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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#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
20struct attribute_group;
21struct device;
22struct module;
23
24struct watchdog_ops;
25struct watchdog_device;
26struct watchdog_core_data;
27struct 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 */
47struct 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 */
98struct 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 */
132static inline bool watchdog_active(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 */
141static inline bool watchdog_hw_running(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 */
147static 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 */
154static 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 */
160static 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 */
166static 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 */
172static inline bool watchdog_timeout_invalid(struct watchdog_device *wdd, unsigned int t)
173{
174 /*
175 * The timeout is invalid if
176 * - the requested value is larger than UINT_MAX / 1000
177 * (since internal calculations are done in milli-seconds),
178 * or
179 * - the requested value is smaller than the configured minimum timeout,
180 * or
181 * - a maximum hardware timeout is not configured, a maximum timeout
182 * is configured, and the requested value is larger than the
183 * configured maximum timeout.
184 */
185 return t > UINT_MAX / 1000 || t < wdd->min_timeout ||
186 (!wdd->max_hw_heartbeat_ms && wdd->max_timeout &&
187 t > wdd->max_timeout);
188}
189
190/* Use the following function to check if a pretimeout value is invalid */
191static inline bool watchdog_pretimeout_invalid(struct watchdog_device *wdd,
192 unsigned int t)
193{
194 return t && wdd->timeout && t >= wdd->timeout;
195}
196
197/* Use the following functions to manipulate watchdog driver specific data */
198static inline void watchdog_set_drvdata(struct watchdog_device *wdd, void *data)
199{
200 wdd->driver_data = data;
201}
202
203static inline void *watchdog_get_drvdata(struct watchdog_device *wdd)
204{
205 return wdd->driver_data;
206}
207
208/* Use the following functions to report watchdog pretimeout event */
209#if IS_ENABLED(CONFIG_WATCHDOG_PRETIMEOUT_GOV)
210void watchdog_notify_pretimeout(struct watchdog_device *wdd);
211#else
212static inline void watchdog_notify_pretimeout(struct watchdog_device *wdd)
213{
214 pr_alert("watchdog%d: pretimeout event\n", wdd->id);
215}
216#endif
217
218/* drivers/watchdog/watchdog_core.c */
219void watchdog_set_restart_priority(struct watchdog_device *wdd, int priority);
220extern int watchdog_init_timeout(struct watchdog_device *wdd,
221 unsigned int timeout_parm, struct device *dev);
222extern int watchdog_register_device(struct watchdog_device *);
223extern void watchdog_unregister_device(struct watchdog_device *);
224int watchdog_dev_suspend(struct watchdog_device *wdd);
225int watchdog_dev_resume(struct watchdog_device *wdd);
226
227int watchdog_set_last_hw_keepalive(struct watchdog_device *, unsigned int);
228
229/* devres register variant */
230int devm_watchdog_register_device(struct device *dev, struct watchdog_device *);
231
232#endif /* ifndef _LINUX_WATCHDOG_H */