/******************************************************************************
*
* Copyright (C) 2004 - 2014 Xilinx, Inc.  All rights reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* Use of the Software is limited solely to applications:
* (a) running on a Xilinx device, or
* (b) that interact with a Xilinx device through a bus or interconnect.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* XILINX CONSORTIUM BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF
* OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*
* Except as contained in this notice, the name of the Xilinx shall not be used
* in advertising or otherwise to promote the sale, use or other dealings in
* this Software without prior written authorization from Xilinx.
*
******************************************************************************/
/*****************************************************************************/
/**
*
* @file xemaclite.c
*
* Functions in this file are the minimum required functions for the EmacLite
* driver. See xemaclite.h for a detailed description of the driver.
*
* <pre>
* MODIFICATION HISTORY:
*
* Ver   Who  Date     Changes
* ----- ---- -------- --------------------------------------------------------
* 1.01a ecm  01/31/04 First release
* 1.11a mta  03/21/07 Updated to new coding style
* 1.11a ecm  05/18/07 Updated the TxBufferAvailable routine to look at both
*                     the active and busy bits
* 1.13a sv   02/1/08  Updated the TxBufferAvailable routine to return
*		      busy status properly
* 2.00a ktn  02/16/09 Added support for MDIO
* 2.01a ktn  07/20/09 Modified XEmacLite_Send function to use Ping buffers
*                     Interrupt enable bit since this alone is used to enable
*                     the interrupts for both Ping and Pong Buffers.
* 3.00a ktn  10/22/09 Updated driver to use the HAL APIs/macros.
*		      The macros have been renamed to remove _m from the name.
* 3.01a ktn  07/08/10 The macro XEmacLite_GetReceiveDataLength is changed to
*		      a static function.
*		      Updated the XEmacLite_GetReceiveDataLength and
*		      XEmacLite_Recv functions to support little endian
*		      MicroBlaze.
* 3.02a sdm  07/22/11 Removed redundant code in XEmacLite_Recv functions for
*		      CR617290
* 3.04a srt  04/13/13 Removed warnings (CR 705000).
*
* </pre>
******************************************************************************/

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

#include "xil_io.h"
#include "xenv.h"
#include "xemaclite.h"
#include "xemaclite_i.h"

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

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

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


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

static u16 XEmacLite_GetReceiveDataLength(u32 BaseAddress);

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

/*****************************************************************************/
/**
*
* Initialize a specific XEmacLite instance/driver.  The initialization entails:
* - Initialize fields of the XEmacLite instance structure.
*
* The driver defaults to polled mode operation.
*
* @param	InstancePtr is a pointer to the XEmacLite instance.
* @param	EmacLiteConfigPtr points to the XEmacLite device configuration
*		structure.
* @param	EffectiveAddr is the device base address in the virtual memory
*		address space. If the address translation is not used then the
*		physical address is passed.
*		Unexpected errors may occur if the address mapping is changed
*		after this function is invoked.
*
* @return
* 		- XST_SUCCESS if initialization was successful.
*
* @note		The initialization of the PHY device is not done in this
*		function. The user needs to use XEmacLite_PhyRead and
*		XEmacLite_PhyWrite functions to access the PHY device.
*
******************************************************************************/
int XEmacLite_CfgInitialize(XEmacLite *InstancePtr,
				XEmacLite_Config *EmacLiteConfigPtr,
				u32 EffectiveAddr)
{

	/*
	 * Verify that each of the inputs are valid.
	 */
	Xil_AssertNonvoid(InstancePtr != NULL);
	Xil_AssertNonvoid(EmacLiteConfigPtr != NULL);

	/*
	 * Zero the provided instance memory.
	 */
	memset(InstancePtr, 0, sizeof(XEmacLite));

	/*
	 * Set some default values for instance data, don't indicate the device
	 * is ready to use until everything has been initialized successfully.
	 */
	InstancePtr->EmacLiteConfig.BaseAddress = EffectiveAddr;
	InstancePtr->EmacLiteConfig.DeviceId = EmacLiteConfigPtr->DeviceId;
	InstancePtr->EmacLiteConfig.TxPingPong = EmacLiteConfigPtr->TxPingPong;
	InstancePtr->EmacLiteConfig.RxPingPong = EmacLiteConfigPtr->RxPingPong;
	InstancePtr->EmacLiteConfig.MdioInclude = EmacLiteConfigPtr->MdioInclude;
	InstancePtr->EmacLiteConfig.Loopback = EmacLiteConfigPtr->Loopback;

	InstancePtr->NextTxBufferToUse = 0x0;
	InstancePtr->NextRxBufferToUse = 0x0;
	InstancePtr->RecvHandler = (XEmacLite_Handler) StubHandler;
	InstancePtr->SendHandler = (XEmacLite_Handler) StubHandler;

	/*
	 * Clear the TX CSR's in case this is a restart.
	 */
	XEmacLite_WriteReg(InstancePtr->EmacLiteConfig.BaseAddress,
				XEL_TSR_OFFSET, 0);
	XEmacLite_WriteReg(InstancePtr->EmacLiteConfig.BaseAddress,
				XEL_BUFFER_OFFSET + XEL_TSR_OFFSET, 0);

	/*
	 * Since there were no failures, indicate the device is ready to use.
	 */
	InstancePtr->IsReady = XIL_COMPONENT_IS_READY;

	return XST_SUCCESS;
}

/*****************************************************************************/
/**
*
* Send an Ethernet frame. The ByteCount is the total frame size, including
* header.
*
* @param	InstancePtr is a pointer to the XEmacLite instance.
* @param	FramePtr is a pointer to frame. For optimal performance, a
*		32-bit aligned buffer should be used but it is not required, the
*		function will align the data if necessary.
* @param	ByteCount is the size, in bytes, of the frame
*
* @return
*		- XST_SUCCESS if data was transmitted.
*		- XST_FAILURE if buffer(s) was (were) full and no valid data was
*	 	transmitted.
*
* @note
*
* This function call is not blocking in nature, i.e. it will not wait until the
* frame is transmitted.
*
******************************************************************************/
int XEmacLite_Send(XEmacLite *InstancePtr, u8 *FramePtr, unsigned ByteCount)
{
	u32 Register;
	u32 BaseAddress;
	u32 EmacBaseAddress;
	u32 IntrEnableStatus;

	/*
	 * Verify that each of the inputs are valid.
	 */
	Xil_AssertNonvoid(InstancePtr != NULL);

	/*
	 * Determine the expected TX buffer address.
	 */
	BaseAddress = XEmacLite_NextTransmitAddr(InstancePtr);
	EmacBaseAddress = InstancePtr->EmacLiteConfig.BaseAddress;

	/*
	 * Check the Length if it is too large, truncate it.
	 * The maximum Tx packet size is
	 * Ethernet header (14 Bytes) + Maximum MTU (1500 bytes).
	 */
	if (ByteCount > XEL_MAX_TX_FRAME_SIZE) {

		ByteCount = XEL_MAX_TX_FRAME_SIZE;
	}

	/*
	 * Determine if the expected buffer address is empty.
	 */
	Register = XEmacLite_GetTxStatus(BaseAddress);

	/*
	 * If the expected buffer is available, fill it with the provided data
	 * Align if necessary.
	 */
	if ((Register & (XEL_TSR_XMIT_BUSY_MASK |
			XEL_TSR_XMIT_ACTIVE_MASK)) == 0) {

		/*
		 * Switch to next buffer if configured.
		 */
		if (InstancePtr->EmacLiteConfig.TxPingPong != 0) {
			InstancePtr->NextTxBufferToUse ^= XEL_BUFFER_OFFSET;
		}

		/*
		 * Write the frame to the buffer.
		 */
		XEmacLite_AlignedWrite(FramePtr, (u32 *) BaseAddress,
				       ByteCount);


		/*
		 * The frame is in the buffer, now send it.
		 */
		XEmacLite_WriteReg(BaseAddress, XEL_TPLR_OFFSET,
					(ByteCount & (XEL_TPLR_LENGTH_MASK_HI |
				   	XEL_TPLR_LENGTH_MASK_LO)));

		/*
		 * Update the Tx Status Register to indicate that there is a
		 * frame to send.
		 * If the interrupt enable bit of Ping buffer(since this
		 * controls both the buffers) is enabled then set the
		 * XEL_TSR_XMIT_ACTIVE_MASK flag which is used by the interrupt
		 * handler to call the callback function provided by the user
		 * to indicate that the frame has been transmitted.
		 */
		Register = XEmacLite_GetTxStatus(BaseAddress);
		Register |= XEL_TSR_XMIT_BUSY_MASK;
		IntrEnableStatus = XEmacLite_GetTxStatus(EmacBaseAddress);
		if ((IntrEnableStatus & XEL_TSR_XMIT_IE_MASK) != 0) {
			Register |= XEL_TSR_XMIT_ACTIVE_MASK;
		}
		XEmacLite_SetTxStatus(BaseAddress, Register);

		return XST_SUCCESS;
	}

	/*
	 * If the expected buffer was full, try the other buffer if configured.
	 */
	if (InstancePtr->EmacLiteConfig.TxPingPong != 0) {

		BaseAddress ^= XEL_BUFFER_OFFSET;

		/*
		 * Determine if the expected buffer address is empty.
		 */
		Register = XEmacLite_GetTxStatus(BaseAddress);

		/*
		 * If the next buffer is available, fill it with the provided
		 * data.
		 */
		if ((Register & (XEL_TSR_XMIT_BUSY_MASK |
				XEL_TSR_XMIT_ACTIVE_MASK)) == 0) {

			/*
			 * Write the frame to the buffer.
			 */
			XEmacLite_AlignedWrite(FramePtr, (u32 *) BaseAddress,
					       ByteCount);

			/*
			 * The frame is in the buffer, now send it.
			 */
			XEmacLite_WriteReg(BaseAddress, XEL_TPLR_OFFSET,
					(ByteCount & (XEL_TPLR_LENGTH_MASK_HI |
					   XEL_TPLR_LENGTH_MASK_LO)));

			/*
			 * Update the Tx Status Register to indicate that there
			 * is a frame to send.
			 * If the interrupt enable bit of Ping buffer(since this
			 * controls both the buffers) is enabled then set the
			 * XEL_TSR_XMIT_ACTIVE_MASK flag which is used by the
			 * interrupt handler to call the callback function
			 * provided by the user to indicate that the frame has
			 * been transmitted.
			 */
			Register = XEmacLite_GetTxStatus(BaseAddress);
			Register |= XEL_TSR_XMIT_BUSY_MASK;
			IntrEnableStatus =
					XEmacLite_GetTxStatus(EmacBaseAddress);
			if ((IntrEnableStatus & XEL_TSR_XMIT_IE_MASK) != 0) {
				Register |= XEL_TSR_XMIT_ACTIVE_MASK;
			}
			XEmacLite_SetTxStatus(BaseAddress, Register);

			/*
			 * Do not switch to next buffer, there is a sync problem
			 * and the expected buffer should not change.
			 */
			return XST_SUCCESS;
		}
	}


	/*
	 * Buffer(s) was(were) full, return failure to allow for polling usage.
	 */
	return XST_FAILURE;
}

/*****************************************************************************/
/**
*
* Receive a frame. Intended to be called from the interrupt context or
* with a wrapper which waits for the receive frame to be available.
*
* @param	InstancePtr is a pointer to the XEmacLite instance.
* @param 	FramePtr is a pointer to a buffer where the frame will
*		be stored. The buffer must be at least XEL_MAX_FRAME_SIZE bytes.
*		For optimal performance, a 32-bit aligned buffer should be used
*		but it is not required, the function will align the data if
*		necessary.
*
* @return
*
* The type/length field of the frame received.  When the type/length field
* contains the type, XEL_MAX_FRAME_SIZE bytes will be copied out of the
* buffer and it is up to the higher layers to sort out the frame.
* Function returns 0 if there is no data waiting in the receive buffer or
* the pong buffer if configured.
*
* @note
*
* This function call is not blocking in nature, i.e. it will not wait until
* a frame arrives.
*
******************************************************************************/
u16 XEmacLite_Recv(XEmacLite *InstancePtr, u8 *FramePtr)
{
	u16 LengthType;
	u16 Length;
	u32 Register;
	u32 BaseAddress;

	/*
	 * Verify that each of the inputs are valid.
	 */

	Xil_AssertNonvoid(InstancePtr != NULL);

	/*
	 * Determine the expected buffer address.
	 */
	BaseAddress = XEmacLite_NextReceiveAddr(InstancePtr);

	/*
	 * Verify which buffer has valid data.
	 */
	Register = XEmacLite_GetRxStatus(BaseAddress);

	if ((Register & XEL_RSR_RECV_DONE_MASK) == XEL_RSR_RECV_DONE_MASK) {

		/*
		 * The driver is in sync, update the next expected buffer if
		 * configured.
		 */

		if (InstancePtr->EmacLiteConfig.RxPingPong != 0) {
			InstancePtr->NextRxBufferToUse ^= XEL_BUFFER_OFFSET;
		}
	}
	else {
		/*
		 * The instance is out of sync, try other buffer if other
		 * buffer is configured, return 0 otherwise. If the instance is
		 * out of sync, do not update the 'NextRxBufferToUse' since it
		 * will correct on subsequent calls.
		 */
		if (InstancePtr->EmacLiteConfig.RxPingPong != 0) {
			BaseAddress ^= XEL_BUFFER_OFFSET;
		}
		else {
			return 0;	/* No data was available */
		}

		/*
		 * Verify that buffer has valid data.
		 */
		Register = XEmacLite_GetRxStatus(BaseAddress);
		if ((Register & XEL_RSR_RECV_DONE_MASK) !=
				XEL_RSR_RECV_DONE_MASK) {
			return 0;	/* No data was available */
		}
	}

	/*
	 * Get the length of the frame that arrived.
	 */
	LengthType = XEmacLite_GetReceiveDataLength(BaseAddress);

	/*
	 * Check if length is valid.
	 */
	if (LengthType > XEL_MAX_FRAME_SIZE) {


		if (LengthType == XEL_ETHER_PROTO_TYPE_IP) {

			/*
			 * The packet is a an IP Packet.
			 */
#ifdef __LITTLE_ENDIAN__
			Length = (XEmacLite_ReadReg((BaseAddress),
					XEL_HEADER_IP_LENGTH_OFFSET +
					XEL_RXBUFF_OFFSET) &
					(XEL_RPLR_LENGTH_MASK_HI |
					XEL_RPLR_LENGTH_MASK_LO));
			Length = (u16) (((Length & 0xFF00) >> 8) | ((Length & 0x00FF) << 8));
#else
			Length = ((XEmacLite_ReadReg((BaseAddress),
					XEL_HEADER_IP_LENGTH_OFFSET +
					XEL_RXBUFF_OFFSET) >>
					XEL_HEADER_SHIFT) &
					(XEL_RPLR_LENGTH_MASK_HI |
					XEL_RPLR_LENGTH_MASK_LO));
#endif

			Length += XEL_HEADER_SIZE + XEL_FCS_SIZE;

		} else if (LengthType == XEL_ETHER_PROTO_TYPE_ARP) {

			/*
			 * The packet is an ARP Packet.
			 */
			Length = XEL_ARP_PACKET_SIZE + XEL_HEADER_SIZE +
					XEL_FCS_SIZE;

		} else {
			/*
			 * Field contains type other than IP or ARP, use max
			 * frame size and let user parse it.
		 	 */
			Length = XEL_MAX_FRAME_SIZE;

		}
	} else {

		/*
		 * Use the length in the frame, plus the header and trailer.
		 */
		Length = LengthType + XEL_HEADER_SIZE + XEL_FCS_SIZE;
	}

	/*
	 * Read from the EmacLite.
	 */
	XEmacLite_AlignedRead(((u32 *) (BaseAddress + XEL_RXBUFF_OFFSET)),
			      FramePtr, Length);

	/*
	 * Acknowledge the frame.
	 */
	Register = XEmacLite_GetRxStatus(BaseAddress);
	Register &= ~XEL_RSR_RECV_DONE_MASK;
	XEmacLite_SetRxStatus(BaseAddress, Register);

	return Length;
}

/*****************************************************************************/
/**
*
* Set the MAC address for this device.  The address is a 48-bit value.
*
* @param	InstancePtr is a pointer to the XEmacLite instance.
* @param	AddressPtr is a pointer to a 6-byte MAC address.
*		the format of the MAC address is major octet to minor octet
*
* @return	None.
*
* @note
*
* 	- TX must be idle and RX should be idle for deterministic results.
*	It is recommended that this function should be called after the
*	initialization and before transmission of any packets from the device.
* 	- Function will not return if hardware is absent or not functioning
* 	properly.
*	- The MAC address can be programmed using any of the two transmit
*	buffers (if configured).
*
******************************************************************************/
void XEmacLite_SetMacAddress(XEmacLite *InstancePtr, u8 *AddressPtr)
{
	u32 BaseAddress;

	/*
	 * Verify that each of the inputs are valid.
	 */
	Xil_AssertVoid(InstancePtr != NULL);

	/*
	 * Determine the expected TX buffer address.
	 */
	BaseAddress = XEmacLite_NextTransmitAddr(InstancePtr);

	/*
	 * Copy the MAC address to the Transmit buffer.
	 */
	XEmacLite_AlignedWrite(AddressPtr,
				(u32 *) BaseAddress,
				XEL_MAC_ADDR_SIZE);

	/*
	 * Set the length.
	 */
	XEmacLite_WriteReg(BaseAddress,
				XEL_TPLR_OFFSET,
				XEL_MAC_ADDR_SIZE);

	/*
	 * Update the MAC address in the EmacLite.
	 */
	XEmacLite_SetTxStatus(BaseAddress, XEL_TSR_PROG_MAC_ADDR);


	/*
	 * Wait for EmacLite to finish with the MAC address update.
	 */
	while ((XEmacLite_GetTxStatus(BaseAddress) &
			XEL_TSR_PROG_MAC_ADDR) != 0);

}

/******************************************************************************/
/**
*
* This is a stub for the send and receive callbacks. The stub
* is here in case the upper layers forget to set the handlers.
*
* @param	CallBackRef is a pointer to the upper layer callback reference.
*
* @return	None.
*
* @note		None.
*
******************************************************************************/
void StubHandler(void *CallBackRef)
{
	(void)(CallBackRef);
	Xil_AssertVoidAlways();
}


/****************************************************************************/
/**
*
* Determine if there is a transmit buffer available.
*
* @param	InstancePtr is the pointer to the instance of the driver to
*		be worked on.
*
* @return
*		- TRUE if there is a TX buffer available for data to be written
*		- FALSE if Tx Buffer is not available.
*
* @note		None.
*
*****************************************************************************/
int XEmacLite_TxBufferAvailable(XEmacLite *InstancePtr)
{

	u32 Register;
	int TxPingBusy;
	int TxPongBusy;

	/*
	 * Verify that each of the inputs are valid.
	 */
	Xil_AssertNonvoid(InstancePtr != NULL);

	/*
	 * Read the Tx Status and determine if the buffer is available.
	 */
	Register = XEmacLite_GetTxStatus(InstancePtr->EmacLiteConfig.
						BaseAddress);

	TxPingBusy = (Register & (XEL_TSR_XMIT_BUSY_MASK |
				 XEL_TSR_XMIT_ACTIVE_MASK));


	/*
 	 * Read the Tx Status of the second buffer register and determine if the
 	 * buffer is available.
	 */
	if (InstancePtr->EmacLiteConfig.TxPingPong != 0) {
		Register = XEmacLite_GetTxStatus(InstancePtr->EmacLiteConfig.
						BaseAddress +
						XEL_BUFFER_OFFSET);

		TxPongBusy = (Register & (XEL_TSR_XMIT_BUSY_MASK |
					XEL_TSR_XMIT_ACTIVE_MASK));

		return (!(TxPingBusy && TxPongBusy));
	}

	return (!TxPingBusy);


}

/****************************************************************************/
/**
*
* Flush the Receive buffers. All data will be lost.
*
* @param	InstancePtr is the pointer to the instance of the driver to
*		be worked on.
*
* @return	None.
*
* @note		None.
*
*****************************************************************************/
void XEmacLite_FlushReceive(XEmacLite *InstancePtr)
{

	u32 Register;

	/*
	 * Verify that each of the inputs are valid.
	 */
	Xil_AssertVoid(InstancePtr != NULL);

	/*
	 * Read the current buffer register and determine if the buffer is
	 * available.
	 */
	Register = XEmacLite_GetRxStatus(InstancePtr->EmacLiteConfig.
						BaseAddress);

	/*
	 * Preserve the IE bit.
	 */
	Register &= XEL_RSR_RECV_IE_MASK;

	/*
	 * Write out the value to flush the RX buffer.
	 */
	XEmacLite_SetRxStatus(InstancePtr->EmacLiteConfig.BaseAddress,
				Register);

	/*
	 * If the pong buffer is available, flush it also.
	 */
	if (InstancePtr->EmacLiteConfig.RxPingPong != 0) {
		/*
		 * Read the current buffer register and determine if the buffer
		 * is available.
		 */
		Register = XEmacLite_GetRxStatus(InstancePtr->EmacLiteConfig.
							BaseAddress +
							XEL_BUFFER_OFFSET);

		/*
		 * Preserve the IE bit.
		 */
		Register &= XEL_RSR_RECV_IE_MASK;

		/*
		 * Write out the value to flush the RX buffer.
		 */
		XEmacLite_SetRxStatus(InstancePtr->EmacLiteConfig.BaseAddress +
					XEL_BUFFER_OFFSET, Register);

	}

}

/******************************************************************************/
/**
*
* Read the specified PHY register.
*
* @param	InstancePtr is the pointer to the instance of the driver.
* @param	PhyAddress is the address of the PHY device. The valid range is
*		is from 0 to 31.
* @param	RegNum is the register number in the PHY device which
*		is to be read. The valid range is is from 0 to 31.
* @param	PhyDataPtr is a pointer to the data in which the data read
*		from the PHY device is returned.
*
* @return
*		- XST_SUCCESS if the data is read from the PHY.
*		- XST_DEVICE_BUSY if MDIO is busy.
*
* @note		This function waits for the completion of MDIO data transfer.
*
*****************************************************************************/
int XEmacLite_PhyRead(XEmacLite *InstancePtr, u32 PhyAddress, u32 RegNum,
			u16 *PhyDataPtr)
{
	u32 PhyAddrReg;
	u32 MdioCtrlReg;

	/*
	 * Verify that each of the inputs are valid.
	 */
	Xil_AssertNonvoid(InstancePtr != NULL);
	Xil_AssertNonvoid(InstancePtr->EmacLiteConfig.MdioInclude == TRUE);
	Xil_AssertNonvoid(PhyAddress <= 31);
	Xil_AssertNonvoid(RegNum <= 31);
	Xil_AssertNonvoid(PhyDataPtr != NULL);

	/*
	 * Verify MDIO master status.
	 */
	if (XEmacLite_ReadReg(InstancePtr->EmacLiteConfig.BaseAddress,
				XEL_MDIOCNTR_OFFSET) &
				XEL_MDIOCNTR_STATUS_MASK) {
		return XST_DEVICE_BUSY;
	}

	PhyAddrReg = ((((PhyAddress << XEL_MDIO_ADDRESS_SHIFT) &
			XEL_MDIO_ADDRESS_MASK) | RegNum) | XEL_MDIO_OP_MASK);
	XEmacLite_WriteReg(InstancePtr->EmacLiteConfig.BaseAddress,
				 XEL_MDIOADDR_OFFSET, PhyAddrReg);

	/*
	 * Enable MDIO and start the transfer.
	 */
	MdioCtrlReg =
		XEmacLite_ReadReg(InstancePtr->EmacLiteConfig.BaseAddress,
					XEL_MDIOCNTR_OFFSET);
	XEmacLite_WriteReg(InstancePtr->EmacLiteConfig.BaseAddress,
				XEL_MDIOCNTR_OFFSET,
				MdioCtrlReg |
				XEL_MDIOCNTR_STATUS_MASK |
				XEL_MDIOCNTR_ENABLE_MASK);

	/*
	 * Wait till the completion of transfer.
	 */
	while ((XEmacLite_ReadReg(InstancePtr->EmacLiteConfig.BaseAddress,
				XEL_MDIOCNTR_OFFSET) &
				XEL_MDIOCNTR_STATUS_MASK));

	/*
	 * Read data from MDIO read data register.
	 */
	*PhyDataPtr = (u16)XEmacLite_ReadReg(InstancePtr->EmacLiteConfig.BaseAddress,
					XEL_MDIORD_OFFSET);

	/*
	 * Disable the MDIO.
	 */
	MdioCtrlReg =
		XEmacLite_ReadReg(InstancePtr->EmacLiteConfig.BaseAddress,
					XEL_MDIOCNTR_OFFSET);

	XEmacLite_WriteReg(InstancePtr->EmacLiteConfig.BaseAddress,
				XEL_MDIOCNTR_OFFSET,
				MdioCtrlReg & ~XEL_MDIOCNTR_ENABLE_MASK);


	return XST_SUCCESS;
}

/******************************************************************************/
/**
*
* Write the given data to the specified register in the PHY device.
*
* @param	InstancePtr is the pointer to the instance of the driver.
* @param	PhyAddress is the address of the PHY device. The valid range is
*		is from 0 to 31.
* @param	RegNum is the register number in the PHY device which
*		is to be written. The valid range is is from 0 to 31.
* @param	PhyData is the data to be written to the specified register in
*		the PHY device.
*
* @return
*		- XST_SUCCESS if the data is written to the PHY.
*		- XST_DEVICE_BUSY if MDIO is busy.
*
* @note		This function waits for the completion of MDIO data transfer.
*
*******************************************************************************/
int XEmacLite_PhyWrite(XEmacLite *InstancePtr, u32 PhyAddress, u32 RegNum,
			u16 PhyData)
{
	u32 PhyAddrReg;
	u32 MdioCtrlReg;

	/*
	 * Verify that each of the inputs are valid.
	 */
	Xil_AssertNonvoid(InstancePtr != NULL);
	Xil_AssertNonvoid(InstancePtr->EmacLiteConfig.MdioInclude == TRUE);
	Xil_AssertNonvoid(PhyAddress <= 31);
	Xil_AssertNonvoid(RegNum <= 31);

	/*
	 * Verify MDIO master status.
	 */
	if (XEmacLite_ReadReg(InstancePtr->EmacLiteConfig.BaseAddress,
				XEL_MDIOCNTR_OFFSET) &
				XEL_MDIOCNTR_STATUS_MASK) {
		return XST_DEVICE_BUSY;
	}



	PhyAddrReg = ((((PhyAddress << XEL_MDIO_ADDRESS_SHIFT) &
			XEL_MDIO_ADDRESS_MASK) | RegNum) & ~XEL_MDIO_OP_MASK);
	XEmacLite_WriteReg(InstancePtr->EmacLiteConfig.BaseAddress,
				XEL_MDIOADDR_OFFSET, PhyAddrReg);

	/*
	 * Write data to MDIO write data register.
	 */
	XEmacLite_WriteReg(InstancePtr->EmacLiteConfig.BaseAddress,
				XEL_MDIOWR_OFFSET, (u32)PhyData);

	/*
	 * Enable MDIO and start the transfer.
	 */
	MdioCtrlReg =
		XEmacLite_ReadReg(InstancePtr->EmacLiteConfig.BaseAddress,
					XEL_MDIOCNTR_OFFSET);
	XEmacLite_WriteReg(InstancePtr->EmacLiteConfig.BaseAddress,
				XEL_MDIOCNTR_OFFSET,
				MdioCtrlReg | XEL_MDIOCNTR_STATUS_MASK |
				XEL_MDIOCNTR_ENABLE_MASK);

	/*
	 * Wait till the completion of transfer.
	 */
	while ((XEmacLite_ReadReg(InstancePtr->EmacLiteConfig.BaseAddress,
				XEL_MDIOCNTR_OFFSET) & XEL_MDIOCNTR_STATUS_MASK));


	/*
	 * Disable the MDIO.
	 */
	MdioCtrlReg =
		XEmacLite_ReadReg(InstancePtr->EmacLiteConfig.BaseAddress,
					XEL_MDIOCNTR_OFFSET);
	XEmacLite_WriteReg(InstancePtr->EmacLiteConfig.BaseAddress,
				XEL_MDIOCNTR_OFFSET,
				MdioCtrlReg & ~XEL_MDIOCNTR_ENABLE_MASK);



	return XST_SUCCESS;
}



/****************************************************************************/
/**
*
* Enable Internal loop back functionality.
*
* @param	InstancePtr is the pointer to the instance of the driver.
*
* @return	None.
*
* @note		None.
*
*****************************************************************************/
void XEmacLite_EnableLoopBack(XEmacLite *InstancePtr)
{
	u32 TsrReg;

	/*
	 * Verify that each of the inputs are valid.
	 */
	Xil_AssertVoid(InstancePtr != NULL);
	Xil_AssertVoid(InstancePtr->EmacLiteConfig.Loopback == TRUE);

	TsrReg = XEmacLite_ReadReg(InstancePtr->EmacLiteConfig.BaseAddress,
					XEL_TSR_OFFSET);
	XEmacLite_WriteReg(InstancePtr->EmacLiteConfig.BaseAddress,
			XEL_TSR_OFFSET,	TsrReg | XEL_TSR_LOOPBACK_MASK);
}

/****************************************************************************/
/**
*
* Disable Internal loop back functionality.
*
* @param	InstancePtr is the pointer to the instance of the driver.
*
* @return	None.
*
* @note		None.
*
*****************************************************************************/
void XEmacLite_DisableLoopBack(XEmacLite *InstancePtr)
{
	u32 TsrReg;

	/*
	 * Verify that each of the inputs are valid.
	 */
	Xil_AssertVoid(InstancePtr != NULL);
	Xil_AssertVoid(InstancePtr->EmacLiteConfig.Loopback == TRUE);

	TsrReg = XEmacLite_ReadReg(InstancePtr->EmacLiteConfig.BaseAddress,
					XEL_TSR_OFFSET);
	XEmacLite_WriteReg(InstancePtr->EmacLiteConfig.BaseAddress,
			XEL_TSR_OFFSET,	TsrReg & (~XEL_TSR_LOOPBACK_MASK));
}


/*****************************************************************************/
/**
*
* Return the length of the data in the Receive Buffer.
*
* @param	BaseAddress contains the base address of the device.
*
* @return	The type/length field of the frame received.
*
* @note		None.
*
******************************************************************************/
static u16 XEmacLite_GetReceiveDataLength(u32 BaseAddress)
{
	u16 Length;

#ifdef __LITTLE_ENDIAN__
	Length = (XEmacLite_ReadReg((BaseAddress),
			XEL_HEADER_OFFSET + XEL_RXBUFF_OFFSET) &
			(XEL_RPLR_LENGTH_MASK_HI | XEL_RPLR_LENGTH_MASK_LO));
	Length = (u16) (((Length & 0xFF00) >> 8) | ((Length & 0x00FF) << 8));
#else
	Length = ((XEmacLite_ReadReg((BaseAddress),
			XEL_HEADER_OFFSET + XEL_RXBUFF_OFFSET) >>
			XEL_HEADER_SHIFT) &
			(XEL_RPLR_LENGTH_MASK_HI | XEL_RPLR_LENGTH_MASK_LO));
#endif

	return Length;
}