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 struct watchdog_governor; 23 24 /** struct watchdog_ops - The watchdog-devices operations 25 * 26 * @owner: The module owner. 27 * @start: The routine for starting the watchdog device. 28 * @stop: The routine for stopping the watchdog device. 29 * @ping: The routine that sends a keepalive ping to the watchdog device. 30 * @status: The routine that shows the status of the watchdog device. 31 * @set_timeout:The routine for setting the watchdog devices timeout value (in seconds). 32 * @set_pretimeout:The routine for setting the watchdog devices pretimeout. 33 * @get_timeleft:The routine that gets the time left before a reset (in seconds). 34 * @restart: The routine for restarting the machine. 35 * @ioctl: The routines that handles extra ioctl calls. 36 * 37 * The watchdog_ops structure contains a list of low-level operations 38 * that control a watchdog device. It also contains the module that owns 39 * these operations. The start and stop function are mandatory, all other 40 * functions are optional. 41 */ 42 struct watchdog_ops { 43 struct module *owner; 44 /* mandatory operations */ 45 int (*start)(struct watchdog_device *); 46 int (*stop)(struct watchdog_device *); 47 /* optional operations */ 48 int (*ping)(struct watchdog_device *); 49 unsigned int (*status)(struct watchdog_device *); 50 int (*set_timeout)(struct watchdog_device *, unsigned int); 51 int (*set_pretimeout)(struct watchdog_device *, unsigned int); 52 unsigned int (*get_timeleft)(struct watchdog_device *); 53 int (*restart)(struct watchdog_device *, unsigned long, void *); 54 long (*ioctl)(struct watchdog_device *, unsigned int, unsigned long); 55 }; 56 57 /** struct watchdog_device - The structure that defines a watchdog device 58 * 59 * @id: The watchdog's ID. (Allocated by watchdog_register_device) 60 * @parent: The parent bus device 61 * @groups: List of sysfs attribute groups to create when creating the 62 * watchdog device. 63 * @info: Pointer to a watchdog_info structure. 64 * @ops: Pointer to the list of watchdog operations. 65 * @gov: Pointer to watchdog pretimeout governor. 66 * @bootstatus: Status of the watchdog device at boot. 67 * @timeout: The watchdog devices timeout value (in seconds). 68 * @pretimeout: The watchdog devices pre_timeout value. 69 * @min_timeout:The watchdog devices minimum timeout value (in seconds). 70 * @max_timeout:The watchdog devices maximum timeout value (in seconds) 71 * as configurable from user space. Only relevant if 72 * max_hw_heartbeat_ms is not provided. 73 * @min_hw_heartbeat_ms: 74 * Hardware limit for minimum time between heartbeats, 75 * in milli-seconds. 76 * @max_hw_heartbeat_ms: 77 * Hardware limit for maximum timeout, in milli-seconds. 78 * Replaces max_timeout if specified. 79 * @reboot_nb: The notifier block to stop watchdog on reboot. 80 * @restart_nb: The notifier block to register a restart function. 81 * @driver_data:Pointer to the drivers private data. 82 * @wd_data: Pointer to watchdog core internal data. 83 * @status: Field that contains the devices internal status bits. 84 * @deferred: Entry in wtd_deferred_reg_list which is used to 85 * register early initialized watchdogs. 86 * 87 * The watchdog_device structure contains all information about a 88 * watchdog timer device. 89 * 90 * The driver-data field may not be accessed directly. It must be accessed 91 * via the watchdog_set_drvdata and watchdog_get_drvdata helpers. 92 * 93 * The lock field is for watchdog core internal use only and should not be 94 * touched. 95 */ 96 struct watchdog_device { 97 int id; 98 struct device *parent; 99 const struct attribute_group **groups; 100 const struct watchdog_info *info; 101 const struct watchdog_ops *ops; 102 const struct watchdog_governor *gov; 103 unsigned int bootstatus; 104 unsigned int timeout; 105 unsigned int pretimeout; 106 unsigned int min_timeout; 107 unsigned int max_timeout; 108 unsigned int min_hw_heartbeat_ms; 109 unsigned int max_hw_heartbeat_ms; 110 struct notifier_block reboot_nb; 111 struct notifier_block restart_nb; 112 void *driver_data; 113 struct watchdog_core_data *wd_data; 114 unsigned long status; 115 /* Bit numbers for status flags */ 116 #define WDOG_ACTIVE 0 /* Is the watchdog running/active */ 117 #define WDOG_NO_WAY_OUT 1 /* Is 'nowayout' feature set ? */ 118 #define WDOG_STOP_ON_REBOOT 2 /* Should be stopped on reboot */ 119 #define WDOG_HW_RUNNING 3 /* True if HW watchdog running */ 120 #define WDOG_STOP_ON_UNREGISTER 4 /* Should be stopped on unregister */ 121 struct list_head deferred; 122 }; 123 124 #define WATCHDOG_NOWAYOUT IS_BUILTIN(CONFIG_WATCHDOG_NOWAYOUT) 125 #define WATCHDOG_NOWAYOUT_INIT_STATUS (WATCHDOG_NOWAYOUT << WDOG_NO_WAY_OUT) 126 127 /* Use the following function to check whether or not the watchdog is active */ 128 static inline bool watchdog_active(struct watchdog_device *wdd) 129 { 130 return test_bit(WDOG_ACTIVE, &wdd->status); 131 } 132 133 /* 134 * Use the following function to check whether or not the hardware watchdog 135 * is running 136 */ 137 static inline bool watchdog_hw_running(struct watchdog_device *wdd) 138 { 139 return test_bit(WDOG_HW_RUNNING, &wdd->status); 140 } 141 142 /* Use the following function to set the nowayout feature */ 143 static inline void watchdog_set_nowayout(struct watchdog_device *wdd, bool nowayout) 144 { 145 if (nowayout) 146 set_bit(WDOG_NO_WAY_OUT, &wdd->status); 147 } 148 149 /* Use the following function to stop the watchdog on reboot */ 150 static inline void watchdog_stop_on_reboot(struct watchdog_device *wdd) 151 { 152 set_bit(WDOG_STOP_ON_REBOOT, &wdd->status); 153 } 154 155 /* Use the following function to stop the watchdog when unregistering it */ 156 static inline void watchdog_stop_on_unregister(struct watchdog_device *wdd) 157 { 158 set_bit(WDOG_STOP_ON_UNREGISTER, &wdd->status); 159 } 160 161 /* Use the following function to check if a timeout value is invalid */ 162 static inline bool watchdog_timeout_invalid(struct watchdog_device *wdd, unsigned int t) 163 { 164 /* 165 * The timeout is invalid if 166 * - the requested value is larger than UINT_MAX / 1000 167 * (since internal calculations are done in milli-seconds), 168 * or 169 * - the requested value is smaller than the configured minimum timeout, 170 * or 171 * - a maximum hardware timeout is not configured, a maximum timeout 172 * is configured, and the requested value is larger than the 173 * configured maximum timeout. 174 */ 175 return t > UINT_MAX / 1000 || t < wdd->min_timeout || 176 (!wdd->max_hw_heartbeat_ms && wdd->max_timeout && 177 t > wdd->max_timeout); 178 } 179 180 /* Use the following function to check if a pretimeout value is invalid */ 181 static inline bool watchdog_pretimeout_invalid(struct watchdog_device *wdd, 182 unsigned int t) 183 { 184 return t && wdd->timeout && t >= wdd->timeout; 185 } 186 187 /* Use the following functions to manipulate watchdog driver specific data */ 188 static inline void watchdog_set_drvdata(struct watchdog_device *wdd, void *data) 189 { 190 wdd->driver_data = data; 191 } 192 193 static inline void *watchdog_get_drvdata(struct watchdog_device *wdd) 194 { 195 return wdd->driver_data; 196 } 197 198 /* Use the following functions to report watchdog pretimeout event */ 199 #if IS_ENABLED(CONFIG_WATCHDOG_PRETIMEOUT_GOV) 200 void watchdog_notify_pretimeout(struct watchdog_device *wdd); 201 #else 202 static inline void watchdog_notify_pretimeout(struct watchdog_device *wdd) 203 { 204 pr_alert("watchdog%d: pretimeout event\n", wdd->id); 205 } 206 #endif 207 208 /* drivers/watchdog/watchdog_core.c */ 209 void watchdog_set_restart_priority(struct watchdog_device *wdd, int priority); 210 extern int watchdog_init_timeout(struct watchdog_device *wdd, 211 unsigned int timeout_parm, struct device *dev); 212 extern int watchdog_register_device(struct watchdog_device *); 213 extern void watchdog_unregister_device(struct watchdog_device *); 214 215 /* devres register variant */ 216 int devm_watchdog_register_device(struct device *dev, struct watchdog_device *); 217 218 #endif /* ifndef _LINUX_WATCHDOG_H */ 219