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