XScuGic_Connect分析

说明

最近在研究ZYNQ中断的事情，感觉搞清楚Xilinx的一些官方函数或许有帮助吧。
一下是笔者对XScuGic_Connect的分析。

---

源代码

XScuGic_Connect函数代码如下，

/*****************************************************************************/
/**
*
* Makes the connection between the Int_Id of the interrupt source and the
* associated handler that is to run when the interrupt is recognized. The
* argument provided in this call as the Callbackref is used as the argument
* for the handler when it is called.
*
* @param	InstancePtr is a pointer to the XScuGic instance.
* @param	Int_Id contains the ID of the interrupt source and should be
*		in the range of 0 to XSCUGIC_MAX_NUM_INTR_INPUTS - 1
* @param	Handler to the handler for that interrupt.
* @param	CallBackRef is the callback reference, usually the instance
*		pointer of the connecting driver.
*
* @return
*
*		- XST_SUCCESS if the handler was connected correctly.
*
* @note
*
* WARNING: The handler provided as an argument will overwrite any handler
* that was previously connected.
*
****************************************************************************/
s32  XScuGic_Connect(XScuGic *InstancePtr, u32 Int_Id,
				Xil_InterruptHandler Handler, void *CallBackRef)
{
	/*
	 * Assert the arguments
	 */
	Xil_AssertNonvoid(InstancePtr != NULL);
	Xil_AssertNonvoid(Int_Id < XSCUGIC_MAX_NUM_INTR_INPUTS);
	Xil_AssertNonvoid(Handler != NULL);
	Xil_AssertNonvoid(InstancePtr->IsReady == XIL_COMPONENT_IS_READY);

	/*
	 * The Int_Id is used as an index into the table to select the proper
	 * handler
	 */
	InstancePtr->Config->HandlerTable[Int_Id].Handler = (Xil_InterruptHandler)Handler;
	InstancePtr->Config->HandlerTable[Int_Id].CallBackRef = CallBackRef;

	return XST_SUCCESS;
}

---

代码分析

结合XScuGic_Connect函数代码，分析如下，

/*****************************************************************************/
/**
*
* 该函数用于将识别中断的函数（handler）与中断源的中断ID（Int_Id）。
* 该函数中的Callbackref参数作为调用中断函数（handler）时的参数。
*
* @参数	InstancePtr 为XScuGic实例的指针。
* @参数	Int_Id包含中断源的ID，其取值应该在 0 到 XSCUGIC_MAX_NUM_INTR_INPUTS - 1
* @参数	中断的处理函数
* @参数	CallBackRef为回调参考，通常为所连接驱动的实例指针。
*
* @返回
*
*		- XST_SUCCESS 如果处理函数（handler）正确连接
*
* @说明
*
* 警告: 作为参数提供的处理函数handler，它将覆盖之前连接的所有处理函数handler。
*
****************************************************************************/
s32  XScuGic_Connect(XScuGic *InstancePtr, u32 Int_Id,
				Xil_InterruptHandler Handler, void *CallBackRef)
{
	/*
	 * 检查输入是否合法
	 */
	Xil_AssertNonvoid(InstancePtr != NULL);  //指针非空
	Xil_AssertNonvoid(Int_Id < XSCUGIC_MAX_NUM_INTR_INPUTS);  //中断ID取值合法
	Xil_AssertNonvoid(Handler != NULL);  //处理函数非空
	Xil_AssertNonvoid(InstancePtr->IsReady == XIL_COMPONENT_IS_READY);  //指针就绪

	/*
	 * 参数Int_Id作为中断表的索引，用于选择相应的中断处理函数handler
	 */
	InstancePtr->Config->HandlerTable[Int_Id].Handler = (Xil_InterruptHandler)Handler;  //处理函数
	InstancePtr->Config->HandlerTable[Int_Id].CallBackRef = CallBackRef;  //回调参数

	return XST_SUCCESS;
}