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Diffstat (limited to '')
| -rw-r--r-- | include/linux/watchdog.h | 219 |
1 files changed, 219 insertions, 0 deletions
diff --git a/include/linux/watchdog.h b/include/linux/watchdog.h new file mode 100644 index 000000000..44985c4a1 --- /dev/null +++ b/include/linux/watchdog.h @@ -0,0 +1,219 @@ +/* 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 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; +}; + +#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 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 */ |