xps2.c

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*
* The number of bytes received.
*
* @note
*
* The number of bytes is not asserted so that this function may be called with
* a value of zero to stop an operation that is already in progress.
*
*****************************************************************************/
unsigned int XPs2_Recv(XPs2 *InstancePtr, Xuint8 *BufferPtr,
                       unsigned int NumBytes)
{
    unsigned int ReceivedCount;

    /*
     * Assert validates the input arguments
     */
    XASSERT_NONVOID(InstancePtr != XNULL);
    XASSERT_NONVOID(BufferPtr != XNULL);
    XASSERT_NONVOID(InstancePtr->IsReady == XCOMPONENT_IS_READY);

    /* 
     * Setup the specified buffer to be sent by setting the instance
     * variables so it can be sent with polled or interrupt mode
     */
    InstancePtr->ReceiveBuffer.RequestedBytes = NumBytes;
    InstancePtr->ReceiveBuffer.RemainingBytes = NumBytes;
    InstancePtr->ReceiveBuffer.NextBytePtr = BufferPtr;

    /* 
     * Receive the data from PS/2 and return the number of bytes 
     * received 
     */
    ReceivedCount = XPs2_ReceiveBuffer(InstancePtr);

    return ReceivedCount;
}

/****************************************************************************/
/**
*
* This function sends a buffer that has been previously specified by setting
* up the instance variables of the instance. This function is designed to be
* an internal function for the XPs2 component such that it may be called
* from a shell function that sets up the buffer or from an interrupt handler.
*
* This function sends the specified buffer of data to the PS/2 port in either
* polled or interrupt driven modes. This function is non-blocking such that
* it will return before the data has been sent.
*
* In a polled mode, this function will only send 1 byte which is as much data 
* transmitter can buffer. The application may need to call it repeatedly to 
* send a buffer.
*
* In interrupt mode, this function will start sending the specified buffer and
* then the interrupt handler of the driver will continue until the buffer
* has been sent. A callback function, as specified by the application, will
* be called to indicate the completion of sending the buffer.
*
* @param    InstancePtr is a pointer to the XPs2 instance to be worked on.
*
* @return
*
* NumBytes is the number of bytes actually sent
*
* @note
*
* None.
*
*****************************************************************************/
unsigned int XPs2_SendBuffer(XPs2 *InstancePtr)
{
    unsigned int SentCount = 0;
    
    /* 
     * If the transmitter is empty send one byte of data
     */ 
    if (!XPs2_mIsTransmitFull(InstancePtr->BaseAddress))
    {
        XPs2_SendByte(InstancePtr->BaseAddress, 
                      InstancePtr->SendBuffer.NextBytePtr[SentCount]);

        SentCount = 1;
    }
    /*
     * Update the buffer to reflect the bytes that were sent
     * from it
     */
    InstancePtr->SendBuffer.NextBytePtr += SentCount;
    InstancePtr->SendBuffer.RemainingBytes -= SentCount;

    /*
     * If interrupts are enabled as indicated by the receive interrupt, then
     * enable the transmit interrupt
     */
    if (XPs2_mIsIntrEnabled((InstancePtr->BaseAddress), XPS2_INT_RX_FULL))
    {
        XPs2_mEnableIntr(InstancePtr->BaseAddress, XPS2_INT_TX_ALL | 
                                                   XPS2_INT_WDT_TOUT);
    }

    return SentCount;
}

/****************************************************************************/
/**
*
* This function receives a buffer that has been previously specified by setting
* up the instance variables of the instance. This function is designed to be
* an internal function for the XPs2 component such that it may be called
* from a shell function that sets up the buffer or from an interrupt handler.
*
* This function will attempt to receive a specified number of bytes of data
* from PS/2 and store it into the specified buffer. This function is
* designed for either polled or interrupt driven modes. It is non-blocking
* such that it will return if there is no data has already received.
*
* In a polled mode, this function will only receive 1 byte which is as much 
* data as the receiver can buffer. The application may need to call it 
* repeatedly to receive a buffer. Polled mode is the default mode of operation 
* for the driver.
*
* In interrupt mode, this function will start receiving and then the interrupt
* handler of the driver will continue until the buffer has been received. A
* callback function, as specified by the application, will be called to indicate
* the completion of receiving the buffer or when any receive errors or timeouts
* occur. Interrupt mode must be enabled using the SetOptions function.
*
* @param    InstancePtr is a pointer to the XPs2 instance to be worked on.
*
* @return
*
* The number of bytes received.
*
* @note
*
* None.
*
*****************************************************************************/
unsigned int XPs2_ReceiveBuffer(XPs2 *InstancePtr)
{
    unsigned int ReceivedCount = 0;

    /*
     * Loop until there is no more date buffered by the PS/2 receiver or the
     * specified number of bytes has been received
     */
    while (ReceivedCount < InstancePtr->ReceiveBuffer.RemainingBytes)
    {
        /*
         * If there is data ready to be read , then put the next byte
         * read into the specified buffer
         */
        if (!XPs2_mIsReceiveEmpty(InstancePtr->BaseAddress))
        {
	    InstancePtr->ReceiveBuffer.NextBytePtr[ReceivedCount++] =
                XPs2_RecvByte(InstancePtr->BaseAddress);
	}

        /*
         * There is no more data buffered, so exit such that this function does
         * not block waiting for data
         */
        else
        {
            break;
	}
    }

    /*
     * Update the receive buffer to reflect the number of bytes that was
     * received
     */
    InstancePtr->ReceiveBuffer.NextBytePtr += ReceivedCount;
    InstancePtr->ReceiveBuffer.RemainingBytes -= ReceivedCount;

    return ReceivedCount;
}

/****************************************************************************/
/**
*
* Looks up the device configuration based on the unique device ID. A table
* contains the configuration info for each device in the system.
*
* @param    DeviceId contains the ID of the device to look up the configuration
*           for.
*
* @return
*
* A pointer to the configuration found or XNULL if the specified device ID was
* not found.
*
* @note
*
* None.
*
******************************************************************************/
XPs2_Config *XPs2_LookupConfig(Xuint16 DeviceId)
{
    XPs2_Config *CfgPtr = XNULL;

    int i;

    for (i=0; i < XPAR_XPS2_NUM_INSTANCES; i++)
    {
        if (XPs2_ConfigTable[i].DeviceId == DeviceId)
        {
            CfgPtr = &XPs2_ConfigTable[i];
        }
    }

    return CfgPtr;
}

/****************************************************************************/
/**
*
* This function is a stub handler that is the default handler such that if the
* application has not set the handler when interrupts are enabled, this
* function will be called. The function interface has to match the interface
* specified for a handler even though none of the arguments are used.
*
* @param    CallBackRef is unused by this function.
* @param    Event is unused by this function.
* @param    ByteCount is unused by this function.
*
* @return
*
* None.
*
* @note
*
* None.
*
*****************************************************************************/
static void XPs2_StubHandler(void *CallBackRef, Xuint32 Event,
                              unsigned int ByteCount)
{
    /*
     * Assert alway occurs since this is a stub and should never be called
     */
    XASSERT_VOID_ALWAYS();
}