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 <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#define WATCHDOG_NOWAYOUT		IS_BUILTIN(CONFIG_WATCHDOG_NOWAYOUT)
101#define WATCHDOG_NOWAYOUT_INIT_STATUS	(WATCHDOG_NOWAYOUT << WDOG_NO_WAY_OUT)
102
103/* Use the following function to check whether or not the watchdog is active */
104static inline bool watchdog_active(struct watchdog_device *wdd)
105{
106	return test_bit(WDOG_ACTIVE, &wdd->status);
107}
108
109/* Use the following function to set the nowayout feature */
110static inline void watchdog_set_nowayout(struct watchdog_device *wdd, bool nowayout)
111{
112	if (nowayout)
113		set_bit(WDOG_NO_WAY_OUT, &wdd->status);
114}
115
116/* Use the following function to check if a timeout value is invalid */
117static inline bool watchdog_timeout_invalid(struct watchdog_device *wdd, unsigned int t)
118{
119	return ((wdd->max_timeout != 0) &&
120		(t < wdd->min_timeout || t > wdd->max_timeout));
121}
122
123/* Use the following functions to manipulate watchdog driver specific data */
124static inline void watchdog_set_drvdata(struct watchdog_device *wdd, void *data)
125{
126	wdd->driver_data = data;
127}
128
129static inline void *watchdog_get_drvdata(struct watchdog_device *wdd)
130{
131	return wdd->driver_data;
132}
133
134/* drivers/watchdog/watchdog_core.c */
135extern int watchdog_init_timeout(struct watchdog_device *wdd,
136				  unsigned int timeout_parm, struct device *dev);
137extern int watchdog_register_device(struct watchdog_device *);
138extern void watchdog_unregister_device(struct watchdog_device *);
139
140#ifdef CONFIG_HARDLOCKUP_DETECTOR
141void watchdog_nmi_disable_all(void);
142void watchdog_nmi_enable_all(void);
143#else
144static inline void watchdog_nmi_disable_all(void) {}
145static inline void watchdog_nmi_enable_all(void) {}
146#endif
147
148#endif  /* ifndef _LINUX_WATCHDOG_H */
149