1 /* 2 * Generic watchdog defines. Derived from.. 3 * 4 * Berkshire PC Watchdog Defines 5 * by Ken Hollis <[email protected]> 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 * @set_pretimeout:The routine for setting the watchdog devices pretimeout. 32 * @get_timeleft:The routine that gets the time left before a reset (in seconds). 33 * @restart: The routine for restarting the machine. 34 * @ioctl: The routines that handles extra ioctl calls. 35 * 36 * The watchdog_ops structure contains a list of low-level operations 37 * that control a watchdog device. It also contains the module that owns 38 * these operations. The start and stop function are mandatory, all other 39 * functions are optional. 40 */ 41 struct watchdog_ops { 42 struct module *owner; 43 /* mandatory operations */ 44 int (*start)(struct watchdog_device *); 45 int (*stop)(struct watchdog_device *); 46 /* optional operations */ 47 int (*ping)(struct watchdog_device *); 48 unsigned int (*status)(struct watchdog_device *); 49 int (*set_timeout)(struct watchdog_device *, unsigned int); 50 int (*set_pretimeout)(struct watchdog_device *, unsigned int); 51 unsigned int (*get_timeleft)(struct watchdog_device *); 52 int (*restart)(struct watchdog_device *, unsigned long, void *); 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 * @parent: The parent bus device 60 * @groups: List of sysfs attribute groups to create when creating the 61 * watchdog 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 * @pretimeout: The watchdog devices pre_timeout value. 67 * @min_timeout:The watchdog devices minimum timeout value (in seconds). 68 * @max_timeout:The watchdog devices maximum timeout value (in seconds) 69 * as configurable from user space. Only relevant if 70 * max_hw_heartbeat_ms is not provided. 71 * @min_hw_heartbeat_ms: 72 * Hardware limit for minimum time between heartbeats, 73 * in milli-seconds. 74 * @max_hw_heartbeat_ms: 75 * Hardware limit for maximum timeout, in milli-seconds. 76 * Replaces max_timeout if specified. 77 * @reboot_nb: The notifier block to stop watchdog on reboot. 78 * @restart_nb: The notifier block to register a restart function. 79 * @driver_data:Pointer to the drivers private data. 80 * @wd_data: Pointer to watchdog core internal data. 81 * @status: Field that contains the devices internal status bits. 82 * @deferred: Entry in wtd_deferred_reg_list which is used to 83 * register early initialized watchdogs. 84 * 85 * The watchdog_device structure contains all information about a 86 * watchdog timer device. 87 * 88 * The driver-data field may not be accessed directly. It must be accessed 89 * via the watchdog_set_drvdata and watchdog_get_drvdata helpers. 90 * 91 * The lock field is for watchdog core internal use only and should not be 92 * touched. 93 */ 94 struct watchdog_device { 95 int id; 96 struct device *parent; 97 const struct attribute_group **groups; 98 const struct watchdog_info *info; 99 const struct watchdog_ops *ops; 100 unsigned int bootstatus; 101 unsigned int timeout; 102 unsigned int pretimeout; 103 unsigned int min_timeout; 104 unsigned int max_timeout; 105 unsigned int min_hw_heartbeat_ms; 106 unsigned int max_hw_heartbeat_ms; 107 struct notifier_block reboot_nb; 108 struct notifier_block restart_nb; 109 void *driver_data; 110 struct watchdog_core_data *wd_data; 111 unsigned long status; 112 /* Bit numbers for status flags */ 113 #define WDOG_ACTIVE 0 /* Is the watchdog running/active */ 114 #define WDOG_NO_WAY_OUT 1 /* Is 'nowayout' feature set ? */ 115 #define WDOG_STOP_ON_REBOOT 2 /* Should be stopped on reboot */ 116 #define WDOG_HW_RUNNING 3 /* True if HW watchdog running */ 117 struct list_head deferred; 118 }; 119 120 #define WATCHDOG_NOWAYOUT IS_BUILTIN(CONFIG_WATCHDOG_NOWAYOUT) 121 #define WATCHDOG_NOWAYOUT_INIT_STATUS (WATCHDOG_NOWAYOUT << WDOG_NO_WAY_OUT) 122 123 /* Use the following function to check whether or not the watchdog is active */ 124 static inline bool watchdog_active(struct watchdog_device *wdd) 125 { 126 return test_bit(WDOG_ACTIVE, &wdd->status); 127 } 128 129 /* 130 * Use the following function to check whether or not the hardware watchdog 131 * is running 132 */ 133 static inline bool watchdog_hw_running(struct watchdog_device *wdd) 134 { 135 return test_bit(WDOG_HW_RUNNING, &wdd->status); 136 } 137 138 /* Use the following function to set the nowayout feature */ 139 static inline void watchdog_set_nowayout(struct watchdog_device *wdd, bool nowayout) 140 { 141 if (nowayout) 142 set_bit(WDOG_NO_WAY_OUT, &wdd->status); 143 } 144 145 /* Use the following function to stop the watchdog on reboot */ 146 static inline void watchdog_stop_on_reboot(struct watchdog_device *wdd) 147 { 148 set_bit(WDOG_STOP_ON_REBOOT, &wdd->status); 149 } 150 151 /* Use the following function to check if a timeout value is invalid */ 152 static inline bool watchdog_timeout_invalid(struct watchdog_device *wdd, unsigned int t) 153 { 154 /* 155 * The timeout is invalid if 156 * - the requested value is larger than UINT_MAX / 1000 157 * (since internal calculations are done in milli-seconds), 158 * or 159 * - the requested value is smaller than the configured minimum timeout, 160 * or 161 * - a maximum hardware timeout is not configured, a maximum timeout 162 * is configured, and the requested value is larger than the 163 * configured maximum timeout. 164 */ 165 return t > UINT_MAX / 1000 || t < wdd->min_timeout || 166 (!wdd->max_hw_heartbeat_ms && wdd->max_timeout && 167 t > wdd->max_timeout); 168 } 169 170 /* Use the following function to check if a pretimeout value is invalid */ 171 static inline bool watchdog_pretimeout_invalid(struct watchdog_device *wdd, 172 unsigned int t) 173 { 174 return t && wdd->timeout && t >= wdd->timeout; 175 } 176 177 /* Use the following functions to manipulate watchdog driver specific data */ 178 static inline void watchdog_set_drvdata(struct watchdog_device *wdd, void *data) 179 { 180 wdd->driver_data = data; 181 } 182 183 static inline void *watchdog_get_drvdata(struct watchdog_device *wdd) 184 { 185 return wdd->driver_data; 186 } 187 188 /* drivers/watchdog/watchdog_core.c */ 189 void watchdog_set_restart_priority(struct watchdog_device *wdd, int priority); 190 extern int watchdog_init_timeout(struct watchdog_device *wdd, 191 unsigned int timeout_parm, struct device *dev); 192 extern int watchdog_register_device(struct watchdog_device *); 193 extern void watchdog_unregister_device(struct watchdog_device *); 194 195 /* devres register variant */ 196 int devm_watchdog_register_device(struct device *dev, struct watchdog_device *); 197 198 #endif /* ifndef _LINUX_WATCHDOG_H */ 199