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       1                 :            : /* SPDX-License-Identifier: GPL-2.0 */
       2                 :            : /*
       3                 :            :  *      Generic watchdog defines. Derived from..
       4                 :            :  *
       5                 :            :  * Berkshire PC Watchdog Defines
       6                 :            :  * by Ken Hollis <khollis@bitgate.com>
       7                 :            :  *
       8                 :            :  */
       9                 :            : #ifndef _LINUX_WATCHDOG_H
      10                 :            : #define _LINUX_WATCHDOG_H
      11                 :            : 
      12                 :            : 
      13                 :            : #include <linux/bitops.h>
      14                 :            : #include <linux/cdev.h>
      15                 :            : #include <linux/device.h>
      16                 :            : #include <linux/kernel.h>
      17                 :            : #include <linux/notifier.h>
      18                 :            : #include <uapi/linux/watchdog.h>
      19                 :            : 
      20                 :            : struct watchdog_ops;
      21                 :            : struct watchdog_device;
      22                 :            : struct watchdog_core_data;
      23                 :            : struct watchdog_governor;
      24                 :            : 
      25                 :            : /** struct watchdog_ops - The watchdog-devices operations
      26                 :            :  *
      27                 :            :  * @owner:      The module owner.
      28                 :            :  * @start:      The routine for starting the watchdog device.
      29                 :            :  * @stop:       The routine for stopping the watchdog device.
      30                 :            :  * @ping:       The routine that sends a keepalive ping to the watchdog device.
      31                 :            :  * @status:     The routine that shows the status of the watchdog device.
      32                 :            :  * @set_timeout:The routine for setting the watchdog devices timeout value (in seconds).
      33                 :            :  * @set_pretimeout:The routine for setting the watchdog devices pretimeout.
      34                 :            :  * @get_timeleft:The routine that gets the time left before a reset (in seconds).
      35                 :            :  * @restart:    The routine for restarting the machine.
      36                 :            :  * @ioctl:      The routines that handles extra ioctl calls.
      37                 :            :  *
      38                 :            :  * The watchdog_ops structure contains a list of low-level operations
      39                 :            :  * that control a watchdog device. It also contains the module that owns
      40                 :            :  * these operations. The start and stop function are mandatory, all other
      41                 :            :  * functions are optional.
      42                 :            :  */
      43                 :            : struct watchdog_ops {
      44                 :            :         struct module *owner;
      45                 :            :         /* mandatory operations */
      46                 :            :         int (*start)(struct watchdog_device *);
      47                 :            :         int (*stop)(struct watchdog_device *);
      48                 :            :         /* optional operations */
      49                 :            :         int (*ping)(struct watchdog_device *);
      50                 :            :         unsigned int (*status)(struct watchdog_device *);
      51                 :            :         int (*set_timeout)(struct watchdog_device *, unsigned int);
      52                 :            :         int (*set_pretimeout)(struct watchdog_device *, unsigned int);
      53                 :            :         unsigned int (*get_timeleft)(struct watchdog_device *);
      54                 :            :         int (*restart)(struct watchdog_device *, unsigned long, void *);
      55                 :            :         long (*ioctl)(struct watchdog_device *, unsigned int, unsigned long);
      56                 :            : };
      57                 :            : 
      58                 :            : /** struct watchdog_device - The structure that defines a watchdog device
      59                 :            :  *
      60                 :            :  * @id:         The watchdog's ID. (Allocated by watchdog_register_device)
      61                 :            :  * @parent:     The parent bus device
      62                 :            :  * @groups:     List of sysfs attribute groups to create when creating the
      63                 :            :  *              watchdog device.
      64                 :            :  * @info:       Pointer to a watchdog_info structure.
      65                 :            :  * @ops:        Pointer to the list of watchdog operations.
      66                 :            :  * @gov:        Pointer to watchdog pretimeout governor.
      67                 :            :  * @bootstatus: Status of the watchdog device at boot.
      68                 :            :  * @timeout:    The watchdog devices timeout value (in seconds).
      69                 :            :  * @pretimeout: The watchdog devices pre_timeout value.
      70                 :            :  * @min_timeout:The watchdog devices minimum timeout value (in seconds).
      71                 :            :  * @max_timeout:The watchdog devices maximum timeout value (in seconds)
      72                 :            :  *              as configurable from user space. Only relevant if
      73                 :            :  *              max_hw_heartbeat_ms is not provided.
      74                 :            :  * @min_hw_heartbeat_ms:
      75                 :            :  *              Hardware limit for minimum time between heartbeats,
      76                 :            :  *              in milli-seconds.
      77                 :            :  * @max_hw_heartbeat_ms:
      78                 :            :  *              Hardware limit for maximum timeout, in milli-seconds.
      79                 :            :  *              Replaces max_timeout if specified.
      80                 :            :  * @reboot_nb:  The notifier block to stop watchdog on reboot.
      81                 :            :  * @restart_nb: The notifier block to register a restart function.
      82                 :            :  * @driver_data:Pointer to the drivers private data.
      83                 :            :  * @wd_data:    Pointer to watchdog core internal data.
      84                 :            :  * @status:     Field that contains the devices internal status bits.
      85                 :            :  * @deferred:   Entry in wtd_deferred_reg_list which is used to
      86                 :            :  *              register early initialized watchdogs.
      87                 :            :  *
      88                 :            :  * The watchdog_device structure contains all information about a
      89                 :            :  * watchdog timer device.
      90                 :            :  *
      91                 :            :  * The driver-data field may not be accessed directly. It must be accessed
      92                 :            :  * via the watchdog_set_drvdata and watchdog_get_drvdata helpers.
      93                 :            :  */
      94                 :            : struct watchdog_device {
      95                 :            :         int id;
      96                 :            :         struct device *parent;
      97                 :            :         const struct attribute_group **groups;
      98                 :            :         const struct watchdog_info *info;
      99                 :            :         const struct watchdog_ops *ops;
     100                 :            :         const struct watchdog_governor *gov;
     101                 :            :         unsigned int bootstatus;
     102                 :            :         unsigned int timeout;
     103                 :            :         unsigned int pretimeout;
     104                 :            :         unsigned int min_timeout;
     105                 :            :         unsigned int max_timeout;
     106                 :            :         unsigned int min_hw_heartbeat_ms;
     107                 :            :         unsigned int max_hw_heartbeat_ms;
     108                 :            :         struct notifier_block reboot_nb;
     109                 :            :         struct notifier_block restart_nb;
     110                 :            :         void *driver_data;
     111                 :            :         struct watchdog_core_data *wd_data;
     112                 :            :         unsigned long status;
     113                 :            : /* Bit numbers for status flags */
     114                 :            : #define WDOG_ACTIVE             0       /* Is the watchdog running/active */
     115                 :            : #define WDOG_NO_WAY_OUT         1       /* Is 'nowayout' feature set ? */
     116                 :            : #define WDOG_STOP_ON_REBOOT     2       /* Should be stopped on reboot */
     117                 :            : #define WDOG_HW_RUNNING         3       /* True if HW watchdog running */
     118                 :            : #define WDOG_STOP_ON_UNREGISTER 4       /* Should be stopped on unregister */
     119                 :            :         struct list_head deferred;
     120                 :            : };
     121                 :            : 
     122                 :            : #define WATCHDOG_NOWAYOUT               IS_BUILTIN(CONFIG_WATCHDOG_NOWAYOUT)
     123                 :            : #define WATCHDOG_NOWAYOUT_INIT_STATUS   (WATCHDOG_NOWAYOUT << WDOG_NO_WAY_OUT)
     124                 :            : 
     125                 :            : /* Use the following function to check whether or not the watchdog is active */
     126                 :            : static inline bool watchdog_active(struct watchdog_device *wdd)
     127                 :            : {
     128                 :            :         return test_bit(WDOG_ACTIVE, &wdd->status);
     129                 :            : }
     130                 :            : 
     131                 :            : /*
     132                 :            :  * Use the following function to check whether or not the hardware watchdog
     133                 :            :  * is running
     134                 :            :  */
     135                 :            : static inline bool watchdog_hw_running(struct watchdog_device *wdd)
     136                 :            : {
     137                 :          0 :         return test_bit(WDOG_HW_RUNNING, &wdd->status);
     138                 :            : }
     139                 :            : 
     140                 :            : /* Use the following function to set the nowayout feature */
     141                 :            : static inline void watchdog_set_nowayout(struct watchdog_device *wdd, bool nowayout)
     142                 :            : {
     143                 :          3 :         if (nowayout)
     144                 :          0 :                 set_bit(WDOG_NO_WAY_OUT, &wdd->status);
     145                 :            : }
     146                 :            : 
     147                 :            : /* Use the following function to stop the watchdog on reboot */
     148                 :            : static inline void watchdog_stop_on_reboot(struct watchdog_device *wdd)
     149                 :            : {
     150                 :          3 :         set_bit(WDOG_STOP_ON_REBOOT, &wdd->status);
     151                 :            : }
     152                 :            : 
     153                 :            : /* Use the following function to stop the watchdog when unregistering it */
     154                 :            : static inline void watchdog_stop_on_unregister(struct watchdog_device *wdd)
     155                 :            : {
     156                 :            :         set_bit(WDOG_STOP_ON_UNREGISTER, &wdd->status);
     157                 :            : }
     158                 :            : 
     159                 :            : /* Use the following function to check if a timeout value is invalid */
     160                 :            : static inline bool watchdog_timeout_invalid(struct watchdog_device *wdd, unsigned int t)
     161                 :            : {
     162                 :            :         /*
     163                 :            :          * The timeout is invalid if
     164                 :            :          * - the requested value is larger than UINT_MAX / 1000
     165                 :            :          *   (since internal calculations are done in milli-seconds),
     166                 :            :          * or
     167                 :            :          * - the requested value is smaller than the configured minimum timeout,
     168                 :            :          * or
     169                 :            :          * - a maximum hardware timeout is not configured, a maximum timeout
     170                 :            :          *   is configured, and the requested value is larger than the
     171                 :            :          *   configured maximum timeout.
     172                 :            :          */
     173                 :          0 :         return t > UINT_MAX / 1000 || t < wdd->min_timeout ||
     174                 :          0 :                 (!wdd->max_hw_heartbeat_ms && wdd->max_timeout &&
     175                 :            :                  t > wdd->max_timeout);
     176                 :            : }
     177                 :            : 
     178                 :            : /* Use the following function to check if a pretimeout value is invalid */
     179                 :            : static inline bool watchdog_pretimeout_invalid(struct watchdog_device *wdd,
     180                 :            :                                                unsigned int t)
     181                 :            : {
     182                 :          0 :         return t && wdd->timeout && t >= wdd->timeout;
     183                 :            : }
     184                 :            : 
     185                 :            : /* Use the following functions to manipulate watchdog driver specific data */
     186                 :            : static inline void watchdog_set_drvdata(struct watchdog_device *wdd, void *data)
     187                 :            : {
     188                 :            :         wdd->driver_data = data;
     189                 :            : }
     190                 :            : 
     191                 :            : static inline void *watchdog_get_drvdata(struct watchdog_device *wdd)
     192                 :            : {
     193                 :          0 :         return wdd->driver_data;
     194                 :            : }
     195                 :            : 
     196                 :            : /* Use the following functions to report watchdog pretimeout event */
     197                 :            : #if IS_ENABLED(CONFIG_WATCHDOG_PRETIMEOUT_GOV)
     198                 :            : void watchdog_notify_pretimeout(struct watchdog_device *wdd);
     199                 :            : #else
     200                 :            : static inline void watchdog_notify_pretimeout(struct watchdog_device *wdd)
     201                 :            : {
     202                 :            :         pr_alert("watchdog%d: pretimeout event\n", wdd->id);
     203                 :            : }
     204                 :            : #endif
     205                 :            : 
     206                 :            : /* drivers/watchdog/watchdog_core.c */
     207                 :            : void watchdog_set_restart_priority(struct watchdog_device *wdd, int priority);
     208                 :            : extern int watchdog_init_timeout(struct watchdog_device *wdd,
     209                 :            :                                   unsigned int timeout_parm, struct device *dev);
     210                 :            : extern int watchdog_register_device(struct watchdog_device *);
     211                 :            : extern void watchdog_unregister_device(struct watchdog_device *);
     212                 :            : 
     213                 :            : /* devres register variant */
     214                 :            : int devm_watchdog_register_device(struct device *dev, struct watchdog_device *);
     215                 :            : 
     216                 :            : #endif  /* ifndef _LINUX_WATCHDOG_H */