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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;
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 */
40struct 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 * Hardware limit for minimum time between heartbeats,
70 * in milli-seconds.
71 * @max_hw_heartbeat_ms:
72 * Hardware limit for maximum timeout, in milli-seconds.
73 * Replaces max_timeout if specified.
74 * @reboot_nb: The notifier block to stop watchdog on reboot.
75 * @restart_nb: The notifier block to register a restart function.
76 * @driver_data:Pointer to the drivers private data.
77 * @wd_data: Pointer to watchdog core internal data.
78 * @status: Field that contains the devices internal status bits.
79 * @deferred: Entry in wtd_deferred_reg_list which is used to
80 * register early initialized watchdogs.
81 *
82 * The watchdog_device structure contains all information about a
83 * watchdog timer device.
84 *
85 * The driver-data field may not be accessed directly. It must be accessed
86 * via the watchdog_set_drvdata and watchdog_get_drvdata helpers.
87 *
88 * The lock field is for watchdog core internal use only and should not be
89 * touched.
90 */
91struct watchdog_device {
92 int id;
93 struct device *parent;
94 const struct attribute_group **groups;
95 const struct watchdog_info *info;
96 const struct watchdog_ops *ops;
97 unsigned int bootstatus;
98 unsigned int timeout;
99 unsigned int min_timeout;
100 unsigned int max_timeout;
101 unsigned int min_hw_heartbeat_ms;
102 unsigned int max_hw_heartbeat_ms;
103 struct notifier_block reboot_nb;
104 struct notifier_block restart_nb;
105 void *driver_data;
106 struct watchdog_core_data *wd_data;
107 unsigned long status;
108/* Bit numbers for status flags */
109#define WDOG_ACTIVE 0 /* Is the watchdog running/active */
110#define WDOG_NO_WAY_OUT 1 /* Is 'nowayout' feature set ? */
111#define WDOG_STOP_ON_REBOOT 2 /* Should be stopped on reboot */
112#define WDOG_HW_RUNNING 3 /* True if HW watchdog running */
113 struct list_head deferred;
114};
115
116#define WATCHDOG_NOWAYOUT IS_BUILTIN(CONFIG_WATCHDOG_NOWAYOUT)
117#define WATCHDOG_NOWAYOUT_INIT_STATUS (WATCHDOG_NOWAYOUT << WDOG_NO_WAY_OUT)
118
119/* Use the following function to check whether or not the watchdog is active */
120static inline bool watchdog_active(struct watchdog_device *wdd)
121{
122 return test_bit(WDOG_ACTIVE, &wdd->status);
123}
124
125/*
126 * Use the following function to check whether or not the hardware watchdog
127 * is running
128 */
129static inline bool watchdog_hw_running(struct watchdog_device *wdd)
130{
131 return test_bit(WDOG_HW_RUNNING, &wdd->status);
132}
133
134/* Use the following function to set the nowayout feature */
135static inline void watchdog_set_nowayout(struct watchdog_device *wdd, bool nowayout)
136{
137 if (nowayout)
138 set_bit(WDOG_NO_WAY_OUT, &wdd->status);
139}
140
141/* Use the following function to stop the watchdog on reboot */
142static inline void watchdog_stop_on_reboot(struct watchdog_device *wdd)
143{
144 set_bit(WDOG_STOP_ON_REBOOT, &wdd->status);
145}
146
147/* Use the following function to check if a timeout value is invalid */
148static inline bool watchdog_timeout_invalid(struct watchdog_device *wdd, unsigned int t)
149{
150 /*
151 * The timeout is invalid if
152 * - the requested value is larger than UINT_MAX / 1000
153 * (since internal calculations are done in milli-seconds),
154 * or
155 * - the requested value is smaller than the configured minimum timeout,
156 * or
157 * - a maximum hardware timeout is not configured, a maximum timeout
158 * is configured, and the requested value is larger than the
159 * configured maximum timeout.
160 */
161 return t > UINT_MAX / 1000 || t < wdd->min_timeout ||
162 (!wdd->max_hw_heartbeat_ms && wdd->max_timeout &&
163 t > wdd->max_timeout);
164}
165
166/* Use the following functions to manipulate watchdog driver specific data */
167static inline void watchdog_set_drvdata(struct watchdog_device *wdd, void *data)
168{
169 wdd->driver_data = data;
170}
171
172static inline void *watchdog_get_drvdata(struct watchdog_device *wdd)
173{
174 return wdd->driver_data;
175}
176
177/* drivers/watchdog/watchdog_core.c */
178void watchdog_set_restart_priority(struct watchdog_device *wdd, int priority);
179extern int watchdog_init_timeout(struct watchdog_device *wdd,
180 unsigned int timeout_parm, struct device *dev);
181extern int watchdog_register_device(struct watchdog_device *);
182extern void watchdog_unregister_device(struct watchdog_device *);
183
184/* devres register variant */
185int devm_watchdog_register_device(struct device *dev, struct watchdog_device *);
186
187#endif /* ifndef _LINUX_WATCHDOG_H */