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//==========================================================================

//

//      termiostty.c

//

//      POSIX Termios compatible TTY I/O driver

//

//==========================================================================

//####ECOSGPLCOPYRIGHTBEGIN####

// -------------------------------------------

// This file is part of eCos, the Embedded Configurable Operating System.

// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.

// Copyright (C) 2003 Jonathan Larmour

//

// eCos is free software; you can redistribute it and/or modify it under

// the terms of the GNU General Public License as published by the Free

// Software Foundation; either version 2 or (at your option) any later version.

//

// eCos is distributed in the hope that it will be useful, but WITHOUT ANY

// WARRANTY; without even the implied warranty of MERCHANTABILITY or

// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

// for more details.

//

// You should have received a copy of the GNU General Public License along

// with eCos; if not, write to the Free Software Foundation, Inc.,

// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.

//

// As a special exception, if other files instantiate templates or use macros

// or inline functions from this file, or you compile this file and link it

// with other works to produce a work based on this file, this file does not

// by itself cause the resulting work to be covered by the GNU General Public

// License. However the source code for this file must still be made available

// in accordance with section (3) of the GNU General Public License.

//

// This exception does not invalidate any other reasons why a work based on

// this file might be covered by the GNU General Public License.

//

// Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.

// at http://sources.redhat.com/ecos/ecos-license/

// -------------------------------------------

//####ECOSGPLCOPYRIGHTEND####

//==========================================================================

//#####DESCRIPTIONBEGIN####

//

// Author(s):    jlarmour

// Contributors: gthomas

// Date:         2000-07-22

// Purpose:      Device driver for termios emulation tty I/O, layered on

//               top of serial I/O

// Description:  TODO: Add OPOST support for 80x25 (configurable) windows

//               TODO: Support _POSIX_VDISABLE

//

//####DESCRIPTIONEND####

//

//==========================================================================

// CONFIGURATION

#include <pkgconf/io_serial.h>

#ifdef CYGPKG_IO_SERIAL_TERMIOS

// INCLUDES

#include <cyg/infra/cyg_type.h>    // Common types 

#include <cyg/infra/cyg_ass.h>     // Assertion support

#include <cyg/infra/cyg_trac.h>    // Tracing support

#include <cyg/io/io.h>

#include <cyg/io/devtab.h>

#include <cyg/io/serialio.h>       // public serial API

#include <termios.h>               // Termios header

#include <cyg/hal/drv_api.h>

#include <stdlib.h>                // malloc

#include <string.h>

#ifdef CYGSEM_IO_SERIAL_TERMIOS_USE_SIGNALS

# include <signal.h>

#endif

//==========================================================================

// FUNCTION PROTOTYPES

static bool

termios_init(struct cyg_devtab_entry *tab);

static Cyg_ErrNo

termios_lookup(struct cyg_devtab_entry **tab,

               struct cyg_devtab_entry *sub_tab,

               const char *name);

static Cyg_ErrNo

termios_write(cyg_io_handle_t handle, const void *buf, cyg_uint32 *len);

static Cyg_ErrNo

termios_read(cyg_io_handle_t handle, void *buf, cyg_uint32 *len);

static Cyg_ErrNo

termios_select(cyg_io_handle_t handle, cyg_uint32 which, CYG_ADDRWORD info);

static Cyg_ErrNo

termios_get_config(cyg_io_handle_t handle, cyg_uint32 key, void *buf,

                   cyg_uint32 *len);

static Cyg_ErrNo

termios_set_config(cyg_io_handle_t handle, cyg_uint32 key, const void *buf,

                   cyg_uint32 *len);

//==========================================================================

// TYPE DEFINITIONS

struct termios_private_info {

    struct termios  termios;

    cyg_io_handle_t dev_handle;

    cyg_drv_mutex_t lock;

    cyg_bool        init;

    cyg_uint8      *errbuf;

    cyg_uint8      *errbufpos;

    cyg_uint32      errbufsize;

};

typedef struct {

    struct termios *termios_p;

    int optact;

} setattr_struct;

//==========================================================================

// STATIC OBJECTS

static DEVIO_TABLE(termios_devio,

                   termios_write,

                   termios_read,

                   termios_select,

                   termios_get_config,

                   termios_set_config);

#ifdef CYGPKG_IO_SERIAL_TERMIOS_TERMIOS0

static struct termios_private_info termios_private_info0;

DEVTAB_ENTRY(termios_io0,

             "/dev/termios0",

             CYGDAT_IO_SERIAL_TERMIOS_TERMIOS0_DEV,

             &termios_devio,

             termios_init,

             termios_lookup,

             &termios_private_info0);

#endif

#ifdef CYGPKG_IO_SERIAL_TERMIOS_TERMIOS1

static struct termios_private_info termios_private_info1;

DEVTAB_ENTRY(termios_io1,

             "/dev/termios1",

             CYGDAT_IO_SERIAL_TERMIOS_TERMIOS1_DEV,

             &termios_devio,

             termios_init,

             termios_lookup,

             &termios_private_info1);

#endif

#ifdef CYGPKG_IO_SERIAL_TERMIOS_TERMIOS2

static struct termios_private_info termios_private_info2;

DEVTAB_ENTRY(termios_io2,

             "/dev/termios2",

             CYGDAT_IO_SERIAL_TERMIOS_TERMIOS2_DEV,

             &termios_devio,

             termios_init,

             termios_lookup,

             &termios_private_info2);

#endif

static const cc_t c_cc_init[ NCCS ] = {

    0x04,     /* EOF == ^D */

    0,        /* EOL */

    0x08,     /* ERASE = BS ; NB DEL=0x7f */

    0x03,     /* INTR = ^C */

    0x15,     /* KILL = ^U */

    0,        /* MIN = 0 */

    0x1c,     /* QUIT = ^\ */

    0x1a,     /* SUSP = ^Z ; NB ignored in this impl - no job control */

    0,        /* TIME = 0 */

#ifdef CYGOPT_IO_SERIAL_FLOW_CONTROL_SOFTWARE

    CYGDAT_IO_SERIAL_FLOW_CONTROL_XON_CHAR,

    CYGDAT_IO_SERIAL_FLOW_CONTROL_XOFF_CHAR,

#else

    17,

    19,

#endif

};

// map eCos bitrates to POSIX bitrates.

static speed_t ecosbaud2posixbaud[] = {

    0, B50, B75, B110, B134, B150, B200, B300, B600, B1200, B2400, B3600,

    B4800, B7200, B9600, B14400, B19200, B38400, B57600, B115200, B230400 };

// map POSIX bitrates to eCos bitrates.

static cyg_serial_baud_rate_t posixbaud2ecosbaud[] = {

    0, CYGNUM_SERIAL_BAUD_50, CYGNUM_SERIAL_BAUD_75, CYGNUM_SERIAL_BAUD_110,

    CYGNUM_SERIAL_BAUD_134_5, CYGNUM_SERIAL_BAUD_150, CYGNUM_SERIAL_BAUD_200,

    CYGNUM_SERIAL_BAUD_300, CYGNUM_SERIAL_BAUD_600, CYGNUM_SERIAL_BAUD_1200,

    CYGNUM_SERIAL_BAUD_1800, CYGNUM_SERIAL_BAUD_2400, CYGNUM_SERIAL_BAUD_3600,

    CYGNUM_SERIAL_BAUD_4800, CYGNUM_SERIAL_BAUD_7200, CYGNUM_SERIAL_BAUD_9600,

    CYGNUM_SERIAL_BAUD_14400, CYGNUM_SERIAL_BAUD_19200,

    CYGNUM_SERIAL_BAUD_38400, CYGNUM_SERIAL_BAUD_57600,

    CYGNUM_SERIAL_BAUD_115200, CYGNUM_SERIAL_BAUD_230400 };

//==========================================================================

// FUNCTIONS

static __inline__ speed_t

map_ecosbaud_to_posixbaud( cyg_serial_baud_rate_t ebaud )

{

    if ( ebaud > (sizeof(ecosbaud2posixbaud) / sizeof(speed_t)) )

        return 0;

    return ecosbaud2posixbaud[ ebaud ];

}

static __inline__ cyg_serial_baud_rate_t

map_posixbaud_to_ecosbaud( speed_t pbaud )

{

    if ( pbaud > (sizeof(posixbaud2ecosbaud)/sizeof(cyg_serial_baud_rate_t)) )

        return 0;

    return posixbaud2ecosbaud[ pbaud ];

}

//==========================================================================

// real_termios_init is used to initialize the termios structure. This is

// called at lookup time, and not from termios_init() because it needs

// to query the serial device which may not be set up yet at that point

// in termios_init()

#ifdef CYGSEM_IO_SERIAL_TERMIOS_USE_SIGNALS

# define C_IFLAG_INIT (ICRNL|IGNBRK|BRKINT)

#else

# define C_IFLAG_INIT (ICRNL|IGNBRK)

#endif

#define C_OFLAG_INIT (ONLCR)

#define C_CFLAG_INIT (CREAD)

#define C_LFLAG_INIT (ECHO|ECHOE|ECHOK|ICANON)

static Cyg_ErrNo

real_termios_init( struct termios_private_info *priv )

{

    Cyg_ErrNo res;

    struct termios *t;

    cyg_serial_info_t dev_conf;

    cyg_serial_buf_info_t dev_buf_conf;

    cyg_uint32 len = sizeof( dev_conf );

    CYG_REPORT_FUNCTYPE("returning %d");

    CYG_REPORT_FUNCARG1XV( priv );

    CYG_CHECK_DATA_PTRC( priv );

    t = &priv->termios;

    // Get info from driver

    res = cyg_io_get_config( priv->dev_handle, CYG_IO_GET_CONFIG_SERIAL_INFO,

                             &dev_conf, &len );

    if ( ENOERR == res ) {

        len = sizeof( dev_buf_conf );

        res = cyg_io_get_config( priv->dev_handle,

                                 CYG_IO_GET_CONFIG_SERIAL_BUFFER_INFO,

                                 &dev_buf_conf, &len );

    }

    priv->errbuf = (cyg_uint8 *)malloc( dev_buf_conf.rx_bufsize );

    if ( NULL == priv->errbuf )

        res = ENOMEM;   // FIXME: Are we allowed to do this?

    priv->errbufpos = priv->errbuf;

    priv->errbufsize = dev_buf_conf.rx_bufsize;

    if ( ENOERR != res ) {

        CYG_REPORT_RETVAL( res );

        return res;

    }

    // we only support symmetric baud rates

    t->c_ispeed = t->c_ospeed = map_ecosbaud_to_posixbaud( dev_conf.baud );

    t->c_iflag = C_IFLAG_INIT;

    t->c_oflag = C_OFLAG_INIT;

    t->c_cflag = C_CFLAG_INIT;

    t->c_lflag = C_LFLAG_INIT;

    memcpy( t->c_cc, c_cc_init, sizeof( t->c_cc ) );

    switch ( dev_conf.parity ) {

    case CYGNUM_SERIAL_PARITY_NONE:

        t->c_iflag |= IGNPAR;

        break;

    case CYGNUM_SERIAL_PARITY_ODD:

        t->c_cflag |= PARODD;

        // DROPTHROUGH

    case CYGNUM_SERIAL_PARITY_EVEN:

        t->c_iflag |= PARENB;

        break;

    default:

        CYG_FAIL( "Unsupported default parity" );

        break;

    }

    switch( dev_conf.word_length ) {

    case CYGNUM_SERIAL_WORD_LENGTH_5:

        t->c_cflag |= CS5;

        break;

    case CYGNUM_SERIAL_WORD_LENGTH_6:

        t->c_cflag |= CS6;

        break;

    case CYGNUM_SERIAL_WORD_LENGTH_7:

        t->c_cflag |= CS7;

        break;

    case CYGNUM_SERIAL_WORD_LENGTH_8:

        t->c_cflag |= CS8;

        break;

    default:

        CYG_FAIL( "Unsupported word length" );

        break;

    }

    switch ( dev_conf.stop ) {

    case CYGNUM_SERIAL_STOP_1:

        // Don't need to do anything

        break;

    case CYGNUM_SERIAL_STOP_2:

        t->c_cflag |= CSTOPB;

        break;

    default:

        CYG_FAIL( "Unsupported number of stop bits" );

        break;

    }

    switch ( dev_conf.flags ) {

    case CYGNUM_SERIAL_FLOW_RTSCTS_RX:

        t->c_cflag |= CRTSCTS;

        // drop through

    case CYGNUM_SERIAL_FLOW_XONXOFF_RX:

        t->c_iflag |= IXOFF;

        break;

    case CYGNUM_SERIAL_FLOW_RTSCTS_TX:

        t->c_cflag |= CRTSCTS;

        // drop through

    case CYGNUM_SERIAL_FLOW_XONXOFF_TX:

        t->c_iflag |= IXON;

        break;

    default:

        // Ignore flags we don't grok

        break;

    }

    return ENOERR;

} // real_termios_init()

//==========================================================================

// set_attr() actually enacts the termios config. We come in here with

// the mutex in priv locked

//

// Possible deviation from standard: POSIX says we should enact which ever

// bits we can and only return EINVAL when none of them can be performed

// Rather than tracking whether *none* of them worked, instead we just

// always claim success. At the very least, setting c_cc is never to

// fail so I'm not sure if this is really non-standard or not!

static Cyg_ErrNo

set_attr( struct termios *t, struct termios_private_info *priv )

{

    Cyg_ErrNo res = ENOERR;

    cyg_serial_info_t dev_conf, new_dev_conf;

    cyg_uint32 len = sizeof( dev_conf );

    cc_t *tempcc = &priv->termios.c_cc[0];

    struct termios *ptermios = &priv->termios;

    // Get info from driver

    res = cyg_io_get_config( priv->dev_handle, CYG_IO_GET_CONFIG_SERIAL_INFO,

                             &dev_conf, &len );

    if ( ENOERR != res )

        return res;

    // We need to set up each facet of config to change one by one because

    // POSIX says we should try and change as much of the config as possible

    // This is tedious and has to be done by steam :-(

    if ( t->c_ospeed != ptermios->c_ospeed ) {

        new_dev_conf = dev_conf;

        new_dev_conf.baud = map_posixbaud_to_ecosbaud( t->c_ospeed );

        if ( 0 != new_dev_conf.baud ) {

            len = sizeof( new_dev_conf );

            res = cyg_io_set_config( priv->dev_handle,

                                     CYG_IO_SET_CONFIG_SERIAL_INFO,

                                     &new_dev_conf, &len );

            if ( ENOERR == res ) {

                // It worked, so update dev_conf to reflect the new state

                dev_conf.baud = new_dev_conf.baud;

                // and termios

                ptermios->c_ispeed = t->c_ospeed;

                ptermios->c_ospeed = t->c_ospeed;

            }

        }

    }

    if ( (t->c_cflag & CSTOPB) != (ptermios->c_cflag & CSTOPB) ) {

        new_dev_conf = dev_conf;

        if ( t->c_cflag & CSTOPB )

            new_dev_conf.stop = CYGNUM_SERIAL_STOP_2;

        else

            new_dev_conf.stop = CYGNUM_SERIAL_STOP_1;

        len = sizeof( new_dev_conf );

        res = cyg_io_set_config( priv->dev_handle,

                                 CYG_IO_SET_CONFIG_SERIAL_INFO,

                                 &new_dev_conf, &len );

        if ( ENOERR == res ) {

            // It worked, so update dev_conf to reflect the new state

            dev_conf.stop = new_dev_conf.stop;

            // and termios

            ptermios->c_cflag &= ~CSTOPB;

            ptermios->c_cflag |= t->c_cflag & CSTOPB;

        }

    }

    if ( ((t->c_cflag & PARENB) != (ptermios->c_cflag & PARENB)) ||

         ((t->c_cflag & PARODD) != (ptermios->c_cflag & PARODD)) ) {

        new_dev_conf = dev_conf;

        if ( t->c_cflag & PARENB )

            if ( t->c_cflag & PARODD )

                new_dev_conf.parity = CYGNUM_SERIAL_PARITY_ODD;

            else

                new_dev_conf.parity = CYGNUM_SERIAL_PARITY_EVEN;

        else

            new_dev_conf.parity = CYGNUM_SERIAL_PARITY_NONE;

        len = sizeof( new_dev_conf );

        res = cyg_io_set_config( priv->dev_handle,

                                 CYG_IO_SET_CONFIG_SERIAL_INFO,

                                 &new_dev_conf, &len );

        if ( ENOERR == res ) {

            // It worked, so update dev_conf to reflect the new state

            dev_conf.parity = new_dev_conf.parity;

            // and termios

            ptermios->c_cflag &= ~(PARENB|PARODD);

            ptermios->c_cflag |= t->c_cflag & (PARENB|PARODD);

        }

    }

    if ( (t->c_cflag & CSIZE) != (ptermios->c_cflag & CSIZE) ) {

        new_dev_conf = dev_conf;

        switch ( t->c_cflag & CSIZE ) {

        case CS5:

            new_dev_conf.word_length = CYGNUM_SERIAL_WORD_LENGTH_5;

            break;

        case CS6:

            new_dev_conf.word_length = CYGNUM_SERIAL_WORD_LENGTH_6;

            break;

        case CS7:

            new_dev_conf.word_length = CYGNUM_SERIAL_WORD_LENGTH_7;

            break;

        case CS8:

            new_dev_conf.word_length = CYGNUM_SERIAL_WORD_LENGTH_8;

            break;

        }

        len = sizeof( new_dev_conf );

        res = cyg_io_set_config( priv->dev_handle,

                                 CYG_IO_SET_CONFIG_SERIAL_INFO,

                                 &new_dev_conf, &len );

        if ( ENOERR == res ) {

            // It worked, so update dev_conf to reflect the new state

            dev_conf.word_length = new_dev_conf.word_length;

            // and termios

            ptermios->c_cflag &= ~CSIZE;

            ptermios->c_cflag |= t->c_cflag & CSIZE;

        }

    }

    if ( (t->c_cflag & IXOFF) != (ptermios->c_cflag & IXOFF) ) {

        new_dev_conf = dev_conf;

        new_dev_conf.flags &=

            ~(CYGNUM_SERIAL_FLOW_XONXOFF_RX|CYGNUM_SERIAL_FLOW_RTSCTS_RX);

        if ( t->c_cflag & IXOFF )

            if ( t->c_cflag & CRTSCTS)

                new_dev_conf.flags |= CYGNUM_SERIAL_FLOW_RTSCTS_RX;

            else

                new_dev_conf.flags |= CYGNUM_SERIAL_FLOW_XONXOFF_RX;

        else

            new_dev_conf.flags |= CYGNUM_SERIAL_FLOW_NONE;

        len = sizeof( new_dev_conf );

        res = cyg_io_set_config( priv->dev_handle,

                                 CYG_IO_SET_CONFIG_SERIAL_INFO,

                                 &new_dev_conf, &len );

        if ( ENOERR == res ) {

            // It worked, so update dev_conf to reflect the new state

            dev_conf.flags = new_dev_conf.flags;

            // and termios

            ptermios->c_cflag &= ~(IXOFF|CRTSCTS);

            ptermios->c_cflag |= t->c_cflag & (IXOFF|CRTSCTS);

        }

    }

    if ( (t->c_cflag & IXON) != (ptermios->c_cflag & IXON) ) {

        new_dev_conf = dev_conf;

        new_dev_conf.flags &=

            ~(CYGNUM_SERIAL_FLOW_XONXOFF_TX|CYGNUM_SERIAL_FLOW_RTSCTS_TX);

        if ( t->c_cflag & IXON )

            if ( t->c_cflag & CRTSCTS)

                new_dev_conf.flags |= CYGNUM_SERIAL_FLOW_RTSCTS_TX;

            else

                new_dev_conf.flags |= CYGNUM_SERIAL_FLOW_XONXOFF_TX;

        else

            new_dev_conf.flags |= CYGNUM_SERIAL_FLOW_NONE;

        len = sizeof( new_dev_conf );

        res = cyg_io_set_config( priv->dev_handle,

                                 CYG_IO_SET_CONFIG_SERIAL_INFO,

                                 &new_dev_conf, &len );

        if ( ENOERR == res ) {

            // It worked, so update dev_conf to reflect the new state

            dev_conf.flags = new_dev_conf.flags;

            // and termios

            ptermios->c_cflag &= ~(IXON|CRTSCTS);

            ptermios->c_cflag |= t->c_cflag & (IXON|CRTSCTS);

        }

    }

    // Input/Output processing flags can just be set as we grok them all

    // with few exceptions (see lflags below)

    ptermios->c_iflag &= ~(BRKINT|ICRNL|IGNBRK|IGNCR|IGNPAR|INLCR|INPCK|

                           ISTRIP|PARMRK);

    ptermios->c_iflag |= t->c_iflag & (

#ifdef CYGSEM_IO_SERIAL_TERMIOS_USE_SIGNALS

                                       BRKINT|

#endif

                                       ICRNL|IGNBRK|IGNCR|IGNPAR|

                                       INLCR|INPCK|ISTRIP|PARMRK );

    ptermios->c_oflag &= ~(OPOST|ONLCR);

    ptermios->c_oflag |= t->c_oflag & (OPOST|ONLCR);

    ptermios->c_cflag &= ~(CLOCAL|CREAD|HUPCL);

    ptermios->c_cflag |= t->c_cflag & (CLOCAL|CREAD|HUPCL);

    ptermios->c_lflag &= ~(ECHO|ECHOE|ECHOK|ECHONL|ICANON|

                                 IEXTEN|ISIG|NOFLSH|TOSTOP);

    // Note we don't support IEXTEN nor TOSTOP so we don't set them

    ptermios->c_lflag |= t->c_lflag & (ECHO|ECHOE|ECHOK|ECHONL|ICANON|

#ifdef CYGSEM_IO_SERIAL_TERMIOS_USE_SIGNALS

                                       ISIG|

#endif

                                       NOFLSH);

    // control characters. We don't support changing of VSTART, VSTOP,

    // VTIME or VSUSP though

    tempcc[VEOF]   = t->c_cc[VEOF];

    tempcc[VEOL]   = t->c_cc[VEOL];

    tempcc[VERASE] = t->c_cc[VERASE];

    tempcc[VINTR]  = t->c_cc[VINTR];

    tempcc[VKILL]  = t->c_cc[VKILL];

    tempcc[VMIN]   = t->c_cc[VMIN];

    tempcc[VQUIT]  = t->c_cc[VQUIT];

    return res;

}

//==========================================================================

static bool

termios_init(struct cyg_devtab_entry *tab)

{

    // can't initialize the termios structure because we can't

    // query the serial driver yet. Wait until lookup time.

    return true;

} // termios_init()

//==========================================================================

static Cyg_ErrNo

termios_lookup(struct cyg_devtab_entry **tab,

           struct cyg_devtab_entry *sub_tab,

           const char *name)

{

    cyg_io_handle_t chan = (cyg_io_handle_t)sub_tab;

    struct termios_private_info *priv =

        (struct termios_private_info *)(*tab)->priv;

    Cyg_ErrNo err = ENOERR;

    if ( !priv->init ) {

        cyg_drv_mutex_lock( &priv->lock );

        if ( !priv->init ) {  // retest as we may have been pre-empted

            priv->dev_handle = chan;

            err = real_termios_init( priv );

        }

        cyg_drv_mutex_unlock( &priv->lock );

    }

    return err;

}

//==========================================================================

#define WRITE_BUFSIZE 100 // FIXME: ->CDL

// #define MAX_CANON 64  FIXME: relevance?

static Cyg_ErrNo

termios_write(cyg_io_handle_t handle, const void *_buf, cyg_uint32 *len)

{

    cyg_devtab_entry_t *t = (cyg_devtab_entry_t *)handle;

    struct termios_private_info *priv = (struct termios_private_info *)t->priv;

    cyg_io_handle_t chan = (cyg_io_handle_t)priv->dev_handle;

    cyg_int32 xbufsize, input_bytes_read;

    cyg_uint8 xbuf[WRITE_BUFSIZE];

    cyg_uint8 *buf = (cyg_uint8 *)_buf;

    Cyg_ErrNo res;

    xbufsize = input_bytes_read = 0;

    while (input_bytes_read++ < *len) {

        if ( (*buf == '\n') && (priv->termios.c_oflag & (OPOST|ONLCR)) ) {

            xbuf[xbufsize++] = '\r';

        }

        xbuf[xbufsize++] = *buf;

        if ((xbufsize >= (WRITE_BUFSIZE-1)) || (input_bytes_read == *len) ||

            (*buf == '\n'))

        {

            cyg_int32 size = xbufsize;

            res = cyg_io_write(chan, xbuf, &size);

            if (res != ENOERR) {

                *len = input_bytes_read - (xbufsize - size);

                return res;

            }

            xbufsize = 0;

        }

        buf++;

    }

    // Everything sent, so *len is correct.

    return ENOERR;

}

//==========================================================================

static Cyg_ErrNo

termios_read(cyg_io_handle_t handle, void *_buf, cyg_uint32 *len)

{

    cyg_devtab_entry_t *dt = (cyg_devtab_entry_t *)handle;

    struct termios_private_info *priv = (struct termios_private_info *)dt->priv;

    cyg_io_handle_t chan = (cyg_io_handle_t)priv->dev_handle;

    struct termios *t = &priv->termios;

    cyg_uint32 clen;

    cyg_uint32 size;

    Cyg_ErrNo res;

    cyg_uint8 c;

    cyg_uint8 *buf = (cyg_uint8 *)_buf;

    cyg_bool discardc; // should c be discarded (not read, not printed)

    cyg_bool returnnow = false; // return back to user after this char

    // if receiver off

    if (0 == (t->c_cflag & CREAD) ) {

        *len = 0;

        return -EINVAL;

    }

    size = 0;

    if ( 0 == (t->c_lflag & ICANON) ) {

        // In non-canonical mode we return the min of *len and the

        // number of bytes available

        // So we query the driver for how many bytes are available - this

        // guarantees we won't block

        cyg_serial_buf_info_t dev_buf_conf;

        cyg_uint32 dbc_len = sizeof( dev_buf_conf );

        res = cyg_io_get_config( chan,

                                 CYG_IO_GET_CONFIG_SERIAL_BUFFER_INFO,

                                 &dev_buf_conf, &dbc_len );

        CYG_ASSERT( res == ENOERR, "Query buffer status failed!" );

        *len = *len < dev_buf_conf.rx_count ? *len : dev_buf_conf.rx_count;

    } // if

    while (!returnnow && size < *len) {

        clen = 1;

        discardc = false;

        res = cyg_io_read(chan, &c, &clen);

        if (res != ENOERR) {

            *len = size;

            return res;

        }

        // lock to prevent termios getting corrupted while we read from it

        cyg_drv_mutex_lock( &priv->lock );

        if ( t->c_iflag & ISTRIP )

            c &= 0x7f;

        // canonical mode: erase, kill, and newline processing

        if ( t->c_lflag & ICANON ) {

            if ( t->c_cc[ VERASE ] == c ) {

                discardc = true;

                // erase on display?

                if ( (t->c_lflag & ECHO) && (t->c_lflag & ECHOE) ) {