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/*  This file is part of the program psim.

    Copyright (C) 1994-1996, Andrew Cagney <cagney@highland.com.au>

    This program 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 of the License, or

    (at your option) any later version.

    This program 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 this program; if not, write to the Free Software

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

    */

#ifndef _HW_COM_C_

#define _HW_COM_C_

#ifndef STATIC_INLINE_HW_COM

#define STATIC_INLINE_HW_COM STATIC_INLINE

#endif

#include "device_table.h"

#ifdef HAVE_STRING_H

#include <string.h>

#else

#ifdef HAVE_STRINGS_H

#include <strings.h>

#endif

#endif

#ifdef HAVE_UNISTD_H

#include <unistd.h>

#endif

#ifdef HAVE_STDLIB_H

#include <stdlib.h>

#endif

/* DEVICE

   com - '550 compatible serial device

   DESCRIPTION

   Models the basics of the 8 register '550 serial device.  The model

   includes an interrupt line, input and output fifos, and status

   information.

   Independent configuration of the devices input and output streams is

   allowed: use either the console or a file (buffered or unbuffered) as

   the data source/sink; specify the real-time delay between each character

   transfer.

   When the devices input stream is being taken from a file, the end of

   file is signaled by a loss of carrier (the loss of carrier may be

   incorrectly proceeded by a single null character).

   PROPERTIES

   reg = <address> <size> ... (optional - note 1)

   List of <address> <size> pairs.  Each pair specifies an address for

   the devices 8 registers.  The address should be 8 byte aligned.

   alternate-reg = <address> <size> ... (optional - note 1)

   Alternative addreses for the registers.

   assigned-addresses = <address> <size> ... (optional - note 1)

   On a PCI bus, this property specifies the addresses assigned to the

   device.  The values reflect the devices configuration base registers.

   Note 1: At least one of "assigned-addresses", "reg" or "alternative-reg"

   must be specified.  If "assigned-addresses" is specified the other

   address specifications are ignored.

   input-file = <file-name> (optional)

   File to take all serial port input from (instead of the simulation

   console).

   output-file = <file-name> (optional)

   File to send all output to (instead of the simulation console).

   input-buffering = "unbuffered" (optional)

   Specifying "unbuffered" buffering disables buffering on the serial

   devices input stream (all data is immediatly read).  In the future,

   this option may be used to provide input buffering alternatives.

   output-buffering = "unbuffered" (optional)

   Specifying "unbuffered" buffering disables buffering on the serial

   devices output stream (all data is immediatly written).  In the future,

   this option may be extended to include other buffering alternatives.

   input-delay = <integer-delay> (optional)

   Specify the number of ticks after the current character has been

   read from the serial port that the next character becomes

   available.

   output-delay = <integer-delay> (optional)

   Specify the number of ticks after a character has been written to

   the empty output fifo that the fifo finishes draining.  Any

   characters written to the output fifo before it has drained will

   not be lost and will still be displayed.

   EXAMPLES

   |  /iobus@0xf0000000/com@0x3000/reg 0x3000 8

   Create a simple console device at address <<0x3000>> within

   <<iobus>>.  Since iobus starts at address <<0xf0000000>> the

   absolute address of the serial port will be <<0xf0003000>>.

   The device will always be ready for I/O (no delay properties specified)

   and both the input and output streams will use the simulation console

   (no file properties).

   |  $ psim \

   |    -o '/cpus/cpu@0' \

   |    -o '/iobus@0xf0000000/com@0x4000/reg 0x4000 8' \

   |    -o '/iobus@0xf0000000/com@0x4000/input-file /etc/passwd' \

   |    -o '/iobus@0xf0000000/com@0x4000/input-delay 1000' \

   |    -o '/iobus@0xf0000000/com@0x4000 > 0 int /cpus/cpu@0x0' \

   |    psim-test/hw-com/cat.be 0xf0004000

   The serial port (at address <<0xf0004000>> is configured so that it

   takes its input from the file <</etc/passwd>> while its output is

   allowed to appear on the simulation console.

   The node <</cpus/cpu@0>> was explicitly specified to ensure that it had

   been created before any interrupts were attached to it.

   The program <<psim-test/hw-com/cat>> copies any characters on the serial

   port's input (<</etc/passwd>>) to its output (the console).

   Consequently, the aove program will display the contents of the file

   <</etc/passwd>> on the screen.

   BUGS

   IEEE 1275 requires that a device on a PCI bus have, as its first reg

   entry, the address of its configuration space registers.  Currently,

   this device does not even implement configuration registers.

   This model does not attempt to model the '550's input and output fifos.

   Instead, the input fifo is limited to a single character at a time,

   while the output fifo is effectivly infinite.  Consequently, unlike the

   '550, this device will not discard output characters once a stream of 16

   have been written to the data output register.

   The input and output can only be taken from a file (or the current

   terminal device).  In the future, the <<com>> device should allow the

   specification of other data streams (such as an xterm or TK window).

   The input blocks if no data is available.

   Interrupts have not been tested.

   */

enum {

  max_hw_com_registers = 8,

};

typedef struct _com_port {

  int ready;

  int delay;

  int interrupting;

  FILE *file;

} com_port;

typedef struct _com_modem {

  int carrier;

  int carrier_changed;

  int interrupting;

} com_modem;

typedef struct _hw_com_device {

  com_port input;

  com_port output;

  com_modem modem;

  char dlab[2];

  char reg[max_hw_com_registers];

  int interrupting;

} hw_com_device;

static void

hw_com_device_init_data(device *me)

{

  hw_com_device *com = (hw_com_device*)device_data(me);

  /* clean up */

  if (com->output.file != NULL)

    fclose(com->output.file);

  if (com->input.file != NULL)

    fclose(com->input.file);

  memset(com, 0, sizeof(hw_com_device));

  /* the fifo speed */

  com->output.delay = (device_find_property(me, "output-delay") != NULL

                       ? device_find_integer_property(me, "output-delay")

                       : 0);

  com->input.delay = (device_find_property(me, "input-delay") != NULL

                      ? device_find_integer_property(me, "input-delay")

                      : 0);

  /* the data source/sink */

  if (device_find_property(me, "input-file") != NULL) {

    const char *input_file = device_find_string_property(me, "input-file");

    com->input.file = fopen(input_file, "r");

    if (com->input.file == NULL)

      device_error(me, "Problem opening input file %s\n", input_file);

    if (device_find_property(me, "input-buffering") != NULL) {

      const char *buffering = device_find_string_property(me, "input-buffering");

      if (strcmp(buffering, "unbuffered") == 0)

        setbuf(com->input.file, NULL);

    }

  }

  if (device_find_property(me, "output-file") != NULL) {

    const char *output_file = device_find_string_property(me, "output-file");

    com->output.file = fopen(output_file, "w");

    if (com->output.file == NULL)

      device_error(me, "Problem opening output file %s\n", output_file);

    if (device_find_property(me, "output-buffering") != NULL) {

      const char *buffering = device_find_string_property(me, "output-buffering");

      if (strcmp(buffering, "unbuffered") == 0)

        setbuf(com->output.file, NULL);

    }

  }

  /* ready from the start */

  com->input.ready = 1;

  com->modem.carrier = 1;

  com->output.ready = 1;

}

static void

update_com_interrupts(device *me,

                      hw_com_device *com)

{

  int interrupting;

  com->modem.interrupting = (com->modem.carrier_changed && (com->reg[1] & 0x80));

  com->input.interrupting = (com->input.ready && (com->reg[1] & 0x1));

  com->output.interrupting = (com->output.ready && (com->reg[1] & 0x2));

  interrupting = (com->input.interrupting

                  || com->output.interrupting

                  || com->modem.interrupting);

  if (interrupting) {

    if (!com->interrupting) {

      device_interrupt_event(me, 0 /*port*/, 1 /*value*/, NULL, 0);

    }

  }

  else /*!interrupting*/ {

    if (com->interrupting)

      device_interrupt_event(me, 0 /*port*/, 0 /*value*/, NULL, 0);

  }

  com->interrupting = interrupting;

}

static void

make_read_ready(void *data)

{

  device *me = (device*)data;

  hw_com_device *com = (hw_com_device*)device_data(me);

  com->input.ready = 1;

  update_com_interrupts(me, com);

}

static void

read_com(device *me,

         hw_com_device *com,

         unsigned_word a,

         char val[1])

{

  unsigned_word addr = a % 8;

  /* the divisor latch is special */

  if (com->reg[3] & 0x8 && addr < 2) {

    *val = com->dlab[addr];

    return;

  }

  switch (addr) {

  case 0:

    /* fifo */

    if (!com->modem.carrier)

      *val = '\0';

    if (com->input.ready) {

      /* read the char in */

      if (com->input.file == NULL) {

        if (sim_io_read_stdin(val, 1) < 0)

          com->modem.carrier_changed = 1;

      }

      else {

        if (fread(val, 1, 1, com->input.file) == 0)

          com->modem.carrier_changed = 1;

      }

      /* setup for next read */

      if (com->modem.carrier_changed) {

        /* once lost carrier, never ready */

        com->modem.carrier = 0;

        com->input.ready = 0;

        *val = '\0';

      }

      else if (com->input.delay > 0) {

        com->input.ready = 0;

        device_event_queue_schedule(me, com->input.delay, make_read_ready, me);

      }

    }

    else {

      /* discard it? */

      /* overflow input fifo? */

      *val = '\0';

    }

    break;

  case 2:

    /* interrupt ident */

    if (com->interrupting) {

      if (com->input.interrupting)

        *val = 0x4;

      else if (com->output.interrupting)

        *val = 0x2;

      else if (com->modem.interrupting == 0)

        *val = 0;

      else

        device_error(me, "bad elif for interrupts\n");

    }

    else

      *val = 0x1;

    break;

  case 5:

    /* line status */

    *val = ((com->input.ready ? 0x1 : 0)

            | (com->output.ready ? 0x60 : 0)

            );

    break;

  case 6:

    /* modem status */

    *val = ((com->modem.carrier_changed ? 0x08 : 0)

            | (com->modem.carrier ? 0x80 : 0)

            );

    com->modem.carrier_changed = 0;

    break;

  default:

    *val = com->reg[addr];

    break;

  }

  update_com_interrupts(me, com);

}

static unsigned

hw_com_io_read_buffer_callback(device *me,

                               void *dest,

                               int space,

                               unsigned_word addr,

                               unsigned nr_bytes,

                               cpu *processor,

                               unsigned_word cia)

{

  hw_com_device *com = device_data(me);

  int i;

  for (i = 0; i < nr_bytes; i++) {

    read_com(me, com, addr + i, &((char*)dest)[i]);

  }

  return nr_bytes;

}

static void

make_write_ready(void *data)

{

  device *me = (device*)data;

  hw_com_device *com = (hw_com_device*)device_data(me);

  com->output.ready = 1;

  update_com_interrupts(me, com);

}

static void

write_com(device *me,

          hw_com_device *com,

          unsigned_word a,

          char val)

{

  unsigned_word addr = a % 8;

  /* the divisor latch is special */

  if (com->reg[3] & 0x8 && addr < 2) {

    com->dlab[addr] = val;

    return;

  }

  switch (addr) {

  case 0:

    /* fifo */

    if (com->output.file == NULL) {

      sim_io_write_stdout(&val, 1);

    }

    else {

      fwrite(&val, 1, 1, com->output.file);

    }

    /* setup for next write */

    if (com->output.ready && com->output.delay > 0) {

      com->output.ready = 0;

      device_event_queue_schedule(me, com->output.delay, make_write_ready, me);

    }

    break;

  default:

    com->reg[addr] = val;

    break;

  }

  update_com_interrupts(me, com);

}

static unsigned

hw_com_io_write_buffer_callback(device *me,

                                const void *source,

                                int space,

                                unsigned_word addr,

                                unsigned nr_bytes,

                                cpu *processor,

                                unsigned_word cia)

{

  hw_com_device *com = device_data(me);

  int i;

  for (i = 0; i < nr_bytes; i++) {

    write_com(me, com, addr + i, ((char*)source)[i]);

  }

  return nr_bytes;

}

/* instances of the hw_com device */

static void

hw_com_instance_delete(device_instance *instance)

{

  /* nothing to delete, the hw_com is attached to the device */

  return;

}

static int

hw_com_instance_read(device_instance *instance,

                     void *buf,

                     unsigned_word len)

{

  device *me = device_instance_device(instance);

  hw_com_device *com = device_data(me);

  if (com->input.file == NULL)

    return sim_io_read_stdin(buf, len);

  else {

    return fread(buf, 1, len, com->input.file);

  }

}

static int

hw_com_instance_write(device_instance *instance,

                      const void *buf,

                      unsigned_word len)

{

  device *me = device_instance_device(instance);

  hw_com_device *com = device_data(me);

  if (com->output.file == NULL)

    return sim_io_write_stdout(buf, len);

  else {

    return fwrite(buf, 1, len, com->output.file);

  }

}

static const device_instance_callbacks hw_com_instance_callbacks = {

  hw_com_instance_delete,

  hw_com_instance_read,

  hw_com_instance_write,

};

static device_instance *

hw_com_create_instance(device *me,

                       const char *path,

                       const char *args)

{

  /* point an instance directly at the device */

  return device_create_instance_from(me, NULL,

                                     device_data(me),

                                     path, args,

                                     &hw_com_instance_callbacks);

}

static device_callbacks const hw_com_callbacks = {

  { generic_device_init_address,

    hw_com_device_init_data },

  { NULL, }, /* address */

  { hw_com_io_read_buffer_callback,

      hw_com_io_write_buffer_callback, },

  { NULL, }, /* DMA */

  { NULL, }, /* interrupt */

  { NULL, }, /* unit */

  hw_com_create_instance,

};

static void *

hw_com_create(const char *name,

              const device_unit *unit_address,

              const char *args)

{

  /* create the descriptor */

  hw_com_device *hw_com = ZALLOC(hw_com_device);

  return hw_com;

}

const device_descriptor hw_com_device_descriptor[] = {

  { "com", hw_com_create, &hw_com_callbacks },

  { NULL },

};

#endif /* _HW_COM_C_ */