1 /**
2  * \file timing.h
3  *
4  * \brief Portable interface to the CPU cycle counter
5  *
6  *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
7  *  SPDX-License-Identifier: Apache-2.0
8  *
9  *  Licensed under the Apache License, Version 2.0 (the "License"); you may
10  *  not use this file except in compliance with the License.
11  *  You may obtain a copy of the License at
12  *
13  *  http://www.apache.org/licenses/LICENSE-2.0
14  *
15  *  Unless required by applicable law or agreed to in writing, software
16  *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
17  *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
18  *  See the License for the specific language governing permissions and
19  *  limitations under the License.
20  *
21  *  This file is part of mbed TLS (https://tls.mbed.org)
22  */
23 #ifndef MBEDTLS_TIMING_ALT_H
24 #define MBEDTLS_TIMING_ALT_H
25 
26 #if !defined(MBEDTLS_CONFIG_FILE)
27 #include "config.h"
28 #else
29 #include MBEDTLS_CONFIG_FILE
30 #endif
31 
32 #include <stdint.h>
33 
34 #ifdef __cplusplus
35 extern "C" {
36 #endif
37 
38 /**
39  * \brief          timer structure
40  */
41 struct mbedtls_timing_hr_time
42 {
43     unsigned char opaque[32];
44 };
45 
46 /**
47  * \brief          Context for mbedtls_timing_set/get_delay()
48  */
49 typedef struct
50 {
51     struct mbedtls_timing_hr_time   timer;
52     uint32_t                        int_ms;
53     uint32_t                        fin_ms;
54 } mbedtls_timing_delay_context;
55 
56 extern volatile int mbedtls_timing_alarmed;
57 
58 /**
59  * \brief          Return the CPU cycle counter value
60  *
61  * \warning        This is only a best effort! Do not rely on this!
62  *                 In particular, it is known to be unreliable on virtual
63  *                 machines.
64  */
65 unsigned long mbedtls_timing_hardclock( void );
66 
67 /**
68  * \brief          Return the elapsed time in milliseconds
69  *
70  * \param val      points to a timer structure
71  * \param reset    if set to 1, the timer is restarted
72  */
73 unsigned long mbedtls_timing_get_timer( struct mbedtls_timing_hr_time *val, int reset );
74 
75 /**
76  * \brief          Setup an alarm clock
77  *
78  * \param seconds  delay before the "mbedtls_timing_alarmed" flag is set
79  *
80  * \warning        Only one alarm at a time  is supported. In a threaded
81  *                 context, this means one for the whole process, not one per
82  *                 thread.
83  */
84 void mbedtls_set_alarm( int seconds );
85 
86 /**
87  * \brief          Set a pair of delays to watch
88  *                 (See \c mbedtls_timing_get_delay().)
89  *
90  * \param data     Pointer to timing data
91  *                 Must point to a valid \c mbedtls_timing_delay_context struct.
92  * \param int_ms   First (intermediate) delay in milliseconds.
93  * \param fin_ms   Second (final) delay in milliseconds.
94  *                 Pass 0 to cancel the current delay.
95  */
96 void mbedtls_timing_set_delay( void *data, uint32_t int_ms, uint32_t fin_ms );
97 
98 /**
99  * \brief          Get the status of delays
100  *                 (Memory helper: number of delays passed.)
101  *
102  * \param data     Pointer to timing data
103  *                 Must point to a valid \c mbedtls_timing_delay_context struct.
104  *
105  * \return         -1 if cancelled (fin_ms = 0)
106  *                  0 if none of the delays are passed,
107  *                  1 if only the intermediate delay is passed,
108  *                  2 if the final delay is passed.
109  */
110 int mbedtls_timing_get_delay( void *data );
111 
112 #ifdef __cplusplus
113 extern "C" {
114 #endif
115 
116 #ifdef __cplusplus
117 }
118 #endif
119 
120 #endif /* timing.h */
121