| 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 */ |