blob: 395b70e0eccf76e0cd31dc1e25afb5d3032fab50 [file] [log] [blame]
* Generic watchdog defines. Derived from..
* Berkshire PC Watchdog Defines
* by Ken Hollis <>
#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 */
/* 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 function to check if a timeout value is invalid */
static inline bool watchdog_timeout_invalid(struct watchdog_device *wdd, unsigned int t)
return ((wdd->max_timeout != 0) &&
(t < wdd->min_timeout || t > wdd->max_timeout));
/* 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/watchdog_core.c */
extern int watchdog_init_timeout(struct watchdog_device *wdd,
unsigned int timeout_parm, struct device *dev);
extern int watchdog_register_device(struct watchdog_device *);
extern void watchdog_unregister_device(struct watchdog_device *);
#endif /* ifndef _LINUX_WATCHDOG_H */