los_tick.c

/*
 * Copyright (c) 2013-2019, Huawei Technologies Co., Ltd. All rights reserved.
 * Copyright (c) 2020, Huawei Device Co., Ltd. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this list of
 *    conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice, this list
 *    of conditions and the following disclaimer in the documentation and/or other materials
 *    provided with the distribution.
 *
 * 3. Neither the name of the copyright holder nor the names of its contributors may be used
 *    to endorse or promote products derived from this software without specific prior written
 *    permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "los_tick_pri.h"
#include "los_swtmr_pri.h"
#include "los_task_pri.h"
#include "los_timeslice_pri.h"
#ifdef LOSCFG_KERNEL_TICKLESS
#include "los_tickless_pri.h"
#endif
#ifdef LOSCFG_KERNEL_VDSO
#include "los_vdso.h"
#endif

#ifdef __cplusplus
#if __cplusplus
extern "C" {
#endif /* __cplusplus */
#endif /* __cplusplus */

LITE_OS_SEC_BSS volatile UINT64 g_tickCount[LOSCFG_KERNEL_CORE_NUM] = {0};//tick计数器,系统一旦启动,一直在++, 为防止溢出,这是一个 UINT64 的变量
LITE_OS_SEC_DATA_INIT UINT32 g_sysClock;//系统时钟,是绝大部分部件工作的时钟源，也是其他所有外设的时钟的来源 
LITE_OS_SEC_DATA_INIT UINT32 g_tickPerSecond;//每秒Tick数,鸿蒙默认是每秒100次,即:10ms
LITE_OS_SEC_BSS DOUBLE g_cycle2NsScale;	//周期转纳秒级

/* spinlock for task module */
LITE_OS_SEC_BSS SPIN_LOCK_INIT(g_tickSpin); //节拍器自旋锁

/*
 * Description : Tick interruption handler
 *///节拍中断处理函数 ,鸿蒙默认10ms触发一次
LITE_OS_SEC_TEXT VOID OsTickHandler(VOID)
{
    UINT32 intSave;

    TICK_LOCK(intSave);
    g_tickCount[ArchCurrCpuid()]++;//当前CPU核 计数器
    TICK_UNLOCK(intSave);

#ifdef LOSCFG_KERNEL_VDSO
    OsUpdateVdsoTimeval();
#endif

#ifdef LOSCFG_KERNEL_TICKLESS
    OsTickIrqFlagSet(OsTicklessFlagGet());
#endif

#if (LOSCFG_BASE_CORE_TICK_HW_TIME == YES)
    HalClockIrqClear(); /* diff from every platform */
#endif

    OsTimesliceCheck();//时间片检查

    OsTaskScan(); /* task timeout scan *///任务扫描

#if (LOSCFG_BASE_CORE_SWTMR == YES)
    OsSwtmrScan();//定时器扫描,看是否有超时的定时器
#endif
}

#ifdef __cplusplus
#if __cplusplus
}
#endif /* __cplusplus */
#endif /* __cplusplus */