text: /*
   *	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/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 */
  	struct list_head deferred;
  };
  
  #define WATCHDOG_NOWAYOUT		IS_BUILTIN(CONFIG_WATCHDOG_NOWAYOUT)
  #define WATCHDOG_NOWAYOUT_INIT_STATUS	(WATCHDOG_NOWAYOUT << WDOG_NO_WAY_OUT)
  
  /* 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 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);
  }
  
  /* 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 stop the watchdog on reboot */
  static inline void watchdog_stop_on_reboot(struct watchdog_device *wdd)
  {
  	set_bit(WDOG_STOP_ON_REBOOT, &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)
  {
  	/*
  	 * 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);
  }
  
  /* 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;
  }
  
  /* 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;
  }
  
  /* 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);
  }
  #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 */
  