xuartlite.c

基于Xilinx-XUPV2P开发平台的嵌入式系统实验例程：实验4编写基本的应用程序

/* $Id: xuartlite.c,v 1.2 2006/03/22 15:58:21 wyang Exp $ */
/*****************************************************************************
*
*       XILINX IS PROVIDING THIS DESIGN, CODE, OR INFORMATION "AS IS"
*       AS A COURTESY TO YOU, SOLELY FOR USE IN DEVELOPING PROGRAMS AND
*       SOLUTIONS FOR XILINX DEVICES.  BY PROVIDING THIS DESIGN, CODE,
*       OR INFORMATION AS ONE POSSIBLE IMPLEMENTATION OF THIS FEATURE,
*       APPLICATION OR STANDARD, XILINX IS MAKING NO REPRESENTATION
*       THAT THIS IMPLEMENTATION IS FREE FROM ANY CLAIMS OF INFRINGEMENT,
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*       FOR YOUR IMPLEMENTATION.  XILINX EXPRESSLY DISCLAIMS ANY
*       WARRANTY WHATSOEVER WITH RESPECT TO THE ADEQUACY OF THE
*       IMPLEMENTATION, INCLUDING BUT NOT LIMITED TO ANY WARRANTIES OR
*       REPRESENTATIONS THAT THIS IMPLEMENTATION IS FREE FROM CLAIMS OF
*       INFRINGEMENT, IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
*       FOR A PARTICULAR PURPOSE.
*
*       (c) Copyright 2002-2005 Xilinx Inc.
*       All rights reserved.
*
*****************************************************************************/
/****************************************************************************/
/**
*
* @file xuartlite.c
*
* Contains required functions for the XUartLite driver. See the xuartlite.h
* header file for more details on this driver.
*
* <pre>
* MODIFICATION HISTORY:
*
* Ver   Who  Date     Changes
* ----- ---- -------- -----------------------------------------------
* 1.00a ecm  08/31/01 First release
* 1.00b jhl  02/21/02 Repartitioned the driver for smaller files
* 1.00b rmm  05/13/03 Fixed diab compiler warnings relating to asserts
* 1.01a jvb  12/13/05 I changed Initialize() into CfgInitialize(), and made
*                     CfgInitialize() take a pointer to a config structure
*                     instead of a device id. I moved Initialize() into
*                     xgpio_sinit.c, and had Initialize() call CfgInitialize()
*                     after it retrieved the config structure using the device
*                     id. I removed include of xparameters.h along with any
*                     dependencies on xparameters.h and the _g.c config table.
*
* </pre>
*
*****************************************************************************/

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

#include "xbasic_types.h"
#include "xstatus.h"
#include "xuartlite.h"
#include "xuartlite_i.h"
#include "xio.h"

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


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


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


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


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

static void StubHandler(void *CallBackRef, unsigned int ByteCount);

/****************************************************************************/
/**
*
* Initialize a XUartLite instance.  The receive and transmit FIFOs of the
* UART are not flushed, so the user may want to flush them. The hardware
* device does not have any way to disable the receiver such that any valid
* data may be present in the receive FIFO.  This function disables the UART
* interrupt. The baudrate and format of the data are fixed in the hardware
* at hardware build time.
*
* @param InstancePtr is a pointer to the XUartLite instance to be worked on.
* @param Config is a reference to a structure containing information about
*        a specific UART Lite device. This function initializes an
*        InstancePtr object for a specific device specified by the contents
*        of Config. This function can initialize multiple instance objects
*        with the use of multiple calls giving different Config information
*        on each call.
* @param EffectiveAddr is the device base address in the virtual memory address
*        space. The caller is responsible for keeping the address mapping
*        from EffectiveAddr to the device physical base address unchanged
*        once this function is invoked. Unexpected errors may occur if the
*        address mapping changes after this function is called. If address
*        translation is not used, use Config->BaseAddress for this parameters,
*        passing the physical address instead.
*
* @return
*
* - XST_SUCCESS if everything starts up as expected.
*
* @note
*
* The Config pointer argument is not used by this function, but is provided
* to keep the function signature consistent with other drivers.
*
*****************************************************************************/
XStatus XUartLite_CfgInitialize(XUartLite *InstancePtr, XUartLite_Config *Config,
                                Xuint32 EffectiveAddr)
{
    /*
     * Assert validates the input arguments
     */
    XASSERT_NONVOID(InstancePtr != XNULL);

    /*
     * Set some default values, including setting the callback
     * handlers to stubs.
     */

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

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

    InstancePtr->IsReady = XCOMPONENT_IS_READY;
    InstancePtr->RegBaseAddress = EffectiveAddr;
    InstancePtr->RecvHandler = StubHandler;
    InstancePtr->SendHandler = StubHandler;

    /* Write to the control register to disable the interrupts, don't
     * reset the FIFOs are the user may want the data that's present
     */
    XIo_Out32(InstancePtr->RegBaseAddress + XUL_CONTROL_REG_OFFSET, 0);

    /*
     * Clear the statistics for this driver
     */
    XUartLite_mClearStats(InstancePtr);

    return XST_SUCCESS;
}

/****************************************************************************/
/**
*
* This functions sends the specified buffer of data using the UART in either
* polled or interrupt driven modes. This function is non-blocking such that it
* will return before the data has been sent by the UART. If the UART is busy
* sending data, it will return and indicate zero bytes were sent.
*
* In a polled mode, this function will only send as much data as the UART can
* buffer in the FIFO. 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 XUartLite 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.
*
******************************************************************************/
unsigned int XUartLite_Send(XUartLite *InstancePtr, Xuint8 *DataBufferPtr,
                            unsigned int NumBytes)
{
    unsigned int BytesSent;
    Xuint32 StatusRegister;

    /*
     * Assert validates the input arguments
     */
    XASSERT_NONVOID(InstancePtr != XNULL);
    XASSERT_NONVOID(DataBufferPtr != XNULL);
    XASSERT_NONVOID(InstancePtr->IsReady == XCOMPONENT_IS_READY);
    XASSERT_NONVOID(((signed)NumBytes) >= 0);

    /* Enter a critical region by disabling the UART interrupts to
     * allow this call to stop a previous operation that may be interrupt
     * driven
     */
    StatusRegister = XUartLite_mGetStatusReg(InstancePtr->RegBaseAddress);

    XIo_Out32(InstancePtr->RegBaseAddress + XUL_CONTROL_REG_OFFSET, 0);

    /* 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 = DataBufferPtr;

    /* Restore the interrupt enable register to it's previous value such
     * that the critical region is exited.
     * This is done here to minimize the amount of time the interrupt is
     * disabled since there is only one interrupt and the receive could
     * be filling up while interrupts are blocked.
     */

    StatusRegister &= XUL_CR_ENABLE_INTR;
    XIo_Out32(InstancePtr->RegBaseAddress + XUL_CONTROL_REG_OFFSET, StatusRegister);

    /* Send the buffer using the UART and return the number of bytes sent */

    BytesSent = XUartLite_SendBuffer(InstancePtr);

    return BytesSent;
}


/****************************************************************************/
/**
*
* This function will attempt to receive a specified number of bytes of data
* from the UART 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 UART.
*
* In a polled mode, this function will only receive as much data as the UART
* can buffer in the FIFO. 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 using the SetOptions function.
*
* @param    InstancePtr is a pointer to the XUartLite 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
*
* 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 XUartLite_Recv(XUartLite *InstancePtr, Xuint8 *DataBufferPtr,
                            unsigned int NumBytes)
{
    unsigned int ReceivedCount;
    Xuint32 StatusRegister;

    /*
     * Assert validates the input arguments
     */
    XASSERT_NONVOID(InstancePtr != XNULL);
    XASSERT_NONVOID(DataBufferPtr != XNULL);
    XASSERT_NONVOID(InstancePtr->IsReady == XCOMPONENT_IS_READY);
    XASSERT_NONVOID(((signed)NumBytes) >= 0);

    /* Enter a critical region by disabling all the UART interrupts to allow
     * this call to stop a previous operation that may be interrupt driven
     */
    StatusRegister = XUartLite_mGetStatusReg(InstancePtr->RegBaseAddress);
    XIo_Out32(InstancePtr->RegBaseAddress + XUL_CONTROL_REG_OFFSET, 0);

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

    /* Restore the interrupt enable register to it's previous value such
     * that the critical region is exited
     */
    StatusRegister &= XUL_CR_ENABLE_INTR;
    XIo_Out32(InstancePtr->RegBaseAddress + XUL_CONTROL_REG_OFFSET, StatusRegister);

    /* Receive the data from the UART and return the number of bytes
     * received
     * This is done here to minimize the amount of time the interrupt is
     * disabled since there is only one interrupt and the transmit could