xemac_intr_dma.c

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/******************************************************************************
*
*     Author: Xilinx, Inc.
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******************************************************************************/
/*****************************************************************************/
/**
*
* @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.
*
******************************************************************************/
XStatus
XEmac_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.
*
******************************************************************************/
XStatus
XEmac_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-