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 *); 50 void (*ref)(struct watchdog_device *) __deprecated; 51 void (*unref)(struct watchdog_device *) __deprecated; 52 long (*ioctl)(struct watchdog_device *, unsigned int, unsigned long); 53 }; 54 55 /** struct watchdog_device - The structure that defines a watchdog device 56 * 57 * @id: The watchdog's ID. (Allocated by watchdog_register_device) 58 * @dev: The device for our watchdog 59 * @parent: The parent bus device 60 * @info: Pointer to a watchdog_info structure. 61 * @ops: Pointer to the list of watchdog operations. 62 * @bootstatus: Status of the watchdog device at boot. 63 * @timeout: The watchdog devices timeout value (in seconds). 64 * @min_timeout:The watchdog devices minimum timeout value (in seconds). 65 * @max_timeout:The watchdog devices maximum timeout value (in seconds). 66 * @reboot_nb: The notifier block to stop watchdog on reboot. 67 * @restart_nb: The notifier block to register a restart function. 68 * @driver_data:Pointer to the drivers private data. 69 * @wd_data: Pointer to watchdog core internal data. 70 * @status: Field that contains the devices internal status bits. 71 * @deferred: entry in wtd_deferred_reg_list which is used to 72 * register early initialized watchdogs. 73 * 74 * The watchdog_device structure contains all information about a 75 * watchdog timer device. 76 * 77 * The driver-data field may not be accessed directly. It must be accessed 78 * via the watchdog_set_drvdata and watchdog_get_drvdata helpers. 79 * 80 * The lock field is for watchdog core internal use only and should not be 81 * touched. 82 */ 83 struct watchdog_device { 84 int id; 85 struct device *dev; 86 struct device *parent; 87 const struct watchdog_info *info; 88 const struct watchdog_ops *ops; 89 unsigned int bootstatus; 90 unsigned int timeout; 91 unsigned int min_timeout; 92 unsigned int max_timeout; 93 struct notifier_block reboot_nb; 94 struct notifier_block restart_nb; 95 void *driver_data; 96 struct watchdog_core_data *wd_data; 97 unsigned long status; 98 /* Bit numbers for status flags */ 99 #define WDOG_ACTIVE 0 /* Is the watchdog running/active */ 100 #define WDOG_NO_WAY_OUT 1 /* Is 'nowayout' feature set ? */ 101 #define WDOG_STOP_ON_REBOOT 2 /* Should be stopped on reboot */ 102 struct list_head deferred; 103 }; 104 105 #define WATCHDOG_NOWAYOUT IS_BUILTIN(CONFIG_WATCHDOG_NOWAYOUT) 106 #define WATCHDOG_NOWAYOUT_INIT_STATUS (WATCHDOG_NOWAYOUT << WDOG_NO_WAY_OUT) 107 108 /* Use the following function to check whether or not the watchdog is active */ 109 static inline bool watchdog_active(struct watchdog_device *wdd) 110 { 111 return test_bit(WDOG_ACTIVE, &wdd->status); 112 } 113 114 /* Use the following function to set the nowayout feature */ 115 static inline void watchdog_set_nowayout(struct watchdog_device *wdd, bool nowayout) 116 { 117 if (nowayout) 118 set_bit(WDOG_NO_WAY_OUT, &wdd->status); 119 } 120 121 /* Use the following function to stop the watchdog on reboot */ 122 static inline void watchdog_stop_on_reboot(struct watchdog_device *wdd) 123 { 124 set_bit(WDOG_STOP_ON_REBOOT, &wdd->status); 125 } 126 127 /* Use the following function to check if a timeout value is invalid */ 128 static inline bool watchdog_timeout_invalid(struct watchdog_device *wdd, unsigned int t) 129 { 130 /* 131 * The timeout is invalid if 132 * - the requested value is smaller than the configured minimum timeout, 133 * or 134 * - a maximum timeout is configured, and the requested value is larger 135 * than the maximum timeout. 136 */ 137 return t < wdd->min_timeout || 138 (wdd->max_timeout && t > wdd->max_timeout); 139 } 140 141 /* Use the following functions to manipulate watchdog driver specific data */ 142 static inline void watchdog_set_drvdata(struct watchdog_device *wdd, void *data) 143 { 144 wdd->driver_data = data; 145 } 146 147 static inline void *watchdog_get_drvdata(struct watchdog_device *wdd) 148 { 149 return wdd->driver_data; 150 } 151 152 /* drivers/watchdog/watchdog_core.c */ 153 void watchdog_set_restart_priority(struct watchdog_device *wdd, int priority); 154 extern int watchdog_init_timeout(struct watchdog_device *wdd, 155 unsigned int timeout_parm, struct device *dev); 156 extern int watchdog_register_device(struct watchdog_device *); 157 extern void watchdog_unregister_device(struct watchdog_device *); 158 159 #endif /* ifndef _LINUX_WATCHDOG_H */ 160