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Tom Rini83d290c2018-05-06 17:58:06 -04001/* SPDX-License-Identifier: GPL-2.0+ */
maxims@google.com0753bc22017-04-17 12:00:21 -07002/*
3 * Copyright 2017 Google, Inc
maxims@google.com0753bc22017-04-17 12:00:21 -07004 */
5
6#ifndef _WDT_H_
7#define _WDT_H_
8
Stefan Roese06985282019-04-11 15:58:44 +02009#include <dm.h>
10#include <dm/read.h>
11
maxims@google.com0753bc22017-04-17 12:00:21 -070012/*
13 * Implement a simple watchdog uclass. Watchdog is basically a timer that
14 * is used to detect or recover from malfunction. During normal operation
15 * the watchdog would be regularly reset to prevent it from timing out.
16 * If, due to a hardware fault or program error, the computer fails to reset
17 * the watchdog, the timer will elapse and generate a timeout signal.
18 * The timeout signal is used to initiate corrective action or actions,
19 * which typically include placing the system in a safe, known state.
20 */
21
22/*
23 * Start the timer
24 *
25 * @dev: WDT Device
Andy Shevchenkoffdec302017-08-04 15:48:28 -060026 * @timeout_ms: Number of ticks (milliseconds) before timer expires
maxims@google.com0753bc22017-04-17 12:00:21 -070027 * @flags: Driver specific flags. This might be used to specify
28 * which action needs to be executed when the timer expires
29 * @return: 0 if OK, -ve on error
30 */
Andy Shevchenkoffdec302017-08-04 15:48:28 -060031int wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags);
maxims@google.com0753bc22017-04-17 12:00:21 -070032
33/*
34 * Stop the timer, thus disabling the Watchdog. Use wdt_start to start it again.
35 *
36 * @dev: WDT Device
37 * @return: 0 if OK, -ve on error
38 */
39int wdt_stop(struct udevice *dev);
40
41/*
42 * Reset the timer, typically restoring the counter to
43 * the value configured by start()
44 *
45 * @dev: WDT Device
46 * @return: 0 if OK, -ve on error
47 */
48int wdt_reset(struct udevice *dev);
49
50/*
51 * Expire the timer, thus executing its action immediately.
52 * This is typically used to reset the board or peripherals.
53 *
54 * @dev: WDT Device
55 * @flags: Driver specific flags
56 * @return 0 if OK -ve on error. If wdt action is system reset,
57 * this function may never return.
58 */
59int wdt_expire_now(struct udevice *dev, ulong flags);
60
61/*
62 * struct wdt_ops - Driver model wdt operations
63 *
64 * The uclass interface is implemented by all wdt devices which use
65 * driver model.
66 */
67struct wdt_ops {
68 /*
69 * Start the timer
70 *
71 * @dev: WDT Device
Andy Shevchenkoffdec302017-08-04 15:48:28 -060072 * @timeout_ms: Number of ticks (milliseconds) before the timer expires
maxims@google.com0753bc22017-04-17 12:00:21 -070073 * @flags: Driver specific flags. This might be used to specify
74 * which action needs to be executed when the timer expires
75 * @return: 0 if OK, -ve on error
76 */
Andy Shevchenkoffdec302017-08-04 15:48:28 -060077 int (*start)(struct udevice *dev, u64 timeout_ms, ulong flags);
maxims@google.com0753bc22017-04-17 12:00:21 -070078 /*
79 * Stop the timer
80 *
81 * @dev: WDT Device
82 * @return: 0 if OK, -ve on error
83 */
84 int (*stop)(struct udevice *dev);
85 /*
86 * Reset the timer, typically restoring the counter to
87 * the value configured by start()
88 *
89 * @dev: WDT Device
90 * @return: 0 if OK, -ve on error
91 */
92 int (*reset)(struct udevice *dev);
93 /*
94 * Expire the timer, thus executing the action immediately (optional)
95 *
96 * If this function is not provided, a default implementation
97 * will be used, which sets the counter to 1
98 * and waits forever. This is good enough for system level
99 * reset, where the function is not expected to return, but might not be
100 * good enough for other use cases.
101 *
102 * @dev: WDT Device
103 * @flags: Driver specific flags
104 * @return 0 if OK -ve on error. May not return.
105 */
106 int (*expire_now)(struct udevice *dev, ulong flags);
107};
108
Stefan Roese06985282019-04-11 15:58:44 +0200109#if defined(CONFIG_WDT)
110#ifndef CONFIG_WATCHDOG_TIMEOUT_MSECS
111#define CONFIG_WATCHDOG_TIMEOUT_MSECS (60 * 1000)
112#endif
113#define WATCHDOG_TIMEOUT_SECS (CONFIG_WATCHDOG_TIMEOUT_MSECS / 1000)
114
115static inline int initr_watchdog(void)
116{
117 u32 timeout = WATCHDOG_TIMEOUT_SECS;
118
119 /*
120 * Init watchdog: This will call the probe function of the
121 * watchdog driver, enabling the use of the device
122 */
123 if (uclass_get_device_by_seq(UCLASS_WDT, 0,
124 (struct udevice **)&gd->watchdog_dev)) {
125 debug("WDT: Not found by seq!\n");
126 if (uclass_get_device(UCLASS_WDT, 0,
127 (struct udevice **)&gd->watchdog_dev)) {
128 printf("WDT: Not found!\n");
129 return 0;
130 }
131 }
132
133 if (CONFIG_IS_ENABLED(OF_CONTROL)) {
134 timeout = dev_read_u32_default(gd->watchdog_dev, "timeout-sec",
135 WATCHDOG_TIMEOUT_SECS);
136 }
137
138 wdt_start(gd->watchdog_dev, timeout * 1000, 0);
139 gd->flags |= GD_FLG_WDT_READY;
140 printf("WDT: Started with%s servicing (%ds timeout)\n",
141 IS_ENABLED(CONFIG_WATCHDOG) ? "" : "out", timeout);
142
143 return 0;
144}
145#endif
146
maxims@google.com0753bc22017-04-17 12:00:21 -0700147#endif /* _WDT_H_ */