cef9572e9a
Certain watchdogs require the watchdog only to be pinged within a specific time window, pinging too early or too late cause the watchdog to fire. In cases where this sort of watchdog has been started before kernel comes up, we must adjust the watchdog keepalive window to match the actually running timer, so add a new driver API for this purpose. Signed-off-by: Tero Kristo <t-kristo@ti.com> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Link: https://lore.kernel.org/r/20200717132958.14304-3-t-kristo@ti.com Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
219 lines
7.8 KiB
C
219 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 function is 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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/* optional operations */
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int (*stop)(struct watchdog_device *);
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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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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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int watchdog_set_last_hw_keepalive(struct watchdog_device *, unsigned int);
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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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