4 * Copyright (c) 2018-2019 Arm Limited and affiliates.
5 * SPDX-License-Identifier: Apache-2.0
6 *
7 * Licensed under the Apache License, Version 2.0 (the "License");
8 * you may not use this file except in compliance with the License.
9 * You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS,
15 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
18 */
19#ifndef MBED_RESET_REASON_API_H
20#define MBED_RESET_REASON_API_H
21
22#if DEVICE_RESET_REASON
23
24#include <stdint.h>
25
26#ifdef __cplusplus
27extern"C" {
28#endif
29
30/**
31 * \defgroup hal_reset_reason ResetReason HAL API
32 * Low-level interface to the ResetReason of a target.
33 *
34 * This module provides a platform-independent method of checking the cause
35 * of the last system reset.
36 *
37 * # Defined behavior
38 * * The function ::hal_reset_reason_clear clears the ResetReason registers
39 * for the next system boot.
40 * * By the time the user calls ::hal_reset_reason_get to read the value,
41 * some other part of the application may have cleared the value. Therefore,
42 * though there may have been a reset reason in the registers when the system
43 * started, the reason may not be available when the user comes to check it.
44 *
45 * # Undefined behavior
46 * * There is no guarantee that the function ::hal_reset_reason_get will
47 * return the same value when you call it repeatedly. Store the value for later
48 * use instead of calling the function repeatedly.
49 * * The function ::hal_reset_reason_clear may not clear the ResetReason
50 * register in time for the next system boot.
51 *
52 * # Notes
53 * * The contents of the targets ResetReason register may be cleared by some
54 * subsystem before it first gets called. This returns a ::RESET_REASON_UNKNOWN
55 * value to the user. To avoid this, the user should call the ResetReason API
56 * as early as possible at boot time.
57 * * If the target doesn't support clearing reset registers,
58 * ::hal_reset_reason_get seems to erroneously return a reset reason even after
59 * clearing.
60 *
61 * @{
62 */
63
64/**
65 * \defgroup hal_reset_reason_tests ResetReason HAL tests
66 * Greentea tests for the ResetReason HAL.
67 *
68 * To run the ResetReason HAL tests, use the command:
69 *
70 * mbed test -t <toolchain> -m <target> -n tests-mbed_hal-reset_reason
71 *
72 */
73
74/** Definitions of different reset reasons
75 */
76typedefenum {
77 RESET_REASON_POWER_ON, /**< Set when power is initially applied to the board. The power-on-reset circuit causes a POWER_ON reset when this occurs */
78 RESET_REASON_PIN_RESET, /**< Set when a reset is triggered by the hardware pin on the board */
79 RESET_REASON_BROWN_OUT, /**< Triggered when the voltage drops below the low voltage detect (LVD) threshold; the system is held in a reset until the voltage rises above the threshold */
80 RESET_REASON_SOFTWARE, /**< Set during software reset, typically triggered by writing the SYSRESETREQ bit in the Application Interrupt and Reset Control register */
81 RESET_REASON_WATCHDOG, /**< Set when a running watchdog timer fails to be refreshed */
82 RESET_REASON_LOCKUP, /**< Set when the core is locked because of an unrecoverable exception */
83 RESET_REASON_WAKE_LOW_POWER, /**< Set when waking from deep sleep mode */
84 RESET_REASON_ACCESS_ERROR, /**< Umbrella value that encompasses any access related reset */
85 RESET_REASON_BOOT_ERROR, /**< Umbrella value that encompasses any boot related reset */
86 RESET_REASON_MULTIPLE, /**< Set if multiple reset reasons are set within the board. Occurs when the reset reason registers aren't cleared between resets */
87 RESET_REASON_PLATFORM, /**< Platform specific reset reason not captured in this enum */
88 RESET_REASON_UNKNOWN /**< Unknown or unreadable reset reason **/
89 } reset_reason_t;
90
91/** Fetch the reset reason for the last system reset.
92 *
93 * This function must return the contents of the system reset reason registers
94 * cast to an appropriate platform independent reset reason. If multiple reset
95 * reasons are set, this function should return ::RESET_REASON_MULTIPLE. If the
96 * reset reason does not match any existing platform independent value, this
97 * function should return ::RESET_REASON_PLATFORM. If no reset reason can be
98 * determined, this function should return ::RESET_REASON_UNKNOWN.
99 *
100 * This function is not idempotent; there is no guarantee the system
101 * reset reason will not be cleared between calls to this function altering the
102 * return value between calls.
103 *
104 * Note: Some platforms contain reset reason registers that persist through
105 * system resets. If the registers haven't been cleared before calling this
106 * function, multiple reasons may be set within the registers. If multiple reset
107 * reasons are detected, this function returns ::RESET_REASON_MULTIPLE.
108 *
109 * @return enum containing the last reset reason for the board.
110 */
111 reset_reason_t hal_reset_reason_get(void);
112
113
114/** Fetch the raw platform specific reset reason register value.
115 *
116 * This function must return the raw contents of the system reset reason
117 * registers cast to a uint32_t value. If the platform contains reset reasons
118 * that span multiple registers/addresses, the value should be concatenated into
119 * the return type.
120 *
121 * This function is not idempotent; there is no guarantee the system
122 * reset reason will not be cleared between calls to this function altering the
123 * return value between calls.
124 *
125 * @return value containing the reset reason register for the given platform.
126 * If the platform contains reset reasons across multiple registers, they
127 * will be concatenated here.
128 */
129 uint32_t hal_reset_reason_get_raw(void);
130
131/** Clear the reset reason from registers.
132 *
133 * Reset the value of the reset status registers. The reset reason persists
134 * between system resets on certain platforms, so the registers should be cleared
135 * before the system resets. Failing to do so may make it difficult to determine
136 * the cause of any subsequent system resets.
137 */
138void hal_reset_reason_clear(void);
139
140/**@}*/
141
142#ifdef __cplusplus
143 }
144#endif
145
146#endif // DEVICE_RESET_REASON
147
148#endif // MBED_RESET_REASON_API_H
149
150/** @}*/
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