liteos中中断的注册

在liteos中通过LOS_HwiCreate来注册一个中断，举例如下：

UINT32 Example_Interrupt(VOID)
{
    UINTPTR uvIntSave;
    uvIntSave = LOS_IntLock();

    Example_Exti0_Init();
#核心是调用这个函数来新建中断，第一个形参是中断号
    LOS_HwiCreate(6, 0, 0, User_IRQHandler, 0);//create interrupt

    LOS_IntRestore(uvIntSave);

    return LOS_OK;
}
继续看看
LITE_OS_SEC_TEXT_INIT UINT32 LOS_HwiCreate( HWI_HANDLE_T  uwHwiNum,
                                      HWI_PRIOR_T   usHwiPrio,
                                      HWI_MODE_T    usMode,
                                      HWI_PROC_FUNC pfnHandler,
                                      HWI_ARG_T     uwArg )
{
    UINTPTR uvIntSave;

#这个数组保存这个所有中断号对应的中断处理函数
    if (m_pstHwiForm[uwHwiNum + OS_SYS_VECTOR_CNT] != (HWI_PROC_FUNC)osHwiDefaultHandler)
    {
        return OS_ERRNO_HWI_ALREADY_CREATED;
    }


    uvIntSave = LOS_IntLock();
#根据中断号更新m_pstHwiForm数组中中断号对应的中断处理函数
#if (OS_HWI_WITH_ARG == YES)
    osSetVector(uwHwiNum, pfnHandler, uwArg);
#else
    osSetVector(uwHwiNum, pfnHandler);
#endif
#使能这个中断
    NVIC_EnableIRQ((IRQn_Type)uwHwiNum);
#设置这个中断的优先级
    NVIC_SetPriority((IRQn_Type)uwHwiNum, usHwiPrio);

    LOS_IntRestore(uvIntSave);

    return LOS_OK;

}
可见osSetVector 中更新了两个数组，其中数组m_pstHwiForm 的中每个回调函数都是osInterrupt
在osInterrupt;中会调用pfnVector
#define osSetVector(uwNum, pfnVector)       \
    m_pstHwiForm[uwNum + OS_SYS_VECTOR_CNT] = osInterrupt;\
    m_pstHwiSlaveForm[uwNum + OS_SYS_VECTOR_CNT] = pfnVector;
#endif
为什么会在LOS_HwiCreate中会判断中断的默认处理函数是osHwiDefaultHandler
if (m_pstHwiForm[uwHwiNum + OS_SYS_VECTOR_CNT] != (HWI_PROC_FUNC)osHwiDefaultHandler)
    {
        return OS_ERRNO_HWI_ALREADY_CREATED;
    }
这个是因为在下面的函数中会默认对m_pstHwiForm中的所有中断号赋一个初值，所以这里增加一个判断是
防止中断的重复注册
LITE_OS_SEC_TEXT_INIT VOID osHwiInit()
{
    UINT32 uwIndex;

    for(uwIndex = OS_SYS_VECTOR_CNT; uwIndex < OS_VECTOR_CNT; uwIndex++)
    {
        m_pstHwiForm[uwIndex] = (HWI_PROC_FUNC)osHwiDefaultHandler;
    }

    /* Interrupt vector table location */
    SCB->VTOR = (UINT32)m_pstHwiForm;
#if (__CORTEX_M >= 0x03U)  /* only for Cortex-M3 and above */
    NVIC_SetPriorityGrouping(OS_NVIC_AIRCR_PRIGROUP);
#endif

    return;
}
liteos中中断的注册

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