1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * Generic watchdog defines. Derived from.. 4 * 5 * Berkshire PC Watchdog Defines 6 * by Ken Hollis <khollis@bitgate.com> 7 * 8 */ 9 #ifndef _LINUX_WATCHDOG_H 10 #define _LINUX_WATCHDOG_H 11 12 #include <linux/bitops.h> 13 #include <linux/limits.h> 14 #include <linux/notifier.h> 15 #include <linux/printk.h> 16 #include <linux/types.h> 17 18 #include <uapi/linux/watchdog.h> 19 20 struct attribute_group; 21 struct device; 22 struct module; 23 24 struct watchdog_ops; 25 struct watchdog_device; 26 struct watchdog_core_data; 27 struct watchdog_governor; 28 29 /** struct watchdog_ops - The watchdog-devices operations 30 * 31 * @owner: The module owner. 32 * @start: The routine for starting the watchdog device. 33 * @stop: The routine for stopping the watchdog device. 34 * @ping: The routine that sends a keepalive ping to the watchdog device. 35 * @status: The routine that shows the status of the watchdog device. 36 * @set_timeout:The routine for setting the watchdog devices timeout value (in seconds). 37 * @set_pretimeout:The routine for setting the watchdog devices pretimeout. 38 * @get_timeleft:The routine that gets the time left before a reset (in seconds). 39 * @restart: The routine for restarting the machine. 40 * @ioctl: The routines that handles extra ioctl calls. 41 * 42 * The watchdog_ops structure contains a list of low-level operations 43 * that control a watchdog device. It also contains the module that owns 44 * these operations. The start function is mandatory, all other 45 * functions are optional. 46 */ 47 struct watchdog_ops { 48 struct module *owner; 49 /* mandatory operations */ 50 int (*start)(struct watchdog_device *); 51 /* optional operations */ 52 int (*stop)(struct watchdog_device *); 53 int (*ping)(struct watchdog_device *); 54 unsigned int (*status)(struct watchdog_device *); 55 int (*set_timeout)(struct watchdog_device *, unsigned int); 56 int (*set_pretimeout)(struct watchdog_device *, unsigned int); 57 unsigned int (*get_timeleft)(struct watchdog_device *); 58 int (*restart)(struct watchdog_device *, unsigned long, void *); 59 long (*ioctl)(struct watchdog_device *, unsigned int, unsigned long); 60 }; 61 62 /** struct watchdog_device - The structure that defines a watchdog device 63 * 64 * @id: The watchdog's ID. (Allocated by watchdog_register_device) 65 * @parent: The parent bus device 66 * @groups: List of sysfs attribute groups to create when creating the 67 * watchdog device. 68 * @info: Pointer to a watchdog_info structure. 69 * @ops: Pointer to the list of watchdog operations. 70 * @gov: Pointer to watchdog pretimeout governor. 71 * @bootstatus: Status of the watchdog device at boot. 72 * @timeout: The watchdog devices timeout value (in seconds). 73 * @pretimeout: The watchdog devices pre_timeout value. 74 * @min_timeout:The watchdog devices minimum timeout value (in seconds). 75 * @max_timeout:The watchdog devices maximum timeout value (in seconds) 76 * as configurable from user space. Only relevant if 77 * max_hw_heartbeat_ms is not provided. 78 * @min_hw_heartbeat_ms: 79 * Hardware limit for minimum time between heartbeats, 80 * in milli-seconds. 81 * @max_hw_heartbeat_ms: 82 * Hardware limit for maximum timeout, in milli-seconds. 83 * Replaces max_timeout if specified. 84 * @reboot_nb: The notifier block to stop watchdog on reboot. 85 * @restart_nb: The notifier block to register a restart function. 86 * @driver_data:Pointer to the drivers private data. 87 * @wd_data: Pointer to watchdog core internal data. 88 * @status: Field that contains the devices internal status bits. 89 * @deferred: Entry in wtd_deferred_reg_list which is used to 90 * register early initialized watchdogs. 91 * 92 * The watchdog_device structure contains all information about a 93 * watchdog timer device. 94 * 95 * The driver-data field may not be accessed directly. It must be accessed 96 * via the watchdog_set_drvdata and watchdog_get_drvdata helpers. 97 */ 98 struct watchdog_device { 99 int id; 100 struct device *parent; 101 const struct attribute_group **groups; 102 const struct watchdog_info *info; 103 const struct watchdog_ops *ops; 104 const struct watchdog_governor *gov; 105 unsigned int bootstatus; 106 unsigned int timeout; 107 unsigned int pretimeout; 108 unsigned int min_timeout; 109 unsigned int max_timeout; 110 unsigned int min_hw_heartbeat_ms; 111 unsigned int max_hw_heartbeat_ms; 112 struct notifier_block reboot_nb; 113 struct notifier_block restart_nb; 114 struct notifier_block pm_nb; 115 void *driver_data; 116 struct watchdog_core_data *wd_data; 117 unsigned long status; 118 /* Bit numbers for status flags */ 119 #define WDOG_ACTIVE 0 /* Is the watchdog running/active */ 120 #define WDOG_NO_WAY_OUT 1 /* Is 'nowayout' feature set ? */ 121 #define WDOG_STOP_ON_REBOOT 2 /* Should be stopped on reboot */ 122 #define WDOG_HW_RUNNING 3 /* True if HW watchdog running */ 123 #define WDOG_STOP_ON_UNREGISTER 4 /* Should be stopped on unregister */ 124 #define WDOG_NO_PING_ON_SUSPEND 5 /* Ping worker should be stopped on suspend */ 125 struct list_head deferred; 126 }; 127 128 #define WATCHDOG_NOWAYOUT IS_BUILTIN(CONFIG_WATCHDOG_NOWAYOUT) 129 #define WATCHDOG_NOWAYOUT_INIT_STATUS (WATCHDOG_NOWAYOUT << WDOG_NO_WAY_OUT) 130 131 /* Use the following function to check whether or not the watchdog is active */ 132 static inline bool watchdog_active(const struct watchdog_device *wdd) 133 { 134 return test_bit(WDOG_ACTIVE, &wdd->status); 135 } 136 137 /* 138 * Use the following function to check whether or not the hardware watchdog 139 * is running 140 */ 141 static inline bool watchdog_hw_running(const struct watchdog_device *wdd) 142 { 143 return test_bit(WDOG_HW_RUNNING, &wdd->status); 144 } 145 146 /* Use the following function to set the nowayout feature */ 147 static inline void watchdog_set_nowayout(struct watchdog_device *wdd, bool nowayout) 148 { 149 if (nowayout) 150 set_bit(WDOG_NO_WAY_OUT, &wdd->status); 151 } 152 153 /* Use the following function to stop the watchdog on reboot */ 154 static inline void watchdog_stop_on_reboot(struct watchdog_device *wdd) 155 { 156 set_bit(WDOG_STOP_ON_REBOOT, &wdd->status); 157 } 158 159 /* Use the following function to stop the watchdog when unregistering it */ 160 static inline void watchdog_stop_on_unregister(struct watchdog_device *wdd) 161 { 162 set_bit(WDOG_STOP_ON_UNREGISTER, &wdd->status); 163 } 164 165 /* Use the following function to stop the wdog ping worker when suspending */ 166 static inline void watchdog_stop_ping_on_suspend(struct watchdog_device *wdd) 167 { 168 set_bit(WDOG_NO_PING_ON_SUSPEND, &wdd->status); 169 } 170 171 /* Use the following function to check if a timeout value is invalid */ 172 static inline bool watchdog_timeout_invalid(const struct watchdog_device *wdd, 173 unsigned int t) 174 { 175 /* 176 * The timeout is invalid if 177 * - the requested value is larger than UINT_MAX / 1000 178 * (since internal calculations are done in milli-seconds), 179 * or 180 * - the requested value is smaller than the configured minimum timeout, 181 * or 182 * - a maximum hardware timeout is not configured, a maximum timeout 183 * is configured, and the requested value is larger than the 184 * configured maximum timeout. 185 */ 186 return t > UINT_MAX / 1000 || t < wdd->min_timeout || 187 (!wdd->max_hw_heartbeat_ms && wdd->max_timeout && 188 t > wdd->max_timeout); 189 } 190 191 /* Use the following function to check if a pretimeout value is invalid */ 192 static inline bool watchdog_pretimeout_invalid(const struct watchdog_device *wdd, 193 unsigned int t) 194 { 195 return t && wdd->timeout && t >= wdd->timeout; 196 } 197 198 /* Use the following functions to manipulate watchdog driver specific data */ 199 static inline void watchdog_set_drvdata(struct watchdog_device *wdd, void *data) 200 { 201 wdd->driver_data = data; 202 } 203 204 static inline void *watchdog_get_drvdata(struct watchdog_device *wdd) 205 { 206 return wdd->driver_data; 207 } 208 209 /* Use the following functions to report watchdog pretimeout event */ 210 #if IS_ENABLED(CONFIG_WATCHDOG_PRETIMEOUT_GOV) 211 void watchdog_notify_pretimeout(struct watchdog_device *wdd); 212 #else 213 static inline void watchdog_notify_pretimeout(struct watchdog_device *wdd) 214 { 215 pr_alert("watchdog%d: pretimeout event\n", wdd->id); 216 } 217 #endif 218 219 /* drivers/watchdog/watchdog_core.c */ 220 void watchdog_set_restart_priority(struct watchdog_device *wdd, int priority); 221 extern int watchdog_init_timeout(struct watchdog_device *wdd, 222 unsigned int timeout_parm, 223 const struct device *dev); 224 extern int watchdog_register_device(struct watchdog_device *); 225 extern void watchdog_unregister_device(struct watchdog_device *); 226 int watchdog_dev_suspend(struct watchdog_device *wdd); 227 int watchdog_dev_resume(struct watchdog_device *wdd); 228 229 int watchdog_set_last_hw_keepalive(struct watchdog_device *, unsigned int); 230 231 /* devres register variant */ 232 int devm_watchdog_register_device(struct device *dev, struct watchdog_device *); 233 234 #endif /* ifndef _LINUX_WATCHDOG_H */ 235