.com>
 *
 */
#ifndef _LINUX_WATCHDOG_H
#define _LINUX_WATCHDOG_H


#include <linux/bitops.h>
#include <linux/device.h>
#include <linux/cdev.h>
#include <uapi/linux/watchdog.h>

struct watchdog_ops;
struct watchdog_device;

/** struct watchdog_ops - The watchdog-devices operations
 *
 * @owner:	The module owner.
 * @start:	The routine for starting the watchdog device.
 * @stop:	The routine for stopping the watchdog device.
 * @ping:	The routine that sends a keepalive ping to the watchdog device.
 * @status:	The routine that shows the status of the watchdog device.
 * @set_timeout:The routine for setting the watchdog devices timeout value.
 * @get_timeleft:The routine that get's the time that's left before a reset.
 * @ref:	The ref operation for dyn. allocated watchdog_device structs
 * @unref:	The unref operation for dyn. allocated watchdog_device structs
 * @ioctl:	The routines that handles extra ioctl calls.
 *
 * The watchdog_ops structure contains a list of low-level operations
 * that control a watchdog device. It also contains the module that owns
 * these operations. The start and stop function are mandatory, all other
 * functions are optonal.
 */
struct watchdog_ops {
	struct module *owner;
	/* mandatory operations */
	int (*start)(struct watchdog_device *);
	int (*stop)(struct watchdog_device *);
	/* optional operations */
	int (*ping)(struct watchdog_device *);
	unsigned int (*status)(struct watchdog_device *);
	int (*set_timeout)(struct watchdog_device *, unsigned int);
	unsigned int (*get_timeleft)(struct watchdog_device *);
	void (*ref)(struct watchdog_device *);
	void (*unref)(struct watchdog_device *);
	long (*ioctl)(struct watchdog_device *, unsigned int, unsigned long);
};

/** struct watchdog_device - The structure that defines a watchdog device
 *
 * @id:		The watchdog's ID. (Allocated by watchdog_register_device)
 * @cdev:	The watchdog's Character device.
 * @dev:	The device for our watchdog
 * @parent:	The parent bus device
 * @info:	Pointer to a watchdog_info structure.
 * @ops:	Pointer to the list of watchdog operations.
 * @bootstatus:	Status of the watchdog device at boot.
 * @timeout:	The watchdog devices timeout value.
 * @min_timeout:The watchdog devices minimum timeout value.
 * @max_timeout:The watchdog devices maximum timeout value.
 * @driver-data:Pointer to the drivers private data.
 * @lock:	Lock for watchdog core internal use only.
 * @status:	Field that contains the devices internal status bits.
 *
 * The watchdog_device structure contains all information about a
 * watchdog timer device.
 *
 * The driver-data field may not be accessed directly. It must be accessed
 * via the watchdog_set_drvdata and watchdog_get_drvdata helpers.
 *
 * The lock field is for watchdog core internal use only and should not be
 * touched.
 */
struct watchdog_device {
	int id;
	struct cdev cdev;
	struct device *dev;
	struct device *parent;
	const struct watchdog_info *info;
	const struct watchdog_ops *ops;
	unsigned int bootstatus;
	unsigned int timeout;
	unsigned int min_timeout;
	unsigned int max_timeout;
	void *driver_data;
	struct mutex lock;
	unsigned long status;
/* Bit numbers for status flags */
#define WDOG_ACTIVE		0	/* Is the watchdog running/active */
#define WDOG_DEV_OPEN		1	/* Opened via /dev/watchdog ? */
#define WDOG_ALLOW_RELEASE	2	/* Did we receive the magic char ? */
#define WDOG_NO_WAY_OUT		3	/* Is 'nowayout' feature set ? */
#define WDOG_UNREGISTERED	4	/* Has the device been unregistered */
};

#ifdef CONFIG_WATCHDOG_NOWAYOUT
#define WATCHDOG_NOWAYOUT		1
#define WATCHDOG_NOWAYOUT_INIT_STATUS	(1 << WDOG_NO_WAY_OUT)
#else
#define WATCHDOG_NOWAYOUT		0
#define WATCHDOG_NOWAYOUT_INIT_STATUS	0
#endif

/* Use the following function to check whether or not the watchdog is active */
static inline bool watchdog_active(struct watchdog_device *wdd)
{
	return test_bit(WDOG_ACTIVE, &wdd->status);
}

/* Use the following function to set the nowayout feature */
static inline void watchdog_set_nowayout(struct watchdog_device *wdd, bool nowayout)
{
	if (nowayout)
		set_bit(WDOG_NO_WAY_OUT, &wdd->status);
}

/* Use the following functions to manipulate watchdog driver specific data */
static inline void watchdog_set_drvdata(struct watchdog_device *wdd, void *data)
{
	wdd->driver_data = data;
}

static inline void *watchdog_get_drvdata(struct watchdog_device *wdd)
{
	return wdd->driver_data;
}

/* drivers/watchdog/core/watchdog_core.c */
extern int watchdog_register_device(struct watchdog_device *);
extern void watchdog_unregister_device(struct watchdog_device *);

#endif  /* ifndef _LINUX_WATCHDOG_H */