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/*

 *  Tty IO Driver

 *  This is a "libio" driver based on libc/support/generic/libio interface

 *  which is on top of the RTEMS IO manager.

 *

 *  These provide UNIX-like read and write calls for the C library.

 *

 *  COPYRIGHT (c) 1994 by Division Incorporated

 *

 *  The license and distribution terms for this file may be

 *  found in the file LICENSE in this distribution or at

 *  http://www.OARcorp.com/rtems/license.html.

 *

 *  $Id: tty.c,v 1.2 2001-09-27 11:59:45 chris Exp $

 */

#include <bsp.h>

#include <rtems/libio.h>

#include <errno.h>

#define PRINT_BUFFER_SIZE    (16 * 1024)

/*

 * NOTE: this structure is dumplicated in print_dump.c utility

 */

struct {

    int  index;

    int  size;

    char buffer[PRINT_BUFFER_SIZE];

} print_buffer;

/* always use printf buffer if non-zero */

int  use_print_buffer;

static int host_read_syscall(int fd, char *buffer, int count);

static int host_write_syscall(int fd, char *buffer, int count);

rtems_device_driver

tty_initialize(

    rtems_device_major_number major,

    rtems_device_minor_number minor,

    void                    * arg

  )

{

    rtems_status_code status;

    status = rtems_io_register_name("/dev/tty00",

                                    major,

                                    (rtems_device_minor_number) 0);

    if (status != RTEMS_SUCCESSFUL)

        rtems_fatal_error_occurred(status);

    return RTEMS_SUCCESSFUL;

}

rtems_device_driver

tty_open(

    rtems_device_major_number major,

    rtems_device_minor_number minor,

    void                    * arg

  )

{

    return RTEMS_SUCCESSFUL;

}

rtems_device_driver

tty_close(

    rtems_device_major_number major,

    rtems_device_minor_number minor,

    void                    * arg

  )

{

    return RTEMS_SUCCESSFUL;

}

rtems_device_driver

tty_control(

    rtems_device_major_number major,

    rtems_device_minor_number minor,

    void                    * arg

  )

{

    return RTEMS_SUCCESSFUL;

}

rtems_device_driver

tty_read(

    rtems_device_major_number major,

    rtems_device_minor_number minor,

    void                    * arg

  )

{

    rtems_libio_rw_args_t *rw_args;

    int count = 0;

    rw_args = (rtems_libio_rw_args_t *) arg;

    /*

     * If we are printing to a buffer, then just return newline on all

     * read's.  If we return 0 bytes read, then the pause() calls in

     * the RTEMS tests get hosed (pause() does a gets())

     */

    if ( use_print_buffer )

    {

        *rw_args->buffer = '\n';

        count = 1;

    }

    else

    {

        count = host_read_syscall(0, rw_args->buffer, rw_args->count);

    }

    if (count >= 0)

    {

        rw_args->bytes_moved = count;

        return RTEMS_SUCCESSFUL;

    }

    return RTEMS_UNSATISFIED;

}

rtems_device_driver

tty_write(

    rtems_device_major_number major,

    rtems_device_minor_number minor,

    void                    * arg

  )

{

    unsigned32 level;

    rtems_libio_rw_args_t *rw_args;

    int count = 0;

    int fd = 1;                 /* XXX fixme; needs to be saved in iop */

    rw_args = (rtems_libio_rw_args_t *) arg;

    /*

     * HACK alert

     *

     * Some of the simulators have real problems when multi cpu and

     * using the system calls.  Until this is fixed, if we are multi

     * cpu then we write to a printf buffer

     */

    if ( use_print_buffer )

    {

        /* save size in memory for dumper */

        if (print_buffer.size == 0)

            print_buffer.size = PRINT_BUFFER_SIZE;

        while (rw_args->count-- > 0)

        {

            rtems_interrupt_disable(level);

            print_buffer.buffer[print_buffer.index] = *rw_args->buffer++;

            print_buffer.index++;

            print_buffer.index &= (PRINT_BUFFER_SIZE - 1);

            print_buffer.buffer[print_buffer.index] = 0;

            rtems_interrupt_enable(level);

            count++;

        }

    }

    else

    {

#if 1

        /*

         * if on a multi cpu system and writing to stdout, redirect to stderr

         * so we can keep them separate

         */

        if ((cpu_number == 1) && (fd == 1))

            fd = 2;

#endif

        count = host_write_syscall(fd, rw_args->buffer, rw_args->count);

    }

    if (count >= 0)

    {

        rw_args->bytes_moved = count;

        return RTEMS_SUCCESSFUL;

    }

    return RTEMS_UNSATISFIED;

}

/*

 * Host system call hack.

 * This little trick gets all the args in the right registers

 * for the system call and permits simpler inline asm.

 * Since this whole thing (syscalls under simulator) is a hack,

 * this little bit more is not going to hurt anything.

 */

static int

host_read_syscall(

    int fd,

    char *buffer,

    int count

  )

{

    unsigned32 level;

    int rc;

    rtems_interrupt_disable(level);

    /* This is an HPUX system call, with return value copied out */

    asm volatile (" stw     %%r19,-28(0,%%r30)\n\

                    ldil    L%%0xc0000000,%%r1\n\

                    ble     4(7,%%r1)\n\

                    ldi     3,%%r22\n\

                    ldw     -28(0,%%r30),%%r19\n\

                    copy    %%r28, %0"

                  : "=r" (rc)

                  : );

    rtems_interrupt_enable(level);

    return rc;

}

static int

host_write_syscall(

    int fd,

    char *buffer,

    int count

  )

{

    unsigned32 level;

    int rc;

    rtems_interrupt_disable(level);

    /* This is an HPUX system call, with return value copied out */

    asm volatile (" stw     %%r19,-28(0,%%r30)\n\

                    ldil    L%%0xc0000000,%%r1\n\

                    ble     4(7,%%r1)\n\

                    ldi     4,%%r22\n\

                    ldw     -28(0,%%r30),%%r19\n\

                    copy    %%r28, %0"

                  : "=r" (rc)

                  : );

    rtems_interrupt_enable(level);

    return rc;

}