/* SPDX-License-Identifier: GPL-2.0 */ /* * 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 function is mandatory, all other * functions are optional. */ 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. * @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(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 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); } /* Use the following function to stop the wdog ping worker when suspending */ static inline void watchdog_stop_ping_on_suspend(struct watchdog_device *wdd) { set_bit(WDOG_NO_PING_ON_SUSPEND, &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 *); int watchdog_dev_suspend(struct watchdog_device *wdd); int watchdog_dev_resume(struct watchdog_device *wdd); int watchdog_set_last_hw_keepalive(struct watchdog_device *, unsigned int); /* devres register variant */ int devm_watchdog_register_device(struct device *dev, struct watchdog_device *); #endif /* ifndef _LINUX_WATCHDOG_H */