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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
19struct watchdog_ops;
20struct watchdog_device;
21struct watchdog_core_data;
22struct 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 */
42struct 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 */
96struct 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 */
128static 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 */
137static 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 */
143static 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 */
150static 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 */
156static 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 */
162static 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 */
181static 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 */
188static inline void watchdog_set_drvdata(struct watchdog_device *wdd, void *data)
189{
190 wdd->driver_data = data;
191}
192
193static 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)
200void watchdog_notify_pretimeout(struct watchdog_device *wdd);
201#else
202static 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 */
209void watchdog_set_restart_priority(struct watchdog_device *wdd, int priority);
210extern int watchdog_init_timeout(struct watchdog_device *wdd,
211 unsigned int timeout_parm, struct device *dev);
212extern int watchdog_register_device(struct watchdog_device *);
213extern void watchdog_unregister_device(struct watchdog_device *);
214
215/* devres register variant */
216int devm_watchdog_register_device(struct device *dev, struct watchdog_device *);
217
218#endif /* ifndef _LINUX_WATCHDOG_H */