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