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/cdev.h> 14 #include <linux/device.h> 15 #include <linux/kernel.h> 16 #include <linux/notifier.h> 17 #include <uapi/linux/watchdog.h> 18 19 struct watchdog_ops; 20 struct watchdog_device; 21 struct watchdog_core_data; 22 23 /** struct watchdog_ops - The watchdog-devices operations 24 * 25 * @owner: The module owner. 26 * @start: The routine for starting the watchdog device. 27 * @stop: The routine for stopping the watchdog device. 28 * @ping: The routine that sends a keepalive ping to the watchdog device. 29 * @status: The routine that shows the status of the watchdog device. 30 * @set_timeout:The routine for setting the watchdog devices timeout value (in seconds). 31 * @get_timeleft:The routine that gets the time left before a reset (in seconds). 32 * @restart: The routine for restarting the machine. 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 *, unsigned long, void *); 51 long (*ioctl)(struct watchdog_device *, unsigned int, unsigned long); 52 }; 53 54 /** struct watchdog_device - The structure that defines a watchdog device 55 * 56 * @id: The watchdog's ID. (Allocated by watchdog_register_device) 57 * @parent: The parent bus device 58 * @groups: List of sysfs attribute groups to create when creating the 59 * watchdog 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 * as configurable from user space. Only relevant if 67 * max_hw_heartbeat_ms is not provided. 68 * @min_hw_heartbeat_ms: 69 * Minimum time between heartbeats, in milli-seconds. 70 * @max_hw_heartbeat_ms: 71 * Hardware limit for maximum timeout, in milli-seconds. 72 * Replaces max_timeout if specified. 73 * @reboot_nb: The notifier block to stop watchdog on reboot. 74 * @restart_nb: The notifier block to register a restart function. 75 * @driver_data:Pointer to the drivers private data. 76 * @wd_data: Pointer to watchdog core internal data. 77 * @status: Field that contains the devices internal status bits. 78 * @deferred: Entry in wtd_deferred_reg_list which is used to 79 * register early initialized watchdogs. 80 * 81 * The watchdog_device structure contains all information about a 82 * watchdog timer device. 83 * 84 * The driver-data field may not be accessed directly. It must be accessed 85 * via the watchdog_set_drvdata and watchdog_get_drvdata helpers. 86 * 87 * The lock field is for watchdog core internal use only and should not be 88 * touched. 89 */ 90 struct watchdog_device { 91 int id; 92 struct device *parent; 93 const struct attribute_group **groups; 94 const struct watchdog_info *info; 95 const struct watchdog_ops *ops; 96 unsigned int bootstatus; 97 unsigned int timeout; 98 unsigned int min_timeout; 99 unsigned int max_timeout; 100 unsigned int min_hw_heartbeat_ms; 101 unsigned int max_hw_heartbeat_ms; 102 struct notifier_block reboot_nb; 103 struct notifier_block restart_nb; 104 void *driver_data; 105 struct watchdog_core_data *wd_data; 106 unsigned long status; 107 /* Bit numbers for status flags */ 108 #define WDOG_ACTIVE 0 /* Is the watchdog running/active */ 109 #define WDOG_NO_WAY_OUT 1 /* Is 'nowayout' feature set ? */ 110 #define WDOG_STOP_ON_REBOOT 2 /* Should be stopped on reboot */ 111 #define WDOG_HW_RUNNING 3 /* True if HW watchdog running */ 112 struct list_head deferred; 113 }; 114 115 #define WATCHDOG_NOWAYOUT IS_BUILTIN(CONFIG_WATCHDOG_NOWAYOUT) 116 #define WATCHDOG_NOWAYOUT_INIT_STATUS (WATCHDOG_NOWAYOUT << WDOG_NO_WAY_OUT) 117 118 /* Use the following function to check whether or not the watchdog is active */ 119 static inline bool watchdog_active(struct watchdog_device *wdd) 120 { 121 return test_bit(WDOG_ACTIVE, &wdd->status); 122 } 123 124 /* 125 * Use the following function to check whether or not the hardware watchdog 126 * is running 127 */ 128 static inline bool watchdog_hw_running(struct watchdog_device *wdd) 129 { 130 return test_bit(WDOG_HW_RUNNING, &wdd->status); 131 } 132 133 /* Use the following function to set the nowayout feature */ 134 static inline void watchdog_set_nowayout(struct watchdog_device *wdd, bool nowayout) 135 { 136 if (nowayout) 137 set_bit(WDOG_NO_WAY_OUT, &wdd->status); 138 } 139 140 /* Use the following function to stop the watchdog on reboot */ 141 static inline void watchdog_stop_on_reboot(struct watchdog_device *wdd) 142 { 143 set_bit(WDOG_STOP_ON_REBOOT, &wdd->status); 144 } 145 146 /* Use the following function to check if a timeout value is invalid */ 147 static inline bool watchdog_timeout_invalid(struct watchdog_device *wdd, unsigned int t) 148 { 149 /* 150 * The timeout is invalid if 151 * - the requested value is larger than UINT_MAX / 1000 152 * (since internal calculations are done in milli-seconds), 153 * or 154 * - the requested value is smaller than the configured minimum timeout, 155 * or 156 * - a maximum hardware timeout is not configured, a maximum timeout 157 * is configured, and the requested value is larger than the 158 * configured maximum timeout. 159 */ 160 return t > UINT_MAX / 1000 || t < wdd->min_timeout || 161 (!wdd->max_hw_heartbeat_ms && wdd->max_timeout && 162 t > wdd->max_timeout); 163 } 164 165 /* Use the following functions to manipulate watchdog driver specific data */ 166 static inline void watchdog_set_drvdata(struct watchdog_device *wdd, void *data) 167 { 168 wdd->driver_data = data; 169 } 170 171 static inline void *watchdog_get_drvdata(struct watchdog_device *wdd) 172 { 173 return wdd->driver_data; 174 } 175 176 /* drivers/watchdog/watchdog_core.c */ 177 void watchdog_set_restart_priority(struct watchdog_device *wdd, int priority); 178 extern int watchdog_init_timeout(struct watchdog_device *wdd, 179 unsigned int timeout_parm, struct device *dev); 180 extern int watchdog_register_device(struct watchdog_device *); 181 extern void watchdog_unregister_device(struct watchdog_device *); 182 183 #endif /* ifndef _LINUX_WATCHDOG_H */ 184