1 /* 2 * Copyright (c) 2020 HiSilicon (Shanghai) Technologies CO., LIMITED. 3 * Licensed under the Apache License, Version 2.0 (the "License"); 4 * you may not use this file except in compliance with the License. 5 * You may obtain a copy of the License at 6 * 7 * http://www.apache.org/licenses/LICENSE-2.0 8 * 9 * Unless required by applicable law or agreed to in writing, software 10 * distributed under the License is distributed on an "AS IS" BASIS, 11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 * See the License for the specific language governing permissions and 13 * limitations under the License. 14 */ 15 /** 16 * @defgroup clock 17 * @ingroup linux 18 */ 19 #ifndef _LINUX_CLOCK_H 20 #define _LINUX_CLOCK_H 21 22 #include "los_typedef.h" 23 24 /** 25 * @ingroup clock 26 * @brief get the system time(ns) 27 * 28 * @par Description: 29 * This API is used to get the system time by read the value of system timer. 30 * @attention 31 * <ul> 32 * <li>system should init the system timer first.</li> 33 * </ul> 34 * 35 * @param None 36 * 37 * @retval unsigned long long the system time(ns). 38 * @par Dependency: 39 * <ul><li>clock.h: the header file that contains the API declaration.</li></ul> 40 * @see None. 41 * @since Huawei LiteOS V200R003C00 42 */ 43 extern unsigned long long sched_clock(void); 44 45 #endif 46