1 /* 2 * Copyright (c) 2018, The OpenThread Authors. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 3. Neither the name of the copyright holder nor the 13 * names of its contributors may be used to endorse or promote products 14 * derived from this software without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE 20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 26 * POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 /** 30 * @file 31 * @brief 32 * This file includes the platform abstraction for the time service. 33 */ 34 35 #ifndef OPENTHREAD_PLATFORM_TIME_H_ 36 #define OPENTHREAD_PLATFORM_TIME_H_ 37 38 #include <stdint.h> 39 40 #ifdef __cplusplus 41 extern "C" { 42 #endif 43 44 #define OT_MS_PER_S 1000 ///< Number of milliseconds per second 45 #define OT_US_PER_MS 1000 ///< Number of microseconds per millisecond 46 #define OT_US_PER_S 1000000 ///< Number of microseconds per second 47 #define OT_NS_PER_US 1000 ///< Number of nanoseconds per microsecond 48 49 /** 50 * @addtogroup plat-time 51 * 52 * @brief 53 * This module includes the platform abstraction for the time service. 54 * 55 * @{ 56 * 57 */ 58 59 /** 60 * Get the current platform time in microseconds referenced to a continuous 61 * monotonic local clock (64 bits width). 62 * 63 * The clock SHALL NOT wrap during the device's uptime. Implementations SHALL 64 * therefore identify and compensate for internal counter overflows. The clock 65 * does not have a defined epoch and it SHALL NOT introduce any continuous or 66 * discontinuous adjustments (e.g. leap seconds). Implementations SHALL 67 * compensate for any sleep times of the device. 68 * 69 * Implementations MAY choose to discipline the platform clock and compensate 70 * for sleep times by any means (e.g. by combining a high precision/low power 71 * RTC with a high resolution counter) as long as the exposed combined clock 72 * provides continuous monotonic microsecond resolution ticks within the 73 * accuracy limits announced by @ref otPlatTimeGetXtalAccuracy. 74 * 75 * @returns The current time in microseconds. 76 * 77 */ 78 uint64_t otPlatTimeGet(void); 79 80 /** 81 * Get the current estimated worst case accuracy (maximum ± deviation from the 82 * nominal frequency) of the local platform clock in units of PPM. 83 * 84 * @note Implementations MAY estimate this value based on current operating 85 * conditions (e.g. temperature). 86 * 87 * In case the implementation does not estimate the current value but returns a 88 * fixed value, this value MUST be the worst-case accuracy over all possible 89 * foreseen operating conditions (temperature, pressure, etc) of the 90 * implementation. 91 * 92 * @returns The current platform clock accuracy, in PPM. 93 * 94 */ 95 uint16_t otPlatTimeGetXtalAccuracy(void); 96 97 /** 98 * @} 99 * 100 */ 101 102 #ifdef __cplusplus 103 } // extern "C" 104 #endif 105 106 #endif // OPENTHREAD_PLATFORM_TIME_H_ 107
