include/linux/watchdog.h

Source file repositories/reference/linux-study-clean/include/linux/watchdog.h

File Facts

System
Linux kernel
Corpus path
include/linux/watchdog.h
Extension
.h
Size
8602 bytes
Lines
239
Domain
Core OS
Bucket
Core Kernel Interface
Inferred role
Core OS: implementation source
Status
source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

struct watchdog_ops {
	struct module *owner;
	/* mandatory operations */
	int (*start)(struct watchdog_device *);
	/* optional operations */
	int (*stop)(struct watchdog_device *);
	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.
 * @pm_nb:	The notifier block to stop watchdog on suspend and restart it
 *		on resume.
 * @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.
 */
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;
	struct notifier_block pm_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 */
#define WDOG_NO_PING_ON_SUSPEND	5	/* Ping worker should be stopped on suspend */
	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(const struct watchdog_device *wdd)
{

Annotation

Implementation Notes