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Release 4.12 include/linux/watchdog.h

Directory: include/linux
 *      Generic watchdog defines. Derived from..
 * Berkshire PC Watchdog Defines
 * by Ken Hollis <>


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

struct watchdog_ops;
struct watchdog_device;
struct watchdog_core_data;
struct watchdog_governor;

/** 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 (in seconds).
 * @set_pretimeout:The routine for setting the watchdog devices pretimeout.
 * @get_timeleft:The routine that gets the time left before a reset (in seconds).
 * @restart:    The routine for restarting the machine.
 * @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 optional.

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);
int (*set_pretimeout)(struct watchdog_device *, unsigned int);
unsigned int (*get_timeleft)(struct watchdog_device *);
int (*restart)(struct watchdog_device *, unsigned long, void *);
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)
 * @parent:     The parent bus device
 * @groups:     List of sysfs attribute groups to create when creating the
 *              watchdog device.
 * @info:       Pointer to a watchdog_info structure.
 * @ops:        Pointer to the list of watchdog operations.
 * @gov:        Pointer to watchdog pretimeout governor.
 * @bootstatus: Status of the watchdog device at boot.
 * @timeout:    The watchdog devices timeout value (in seconds).
 * @pretimeout: The watchdog devices pre_timeout value.
 * @min_timeout:The watchdog devices minimum timeout value (in seconds).
 * @max_timeout:The watchdog devices maximum timeout value (in seconds)
 *              as configurable from user space. Only relevant if
 *              max_hw_heartbeat_ms is not provided.
 * @min_hw_heartbeat_ms:
 *              Hardware limit for minimum time between heartbeats,
 *              in milli-seconds.
 * @max_hw_heartbeat_ms:
 *              Hardware limit for maximum timeout, in milli-seconds.
 *              Replaces max_timeout if specified.
 * @reboot_nb:  The notifier block to stop watchdog on reboot.
 * @restart_nb: The notifier block to register a restart function.
 * @driver_data:Pointer to the drivers private data.
 * @wd_data:    Pointer to watchdog core internal data.
 * @status:     Field that contains the devices internal status bits.
 * @deferred:   Entry in wtd_deferred_reg_list which is used to
 *              register early initialized watchdogs.
 * 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 device *parent;
const struct attribute_group **groups;
const struct watchdog_info *info;
const struct watchdog_ops *ops;
const struct watchdog_governor *gov;
unsigned int bootstatus;
unsigned int timeout;
unsigned int pretimeout;
unsigned int min_timeout;
unsigned int max_timeout;
unsigned int min_hw_heartbeat_ms;
unsigned int max_hw_heartbeat_ms;
struct notifier_block reboot_nb;
struct notifier_block restart_nb;
void *driver_data;
struct watchdog_core_data *wd_data;
unsigned long status;
/* Bit numbers for status flags */

#define WDOG_ACTIVE		0	/* Is the watchdog running/active */

#define WDOG_NO_WAY_OUT		1	/* Is 'nowayout' feature set ? */

#define WDOG_STOP_ON_REBOOT	2	/* Should be stopped on reboot */

#define WDOG_HW_RUNNING		3	/* True if HW watchdog running */

#define WDOG_STOP_ON_UNREGISTER	4	/* Should be stopped on unregister */
struct list_head deferred;



/* 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); }


Viresh Kumar23100.00%1100.00%

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


Guenter Roeck23100.00%1100.00%

/* 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); }


Wim Van Sebroeck29100.00%2100.00%

/* Use the following function to stop the watchdog on reboot */
static inline void watchdog_stop_on_reboot(struct watchdog_device *wdd) { set_bit(WDOG_STOP_ON_REBOOT, &wdd->status); }


Damien Riegel22100.00%1100.00%

/* Use the following function to stop the watchdog when unregistering it */
static inline void watchdog_stop_on_unregister(struct watchdog_device *wdd) { set_bit(WDOG_STOP_ON_UNREGISTER, &wdd->status); }


Guenter Roeck22100.00%1100.00%

/* 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) { /* * The timeout is invalid if * - the requested value is larger than UINT_MAX / 1000 * (since internal calculations are done in milli-seconds), * or * - the requested value is smaller than the configured minimum timeout, * or * - a maximum hardware timeout is not configured, a maximum timeout * is configured, and the requested value is larger than the * configured maximum timeout. */ return t > UINT_MAX / 1000 || t < wdd->min_timeout || (!wdd->max_hw_heartbeat_ms && wdd->max_timeout && t > wdd->max_timeout); }


Fabio Porcedda3063.83%133.33%
Guenter Roeck1736.17%266.67%

/* Use the following function to check if a pretimeout value is invalid */
static inline bool watchdog_pretimeout_invalid(struct watchdog_device *wdd, unsigned int t) { return t && wdd->timeout && t >= wdd->timeout; }


Wolfram Sang29100.00%1100.00%

/* 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; }


Wim Van Sebroeck22100.00%1100.00%

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


Wim Van Sebroeck18100.00%1100.00%

/* Use the following functions to report watchdog pretimeout event */ #if IS_ENABLED(CONFIG_WATCHDOG_PRETIMEOUT_GOV) void watchdog_notify_pretimeout(struct watchdog_device *wdd); #else
static inline void watchdog_notify_pretimeout(struct watchdog_device *wdd) { pr_alert("watchdog%d: pretimeout event\n", wdd->id); }


Vladimir Zapolskiy21100.00%1100.00%

#endif /* drivers/watchdog/watchdog_core.c */ void watchdog_set_restart_priority(struct watchdog_device *wdd, int priority); 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 *); /* devres register variant */ int devm_watchdog_register_device(struct device *dev, struct watchdog_device *); #endif /* ifndef _LINUX_WATCHDOG_H */

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Directory: include/linux
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