/********************************************************************************     Author: Xilinx, Inc.***     This program is free software; you can redistribute it and/or modify it*     under the terms of the GNU General Public License as published by the*     Free Software Foundation; either version 2 of the License, or (at your*     option) any later version.***     XILINX IS PROVIDING THIS DESIGN, CODE, OR INFORMATION "AS IS" AS A*     COURTESY TO YOU. 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Use in such applications is*     expressly prohibited.***     (c) Copyright 2002-2004 Xilinx Inc.*     All rights reserved.***     You should have received a copy of the GNU General Public License along*     with this program; if not, write to the Free Software Foundation, Inc.,*     675 Mass Ave, Cambridge, MA 02139, USA.*******************************************************************************//*****************************************************************************//**** @file xemac_intr_dma.c** Contains functions used in interrupt mode when configured with scatter-gather* DMA.** The interrupt handler, XEmac_IntrHandlerDma(), must be connected by the user* to the interrupt controller.** <pre>* MODIFICATION HISTORY:** Ver   Who  Date     Changes* ----- ---- -------- ---------------------------------------------------------* 1.00a rpm  07/31/01 First release* 1.00b rpm  02/20/02 Repartitioned files and functions* 1.00c rpm  12/05/02 New version includes support for simple DMA and the delay*                     argument to SgSend* 1.00c rpm  02/03/03 The XST_DMA_SG_COUNT_EXCEEDED return code was removed*                     from SetPktThreshold in the internal DMA driver. Also*                     avoided compiler warnings by initializing Result in the*                     interrupt service routines.* 1.00c rpm  03/26/03 Fixed a problem in the interrupt service routines where*                     the interrupt status was toggled clear after a call to*                     ErrorHandler, but if ErrorHandler reset the device the*                     toggle actually asserted the interrupt because the*                     reset had cleared it.* </pre>*******************************************************************************//***************************** Include Files *********************************/#include "xbasic_types.h"#include "xemac_i.h"#include "xio.h"#include "xbuf_descriptor.h"#include "xdma_channel.h"#include "xipif_v1_23_b.h"	/* Uses v1.23b of the IPIF *//************************** Constant Definitions *****************************//**************************** Type Definitions *******************************//***************** Macros (Inline Functions) Definitions *********************//************************** Variable Definitions *****************************//************************** Function Prototypes ******************************/static void HandleDmaRecvIntr(XEmac * InstancePtr);static void HandleDmaSendIntr(XEmac * InstancePtr);static void HandleEmacDmaIntr(XEmac * InstancePtr);/*****************************************************************************//**** Send an Ethernet frame using scatter-gather DMA. The caller attaches the* frame to one or more buffer descriptors, then calls this function once for* each descriptor. The caller is responsible for allocating and setting up the* descriptor. An entire Ethernet frame may or may not be contained within one* descriptor.  This function simply inserts the descriptor into the scatter-* gather engine's transmit list. The caller is responsible for providing mutual* exclusion to guarantee that a frame is contiguous in the transmit list. The* buffer attached to the descriptor must be word-aligned.** The driver updates the descriptor with the device control register before* being inserted into the transmit list.  If this is the last descriptor in* the frame, the inserts are committed, which means the descriptors for this* frame are now available for transmission.** It is assumed that the upper layer software supplies a correctly formatted* Ethernet frame, including the destination and source addresses, the* type/length field, and the data field.  It is also assumed that upper layer* software does not append FCS at the end of the frame.** The buffer attached to the descriptor must be word-aligned on the front end.** This call is non-blocking.  Notification of error or successful transmission* is done asynchronously through the send or error callback function.** @param InstancePtr is a pointer to the XEmac instance to be worked on.* @param BdPtr is the address of a descriptor to be inserted into the transmit*        ring.* @param Delay indicates whether to start the scatter-gather DMA channel*        immediately, or whether to wait. This allows the user to build up a*        list of more than one descriptor before starting the transmission of*        the packets, which allows the application to keep up with DMA and have*        a constant stream of frames being transmitted. Use XEM_SGDMA_NODELAY or*        XEM_SGDMA_DELAY, defined in xemac.h, as the value of this argument. If*        the user chooses to delay and build a list, the user must call this*        function with the XEM_SGDMA_NODELAY option or call XEmac_Start() to*        kick off the tranmissions.** @return** - XST_SUCCESS if the buffer was successfull sent* - XST_DEVICE_IS_STOPPED if the Ethernet MAC has not been started yet* - XST_NOT_SGDMA if the device is not in scatter-gather DMA mode* - XST_DMA_SG_LIST_FULL if the descriptor list for the DMA channel is full* - XST_DMA_SG_BD_LOCKED if the DMA channel cannot insert the descriptor into*   the list because a locked descriptor exists at the insert point* - XST_DMA_SG_NOTHING_TO_COMMIT if even after inserting a descriptor into the*   list, the DMA channel believes there are no new descriptors to commit. If*   this is ever encountered, there is likely a thread mutual exclusion problem*   on transmit.** @note** This function is not thread-safe. The user must provide mutually exclusive* access to this function if there are to be multiple threads that can call it.** @internal** A status that should never be returned from this function, although* the code is set up to handle it, is XST_DMA_SG_NO_LIST. Starting the device* requires a list to be created, and this function requires the device to be* started.*******************************************************************************/XStatusXEmac_SgSend(XEmac * InstancePtr, XBufDescriptor * BdPtr, int Delay){	XStatus Result;	u32 BdControl;	XASSERT_NONVOID(InstancePtr != NULL);	XASSERT_NONVOID(BdPtr != NULL);	XASSERT_NONVOID(InstancePtr->IsReady == XCOMPONENT_IS_READY);	/*	 * Be sure the device is configured for scatter-gather DMA, then be sure	 * it is started.	 */	if (!XEmac_mIsSgDma(InstancePtr)) {		return XST_NOT_SGDMA;	}	/*	 * Set some descriptor control word defaults (source address increment	 * and local destination address) and the destination address	 * (the FIFO).  These are the same for every transmit descriptor.	 */	BdControl = XBufDescriptor_GetControl(BdPtr);	XBufDescriptor_SetControl(BdPtr, BdControl | XEM_DFT_SEND_BD_MASK);	XBufDescriptor_SetDestAddress(BdPtr,				      InstancePtr->BaseAddress +				      XEM_PFIFO_TXDATA_OFFSET);	/*	 * Put the descriptor in the send list. The DMA component accesses data	 * here that can also be modified in interrupt context, so a critical	 * section is required.	 */	XIIF_V123B_GINTR_DISABLE(InstancePtr->BaseAddress);	Result = XDmaChannel_PutDescriptor(&InstancePtr->SendChannel, BdPtr);	if (Result != XST_SUCCESS) {		XIIF_V123B_GINTR_ENABLE(InstancePtr->BaseAddress);		return Result;	}	/*	 * If this is the last buffer in the frame, commit the inserts and start	 * the DMA engine if necessary	 */	if (XBufDescriptor_IsLastControl(BdPtr)) {		Result = XDmaChannel_CommitPuts(&InstancePtr->SendChannel);		if (Result != XST_SUCCESS) {			XIIF_V123B_GINTR_ENABLE(InstancePtr->BaseAddress);			return Result;		}		if (Delay == XEM_SGDMA_NODELAY) {			/*			 * Start the DMA channel. Ignore the return status since we know the			 * list exists and has at least one entry and we don't care if the			 * channel is already started.  The DMA component accesses data here			 * that can be modified at interrupt or task levels, so a critical			 * section is required.			 */			(void) XDmaChannel_SgStart(&InstancePtr->SendChannel);		}	}	XIIF_V123B_GINTR_ENABLE(InstancePtr->BaseAddress);	return XST_SUCCESS;}/*****************************************************************************//**** Add a descriptor, with an attached empty buffer, into the receive descriptor* list. The buffer attached to the descriptor must be word-aligned. This is* used by the upper layer software during initialization when first setting up* the receive descriptors, and also during reception of frames to replace* filled buffers with empty buffers. This function can be called when the* device is started or stopped. Note that it does start the scatter-gather DMA* engine.  Although this is not necessary during initialization, it is not a* problem during initialization because the MAC receiver is not yet started.** The buffer attached to the descriptor must be word-aligned on both the front* end and the back end.** Notification of received frames are done asynchronously through the receive* callback function.** @param InstancePtr is a pointer to the XEmac instance to be worked on.* @param BdPtr is a pointer to the buffer descriptor that will be added to the*        descriptor list.** @return** - XST_SUCCESS if a descriptor was successfully returned to the driver* - XST_NOT_SGDMA if the device is not in scatter-gather DMA mode* - XST_DMA_SG_LIST_FULL if the receive descriptor list is full* - XST_DMA_SG_BD_LOCKED if the DMA channel cannot insert the descriptor into*   the list because a locked descriptor exists at the insert point.* - XST_DMA_SG_NOTHING_TO_COMMIT if even after inserting a descriptor into the*   list, the DMA channel believes there are no new descriptors to commit.** @internal** A status that should never be returned from this function, although* the code is set up to handle it, is XST_DMA_SG_NO_LIST. Starting the device* requires a list to be created, and this function requires the device to be* started.*******************************************************************************/XStatusXEmac_SgRecv(XEmac * InstancePtr, XBufDescriptor * BdPtr){	XStatus Result;	u32 BdControl;	XASSERT_NONVOID(InstancePtr != NULL);	XASSERT_NONVOID(BdPtr != NULL);	XASSERT_NONVOID(InstancePtr->IsReady == XCOMPONENT_IS_READY);	/*	 * Be sure the device is configured for scatter-gather DMA	 */	if (!XEmac_mIsSgDma(InstancePtr)) {		return XST_NOT_SGDMA;	}	/*	 * Set some descriptor control word defaults (destination address increment	 * and local source address) and the source address (the FIFO). These are	 * the same for every receive descriptor.	 */	BdControl = XBufDescriptor_GetControl(BdPtr);	XBufDescriptor_SetControl(BdPtr, BdControl | XEM_DFT_RECV_BD_MASK);	XBufDescriptor_SetSrcAddress(BdPtr,				     InstancePtr->BaseAddress +				     XEM_PFIFO_RXDATA_OFFSET);	/*	 * Put the descriptor into the channel's descriptor list and commit.	 * Although this function is likely called within interrupt context, there	 * is the possibility that the upper layer software queues it to a task.	 * In this case, a critical section is needed here to protect shared data	 * in the DMA component.	 */	XIIF_V123B_GINTR_DISABLE(InstancePtr->BaseAddress);	Result = XDmaChannel_PutDescriptor(&InstancePtr->RecvChannel, BdPtr);	if (Result != XST_SUCCESS) {		XIIF_V123B_GINTR_ENABLE(InstancePtr->BaseAddress);		return Result;	}	Result = XDmaChannel_CommitPuts(&InstancePtr->RecvChannel);	if (Result != XST_SUCCESS) {		XIIF_V123B_GINTR_ENABLE(InstancePtr->BaseAddress);		return Result;	}	/*	 * Start the DMA channel. Ignore the return status since we know the list	 * exists and has at least one entry and we don't care if the channel is	 * already started. The DMA component accesses data here that can be	 * modified at interrupt or task levels, so a critical section is required.	 */	(void) XDmaChannel_SgStart(&InstancePtr->RecvChannel);	XIIF_V123B_GINTR_ENABLE(InstancePtr->BaseAddress);	return XST_SUCCESS;}/*****************************************************************************//**** The interrupt handler for the Ethernet driver when configured with scatter-