/* $Id: xscuwdt_selftest.c,v 1.1.2.1 2011/01/20 04:04:40 sadanan Exp $ */
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/**
*
* @file xscuwdt_selftest.c
*
* Contains diagnostic self-test functions for the XScuWdt driver.
*
* <pre>
* MODIFICATION HISTORY:
*
* Ver   Who Date     Changes
* ----- --- -------- ---------------------------------------------
* 1.00a sdm 01/15/10 First release
* </pre>
*
******************************************************************************/

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

#include "xscuwdt.h"

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

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

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

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

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

/****************************************************************************/
/**
*
* Run a self-test on the WDT. This test stops the watchdog, writes a value to
* the watchdog load register, starts the watchdog and verifies that the value
* read from the counter register is less that the value written to the load
* register. It then restores the control register and the watchdog load
* register.
*
* @param	InstancePtr is a pointer to the XScuWdt instance.
*
* @return
*		- XST_SUCCESS if self-test was successful.
*		- XST_FAILURE if the WDT is not decrementing.
*
* @note		None.
*
******************************************************************************/
int XScuWdt_SelfTest(XScuWdt *InstancePtr)
{
	u32 Register;
	u32 CtrlOrig;
	u32 LoadOrig;

	/*
	 * Assert to ensure the inputs are valid and the instance has been
	 * initialized.
	 */
	Xil_AssertNonvoid(InstancePtr != NULL);
	Xil_AssertNonvoid(InstancePtr->IsReady == XIL_COMPONENT_IS_READY);

	/*
	 * Stop the watchdog timer.
	 */
	CtrlOrig = XScuWdt_GetControlReg(InstancePtr);
	XScuWdt_SetControlReg(InstancePtr,
			      CtrlOrig & ~XSCUWDT_CONTROL_WD_ENABLE_MASK);

	LoadOrig = XScuWdt_ReadReg((InstancePtr)->Config.BaseAddr,
				   XSCUWDT_LOAD_OFFSET);
	XScuWdt_LoadWdt(InstancePtr, 0xFFFFFFFF);

	/*
	 * Start the watchdog timer and check if the watchdog counter is
	 * decrementing.
	 */
	XScuWdt_SetControlReg(InstancePtr,
			      CtrlOrig | XSCUWDT_CONTROL_WD_ENABLE_MASK);

	Register = XScuWdt_ReadReg((InstancePtr)->Config.BaseAddr,
				   XSCUWDT_COUNTER_OFFSET);

	XScuWdt_LoadWdt(InstancePtr, LoadOrig);
	XScuWdt_SetControlReg(InstancePtr, CtrlOrig);

	if (Register == 0xFFFFFFFF) {
		return XST_FAILURE;
	}

	return XST_SUCCESS;
}
