xwdtps.c

自学ZedBoard：使用IP通过ARM PS访问FPGA（源代码）

/* $Id: xwdtps.c,v 1.1.2.1 2011/01/20 04:17:15 sadanan Exp $ */
/******************************************************************************
*
* (c) Copyright 2010 Xilinx, Inc. All rights reserved.
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******************************************************************************/
/****************************************************************************/
/**
*
* @file xwdtps.c
*
* Contains the implementation of interface functions of the XWdtPs driver.
* See xwdtps.h for a description of the driver.
*
* <pre>
* MODIFICATION HISTORY:
*
* Ver   Who    Date     Changes
* ----- ------ -------- ---------------------------------------------
* 1.00a ecm/jz 01/15/10 First release
* </pre>
*
******************************************************************************/

/***************************** Include Files *********************************/

#include "xwdtps.h"

/************************** Constant Definitions *****************************/


/**************************** Type Definitions *******************************/


/***************** Macros (Inline Functions) Definitions *********************/


/************************** Function Prototypes ******************************/


/************************** Variable Definitions *****************************/


/****************************************************************************/
/**
*
* Initialize a specific watchdog timer instance/driver. This function
* must be called before other functions of the driver are called.
*
* @param	InstancePtr is a pointer to the XWdtPs instance.
* @param	ConfigPtr is the config structure.
* @param	EffectiveAddress is the base address for the device. It could be
*		a virtual address if address translation is supported in the
*		system, otherwise it is the physical address.
*
* @return
*		- XST_SUCCESS if initialization was successful.
*		- XST_DEVICE_IS_STARTED if the device has already been started.
*
* @note		None.
*
******************************************************************************/
int XWdtPs_CfgInitialize(XWdtPs *InstancePtr,
			XWdtPs_Config *ConfigPtr, u32 EffectiveAddress)
{
	Xil_AssertNonvoid(InstancePtr != NULL);
	Xil_AssertNonvoid(ConfigPtr != NULL);

	/*
	 * If the device is started, disallow the initialize and return a
	 * status indicating it is started. This allows the user to stop the
	 * device and reinitialize, but prevents a user from inadvertently
	 * initializing.
	 */
	if (InstancePtr->IsStarted == XIL_COMPONENT_IS_STARTED) {
		return XST_DEVICE_IS_STARTED;
	}

	/*
	 * Copy configuration into instance.
	 */
	InstancePtr->Config.DeviceId = ConfigPtr->DeviceId;

	/*
	 * Save the base address pointer such that the registers of the block
	 * can be accessed and indicate it has not been started yet.
	 */
	InstancePtr->Config.BaseAddress = EffectiveAddress;
	InstancePtr->IsStarted = 0;

	/*
	 * Indicate the instance is ready to use, successfully initialized.
	 */
	InstancePtr->IsReady = XIL_COMPONENT_IS_READY;

	return XST_SUCCESS;
}

/****************************************************************************/
/**
*
* Start the watchdog timer of the device.
*
* @param	InstancePtr is a pointer to the XWdtPs instance.
*
* @return	None.
*
* @note		None.
*
******************************************************************************/
void XWdtPs_Start(XWdtPs *InstancePtr)
{
	u32 Register;

	Xil_AssertVoid(InstancePtr != NULL);
	Xil_AssertVoid(InstancePtr->IsReady == XIL_COMPONENT_IS_READY);

	/*
	 * Read the contents of the ZMR register.
	 */
	Register = XWdtPs_ReadReg(InstancePtr->Config.BaseAddress,
				 XWDTPS_ZMR_OFFSET);

	/*
	 * Enable the Timer field in the register and Set the access key so the
	 * write takes place.
	 */
	Register |= XWDTPS_ZMR_WDEN_MASK;
	Register |= XWDTPS_ZMR_ZKEY_VAL;

	/*
	 * Update the ZMR with the new value.
	 */
	XWdtPs_WriteReg(InstancePtr->Config.BaseAddress, XWDTPS_ZMR_OFFSET,
			  Register);

	/*
	 * Indicate that the device is started.
	 */
	InstancePtr->IsStarted = XIL_COMPONENT_IS_STARTED;

}

/****************************************************************************/
/**
*
* Disable the watchdog timer.
*
* It is the caller's responsibility to disconnect the interrupt handler
* of the watchdog timer from the interrupt source, typically an interrupt
* controller, and disable the interrupt in the interrupt controller.
*
* @param	InstancePtr is a pointer to the XWdtPs instance.
*
* @return	None.
*
* @note		None.
*
******************************************************************************/
void XWdtPs_Stop(XWdtPs *InstancePtr)
{
	u32 Register;

	Xil_AssertVoid(InstancePtr != NULL);
	Xil_AssertVoid(InstancePtr->IsReady == XIL_COMPONENT_IS_READY);

	/*
	 * Read the contents of the ZMR register.
	 */
	Register = XWdtPs_ReadReg(InstancePtr->Config.BaseAddress,
				 XWDTPS_ZMR_OFFSET);

	/*
	 * Disable the Timer field in the register and
	 * Set the access key for the write to be done the register.
	 */
	Register &= ~XWDTPS_ZMR_WDEN_MASK;
	Register |= XWDTPS_ZMR_ZKEY_VAL;

	/*
	 * Update the ZMR with the new value.
	 */
	XWdtPs_WriteReg(InstancePtr->Config.BaseAddress, XWDTPS_ZMR_OFFSET,
			  Register);

	InstancePtr->IsStarted = 0;
}

/****************************************************************************/
/**
*
* Returns the current pulse length setting for the External output.
*
* @param	InstancePtr is a pointer to the XWdtPs instance.
*
* @return	The contents of the requested signal length field in the Zero
*		Mode Register (XWDTPS_ZMR_OFFSET).
*
* @note		None.
*
******************************************************************************/
u32 XWdtPs_GetExternalSignalLength(XWdtPs *InstancePtr)
{
	u32 Register;
	u32 ReturnValue = 0;

	Xil_AssertNonvoid(InstancePtr != NULL);
	Xil_AssertNonvoid(InstancePtr->IsReady == XIL_COMPONENT_IS_READY);

	/*
	 * Read the contents of the ZMR register.
	 */
	Register = XWdtPs_ReadReg(InstancePtr->Config.BaseAddress,
				 XWDTPS_ZMR_OFFSET);

	/*
	 * Mask off the field in the register.
	 */
	Register &= XWDTPS_ZMR_EXLN_MASK;

	/*
	 * Shift over to the right most positions.
	 */
	ReturnValue = Register >> XWDTPS_ZMR_EXLN_SHIFT;

	return ReturnValue;
}

/****************************************************************************/
/**
*
* Set the pulse length setting for the External output.
* Performs a read/modify/write cycle to update the value correctly.
*
* @param	InstancePtr is a pointer to the XWdtPs instance.
* @param	Length is the desired count value. Use XWDTPS_ZMR_EXLN_XXXX
*		defined in xwdtps_hw.h
*
* @return	None.
*
* @note		None.
*
******************************************************************************/
void XWdtPs_SetExternalSignalLength(XWdtPs *InstancePtr, u32 Length)
{
	u32 Register = 0;

	Xil_AssertVoid(InstancePtr != NULL);
	Xil_AssertVoid(InstancePtr->IsReady == XIL_COMPONENT_IS_READY);

	/*
	 * Read the contents of the ZMR register.
	 */