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/* ps2kbd.c -- Very simple (and limited) PS/2 keyboard simulation

   Copyright (C) 2002 Marko Mlinar, markom@opencores.org

This file is part of OpenRISC 1000 Architectural Simulator.

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., 675 Mass Ave, Cambridge, MA 02139, USA. */

#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#include "ps2kbd.h"

#include "sim-config.h"

#include "abstract.h"

/* ASCII to scan code conversion table */

const static struct {

  /* Whether shift must be pressed */

  unsigned char shift;

  /* Scan code to be generated */

  unsigned char code;

} scan_table [128] = {

/* 0 - 15 */

{0, 0x00}, {0, 0x00}, {0, 0x00}, {0, 0x00}, {0, 0x00}, {0, 0x00}, {0, 0x00}, {0, 0x00},

{0, 0x0E}, {0, 0x0F}, {0, 0x1C}, {0, 0x00}, {0, 0x00}, {0, 0x00}, {0, 0x00}, {0, 0x00},

/* 16 - 31 */

{0, 0x00}, {0, 0x00}, {0, 0x00}, {0, 0x00}, {0, 0x00}, {0, 0x00}, {0, 0x00}, {0, 0x00},

{0, 0x00}, {0, 0x00}, {0, 0x00}, {0, 0x01}, {0, 0x00}, {0, 0x00}, {0, 0x00}, {0, 0x00},

/* 32 - 47 */

{0, 0x39}, {1, 0x02}, {1, 0x28}, {1, 0x04}, {1, 0x05}, {1, 0x06}, {1, 0x08}, {0, 0x28},

{1, 0x0A}, {1, 0x0B}, {1, 0x09}, {1, 0x0D}, {0, 0x33}, {0, 0x0C}, {0, 0x34}, {0, 0x35},

/* 48 - 63 */

{0, 0x0B}, {0, 0x02}, {0, 0x03}, {0, 0x04}, {0, 0x05}, {0, 0x06}, {0, 0x07}, {0, 0x08},

{0, 0x09}, {0, 0x0A}, {1, 0x27}, {0, 0x27}, {1, 0x33}, {0, 0x0D}, {1, 0x34}, {1, 0x35},

/* 64 - 79 */

{1, 0x03}, {1, 0x1E}, {1, 0x30}, {1, 0x2E}, {1, 0x20}, {1, 0x12}, {1, 0x21}, {1, 0x22},

{1, 0x23}, {1, 0x17}, {1, 0x24}, {1, 0x25}, {1, 0x26}, {1, 0x32}, {1, 0x31}, {1, 0x18},

/* 80 - 95 */

{1, 0x19}, {1, 0x10}, {1, 0x13}, {1, 0x1F}, {1, 0x14}, {1, 0x16}, {1, 0x2F}, {1, 0x11},

{1, 0x2D}, {1, 0x15}, {1, 0x2C}, {0, 0x1A}, {0, 0x2B}, {0, 0x1B}, {1, 0x07}, {1, 0x0C},

/* 96 - 111 */

{0, 0x29}, {0, 0x1E}, {0, 0x30}, {0, 0x2E}, {0, 0x20}, {0, 0x12}, {0, 0x21}, {0, 0x22},

{0, 0x23}, {0, 0x17}, {0, 0x24}, {0, 0x25}, {0, 0x26}, {0, 0x32}, {0, 0x31}, {0, 0x18},

/* 112 - 127 */

{0, 0x19}, {0, 0x10}, {0, 0x13}, {0, 0x1F}, {0, 0x14}, {0, 0x16}, {0, 0x2F}, {0, 0x11},

{0, 0x2D}, {0, 0x15}, {0, 0x2C}, {1, 0x1A}, {1, 0x2B}, {1, 0x1B}, {1, 0x29}, {0, 0x00}

};

/* Temporary buffer to store incoming scan codes */

static unsigned char kbd_buf[KBD_MAX_BUF] = {0};

/* Number of scan codes in buffer */

static unsigned long kbd_buf_count = 0;

static unsigned long kbd_buf_head = 0;

static unsigned long kbd_buf_tail = 0;

/* Input stream */

static FILE *kbd_rxfs = NULL;

static void kbd_put (unsigned char c)

{

  if (kbd_buf_count >= KBD_MAX_BUF) {

    fprintf (stderr, "WARNING: Keyboard buffer overflow.\n");

  } else {

    kbd_buf[kbd_buf_head] = c;

    kbd_buf_head = (kbd_buf_head + 1) % KBD_MAX_BUF;

    kbd_buf_count++;

  }

}

/* Decodes ascii code c into multiple scan codes, placed into buf, length is returned */

static void scan_decode (unsigned char c)

{

  /* Do not handle special characters and extended ascii */

  if (c >= 128 || !scan_table[c].code)

    return;

  /* Make shift? */

  if (scan_table[c].shift) kbd_put (0x2a);

  /* Make char */

  kbd_put (scan_table[c].code);

  /* Break char */

  kbd_put (scan_table[c].code | 0x80);

  /* Break shift? */

  if (scan_table[c].shift) kbd_put (0xaa);

}

/* Write a register */

void kbd_write8 (unsigned long addr, unsigned long value)

{

  int a = (addr - config.kbd.baseaddr);

  switch (a) {

    case KBD_CTRL:    break;

    case KBD_DATA:    break;

    default:

      fprintf (stderr, "Write out of keyboard space (0x%08x)!\n", addr);

      cont_run = 0;

      break;

  }

}

/* Read a register */

unsigned long kbd_read8 (unsigned long addr)

{

  int a = (addr - config.kbd.baseaddr);

  switch (a) {

    case KBD_CTRL:    return 0; break;

    case KBD_DATA:

      if (kbd_buf_count) {

        unsigned long c = kbd_buf[kbd_buf_tail];

        kbd_buf_tail = (kbd_buf_tail + 1) % KBD_MAX_BUF;

        kbd_buf_count--;

        return c;

      }

      return 0;

    default:

      fprintf (stderr, "Read out of keyboard space (0x%08x)!\n", addr);

      cont_run = 0;

      return 0;

  }

}

/* Reset all VGAs */

void kbd_reset ()

{

  if (config.kbd.enabled) {

    kbd_buf_count = 0;

    kbd_buf_head = 0;

    kbd_buf_tail = 0;

    register_memoryarea(config.kbd.baseaddr, KBD_SPACE, 1, kbd_read8, kbd_write8);

    if (!(kbd_rxfs = fopen(config.kbd.rxfile, "r"))

     && !(kbd_rxfs = fopen(config.kbd.rxfile, "r+"))) {

      fprintf (stderr, "WARNING: Keyboard has problems with RX file stream.\n");

    }

  }

}

/* Simulation hook. Must be called every clock cycle to simulate incomming data. */

void kbd_clock()

{

  int c;

  /* Check if there is something waiting, and decode it into kdb_buf */

  if((c = fgetc(kbd_rxfs)) != EOF) {

    scan_decode (c);

  }

  if (kbd_buf_count) report_interrupt(config.kbd.irq);

}