FreeRTOS-Plus/Source/FreeRTOS-Plus-TCP/portable/NetworkInterface/Zynq/x_emacpsif_dma.c - third_party/github/FreeRTOS/FreeRTOS-Kernel - Git at Google

 /*
 FreeRTOS+TCP V2.0.11
 Copyright (C) 2017 Amazon.com, Inc. or its affiliates.  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.

 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 AUTHORS OR
 COPYRIGHT HOLDERS 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.

  http://aws.amazon.com/freertos
  http://www.FreeRTOS.org
 */

 #include "Zynq/x_emacpsif.h"
 #include "Zynq/x_topology.h"
 #include "xstatus.h"

 #include "xparameters.h"
 #include "xparameters_ps.h"
 #include "xil_exception.h"
 #include "xil_mmu.h"

 #include "FreeRTOS.h"
 #include "task.h"
 #include "timers.h"
 #include "semphr.h"

 /* FreeRTOS+TCP includes. */
 #include "FreeRTOS_IP.h"
 #include "FreeRTOS_Sockets.h"
 #include "FreeRTOS_IP_Private.h"
 #include "NetworkBufferManagement.h"

 #include "uncached_memory.h"

 /* Two defines used to set or clear the EMAC interrupt */
 #define INTC_BASE_ADDR		XPAR_SCUGIC_CPU_BASEADDR
 #define INTC_DIST_BASE_ADDR	XPAR_SCUGIC_DIST_BASEADDR


 #if( ipconfigPACKET_FILLER_SIZE != 2 )
 	#error Please define ipconfigPACKET_FILLER_SIZE as the value '2'
 #endif
 #define TX_OFFSET				ipconfigPACKET_FILLER_SIZE

 #define RX_BUFFER_ALIGNMENT	14

 /* Defined in NetworkInterface.c */
 extern TaskHandle_t xEMACTaskHandle;

 /*
 	pxDMA_tx_buffers: these are character arrays, each one is big enough to hold 1 MTU.
 	The actual TX buffers are located in uncached RAM.
 */
 static unsigned char *pxDMA_tx_buffers[ ipconfigNIC_N_TX_DESC ] = { NULL };

 /*
 	pxDMA_rx_buffers: these are pointers to 'NetworkBufferDescriptor_t'.
 	Once a message has been received by the EMAC, the descriptor can be passed
 	immediately to the IP-task.
 */
 static NetworkBufferDescriptor_t *pxDMA_rx_buffers[ ipconfigNIC_N_RX_DESC ] = { NULL };

 /*
 	The FreeRTOS+TCP port is using a fixed 'topology', which is declared in
 	./portable/NetworkInterface/Zynq/NetworkInterface.c
 */
 extern struct xtopology_t xXTopology;

 static SemaphoreHandle_t xTXDescriptorSemaphore = NULL;

 /*
 	The FreeRTOS+TCP port does not make use of "src/xemacps_bdring.c".
 	In stead 'struct xemacpsif_s' has a "head" and a "tail" index.
 	"head" is the next index to be written, used.
 	"tail" is the next index to be read, freed.
 */

 int is_tx_space_available( xemacpsif_s *xemacpsif )
 {
 size_t uxCount;

 	if( xTXDescriptorSemaphore != NULL )
 	{
 		uxCount = ( ( UBaseType_t ) ipconfigNIC_N_TX_DESC ) - uxSemaphoreGetCount( xTXDescriptorSemaphore );
 	}
 	else
 	{
 		uxCount = ( UBaseType_t ) 0u;
 	}

 	return uxCount;
 }

 void emacps_check_tx( xemacpsif_s *xemacpsif )
 {
 int tail = xemacpsif->txTail;
 int head = xemacpsif->txHead;
 size_t uxCount = ( ( UBaseType_t ) ipconfigNIC_N_TX_DESC ) - uxSemaphoreGetCount( xTXDescriptorSemaphore );

 	/* uxCount is the number of TX descriptors that are in use by the DMA. */
 	/* When done, "TXBUF_USED" will be set. */

 	while( ( uxCount > 0 ) && ( ( xemacpsif->txSegments[ tail ].flags & XEMACPS_TXBUF_USED_MASK ) != 0 ) )
 	{
 		if( ( tail == head ) && ( uxCount != ipconfigNIC_N_TX_DESC ) )
 		{
 			break;
 		}
 #if( ipconfigZERO_COPY_TX_DRIVER != 0 )
 #warning ipconfigZERO_COPY_TX_DRIVER is defined
 		{
 		void *pvBuffer = pxDMA_tx_buffers[ tail ];
 		NetworkBufferDescriptor_t *pxBuffer;

 			if( pvBuffer != NULL )
 			{
 				pxDMA_tx_buffers[ tail ] = NULL;
 				pxBuffer = pxPacketBuffer_to_NetworkBuffer( pvBuffer );
 				if( pxBuffer != NULL )
 				{
 					vReleaseNetworkBufferAndDescriptor( pxBuffer );
 				}
 				else
 				{
 					FreeRTOS_printf( ( "emacps_check_tx: Can not find network buffer\n" ) );
 				}
 			}
 		}
 #endif
 		/* Clear all but the "used" and "wrap" bits. */
 		if( tail < ipconfigNIC_N_TX_DESC - 1 )
 		{
 			xemacpsif->txSegments[ tail ].flags = XEMACPS_TXBUF_USED_MASK;
 		}
 		else
 		{
 			xemacpsif->txSegments[ tail ].flags = XEMACPS_TXBUF_USED_MASK | XEMACPS_TXBUF_WRAP_MASK;
 		}
 		uxCount--;
 		/* Tell the counting semaphore that one more TX descriptor is available. */
 		xSemaphoreGive( xTXDescriptorSemaphore );
 		if( ++tail == ipconfigNIC_N_TX_DESC )
 		{
 			tail = 0;
 		}
 		xemacpsif->txTail = tail;
 	}

 	return;
 }

 void emacps_send_handler(void *arg)
 {
 xemacpsif_s   *xemacpsif;
 BaseType_t xHigherPriorityTaskWoken = pdFALSE;

 	xemacpsif = (xemacpsif_s *)(arg);

 	/* In this port for FreeRTOS+TCP, the EMAC interrupts will only set a bit in
 	"isr_events". The task in NetworkInterface will wake-up and do the necessary work.
 	*/
 	xemacpsif->isr_events |= EMAC_IF_TX_EVENT;
 	xemacpsif->txBusy = pdFALSE;

 	if( xEMACTaskHandle != NULL )
 	{
 		vTaskNotifyGiveFromISR( xEMACTaskHandle, &xHigherPriorityTaskWoken );
 	}

 	portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
 }

 static BaseType_t xValidLength( BaseType_t xLength )
 {
 BaseType_t xReturn;

 	if( ( xLength >= ( BaseType_t ) sizeof( struct xARP_PACKET ) ) && ( ( ( uint32_t ) xLength ) <= ipTOTAL_ETHERNET_FRAME_SIZE ) )
 	{
 		xReturn = pdTRUE;
 	}
 	else
 	{
 		xReturn =  pdFALSE;
 	}

 	return xReturn;
 }

 XStatus emacps_send_message(xemacpsif_s *xemacpsif, NetworkBufferDescriptor_t *pxBuffer, int iReleaseAfterSend )
 {
 int head = xemacpsif->txHead;
 int iHasSent = 0;
 uint32_t ulBaseAddress = xemacpsif->emacps.Config.BaseAddress;
 TickType_t xBlockTimeTicks = pdMS_TO_TICKS( 5000u );

 	#if( ipconfigZERO_COPY_TX_DRIVER != 0 )
 	{
 		/* This driver wants to own all network buffers which are to be transmitted. */
 		configASSERT( iReleaseAfterSend != pdFALSE );
 	}
 	#endif

 	/* Open a do {} while ( 0 ) loop to be able to call break. */
 	do
 	{
 	uint32_t ulFlags = 0;

 		if( xValidLength( pxBuffer->xDataLength ) != pdTRUE )
 		{
 			break;
 		}

 		if( xTXDescriptorSemaphore == NULL )
 		{
 			break;
 		}

 		if( xSemaphoreTake( xTXDescriptorSemaphore, xBlockTimeTicks ) != pdPASS )
 		{
 			FreeRTOS_printf( ( "emacps_send_message: Time-out waiting for TX buffer\n" ) );
 			break;
 		}

 #if( ipconfigZERO_COPY_TX_DRIVER != 0 )
 		/* Pass the pointer (and its ownership) directly to DMA. */
 		pxDMA_tx_buffers[ head ] = pxBuffer->pucEthernetBuffer;
 		if( ucIsCachedMemory( pxBuffer->pucEthernetBuffer ) != 0 )
 		{
 			Xil_DCacheFlushRange( ( unsigned )pxBuffer->pucEthernetBuffer, pxBuffer->xDataLength );
 		}
 		/* Buffer has been transferred, do not release it. */
 		iReleaseAfterSend = pdFALSE;
 #else
 		if( pxDMA_tx_buffers[ head ] == NULL )
 		{
 			FreeRTOS_printf( ( "emacps_send_message: pxDMA_tx_buffers[ %d ] == NULL\n", head ) );
 			break;
 		}
 		/* Copy the message to unbuffered space in RAM. */
 		memcpy( pxDMA_tx_buffers[ head ], pxBuffer->pucEthernetBuffer, pxBuffer->xDataLength );
 #endif
 		/* Packets will be sent one-by-one, so for each packet
 		the TXBUF_LAST bit will be set. */
 		ulFlags |= XEMACPS_TXBUF_LAST_MASK;
 		ulFlags |= ( pxBuffer->xDataLength & XEMACPS_TXBUF_LEN_MASK );
 		if( head == ( ipconfigNIC_N_TX_DESC - 1 ) )
 		{
 			ulFlags |= XEMACPS_TXBUF_WRAP_MASK;
 		}

 		/* Copy the address of the buffer and set the flags. */
 		xemacpsif->txSegments[ head ].address = ( uint32_t )pxDMA_tx_buffers[ head ];
 		xemacpsif->txSegments[ head ].flags = ulFlags;

 		iHasSent = pdTRUE;
 		if( ++head == ipconfigNIC_N_TX_DESC )
 		{
 			head = 0;
 		}
 		/* Update the TX-head index. These variable are declared volatile so they will be
 		accessed as little as possible.	*/
 		xemacpsif->txHead = head;
 	} while( pdFALSE );

 	if( iReleaseAfterSend != pdFALSE )
 	{
 		vReleaseNetworkBufferAndDescriptor( pxBuffer );
 		pxBuffer = NULL;
 	}

 	/* Data Synchronization Barrier */
 	dsb();

 	if( iHasSent != pdFALSE )
 	{
 		/* Make STARTTX high */
 		uint32_t ulValue = XEmacPs_ReadReg( ulBaseAddress, XEMACPS_NWCTRL_OFFSET);
 		/* Start transmit */
 		xemacpsif->txBusy = pdTRUE;
 		XEmacPs_WriteReg( ulBaseAddress, XEMACPS_NWCTRL_OFFSET, ( ulValue | XEMACPS_NWCTRL_STARTTX_MASK ) );
 	}
 	dsb();

 	return 0;
 }

 void emacps_recv_handler(void *arg)
 {
 	xemacpsif_s *xemacpsif;
 	BaseType_t xHigherPriorityTaskWoken = pdFALSE;

 	xemacpsif = (xemacpsif_s *)(arg);
 	xemacpsif->isr_events |= EMAC_IF_RX_EVENT;

 	if( xEMACTaskHandle != NULL )
 	{
 		vTaskNotifyGiveFromISR( xEMACTaskHandle, &xHigherPriorityTaskWoken );
 	}

 	portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
 }

 static NetworkBufferDescriptor_t *ethMsg = NULL;
 static NetworkBufferDescriptor_t *ethLast = NULL;

 static void passEthMessages( void )
 {
 IPStackEvent_t xRxEvent;

 	xRxEvent.eEventType = eNetworkRxEvent;
 	xRxEvent.pvData = ( void * ) ethMsg;

 	if( xSendEventStructToIPTask( &xRxEvent, ( TickType_t ) 1000 ) != pdPASS )
 	{
 		/* The buffer could not be sent to the stack so	must be released again.
 		This is a deferred handler taskr, not a real interrupt, so it is ok to
 		use the task level function here. */
 		do
 		{
 			NetworkBufferDescriptor_t *xNext = ethMsg->pxNextBuffer;
 			vReleaseNetworkBufferAndDescriptor( ethMsg );
 			ethMsg = xNext;
 		} while( ethMsg != NULL );

 		iptraceETHERNET_RX_EVENT_LOST();
 		FreeRTOS_printf( ( "passEthMessages: Can not queue return packet!\n" ) );
 	}

 	ethMsg = ethLast = NULL;
 }

 int emacps_check_rx( xemacpsif_s *xemacpsif )
 {
 NetworkBufferDescriptor_t *pxBuffer, *pxNewBuffer;
 int rx_bytes;
 volatile int msgCount = 0;
 int head = xemacpsif->rxHead;

 	/* There seems to be an issue (SI# 692601), see comments below. */
 	resetrx_on_no_rxdata(xemacpsif);

 	/* This FreeRTOS+TCP driver shall be compiled with the option
 	"ipconfigUSE_LINKED_RX_MESSAGES" enabled.  It allows the driver to send a
 	chain of RX messages within one message to the IP-task.	*/
 	for( ;; )
 	{
 		if( ( ( xemacpsif->rxSegments[ head ].address & XEMACPS_RXBUF_NEW_MASK ) == 0 ) ||
 			( pxDMA_rx_buffers[ head ] == NULL ) )
 		{
 			break;
 		}

 		pxNewBuffer = pxGetNetworkBufferWithDescriptor( ipTOTAL_ETHERNET_FRAME_SIZE + RX_BUFFER_ALIGNMENT, ( TickType_t ) 0 );
 		if( pxNewBuffer == NULL )
 		{
 			/* A packet has been received, but there is no replacement for this Network Buffer.
 			The packet will be dropped, and it Network Buffer will stay in place. */
 			FreeRTOS_printf( ("emacps_check_rx: unable to allocate a Netwrok Buffer\n" ) );
 			pxNewBuffer = ( NetworkBufferDescriptor_t * )pxDMA_rx_buffers[ head ];
 		}
 		else
 		{
 			pxBuffer = ( NetworkBufferDescriptor_t * )pxDMA_rx_buffers[ head ];

 			/* Just avoiding to use or refer to the same buffer again */
 			pxDMA_rx_buffers[ head ] = pxNewBuffer;

 			/*
 			 * Adjust the buffer size to the actual number of bytes received.
 			 */
 			rx_bytes = xemacpsif->rxSegments[ head ].flags & XEMACPS_RXBUF_LEN_MASK;

 			pxBuffer->xDataLength = rx_bytes;

 			if( ucIsCachedMemory( pxBuffer->pucEthernetBuffer ) != 0 )
 			{
 				Xil_DCacheInvalidateRange( ( ( uint32_t )pxBuffer->pucEthernetBuffer ) - ipconfigPACKET_FILLER_SIZE, (unsigned)rx_bytes );
 			}

 			/* store it in the receive queue, where it'll be processed by a
 			different handler. */
 			iptraceNETWORK_INTERFACE_RECEIVE();
 			pxBuffer->pxNextBuffer = NULL;

 			if( ethMsg == NULL )
 			{
 				// Becomes the first message
 				ethMsg = pxBuffer;
 			}
 			else if( ethLast != NULL )
 			{
 				// Add to the tail
 				ethLast->pxNextBuffer = pxBuffer;
 			}

 			ethLast = pxBuffer;
 			msgCount++;
 		}
 		{
 			if( ucIsCachedMemory( pxNewBuffer->pucEthernetBuffer ) != 0 )
 			{
 				Xil_DCacheInvalidateRange( ( ( uint32_t )pxNewBuffer->pucEthernetBuffer ) - ipconfigPACKET_FILLER_SIZE, (unsigned)ipTOTAL_ETHERNET_FRAME_SIZE + RX_BUFFER_ALIGNMENT);
 			}
 			{
 				uint32_t addr = ( ( uint32_t )pxNewBuffer->pucEthernetBuffer ) & XEMACPS_RXBUF_ADD_MASK;
 				if( head == ( ipconfigNIC_N_RX_DESC - 1 ) )
 				{
 					addr |= XEMACPS_RXBUF_WRAP_MASK;
 				}
 				/* Clearing 'XEMACPS_RXBUF_NEW_MASK'       0x00000001 *< Used bit.. */
 				xemacpsif->rxSegments[ head ].address = addr;
 				xemacpsif->rxSegments[ head ].flags = 0;
 			}
 		}

 		if( ++head == ipconfigNIC_N_RX_DESC )
 		{
 			head = 0;
 		}
 		xemacpsif->rxHead = head;
 	}

 	if( ethMsg != NULL )
 	{
 		passEthMessages( );
 	}

 	return msgCount;
 }

 void clean_dma_txdescs(xemacpsif_s *xemacpsif)
 {
 int index;
 unsigned char *ucTxBuffer;

 	/* Clear all TX descriptors and assign uncached memory to each descriptor.
 	"tx_space" points to the first available TX buffer. */
 	ucTxBuffer = xemacpsif->tx_space;

 	for( index = 0; index < ipconfigNIC_N_TX_DESC; index++ )
 	{
 		xemacpsif->txSegments[ index ].address = ( uint32_t )ucTxBuffer;
 		xemacpsif->txSegments[ index ].flags = XEMACPS_TXBUF_USED_MASK;
 #if( ipconfigZERO_COPY_TX_DRIVER != 0 )
 		pxDMA_tx_buffers[ index ] = ( void* )NULL;
 #else
 		pxDMA_tx_buffers[ index ] = ( void* )( ucTxBuffer + TX_OFFSET );
 #endif
 		ucTxBuffer += xemacpsif->uTxUnitSize;
 	}
 	xemacpsif->txSegments[ ipconfigNIC_N_TX_DESC - 1 ].flags =
 		XEMACPS_TXBUF_USED_MASK | XEMACPS_TXBUF_WRAP_MASK;
 }

 XStatus init_dma(xemacpsif_s *xemacpsif)
 {
 	NetworkBufferDescriptor_t *pxBuffer;

 	int iIndex;
 	UBaseType_t xRxSize;
 	UBaseType_t xTxSize;
 	struct xtopology_t *xtopologyp = &xXTopology;

 	xRxSize = ipconfigNIC_N_RX_DESC * sizeof( xemacpsif->rxSegments[ 0 ] );

 	xTxSize = ipconfigNIC_N_TX_DESC * sizeof( xemacpsif->txSegments[ 0 ] );

 	/* Also round-up to 4KB */
 	xemacpsif->uTxUnitSize = ( ipTOTAL_ETHERNET_FRAME_SIZE + 0x1000ul ) & ~0xffful;
 	/*
 	 * We allocate 65536 bytes for RX BDs which can accommodate a
 	 * maximum of 8192 BDs which is much more than any application
 	 * will ever need.
 	 */
 	xemacpsif->rxSegments = ( struct xBD_TYPE * )( pucGetUncachedMemory ( xRxSize )  );
 	xemacpsif->txSegments = ( struct xBD_TYPE * )( pucGetUncachedMemory ( xTxSize ) );
 	xemacpsif->tx_space   = ( unsigned char *   )( pucGetUncachedMemory ( ipconfigNIC_N_TX_DESC * xemacpsif->uTxUnitSize ) );

 	/* These variables will be used in XEmacPs_Start (see src/xemacps.c). */
 	xemacpsif->emacps.RxBdRing.BaseBdAddr = ( uint32_t ) xemacpsif->rxSegments;
 	xemacpsif->emacps.TxBdRing.BaseBdAddr = ( uint32_t ) xemacpsif->txSegments;

 	if( xTXDescriptorSemaphore == NULL )
 	{
 		xTXDescriptorSemaphore = xSemaphoreCreateCounting( ( UBaseType_t ) ipconfigNIC_N_TX_DESC, ( UBaseType_t ) ipconfigNIC_N_TX_DESC );
 		configASSERT( xTXDescriptorSemaphore );
 	}
 	/*
 	 * Allocate RX descriptors, 1 RxBD at a time.
 	 */
 	for( iIndex = 0; iIndex < ipconfigNIC_N_RX_DESC; iIndex++ )
 	{
 		pxBuffer = pxDMA_rx_buffers[ iIndex ];
 		if( pxBuffer == NULL )
 		{
 			pxBuffer = pxGetNetworkBufferWithDescriptor( ipTOTAL_ETHERNET_FRAME_SIZE + RX_BUFFER_ALIGNMENT, ( TickType_t ) 0 );
 			if( pxBuffer == NULL )
 			{
 				FreeRTOS_printf( ("Unable to allocate a network buffer in recv_handler\n" ) );
 				return -1;
 			}
 		}

 		xemacpsif->rxSegments[ iIndex ].flags = 0;
 		xemacpsif->rxSegments[ iIndex ].address = ( ( uint32_t )pxBuffer->pucEthernetBuffer ) & XEMACPS_RXBUF_ADD_MASK;

 		pxDMA_rx_buffers[ iIndex ] = pxBuffer;
 		/* Make sure this memory is not in cache for now. */
 		if( ucIsCachedMemory( pxBuffer->pucEthernetBuffer ) != 0 )
 		{
 			Xil_DCacheInvalidateRange( ( ( uint32_t )pxBuffer->pucEthernetBuffer ) - ipconfigPACKET_FILLER_SIZE,
 				(unsigned)ipTOTAL_ETHERNET_FRAME_SIZE + RX_BUFFER_ALIGNMENT);
 		}
 	}

 	xemacpsif->rxSegments[ ipconfigNIC_N_RX_DESC - 1 ].address |= XEMACPS_RXBUF_WRAP_MASK;

 	memset( xemacpsif->tx_space, '\0', ipconfigNIC_N_TX_DESC * xemacpsif->uTxUnitSize );

 	clean_dma_txdescs( xemacpsif );

 	{
 		uint32_t value;
 		value = XEmacPs_ReadReg( xemacpsif->emacps.Config.BaseAddress, XEMACPS_DMACR_OFFSET );

 		// 1xxxx: Attempt to use INCR16 AHB bursts
 		value = ( value & ~( XEMACPS_DMACR_BLENGTH_MASK ) ) | XEMACPS_DMACR_INCR16_AHB_BURST;
 #if( ipconfigDRIVER_INCLUDED_TX_IP_CHECKSUM != 0 )
 		value |= XEMACPS_DMACR_TCPCKSUM_MASK;
 #else
 #warning Are you sure the EMAC should not calculate outgoing checksums?
 		value &= ~XEMACPS_DMACR_TCPCKSUM_MASK;
 #endif
 		XEmacPs_WriteReg( xemacpsif->emacps.Config.BaseAddress, XEMACPS_DMACR_OFFSET, value );
 	}
 	{
 		uint32_t value;
 		value = XEmacPs_ReadReg( xemacpsif->emacps.Config.BaseAddress, XEMACPS_NWCFG_OFFSET );

 		/* Network buffers are 32-bit aligned + 2 bytes (because ipconfigPACKET_FILLER_SIZE = 2 ).
 		Now tell the EMAC that received messages should be stored at "address + 2". */
 		value = ( value & ~XEMACPS_NWCFG_RXOFFS_MASK ) | 0x8000;

 #if( ipconfigDRIVER_INCLUDED_RX_IP_CHECKSUM != 0 )
 		value |= XEMACPS_NWCFG_RXCHKSUMEN_MASK;
 #else
 #warning Are you sure the EMAC should not calculate incoming checksums?
 		value &= ~XEMACPS_NWCFG_RXCHKSUMEN_MASK;
 #endif
 		XEmacPs_WriteReg( xemacpsif->emacps.Config.BaseAddress, XEMACPS_NWCFG_OFFSET, value );
 	}

 	/*
 	 * Connect the device driver handler that will be called when an
 	 * interrupt for the device occurs, the handler defined above performs
 	 * the specific interrupt processing for the device.
 	 */
 	XScuGic_RegisterHandler(INTC_BASE_ADDR, xtopologyp->scugic_emac_intr,
 		(Xil_ExceptionHandler)XEmacPs_IntrHandler,
 		(void *)&xemacpsif->emacps);
 	/*
 	 * Enable the interrupt for emacps.
 	 */
 	EmacEnableIntr( );

 	return 0;
 }

 /*
  * resetrx_on_no_rxdata():
  *
  * It is called at regular intervals through the API xemacpsif_resetrx_on_no_rxdata
  * called by the user.
  * The EmacPs has a HW bug (SI# 692601) on the Rx path for heavy Rx traffic.
  * Under heavy Rx traffic because of the HW bug there are times when the Rx path
  * becomes unresponsive. The workaround for it is to check for the Rx path for
  * traffic (by reading the stats registers regularly). If the stats register
  * does not increment for sometime (proving no Rx traffic), the function resets
  * the Rx data path.
  *
  */

 void resetrx_on_no_rxdata(xemacpsif_s *xemacpsif)
 {
 	unsigned long regctrl;
 	unsigned long tempcntr;

 	tempcntr = XEmacPs_ReadReg( xemacpsif->emacps.Config.BaseAddress, XEMACPS_RXCNT_OFFSET );
 	if ( ( tempcntr == 0 ) && ( xemacpsif->last_rx_frms_cntr == 0 ) )
 	{
 		regctrl = XEmacPs_ReadReg(xemacpsif->emacps.Config.BaseAddress,
 				XEMACPS_NWCTRL_OFFSET);
 		regctrl &= (~XEMACPS_NWCTRL_RXEN_MASK);
 		XEmacPs_WriteReg(xemacpsif->emacps.Config.BaseAddress,
 				XEMACPS_NWCTRL_OFFSET, regctrl);
 		regctrl = XEmacPs_ReadReg(xemacpsif->emacps.Config.BaseAddress, XEMACPS_NWCTRL_OFFSET);
 		regctrl |= (XEMACPS_NWCTRL_RXEN_MASK);
 		XEmacPs_WriteReg(xemacpsif->emacps.Config.BaseAddress, XEMACPS_NWCTRL_OFFSET, regctrl);
 	}
 	xemacpsif->last_rx_frms_cntr = tempcntr;
 }

 void EmacDisableIntr(void)
 {
 	XScuGic_DisableIntr(INTC_DIST_BASE_ADDR, xXTopology.scugic_emac_intr);
 }

 void EmacEnableIntr(void)
 {
 	XScuGic_EnableIntr(INTC_DIST_BASE_ADDR, xXTopology.scugic_emac_intr);
 }
	/*
	FreeRTOS+TCP V2.0.11
	Copyright (C) 2017 Amazon.com, Inc. or its affiliates. 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.

	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 AUTHORS OR
	COPYRIGHT HOLDERS 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.

	http://aws.amazon.com/freertos
	http://www.FreeRTOS.org
	*/

	#include "Zynq/x_emacpsif.h"
	#include "Zynq/x_topology.h"
	#include "xstatus.h"

	#include "xparameters.h"
	#include "xparameters_ps.h"
	#include "xil_exception.h"
	#include "xil_mmu.h"

	#include "FreeRTOS.h"
	#include "task.h"
	#include "timers.h"
	#include "semphr.h"

	/* FreeRTOS+TCP includes. */
	#include "FreeRTOS_IP.h"
	#include "FreeRTOS_Sockets.h"
	#include "FreeRTOS_IP_Private.h"
	#include "NetworkBufferManagement.h"

	#include "uncached_memory.h"

	/* Two defines used to set or clear the EMAC interrupt */
	#define INTC_BASE_ADDR XPAR_SCUGIC_CPU_BASEADDR
	#define INTC_DIST_BASE_ADDR XPAR_SCUGIC_DIST_BASEADDR



	#if( ipconfigPACKET_FILLER_SIZE != 2 )
	#error Please define ipconfigPACKET_FILLER_SIZE as the value '2'
	#endif
	#define TX_OFFSET ipconfigPACKET_FILLER_SIZE

	#define RX_BUFFER_ALIGNMENT 14

	/* Defined in NetworkInterface.c */
	extern TaskHandle_t xEMACTaskHandle;

	/*
	pxDMA_tx_buffers: these are character arrays, each one is big enough to hold 1 MTU.
	The actual TX buffers are located in uncached RAM.
	*/
	static unsigned char *pxDMA_tx_buffers[ ipconfigNIC_N_TX_DESC ] = { NULL };

	/*
	pxDMA_rx_buffers: these are pointers to 'NetworkBufferDescriptor_t'.
	Once a message has been received by the EMAC, the descriptor can be passed
	immediately to the IP-task.
	*/
	static NetworkBufferDescriptor_t *pxDMA_rx_buffers[ ipconfigNIC_N_RX_DESC ] = { NULL };

	/*
	The FreeRTOS+TCP port is using a fixed 'topology', which is declared in
	./portable/NetworkInterface/Zynq/NetworkInterface.c
	*/
	extern struct xtopology_t xXTopology;

	static SemaphoreHandle_t xTXDescriptorSemaphore = NULL;

	/*
	The FreeRTOS+TCP port does not make use of "src/xemacps_bdring.c".
	In stead 'struct xemacpsif_s' has a "head" and a "tail" index.
	"head" is the next index to be written, used.
	"tail" is the next index to be read, freed.
	*/

	int is_tx_space_available( xemacpsif_s *xemacpsif )
	{
	size_t uxCount;

	if( xTXDescriptorSemaphore != NULL )
	{
	uxCount = ( ( UBaseType_t ) ipconfigNIC_N_TX_DESC ) - uxSemaphoreGetCount( xTXDescriptorSemaphore );
	}
	else
	{
	uxCount = ( UBaseType_t ) 0u;
	}

	return uxCount;
	}

	void emacps_check_tx( xemacpsif_s *xemacpsif )
	{
	int tail = xemacpsif->txTail;
	int head = xemacpsif->txHead;
	size_t uxCount = ( ( UBaseType_t ) ipconfigNIC_N_TX_DESC ) - uxSemaphoreGetCount( xTXDescriptorSemaphore );

	/* uxCount is the number of TX descriptors that are in use by the DMA. */
	/* When done, "TXBUF_USED" will be set. */

	while( ( uxCount > 0 ) && ( ( xemacpsif->txSegments[ tail ].flags & XEMACPS_TXBUF_USED_MASK ) != 0 ) )
	{
	if( ( tail == head ) && ( uxCount != ipconfigNIC_N_TX_DESC ) )
	{
	break;
	}
	#if( ipconfigZERO_COPY_TX_DRIVER != 0 )
	#warning ipconfigZERO_COPY_TX_DRIVER is defined
	{
	void *pvBuffer = pxDMA_tx_buffers[ tail ];
	NetworkBufferDescriptor_t *pxBuffer;

	if( pvBuffer != NULL )
	{
	pxDMA_tx_buffers[ tail ] = NULL;
	pxBuffer = pxPacketBuffer_to_NetworkBuffer( pvBuffer );
	if( pxBuffer != NULL )
	{
	vReleaseNetworkBufferAndDescriptor( pxBuffer );
	}
	else
	{
	FreeRTOS_printf( ( "emacps_check_tx: Can not find network buffer\n" ) );
	}
	}
	}
	#endif
	/* Clear all but the "used" and "wrap" bits. */
	if( tail < ipconfigNIC_N_TX_DESC - 1 )
	{
	xemacpsif->txSegments[ tail ].flags = XEMACPS_TXBUF_USED_MASK;
	}
	else
	{
	xemacpsif->txSegments[ tail ].flags = XEMACPS_TXBUF_USED_MASK \| XEMACPS_TXBUF_WRAP_MASK;
	}
	uxCount--;
	/* Tell the counting semaphore that one more TX descriptor is available. */
	xSemaphoreGive( xTXDescriptorSemaphore );
	if( ++tail == ipconfigNIC_N_TX_DESC )
	{
	tail = 0;
	}
	xemacpsif->txTail = tail;
	}

	return;
	}

	void emacps_send_handler(void *arg)
	{
	xemacpsif_s *xemacpsif;
	BaseType_t xHigherPriorityTaskWoken = pdFALSE;

	xemacpsif = (xemacpsif_s *)(arg);

	/* In this port for FreeRTOS+TCP, the EMAC interrupts will only set a bit in
	"isr_events". The task in NetworkInterface will wake-up and do the necessary work.
	*/
	xemacpsif->isr_events \|= EMAC_IF_TX_EVENT;
	xemacpsif->txBusy = pdFALSE;

	if( xEMACTaskHandle != NULL )
	{
	vTaskNotifyGiveFromISR( xEMACTaskHandle, &xHigherPriorityTaskWoken );
	}

	portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
	}

	static BaseType_t xValidLength( BaseType_t xLength )
	{
	BaseType_t xReturn;

	if( ( xLength >= ( BaseType_t ) sizeof( struct xARP_PACKET ) ) && ( ( ( uint32_t ) xLength ) <= ipTOTAL_ETHERNET_FRAME_SIZE ) )
	{
	xReturn = pdTRUE;
	}
	else
	{
	xReturn = pdFALSE;
	}

	return xReturn;
	}

	XStatus emacps_send_message(xemacpsif_s xemacpsif, NetworkBufferDescriptor_t pxBuffer, int iReleaseAfterSend )
	{
	int head = xemacpsif->txHead;
	int iHasSent = 0;
	uint32_t ulBaseAddress = xemacpsif->emacps.Config.BaseAddress;
	TickType_t xBlockTimeTicks = pdMS_TO_TICKS( 5000u );

	#if( ipconfigZERO_COPY_TX_DRIVER != 0 )
	{
	/* This driver wants to own all network buffers which are to be transmitted. */
	configASSERT( iReleaseAfterSend != pdFALSE );
	}
	#endif

	/* Open a do {} while ( 0 ) loop to be able to call break. */
	do
	{
	uint32_t ulFlags = 0;

	if( xValidLength( pxBuffer->xDataLength ) != pdTRUE )
	{
	break;
	}

	if( xTXDescriptorSemaphore == NULL )
	{
	break;
	}

	if( xSemaphoreTake( xTXDescriptorSemaphore, xBlockTimeTicks ) != pdPASS )
	{
	FreeRTOS_printf( ( "emacps_send_message: Time-out waiting for TX buffer\n" ) );
	break;
	}

	#if( ipconfigZERO_COPY_TX_DRIVER != 0 )
	/* Pass the pointer (and its ownership) directly to DMA. */
	pxDMA_tx_buffers[ head ] = pxBuffer->pucEthernetBuffer;
	if( ucIsCachedMemory( pxBuffer->pucEthernetBuffer ) != 0 )
	{
	Xil_DCacheFlushRange( ( unsigned )pxBuffer->pucEthernetBuffer, pxBuffer->xDataLength );
	}
	/* Buffer has been transferred, do not release it. */
	iReleaseAfterSend = pdFALSE;
	#else
	if( pxDMA_tx_buffers[ head ] == NULL )
	{
	FreeRTOS_printf( ( "emacps_send_message: pxDMA_tx_buffers[ %d ] == NULL\n", head ) );
	break;
	}
	/* Copy the message to unbuffered space in RAM. */
	memcpy( pxDMA_tx_buffers[ head ], pxBuffer->pucEthernetBuffer, pxBuffer->xDataLength );
	#endif
	/* Packets will be sent one-by-one, so for each packet
	the TXBUF_LAST bit will be set. */
	ulFlags \|= XEMACPS_TXBUF_LAST_MASK;
	ulFlags \|= ( pxBuffer->xDataLength & XEMACPS_TXBUF_LEN_MASK );
	if( head == ( ipconfigNIC_N_TX_DESC - 1 ) )
	{
	ulFlags \|= XEMACPS_TXBUF_WRAP_MASK;
	}

	/* Copy the address of the buffer and set the flags. */
	xemacpsif->txSegments[ head ].address = ( uint32_t )pxDMA_tx_buffers[ head ];
	xemacpsif->txSegments[ head ].flags = ulFlags;

	iHasSent = pdTRUE;
	if( ++head == ipconfigNIC_N_TX_DESC )
	{
	head = 0;
	}
	/* Update the TX-head index. These variable are declared volatile so they will be
	accessed as little as possible. */
	xemacpsif->txHead = head;
	} while( pdFALSE );

	if( iReleaseAfterSend != pdFALSE )
	{
	vReleaseNetworkBufferAndDescriptor( pxBuffer );
	pxBuffer = NULL;
	}

	/* Data Synchronization Barrier */
	dsb();

	if( iHasSent != pdFALSE )
	{
	/* Make STARTTX high */
	uint32_t ulValue = XEmacPs_ReadReg( ulBaseAddress, XEMACPS_NWCTRL_OFFSET);
	/* Start transmit */
	xemacpsif->txBusy = pdTRUE;
	XEmacPs_WriteReg( ulBaseAddress, XEMACPS_NWCTRL_OFFSET, ( ulValue \| XEMACPS_NWCTRL_STARTTX_MASK ) );
	}
	dsb();

	return 0;
	}

	void emacps_recv_handler(void *arg)
	{
	xemacpsif_s *xemacpsif;
	BaseType_t xHigherPriorityTaskWoken = pdFALSE;

	xemacpsif = (xemacpsif_s *)(arg);
	xemacpsif->isr_events \|= EMAC_IF_RX_EVENT;

	if( xEMACTaskHandle != NULL )
	{
	vTaskNotifyGiveFromISR( xEMACTaskHandle, &xHigherPriorityTaskWoken );
	}

	portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
	}

	static NetworkBufferDescriptor_t *ethMsg = NULL;
	static NetworkBufferDescriptor_t *ethLast = NULL;

	static void passEthMessages( void )
	{
	IPStackEvent_t xRxEvent;

	xRxEvent.eEventType = eNetworkRxEvent;
	xRxEvent.pvData = ( void * ) ethMsg;

	if( xSendEventStructToIPTask( &xRxEvent, ( TickType_t ) 1000 ) != pdPASS )
	{
	/* The buffer could not be sent to the stack so must be released again.
	This is a deferred handler taskr, not a real interrupt, so it is ok to
	use the task level function here. */
	do
	{
	NetworkBufferDescriptor_t *xNext = ethMsg->pxNextBuffer;
	vReleaseNetworkBufferAndDescriptor( ethMsg );
	ethMsg = xNext;
	} while( ethMsg != NULL );

	iptraceETHERNET_RX_EVENT_LOST();
	FreeRTOS_printf( ( "passEthMessages: Can not queue return packet!\n" ) );
	}

	ethMsg = ethLast = NULL;
	}

	int emacps_check_rx( xemacpsif_s *xemacpsif )
	{
	NetworkBufferDescriptor_t pxBuffer, pxNewBuffer;
	int rx_bytes;
	volatile int msgCount = 0;
	int head = xemacpsif->rxHead;

	/* There seems to be an issue (SI# 692601), see comments below. */
	resetrx_on_no_rxdata(xemacpsif);

	/* This FreeRTOS+TCP driver shall be compiled with the option
	"ipconfigUSE_LINKED_RX_MESSAGES" enabled. It allows the driver to send a
	chain of RX messages within one message to the IP-task. */
	for( ;; )
	{
	if( ( ( xemacpsif->rxSegments[ head ].address & XEMACPS_RXBUF_NEW_MASK ) == 0 ) \|\|
	( pxDMA_rx_buffers[ head ] == NULL ) )
	{
	break;
	}

	pxNewBuffer = pxGetNetworkBufferWithDescriptor( ipTOTAL_ETHERNET_FRAME_SIZE + RX_BUFFER_ALIGNMENT, ( TickType_t ) 0 );
	if( pxNewBuffer == NULL )
	{
	/* A packet has been received, but there is no replacement for this Network Buffer.
	The packet will be dropped, and it Network Buffer will stay in place. */
	FreeRTOS_printf( ("emacps_check_rx: unable to allocate a Netwrok Buffer\n" ) );
	pxNewBuffer = ( NetworkBufferDescriptor_t * )pxDMA_rx_buffers[ head ];
	}
	else
	{
	pxBuffer = ( NetworkBufferDescriptor_t * )pxDMA_rx_buffers[ head ];

	/* Just avoiding to use or refer to the same buffer again */
	pxDMA_rx_buffers[ head ] = pxNewBuffer;

	/*
	* Adjust the buffer size to the actual number of bytes received.
	*/
	rx_bytes = xemacpsif->rxSegments[ head ].flags & XEMACPS_RXBUF_LEN_MASK;

	pxBuffer->xDataLength = rx_bytes;

	if( ucIsCachedMemory( pxBuffer->pucEthernetBuffer ) != 0 )
	{
	Xil_DCacheInvalidateRange( ( ( uint32_t )pxBuffer->pucEthernetBuffer ) - ipconfigPACKET_FILLER_SIZE, (unsigned)rx_bytes );
	}

	/* store it in the receive queue, where it'll be processed by a
	different handler. */
	iptraceNETWORK_INTERFACE_RECEIVE();
	pxBuffer->pxNextBuffer = NULL;

	if( ethMsg == NULL )
	{
	// Becomes the first message
	ethMsg = pxBuffer;
	}
	else if( ethLast != NULL )
	{
	// Add to the tail
	ethLast->pxNextBuffer = pxBuffer;
	}

	ethLast = pxBuffer;
	msgCount++;
	}
	{
	if( ucIsCachedMemory( pxNewBuffer->pucEthernetBuffer ) != 0 )
	{
	Xil_DCacheInvalidateRange( ( ( uint32_t )pxNewBuffer->pucEthernetBuffer ) - ipconfigPACKET_FILLER_SIZE, (unsigned)ipTOTAL_ETHERNET_FRAME_SIZE + RX_BUFFER_ALIGNMENT);
	}
	{
	uint32_t addr = ( ( uint32_t )pxNewBuffer->pucEthernetBuffer ) & XEMACPS_RXBUF_ADD_MASK;
	if( head == ( ipconfigNIC_N_RX_DESC - 1 ) )
	{
	addr \|= XEMACPS_RXBUF_WRAP_MASK;
	}
	/* Clearing 'XEMACPS_RXBUF_NEW_MASK' 0x00000001 < Used bit.. /
	xemacpsif->rxSegments[ head ].address = addr;
	xemacpsif->rxSegments[ head ].flags = 0;
	}
	}

	if( ++head == ipconfigNIC_N_RX_DESC )
	{
	head = 0;
	}
	xemacpsif->rxHead = head;
	}

	if( ethMsg != NULL )
	{
	passEthMessages( );
	}

	return msgCount;
	}

	void clean_dma_txdescs(xemacpsif_s *xemacpsif)
	{
	int index;
	unsigned char *ucTxBuffer;

	/* Clear all TX descriptors and assign uncached memory to each descriptor.
	"tx_space" points to the first available TX buffer. */
	ucTxBuffer = xemacpsif->tx_space;

	for( index = 0; index < ipconfigNIC_N_TX_DESC; index++ )
	{
	xemacpsif->txSegments[ index ].address = ( uint32_t )ucTxBuffer;
	xemacpsif->txSegments[ index ].flags = XEMACPS_TXBUF_USED_MASK;
	#if( ipconfigZERO_COPY_TX_DRIVER != 0 )
	pxDMA_tx_buffers[ index ] = ( void* )NULL;
	#else
	pxDMA_tx_buffers[ index ] = ( void* )( ucTxBuffer + TX_OFFSET );
	#endif
	ucTxBuffer += xemacpsif->uTxUnitSize;
	}
	xemacpsif->txSegments[ ipconfigNIC_N_TX_DESC - 1 ].flags =
	XEMACPS_TXBUF_USED_MASK \| XEMACPS_TXBUF_WRAP_MASK;
	}

	XStatus init_dma(xemacpsif_s *xemacpsif)
	{
	NetworkBufferDescriptor_t *pxBuffer;

	int iIndex;
	UBaseType_t xRxSize;
	UBaseType_t xTxSize;
	struct xtopology_t *xtopologyp = &xXTopology;

	xRxSize = ipconfigNIC_N_RX_DESC * sizeof( xemacpsif->rxSegments[ 0 ] );

	xTxSize = ipconfigNIC_N_TX_DESC * sizeof( xemacpsif->txSegments[ 0 ] );

	/* Also round-up to 4KB */
	xemacpsif->uTxUnitSize = ( ipTOTAL_ETHERNET_FRAME_SIZE + 0x1000ul ) & ~0xffful;
	/*
	* We allocate 65536 bytes for RX BDs which can accommodate a
	* maximum of 8192 BDs which is much more than any application
	* will ever need.
	*/
	xemacpsif->rxSegments = ( struct xBD_TYPE * )( pucGetUncachedMemory ( xRxSize ) );
	xemacpsif->txSegments = ( struct xBD_TYPE * )( pucGetUncachedMemory ( xTxSize ) );
	xemacpsif->tx_space = ( unsigned char * )( pucGetUncachedMemory ( ipconfigNIC_N_TX_DESC * xemacpsif->uTxUnitSize ) );

	/* These variables will be used in XEmacPs_Start (see src/xemacps.c). */
	xemacpsif->emacps.RxBdRing.BaseBdAddr = ( uint32_t ) xemacpsif->rxSegments;
	xemacpsif->emacps.TxBdRing.BaseBdAddr = ( uint32_t ) xemacpsif->txSegments;

	if( xTXDescriptorSemaphore == NULL )
	{
	xTXDescriptorSemaphore = xSemaphoreCreateCounting( ( UBaseType_t ) ipconfigNIC_N_TX_DESC, ( UBaseType_t ) ipconfigNIC_N_TX_DESC );
	configASSERT( xTXDescriptorSemaphore );
	}
	/*
	* Allocate RX descriptors, 1 RxBD at a time.
	*/
	for( iIndex = 0; iIndex < ipconfigNIC_N_RX_DESC; iIndex++ )
	{
	pxBuffer = pxDMA_rx_buffers[ iIndex ];
	if( pxBuffer == NULL )
	{
	pxBuffer = pxGetNetworkBufferWithDescriptor( ipTOTAL_ETHERNET_FRAME_SIZE + RX_BUFFER_ALIGNMENT, ( TickType_t ) 0 );
	if( pxBuffer == NULL )
	{
	FreeRTOS_printf( ("Unable to allocate a network buffer in recv_handler\n" ) );
	return -1;
	}
	}

	xemacpsif->rxSegments[ iIndex ].flags = 0;
	xemacpsif->rxSegments[ iIndex ].address = ( ( uint32_t )pxBuffer->pucEthernetBuffer ) & XEMACPS_RXBUF_ADD_MASK;

	pxDMA_rx_buffers[ iIndex ] = pxBuffer;
	/* Make sure this memory is not in cache for now. */
	if( ucIsCachedMemory( pxBuffer->pucEthernetBuffer ) != 0 )
	{
	Xil_DCacheInvalidateRange( ( ( uint32_t )pxBuffer->pucEthernetBuffer ) - ipconfigPACKET_FILLER_SIZE,
	(unsigned)ipTOTAL_ETHERNET_FRAME_SIZE + RX_BUFFER_ALIGNMENT);
	}
	}

	xemacpsif->rxSegments[ ipconfigNIC_N_RX_DESC - 1 ].address \|= XEMACPS_RXBUF_WRAP_MASK;

	memset( xemacpsif->tx_space, '\0', ipconfigNIC_N_TX_DESC * xemacpsif->uTxUnitSize );

	clean_dma_txdescs( xemacpsif );

	{
	uint32_t value;
	value = XEmacPs_ReadReg( xemacpsif->emacps.Config.BaseAddress, XEMACPS_DMACR_OFFSET );

	// 1xxxx: Attempt to use INCR16 AHB bursts
	value = ( value & ~( XEMACPS_DMACR_BLENGTH_MASK ) ) \| XEMACPS_DMACR_INCR16_AHB_BURST;
	#if( ipconfigDRIVER_INCLUDED_TX_IP_CHECKSUM != 0 )
	value \|= XEMACPS_DMACR_TCPCKSUM_MASK;
	#else
	#warning Are you sure the EMAC should not calculate outgoing checksums?
	value &= ~XEMACPS_DMACR_TCPCKSUM_MASK;
	#endif
	XEmacPs_WriteReg( xemacpsif->emacps.Config.BaseAddress, XEMACPS_DMACR_OFFSET, value );
	}
	{
	uint32_t value;
	value = XEmacPs_ReadReg( xemacpsif->emacps.Config.BaseAddress, XEMACPS_NWCFG_OFFSET );

	/* Network buffers are 32-bit aligned + 2 bytes (because ipconfigPACKET_FILLER_SIZE = 2 ).
	Now tell the EMAC that received messages should be stored at "address + 2". */
	value = ( value & ~XEMACPS_NWCFG_RXOFFS_MASK ) \| 0x8000;

	#if( ipconfigDRIVER_INCLUDED_RX_IP_CHECKSUM != 0 )
	value \|= XEMACPS_NWCFG_RXCHKSUMEN_MASK;
	#else
	#warning Are you sure the EMAC should not calculate incoming checksums?
	value &= ~XEMACPS_NWCFG_RXCHKSUMEN_MASK;
	#endif
	XEmacPs_WriteReg( xemacpsif->emacps.Config.BaseAddress, XEMACPS_NWCFG_OFFSET, value );
	}

	/*
	* Connect the device driver handler that will be called when an
	* interrupt for the device occurs, the handler defined above performs
	* the specific interrupt processing for the device.
	*/
	XScuGic_RegisterHandler(INTC_BASE_ADDR, xtopologyp->scugic_emac_intr,
	(Xil_ExceptionHandler)XEmacPs_IntrHandler,
	(void *)&xemacpsif->emacps);
	/*
	* Enable the interrupt for emacps.
	*/
	EmacEnableIntr( );

	return 0;
	}

	/*
	* resetrx_on_no_rxdata():
	*
	* It is called at regular intervals through the API xemacpsif_resetrx_on_no_rxdata
	* called by the user.
	* The EmacPs has a HW bug (SI# 692601) on the Rx path for heavy Rx traffic.
	* Under heavy Rx traffic because of the HW bug there are times when the Rx path
	* becomes unresponsive. The workaround for it is to check for the Rx path for
	* traffic (by reading the stats registers regularly). If the stats register
	* does not increment for sometime (proving no Rx traffic), the function resets
	* the Rx data path.
	*
	*/

	void resetrx_on_no_rxdata(xemacpsif_s *xemacpsif)
	{
	unsigned long regctrl;
	unsigned long tempcntr;

	tempcntr = XEmacPs_ReadReg( xemacpsif->emacps.Config.BaseAddress, XEMACPS_RXCNT_OFFSET );
	if ( ( tempcntr == 0 ) && ( xemacpsif->last_rx_frms_cntr == 0 ) )
	{
	regctrl = XEmacPs_ReadReg(xemacpsif->emacps.Config.BaseAddress,
	XEMACPS_NWCTRL_OFFSET);
	regctrl &= (~XEMACPS_NWCTRL_RXEN_MASK);
	XEmacPs_WriteReg(xemacpsif->emacps.Config.BaseAddress,
	XEMACPS_NWCTRL_OFFSET, regctrl);
	regctrl = XEmacPs_ReadReg(xemacpsif->emacps.Config.BaseAddress, XEMACPS_NWCTRL_OFFSET);
	regctrl \|= (XEMACPS_NWCTRL_RXEN_MASK);
	XEmacPs_WriteReg(xemacpsif->emacps.Config.BaseAddress, XEMACPS_NWCTRL_OFFSET, regctrl);
	}
	xemacpsif->last_rx_frms_cntr = tempcntr;
	}

	void EmacDisableIntr(void)
	{
	XScuGic_DisableIntr(INTC_DIST_BASE_ADDR, xXTopology.scugic_emac_intr);
	}

	void EmacEnableIntr(void)
	{
	XScuGic_EnableIntr(INTC_DIST_BASE_ADDR, xXTopology.scugic_emac_intr);
	}