xuartns550.c

powerpc405下linux的串口驱动程序

/* $Id: xuartns550.c,v 1.1 2006/02/17 22:43:40 moleres 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,
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*       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 xuartns550.c
*
* This file contains the required functions for the 16450/16550 UART driver.
* Refer to the header file xuartns550.h for more detailed information.
*
* <pre>
* MODIFICATION HISTORY:
*
* Ver   Who  Date     Changes
* ----- ---- -------- -----------------------------------------------
* 1.00a ecm  08/16/01 First release
* 1.00b jhl  03/11/02 Repartitioned driver for smaller files.
* 1.00b rmm  05/14/03 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 "xstatus.h"
#include "xuartns550.h"
#include "xuartns550_i.h"
#include "xio.h"

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

/* The following constant defines the amount of error that is allowed for
 * a specified baud rate. This error is the difference between the actual
 * baud rate that will be generated using the specified clock and the
 * desired baud rate.
 */
#define XUN_MAX_BAUD_ERROR_RATE         3    /* max % error allowed */

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


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


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


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

static void XUartNs550_StubHandler(void *CallBackRef, Xuint32 Event,
                                   unsigned int ByteCount);

/****************************************************************************/
/**
*
* Initializes a specific XUartNs550 instance such that it is ready to be used.
* The data format of the device is setup for 8 data bits, 1 stop bit, and no
* parity by default. The baud rate is set to a default value specified by
* Config->DefaultBaudRate if set, otherwise it is set to 19.2K baud. If the
* device has FIFOs (16550), they are enabled and the a receive FIFO threshold
* is set for 8 bytes. The default operating mode of the driver is polled mode.
*
* @param InstancePtr is a pointer to the XUartNs550 instance to be worked on.
* @param Config is a reference to a structure containing information about
*        a specific UART 16450/16550 device. XUartNs550_Init initializes an
*        InstancePtr object for a specific device specified by the contents
*        of Config. XUartNs550_Init 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 initialization was successful
* - XST_UART_BAUD_ERROR if the baud rate is not possible because the input
*           clock frequency is not divisible with an acceptable amount of error
*
* @note
*
* None.
*
*****************************************************************************/
XStatus XUartNs550_CfgInitialize(XUartNs550 *InstancePtr,
                                 XUartNs550_Config *Config,
                                 Xuint32 EffectiveAddr)
{
    XStatus Status;
    Xuint8 LcrRegister;
    Xuint32 BaudRate;

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

    /*
     * Setup the data that is from the configuration information
     */
    InstancePtr->BaseAddress = EffectiveAddr;
    InstancePtr->InputClockHz = Config->InputClockHz;

    /*
     * Initialize the instance data to some default values and setup a default
     * handler
     */
    InstancePtr->Handler = XUartNs550_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;

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

    /*
     * set the default Baud rate here, can be changed prior to
     * starting the device
     */
    BaudRate = Config->DefaultBaudRate;
    if (! BaudRate)
    {
        BaudRate = 19200;
    }

    Status = XUartNs550_SetBaudRate(InstancePtr, BaudRate);

    if (Status != XST_SUCCESS)
    {
        InstancePtr->IsReady = 0;
        return Status;
    }


    /*
     * Set up the default format for the data, 8 bit data, 1 stop bit, no
     * parity
     */
    LcrRegister = XIo_In8(InstancePtr->BaseAddress + XUN_LCR_OFFSET);
    XIo_Out8(InstancePtr->BaseAddress + XUN_LCR_OFFSET,
             XUN_FORMAT_8_BITS);

    /* Enable the FIFOs assuming they are present and set the receive FIFO
     * trigger level for 8 bytes assuming that this will work best with most
     * baud rates, enabling the FIFOs also clears them, note that this must
     * be done with 2 writes, 1st enabling the FIFOs then set the trigger level
     */
    XIo_Out8(InstancePtr->BaseAddress + XUN_FCR_OFFSET,
             XUN_FIFO_ENABLE);
    XIo_Out8(InstancePtr->BaseAddress + XUN_FCR_OFFSET,
             XUN_FIFO_ENABLE | XUN_FIFO_RX_TRIG_MSB);
    /*
     * Clear the statistics for this driver
     */
    XUartNs550_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, either in the transmitter or in the FIFO if present and enabled. 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 XUartNs550 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 and the XUartNs550_SetOptions() function modify shared data
* such that there may be a need for mutual exclusion in a multithreaded
* environment and if XUartNs550_SetOptions() if called from a handler.
*
*****************************************************************************/
unsigned int XUartNs550_Send(XUartNs550 *InstancePtr, Xuint8 *BufferPtr,
                             unsigned int NumBytes)
{
    unsigned int BytesSent;
    Xuint8 IerRegister;

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

    /* Enter a critical region by disabling the UART 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
     */
    IerRegister = XIo_In8(InstancePtr->BaseAddress + XUN_IER_OFFSET);
    XIo_Out8(InstancePtr->BaseAddress + XUN_IER_OFFSET,
             IerRegister & ~XUN_IER_TX_EMPTY);

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

    BytesSent = XUartNs550_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
     * tranmit 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 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, either in the receiver or in the FIFO if present and enabled.
* 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 XUartNs550 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 XUartNs550_Recv(XUartNs550 *InstancePtr,
                             Xuint8 *BufferPtr,
                             unsigned int NumBytes)
{
    unsigned int ReceivedCount;
    Xuint8 IerRegister;

    /*
     * Assert validates the input arguments
     */
    XASSERT_NONVOID(InstancePtr != XNULL);
    XASSERT_NONVOID(BufferPtr != 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
     */
    IerRegister = XIo_In8(InstancePtr->BaseAddress + XUN_IER_OFFSET);
    XIo_Out8(InstancePtr->BaseAddress + XUN_IER_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 = BufferPtr;

    /* Receive the data from the UART and return the number of bytes
     * received
     */
    ReceivedCount = XUartNs550_ReceiveBuffer(InstancePtr);

    /* Restore the interrupt enable register to it's previous value such
     * that the critical region is exited
     */
    XIo_Out8(InstancePtr->BaseAddress + XUN_IER_OFFSET, IerRegister);

    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 XUartNs550 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 UART in either