220 lines
7.8 KiB
C
220 lines
7.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Generic watchdog defines. Derived from..
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*
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* Berkshire PC Watchdog Defines
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* by Ken Hollis <khollis@bitgate.com>
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*
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*/
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#ifndef _LINUX_WATCHDOG_H
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#define _LINUX_WATCHDOG_H
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#include <linux/bitops.h>
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#include <linux/cdev.h>
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#include <linux/device.h>
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#include <linux/kernel.h>
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#include <linux/notifier.h>
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#include <uapi/linux/watchdog.h>
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struct watchdog_ops;
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struct watchdog_device;
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struct watchdog_core_data;
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struct watchdog_governor;
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/** struct watchdog_ops - The watchdog-devices operations
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*
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* @owner: The module owner.
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* @start: The routine for starting the watchdog device.
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* @stop: The routine for stopping the watchdog device.
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* @ping: The routine that sends a keepalive ping to the watchdog device.
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* @status: The routine that shows the status of the watchdog device.
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* @set_timeout:The routine for setting the watchdog devices timeout value (in seconds).
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* @set_pretimeout:The routine for setting the watchdog devices pretimeout.
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* @get_timeleft:The routine that gets the time left before a reset (in seconds).
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* @restart: The routine for restarting the machine.
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* @ioctl: The routines that handles extra ioctl calls.
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*
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* The watchdog_ops structure contains a list of low-level operations
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* that control a watchdog device. It also contains the module that owns
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* these operations. The start and stop function are mandatory, all other
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* functions are optional.
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*/
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struct watchdog_ops {
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struct module *owner;
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/* mandatory operations */
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int (*start)(struct watchdog_device *);
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int (*stop)(struct watchdog_device *);
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/* optional operations */
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int (*ping)(struct watchdog_device *);
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unsigned int (*status)(struct watchdog_device *);
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int (*set_timeout)(struct watchdog_device *, unsigned int);
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int (*set_pretimeout)(struct watchdog_device *, unsigned int);
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unsigned int (*get_timeleft)(struct watchdog_device *);
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int (*restart)(struct watchdog_device *, unsigned long, void *);
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long (*ioctl)(struct watchdog_device *, unsigned int, unsigned long);
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};
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/** struct watchdog_device - The structure that defines a watchdog device
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*
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* @id: The watchdog's ID. (Allocated by watchdog_register_device)
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* @parent: The parent bus device
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* @groups: List of sysfs attribute groups to create when creating the
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* watchdog device.
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* @info: Pointer to a watchdog_info structure.
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* @ops: Pointer to the list of watchdog operations.
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* @gov: Pointer to watchdog pretimeout governor.
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* @bootstatus: Status of the watchdog device at boot.
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* @timeout: The watchdog devices timeout value (in seconds).
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* @pretimeout: The watchdog devices pre_timeout value.
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* @min_timeout:The watchdog devices minimum timeout value (in seconds).
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* @max_timeout:The watchdog devices maximum timeout value (in seconds)
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* as configurable from user space. Only relevant if
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* max_hw_heartbeat_ms is not provided.
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* @min_hw_heartbeat_ms:
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* Hardware limit for minimum time between heartbeats,
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* in milli-seconds.
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* @max_hw_heartbeat_ms:
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* Hardware limit for maximum timeout, in milli-seconds.
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* Replaces max_timeout if specified.
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* @reboot_nb: The notifier block to stop watchdog on reboot.
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* @restart_nb: The notifier block to register a restart function.
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* @driver_data:Pointer to the drivers private data.
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* @wd_data: Pointer to watchdog core internal data.
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* @status: Field that contains the devices internal status bits.
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* @deferred: Entry in wtd_deferred_reg_list which is used to
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* register early initialized watchdogs.
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*
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* The watchdog_device structure contains all information about a
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* watchdog timer device.
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*
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* The driver-data field may not be accessed directly. It must be accessed
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* via the watchdog_set_drvdata and watchdog_get_drvdata helpers.
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*
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* The lock field is for watchdog core internal use only and should not be
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* touched.
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*/
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struct watchdog_device {
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int id;
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struct device *parent;
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const struct attribute_group **groups;
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const struct watchdog_info *info;
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const struct watchdog_ops *ops;
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const struct watchdog_governor *gov;
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unsigned int bootstatus;
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unsigned int timeout;
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unsigned int pretimeout;
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unsigned int min_timeout;
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unsigned int max_timeout;
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unsigned int min_hw_heartbeat_ms;
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unsigned int max_hw_heartbeat_ms;
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struct notifier_block reboot_nb;
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struct notifier_block restart_nb;
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void *driver_data;
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struct watchdog_core_data *wd_data;
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unsigned long status;
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/* Bit numbers for status flags */
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#define WDOG_ACTIVE 0 /* Is the watchdog running/active */
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#define WDOG_NO_WAY_OUT 1 /* Is 'nowayout' feature set ? */
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#define WDOG_STOP_ON_REBOOT 2 /* Should be stopped on reboot */
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#define WDOG_HW_RUNNING 3 /* True if HW watchdog running */
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#define WDOG_STOP_ON_UNREGISTER 4 /* Should be stopped on unregister */
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struct list_head deferred;
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};
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#define WATCHDOG_NOWAYOUT IS_BUILTIN(CONFIG_WATCHDOG_NOWAYOUT)
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#define WATCHDOG_NOWAYOUT_INIT_STATUS (WATCHDOG_NOWAYOUT << WDOG_NO_WAY_OUT)
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/* Use the following function to check whether or not the watchdog is active */
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static inline bool watchdog_active(struct watchdog_device *wdd)
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{
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return test_bit(WDOG_ACTIVE, &wdd->status);
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}
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/*
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* Use the following function to check whether or not the hardware watchdog
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* is running
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*/
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static inline bool watchdog_hw_running(struct watchdog_device *wdd)
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{
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return test_bit(WDOG_HW_RUNNING, &wdd->status);
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}
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/* Use the following function to set the nowayout feature */
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static inline void watchdog_set_nowayout(struct watchdog_device *wdd, bool nowayout)
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{
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if (nowayout)
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set_bit(WDOG_NO_WAY_OUT, &wdd->status);
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}
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/* Use the following function to stop the watchdog on reboot */
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static inline void watchdog_stop_on_reboot(struct watchdog_device *wdd)
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{
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set_bit(WDOG_STOP_ON_REBOOT, &wdd->status);
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}
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/* Use the following function to stop the watchdog when unregistering it */
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static inline void watchdog_stop_on_unregister(struct watchdog_device *wdd)
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{
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set_bit(WDOG_STOP_ON_UNREGISTER, &wdd->status);
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}
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/* Use the following function to check if a timeout value is invalid */
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static inline bool watchdog_timeout_invalid(struct watchdog_device *wdd, unsigned int t)
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{
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/*
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* The timeout is invalid if
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* - the requested value is larger than UINT_MAX / 1000
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* (since internal calculations are done in milli-seconds),
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* or
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* - the requested value is smaller than the configured minimum timeout,
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* or
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* - a maximum hardware timeout is not configured, a maximum timeout
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* is configured, and the requested value is larger than the
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* configured maximum timeout.
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*/
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return t > UINT_MAX / 1000 || t < wdd->min_timeout ||
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(!wdd->max_hw_heartbeat_ms && wdd->max_timeout &&
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t > wdd->max_timeout);
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}
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/* Use the following function to check if a pretimeout value is invalid */
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static inline bool watchdog_pretimeout_invalid(struct watchdog_device *wdd,
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unsigned int t)
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{
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return t && wdd->timeout && t >= wdd->timeout;
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}
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/* Use the following functions to manipulate watchdog driver specific data */
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static inline void watchdog_set_drvdata(struct watchdog_device *wdd, void *data)
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{
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wdd->driver_data = data;
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}
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static inline void *watchdog_get_drvdata(struct watchdog_device *wdd)
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{
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return wdd->driver_data;
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}
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/* Use the following functions to report watchdog pretimeout event */
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#if IS_ENABLED(CONFIG_WATCHDOG_PRETIMEOUT_GOV)
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void watchdog_notify_pretimeout(struct watchdog_device *wdd);
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#else
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static inline void watchdog_notify_pretimeout(struct watchdog_device *wdd)
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{
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pr_alert("watchdog%d: pretimeout event\n", wdd->id);
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}
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#endif
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/* drivers/watchdog/watchdog_core.c */
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void watchdog_set_restart_priority(struct watchdog_device *wdd, int priority);
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extern int watchdog_init_timeout(struct watchdog_device *wdd,
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unsigned int timeout_parm, struct device *dev);
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extern int watchdog_register_device(struct watchdog_device *);
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extern void watchdog_unregister_device(struct watchdog_device *);
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/* devres register variant */
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int devm_watchdog_register_device(struct device *dev, struct watchdog_device *);
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#endif /* ifndef _LINUX_WATCHDOG_H */
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