xps2.c

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/*****************************************************************************
*
*       XILINX IS PROVIDING THIS DESIGN, CODE, OR INFORMATION "AS IS"
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*       INFRINGEMENT, IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
*       FOR A PARTICULAR PURPOSE.
*
*       (c) Copyright 2002 Xilinx Inc.
*       All rights reserved.
*
*****************************************************************************/
/****************************************************************************/
/**
*
* @file xps2.c
*
* This file contains the required functions for the PS/2 driver.
* Refer to the header file xps2.h for more detailed information.
*
* <pre>
* MODIFICATION HISTORY:
*
* Ver   Who  Date     Changes
* ----- ---- -------- -----------------------------------------------
* 1.00a ch   06/18/02 First release
* 1.00a rmm  05/14/03 Fixed diab compiler warnings relating to asserts.
* </pre>
*
*****************************************************************************/

/***************************** Include Files ********************************/

#include "xstatus.h"
#include "xparameters.h"
#include "xps2.h"
#include "xps2_i.h"
#include "xps2_l.h"
#include "xio.h"

/************************** Constant Definitions ****************************/

/**************************** Type Definitions ******************************/

/***************** Macros (Inline Functions) Definitions ********************/

/************************** Variable Definitions ****************************/

/************************** Function Prototypes *****************************/

static void XPs2_StubHandler(void *CallBackRef, Xuint32 Event,
                             unsigned int ByteCount);

/****************************************************************************/
/**
*
* Initializes a specific PS/2 instance such that it is ready to be used.
* The default operating mode of the driver is polled mode.
*
* @param    InstancePtr is a pointer to the XPs2 instance to be worked on.
* @param    DeviceId is the unique id of the device controlled by this
*           XPs2 instance. Passing in a device id associates the generic
*           XPs2 instance to a specific device, as chosen by the caller
*           or application developer.
*
* @return
*
* - XST_SUCCESS if initialization was successful
* - XST_DEVICE_NOT_FOUND if the device ID could not be found in the
*           configuration table
*
* @note
*
* None.
*
*****************************************************************************/
XStatus XPs2_Initialize(XPs2 *InstancePtr, Xuint16 DeviceId)
{
    XPs2_Config *Ps2ConfigPtr;

    /*
     * Assert validates the input arguments
     */
    XASSERT_NONVOID(InstancePtr != XNULL);

    /*
     * Lookup the device configuration in the temporary CROM table. Use this
     * configuration info down below when initializing this component.
     */
    Ps2ConfigPtr = XPs2_LookupConfig(DeviceId);

    if (Ps2ConfigPtr == (XPs2_Config *)XNULL)
    {
       return XST_DEVICE_NOT_FOUND;
    }

    /*
     * Setup the data that is from the configuration information
     */
    InstancePtr->BaseAddress = Ps2ConfigPtr->BaseAddress;
    
    /*
     * Initialize the instance data to some default values and setup a default
     * handler
     */
    InstancePtr->Handler = XPs2_StubHandler;

    InstancePtr->SendBuffer.NextBytePtr = XNULL;
    InstancePtr->SendBuffer.RemainingBytes = 0;
    InstancePtr->SendBuffer.RequestedBytes = 0;

    InstancePtr->ReceiveBuffer.NextBytePtr = XNULL;
    InstancePtr->ReceiveBuffer.RemainingBytes = 0;
    InstancePtr->ReceiveBuffer.RequestedBytes = 0;

    /*
     * Reset the PS/2 Hardware
     */
    XPs2_mReset(InstancePtr->BaseAddress);

    /*
     * Disable all PS/2 interrupts
     */
    XPs2_mDisableIntr(InstancePtr->BaseAddress, XPS2_INT_ALL);

    /*
     * Indicate the instance is now ready to use, initialized without error
     */
    InstancePtr->IsReady = XCOMPONENT_IS_READY;

    return XST_SUCCESS;
}

/****************************************************************************/
/**
*
* This functions 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 thorugh PS/2. If the port is busy
* sending data, it will return and indicate zero bytes were sent.
*
* In a polled mode, this function will only send 1 byte which is as much data 
* as the 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 sending data 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.
* @param    BufferPtr is pointer to a buffer of data to be sent.
* @param    NumBytes contains the number of bytes to be sent. A value of zero
*           will stop a previous send operation that is in progress in interrupt
*           mode. Any data that was already put into the transmit FIFO will be
*           sent.
*
* @return
*
* The number of bytes actually sent.
*
* @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.
* <br><br>
* This function modifies shared data such that there may be a need for mutual
* exclusion in a multithreaded environment 
*
*****************************************************************************/
unsigned int XPs2_Send(XPs2 *InstancePtr, Xuint8 *BufferPtr,
                       unsigned int NumBytes)
{
    unsigned int BytesSent;
    
    /*
     * Assert validates the input arguments
     */
    XASSERT_NONVOID(InstancePtr != XNULL);
    XASSERT_NONVOID(BufferPtr != XNULL);
    XASSERT_NONVOID(InstancePtr->IsReady == XCOMPONENT_IS_READY);

    /*
     * Enter a critical region by disabling the PS/2 transmit interrupts to
     * allow this call to stop a previous operation that may be interrupt
     * driven, only stop the transmit interrupt since this critical region is
     * not really exited in the normal manner
     */
    XPs2_mDisableIntr(InstancePtr->BaseAddress, XPS2_INT_TX_ALL);

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

    /*
     * Send the buffer and return the number of bytes sent 
     */
    BytesSent = XPs2_SendBuffer(InstancePtr);

    /*
     * The critical region is not exited in this function because of the way
     * the transmit interrupts work. The other function called enables the 
     * transmit interrupt such that this function can't restore a value to the
     * interrupt enable register and does not need to exit the critical region
     */
    return BytesSent;
}


/****************************************************************************/
/**
*
* 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 no data has already received by the PS/2 port.
*
* 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 receiving data 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.
*
* @param    InstancePtr is a pointer to the XPs2 instance to be worked on.
* @param    BufferPtr is pointer to buffer for data to be received into
* @param    NumBytes is the number of bytes to be received. A value of zero will
*           stop a previous receive operation that is in progress in interrupt mode.
*
* @return