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