include/linux/watchdog.h

   1 /*
   2  *      Generic watchdog defines. Derived from..
   3  *
   4  * Berkshire PC Watchdog Defines
   5  * by Ken Hollis <khollis@bitgate.com>
   6  *
   7  */
   8 #ifndef _LINUX_WATCHDOG_H
   9 #define _LINUX_WATCHDOG_H
  10
  11
  12 #include <linux/bitops.h>
  13 #include <linux/device.h>
  14 #include <linux/cdev.h>
  15 #include <linux/notifier.h>
  16 #include <uapi/linux/watchdog.h>
  17
  18 struct watchdog_ops;
  19 struct watchdog_device;
  20 struct watchdog_core_data;
  21
  22 /** struct watchdog_ops - The watchdog-devices operations
  23  *
  24  * @owner:      The module owner.
  25  * @start:      The routine for starting the watchdog device.
  26  * @stop:       The routine for stopping the watchdog device.
  27  * @ping:       The routine that sends a keepalive ping to the watchdog device.
  28  * @status:     The routine that shows the status of the watchdog device.
  29  * @set_timeout:The routine for setting the watchdog devices timeout value (in seconds).
  30  * @get_timeleft:The routine that gets the time left before a reset (in seconds).
  31  * @restart:    The routine for restarting the machine.
  32  * @ioctl:      The routines that handles extra ioctl calls.
  33  *
  34  * The watchdog_ops structure contains a list of low-level operations
  35  * that control a watchdog device. It also contains the module that owns
  36  * these operations. The start and stop function are mandatory, all other
  37  * functions are optional.
  38  */
  39 struct watchdog_ops {
  40         struct module *owner;
  41         /* mandatory operations */
  42         int (*start)(struct watchdog_device *);
  43         int (*stop)(struct watchdog_device *);
  44         /* optional operations */
  45         int (*ping)(struct watchdog_device *);
  46         unsigned int (*status)(struct watchdog_device *);
  47         int (*set_timeout)(struct watchdog_device *, unsigned int);
  48         unsigned int (*get_timeleft)(struct watchdog_device *);
  49         int (*restart)(struct watchdog_device *, unsigned long, void *);
  50         long (*ioctl)(struct watchdog_device *, unsigned int, unsigned long);
  51 };
  52
  53 /** struct watchdog_device - The structure that defines a watchdog device
  54  *
  55  * @id:         The watchdog's ID. (Allocated by watchdog_register_device)
  56  * @parent:     The parent bus device
  57  * @groups:     List of sysfs attribute groups to create when creating the
  58  *              watchdog device.
  59  * @info:       Pointer to a watchdog_info structure.
  60  * @ops:        Pointer to the list of watchdog operations.
  61  * @bootstatus: Status of the watchdog device at boot.
  62  * @timeout:    The watchdog devices timeout value (in seconds).
  63  * @min_timeout:The watchdog devices minimum timeout value (in seconds).
  64  * @max_timeout:The watchdog devices maximum timeout value (in seconds).
  65  * @reboot_nb:  The notifier block to stop watchdog on reboot.
  66  * @restart_nb: The notifier block to register a restart function.
  67  * @driver_data:Pointer to the drivers private data.
  68  * @wd_data:    Pointer to watchdog core internal data.
  69  * @status:     Field that contains the devices internal status bits.
  70  * @deferred: entry in wtd_deferred_reg_list which is used to
  71  *                         register early initialized watchdogs.
  72  *
  73  * The watchdog_device structure contains all information about a
  74  * watchdog timer device.
  75  *
  76  * The driver-data field may not be accessed directly. It must be accessed
  77  * via the watchdog_set_drvdata and watchdog_get_drvdata helpers.
  78  *
  79  * The lock field is for watchdog core internal use only and should not be
  80  * touched.
  81  */
  82 struct watchdog_device {
  83         int id;
  84         struct device *parent;
  85         const struct attribute_group **groups;
  86         const struct watchdog_info *info;
  87         const struct watchdog_ops *ops;
  88         unsigned int bootstatus;
  89         unsigned int timeout;
  90         unsigned int min_timeout;
  91         unsigned int max_timeout;
  92         struct notifier_block reboot_nb;
  93         struct notifier_block restart_nb;
  94         void *driver_data;
  95         struct watchdog_core_data *wd_data;
  96         unsigned long status;
  97 /* Bit numbers for status flags */
  98 #define WDOG_ACTIVE             0       /* Is the watchdog running/active */
  99 #define WDOG_NO_WAY_OUT         1       /* Is 'nowayout' feature set ? */
 100 #define WDOG_STOP_ON_REBOOT     2       /* Should be stopped on reboot */
 101         struct list_head deferred;
 102 };
 103
 104 #define WATCHDOG_NOWAYOUT               IS_BUILTIN(CONFIG_WATCHDOG_NOWAYOUT)
 105 #define WATCHDOG_NOWAYOUT_INIT_STATUS   (WATCHDOG_NOWAYOUT << WDOG_NO_WAY_OUT)
 106
 107 /* Use the following function to check whether or not the watchdog is active */
 108 static inline bool watchdog_active(struct watchdog_device *wdd)
 109 {
 110         return test_bit(WDOG_ACTIVE, &wdd->status);
 111 }
 112
 113 /* Use the following function to set the nowayout feature */
 114 static inline void watchdog_set_nowayout(struct watchdog_device *wdd, bool nowayout)
 115 {
 116         if (nowayout)
 117                 set_bit(WDOG_NO_WAY_OUT, &wdd->status);
 118 }
 119
 120 /* Use the following function to stop the watchdog on reboot */
 121 static inline void watchdog_stop_on_reboot(struct watchdog_device *wdd)
 122 {
 123         set_bit(WDOG_STOP_ON_REBOOT, &wdd->status);
 124 }
 125
 126 /* Use the following function to check if a timeout value is invalid */
 127 static inline bool watchdog_timeout_invalid(struct watchdog_device *wdd, unsigned int t)
 128 {
 129         /*
 130          * The timeout is invalid if
 131          * - the requested value is smaller than the configured minimum timeout,
 132          * or
 133          * - a maximum timeout is configured, and the requested value is larger
 134          *   than the maximum timeout.
 135          */
 136         return t < wdd->min_timeout ||
 137                 (wdd->max_timeout && t > wdd->max_timeout);
 138 }
 139
 140 /* Use the following functions to manipulate watchdog driver specific data */
 141 static inline void watchdog_set_drvdata(struct watchdog_device *wdd, void *data)
 142 {
 143         wdd->driver_data = data;
 144 }
 145
 146 static inline void *watchdog_get_drvdata(struct watchdog_device *wdd)
 147 {
 148         return wdd->driver_data;
 149 }
 150
 151 /* drivers/watchdog/watchdog_core.c */
 152 void watchdog_set_restart_priority(struct watchdog_device *wdd, int priority);
 153 extern int watchdog_init_timeout(struct watchdog_device *wdd,
 154                                   unsigned int timeout_parm, struct device *dev);
 155 extern int watchdog_register_device(struct watchdog_device *);
 156 extern void watchdog_unregister_device(struct watchdog_device *);
 157
 158 #endif  /* ifndef _LINUX_WATCHDOG_H */