xemac_intr_dma.c

powerpc405开发板的linux网口驱动程序

    }

    return XST_SUCCESS;
}

/*****************************************************************************/
/**
*
* Give the driver the memory space to be used for the scatter-gather DMA
* receive descriptor list. This function should only be called once, during
* initialization of the Ethernet driver. The memory space must be big enough
* to hold some number of descriptors, depending on the needs of the system.
* The xemac.h file defines minimum and default numbers of descriptors
* which can be used to allocate this memory space.
*
* The memory space must be 32-bit aligned. An assert will occur if asserts
* are turned on and the memory is not aligned.
*
* @param InstancePtr is a pointer to the XEmac instance to be worked on.
* @param MemoryPtr is a pointer to the aligned memory.
* @param ByteCount is the length, in bytes, of the memory space.
*
* @return
*
* - XST_SUCCESS if the space was initialized successfully
* - XST_NOT_SGDMA if the MAC is not configured for scatter-gather DMA
* - XST_DMA_SG_LIST_EXISTS if this list space has already been created
*
* @note
*
* If the device is configured for scatter-gather DMA, this function must be
* called AFTER the XEmac_Initialize() function because the DMA channel
* components must be initialized before the memory space is set.
*
******************************************************************************/
XStatus XEmac_SetSgRecvSpace(XEmac *InstancePtr, Xuint32 *MemoryPtr,
                             Xuint32 ByteCount)
{
    XASSERT_NONVOID(InstancePtr != NULL);
    XASSERT_NONVOID(MemoryPtr != NULL);
    XASSERT_NONVOID(ByteCount != 0);
    XASSERT_NONVOID(InstancePtr->IsReady == XCOMPONENT_IS_READY);

    if (!XEmac_mIsSgDma(InstancePtr))
    {
        return XST_NOT_SGDMA;
    }

    return XDmaChannel_CreateSgList(&InstancePtr->RecvChannel, MemoryPtr,
                                    ByteCount);
}

/*****************************************************************************/
/**
*
* Give the driver the memory space to be used for the scatter-gather DMA
* transmit descriptor list. This function should only be called once, during
* initialization of the Ethernet driver. The memory space must be big enough
* to hold some number of descriptors, depending on the needs of the system.
* The xemac.h file defines minimum and default numbers of descriptors
* which can be used to allocate this memory space.
*
* The memory space must be 32-bit aligned. An assert will occur if asserts
* are turned on and the memory is not aligned.
*
* @param InstancePtr is a pointer to the XEmac instance to be worked on.
* @param MemoryPtr is a pointer to the aligned memory.
* @param ByteCount is the length, in bytes, of the memory space.
*
* @return
*
* - XST_SUCCESS if the space was initialized successfully
* - XST_NOT_SGDMA if the MAC is not configured for scatter-gather DMA
* - XST_DMA_SG_LIST_EXISTS if this list space has already been created
*
* @note
*
* If the device is configured for scatter-gather DMA, this function must be
* called AFTER the XEmac_Initialize() function because the DMA channel
* components must be initialized before the memory space is set.
*
******************************************************************************/
XStatus XEmac_SetSgSendSpace(XEmac *InstancePtr, Xuint32 *MemoryPtr,
                             Xuint32 ByteCount)
{
    XASSERT_NONVOID(InstancePtr != NULL);
    XASSERT_NONVOID(MemoryPtr != NULL);
    XASSERT_NONVOID(ByteCount != 0);
    XASSERT_NONVOID(InstancePtr->IsReady == XCOMPONENT_IS_READY);

    if (!XEmac_mIsSgDma(InstancePtr))
    {
        return XST_NOT_SGDMA;
    }

    return XDmaChannel_CreateSgList(&InstancePtr->SendChannel, MemoryPtr,
                                    ByteCount);
}

/*****************************************************************************/
/**
*
* Return the number of free buffer descriptor slots that can be added to the
* send descriptor ring with XEmac_SgSend() before filling it up.
*
* @param InstancePtr is a pointer to the XEmac instance to be worked on.
*
* @return
*
* - The number of descriptors that can be given to the HW with XEmac_SgSend()
* - 0 if no room is left or the device is not configured for SG DMA
*
* @note
*
* None.
*
******************************************************************************/
unsigned XEmac_GetSgSendFreeDesc(XEmac *InstancePtr)
{
    unsigned Slots;

    XASSERT_NONVOID(InstancePtr != NULL);
    XASSERT_NONVOID(InstancePtr->IsReady == XCOMPONENT_IS_READY);

    Slots = InstancePtr->SendChannel.TotalDescriptorCount -
        InstancePtr->SendChannel.ActiveDescriptorCount;

    return Slots;
}


/*****************************************************************************/
/**
*
* Return the number of free buffer descriptor slots that can be added to the
* receive descriptor ring with XEmac_SgRecv() before filling it up.
*
* @param InstancePtr is a pointer to the XEmac instance to be worked on.
*
* @return
*
* - The number of descriptors that can be given to the HW with XEmac_SgRecv()
* - 0 if no room is left or the device is not configured for SG DMA
*
* @note
*
* None.
*
******************************************************************************/
unsigned XEmac_GetSgRecvFreeDesc(XEmac *InstancePtr)
{
    unsigned Slots;

    XASSERT_NONVOID(InstancePtr != NULL);
    XASSERT_NONVOID(InstancePtr->IsReady == XCOMPONENT_IS_READY);

    Slots = InstancePtr->RecvChannel.TotalDescriptorCount -
        InstancePtr->RecvChannel.ActiveDescriptorCount;

    return Slots;
}


/*****************************************************************************/
/**
*
* Set the callback function for handling received frames in scatter-gather DMA
* mode.  The upper layer software should call this function during
* initialization.  The callback is called once per frame received. The head of
* a descriptor list is passed in along with the number of descriptors in the
* list. Before leaving the callback, the upper layer software should attach a
* new buffer to each descriptor in the list.
*
* The callback is invoked by the driver within interrupt context, so it needs
* to do its job quickly. Sending the received frame up the protocol stack
* should be done at task-level. If there are other potentially slow operations
* within the callback, these too should be done at task-level.
*
* @param InstancePtr is a pointer to the XEmac instance to be worked on.
* @param CallBackRef is a reference pointer to be passed back to the adapter in
*        the callback. This helps the adapter correlate the callback to a
*        particular driver.
* @param FuncPtr is the pointer to the callback function.
*
* @return
*
* None.
*
* @note
*
* None.
*
******************************************************************************/
void XEmac_SetSgRecvHandler(XEmac *InstancePtr, void *CallBackRef,
                            XEmac_SgHandler FuncPtr)
{
    /*
     * Asserted IsDmaSg here instead of run-time check because there is really
     * no ill-effects of setting these when not configured for scatter-gather.
     */
    XASSERT_VOID(InstancePtr != XNULL);
    XASSERT_VOID(FuncPtr != XNULL);
    XASSERT_VOID(XEmac_mIsSgDma(InstancePtr));
    XASSERT_VOID(InstancePtr->IsReady == XCOMPONENT_IS_READY);

    InstancePtr->SgRecvHandler = FuncPtr;
    InstancePtr->SgRecvRef = CallBackRef;
}

/*****************************************************************************/
/**
*
* Set the callback function for handling confirmation of transmitted frames in
* scatter-gather DMA mode.  The upper layer software should call this function
* during initialization.  The callback is called once per frame sent. The head
* of a descriptor list is passed in along with the number of descriptors in
* the list. The callback is responsible for freeing buffers attached to these
* descriptors.
*
* The callback is invoked by the driver within interrupt context, so it needs
* to do its job quickly. If there are potentially slow operations within the
* callback, these should be done at task-level.
*
* @param InstancePtr is a pointer to the XEmac instance to be worked on.
* @param CallBackRef is a reference pointer to be passed back to the adapter in
*        the callback. This helps the adapter correlate the callback to a
*        particular driver.
* @param FuncPtr is the pointer to the callback function.
*
* @return
*
* None.
*
* @note
*
* None.
*
******************************************************************************/
void XEmac_SetSgSendHandler(XEmac *InstancePtr, void *CallBackRef,
                            XEmac_SgHandler FuncPtr)
{
    /*
     * Asserted IsDmaSg here instead of run-time check because there is really
     * no ill-effects of setting these when not configured for scatter-gather.
     */
    XASSERT_VOID(InstancePtr != XNULL);
    XASSERT_VOID(FuncPtr != XNULL);
    XASSERT_VOID(XEmac_mIsSgDma(InstancePtr));
    XASSERT_VOID(InstancePtr->IsReady == XCOMPONENT_IS_READY);

    InstancePtr->SgSendHandler = FuncPtr;
    InstancePtr->SgSendRef = CallBackRef;
}

/*****************************************************************************/
/*
*
* Handle an interrupt from the DMA receive channel. DMA interrupts are:
*
* - DMA error. DMA encountered a bus error or timeout. This is a fatal error
*   that requires reset of the channel.  The driver calls the error handler
*   of the upper layer software with an error code indicating the device should
*   be reset.
* - Packet count threshold reached.  For scatter-gather operations, indicates
*   the threshold for the number of packets not serviced by software has been
*   reached. The driver behaves as follows:
*       - Get the value of the packet counter, which tells us how many packets
*         are ready to be serviced
*       - For each packet
*           - For each descriptor, remove it from the scatter-gather list
*           - Check for the last descriptor in the frame, and if set
*               - Bump frame statistics
*               - Decrement the packet counter by one
*       - Call the scatter-gather receive callback function
*       Note that there are no receive errors reported in the status word of
*       the buffer descriptor.  If receive errors occur, the MAC drops the
*       packet, and we only find out about the errors through various error
*       count registers.
* - Packet wait bound reached.  For scatter-gather, indicates the time to wait
*   for the next packet has expired.  The driver follows the same logic as when
*   the packet count threshold interrupt is received.
* - Scatter-gather end acknowledge.  Hardware has reached the end of the
*   descriptor list.  The driver follows the same logic as when the packet count
*   threshold interrupt is received. In addition, the driver restarts the DMA
*   scatter-gather channel in case there are newly inserted descriptors.
*
* @param InstancePtr is a pointer to the XEmac instance to be worked on.
*
* @return
*
* Although the function returns void, there are asynchronous errors that can
* be generated (by calling the ErrorHandler) from this function.  These are:
* - XST_DMA_SG_LIST_EMPTY indicates we tried to get a buffer descriptor from the
*   DMA channel, but there was not one ready for software.
* - XST_DMA_ERROR indicates a DMA bus error or timeout occurred. This is a fatal
*   error that requires reset.
*
* @note
*
* None.
*
******************************************************************************/
static void HandleDmaRecvIntr(XEmac *InstancePtr)
{
    XStatus Result;
    Xuint32 IntrStatus;
    Xuint32 NumBds;
    Xuint32 PacketsLeft;
    XBufDescriptor *BdHeadPtr;
    XBufDescriptor *BdPtr;

    /*
     * Read the interrupt status
     */
    IntrStatus = XDmaChannel_GetIntrStatus(&InstancePtr->RecvChannel);

    /*
     * For packet threshold or wait bound interrupts, process desciptors. Also
     * process descriptors on a SG end acknowledgement, which means the end of
     * the descriptor list has been reached by the hardware. For receive, this
     * is potentially trouble since it means the descriptor list is full,
     * unless software can process enough packets quickly enough so the
     * hardware has room to put new packets.
     */
    if (IntrStatus & (XDC_IXR_PKT_THRESHOLD_MASK |
        XDC_IXR_PKT_WAIT_BOUND_MASK | XDC_IXR_SG_END_MASK))
    {
        /* Get the number of packets that need processing */
        PacketsLeft = XDmaChannel_GetPktCount(&InstancePtr->RecvChannel);

        if (PacketsLeft)
        {
            /* Get the buffer descriptor at the head of the list */
            Result = XDmaChannel_GetDescriptor(&InstancePtr->RecvChannel,
                                               &BdHeadPtr);
            BdPtr = BdHeadPtr;
            NumBds = 0;

            /* Loop until all packets have been pulled or an error occurs */
            while(1)
            {
                NumBds++;

                /*
                 * An error getting a buffer descriptor from the list.
                 * This should not happen, but if it does, report it to
                 * the error callback and break out of the loop to service
                 * other interrupts.
                 */
                if (Result != XST_SUCCESS)
                {
                    InstancePtr->ErrorHandler(InstancePtr->ErrorRef, Result);