/*
 * foo.c:
 *
 * Copyright (c) 2000 James McKenzie <james@fishsoup.dhs.org>.
 * All rights reserved.
 *
 * $Log: irda.c,v $
 * Revision 1.24  2001/01/30 06:16:31  root
 * #
 *
 * Revision 1.23  2000/12/01 04:42:19  root
 * #
 *
 * Revision 1.22  2000/11/23 23:45:28  root
 * #
 *
 * Revision 1.21  2000/10/07 18:30:10  root
 * #
 *
 * Revision 1.20  2000/10/06 19:52:45  root
 * #
 *
 * Revision 1.19  2000/09/29 07:53:48  root
 * #
 *
 * Revision 1.18  2000/09/29 07:53:02  root
 * #
 *
 * Revision 1.17  2000/09/24 01:46:07  root
 * #
 *
 * Revision 1.16  2000/09/24 01:12:53  root
 * #
 *
 * Revision 1.15  2000/02/21 04:01:01  root
 * #
 *
 * Revision 1.14  2000/02/20 18:23:01  root
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 * Revision 1.13  2000/02/20 02:51:44  root
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 *
 * Revision 1.12  2000/02/16 11:34:21  root
 * #
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 * Revision 1.11  2000/02/15 04:15:06  root
 * #
 *
 * Revision 1.10  2000/02/15 04:14:52  root
 * #
 *
 * Revision 1.9  2000/02/14 22:17:05  root
 * #
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 * Revision 1.8  2000/02/14 04:08:55  root
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 * Revision 1.7  2000/02/14 03:46:11  root
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 * Revision 1.6  2000/02/14 03:45:03  root
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 * Revision 1.5  2000/02/13 21:22:24  root
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 * Revision 1.4  2000/02/13 21:13:27  root
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 * Revision 1.3  2000/02/13 21:13:14  root
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 * Revision 1.2  2000/02/13 19:15:34  root
 * #
 *
 * Revision 1.1  2000/02/13 17:44:10  root
 * Initial revision
 *
 *
 */

static char rcsid[] = "$Id: irda.c,v 1.24 2001/01/30 06:16:31 root Exp $";

#include "project.h"

#define IRDA_COMMAND		0x1
#define IRDA_RESPONSE		0x0
#define IRDA_DEST_BROADCAST	0xfe


#define BOF  0xc0               /* Beginning of frame */
#define XBOF 0xff
#define EOF  0xc1               /* End of frame */
#define CE   0x7d               /* Control escape */

#define STA BOF                 /* Start flag */
#define STO EOF                 /* End flag */

#define IRDA_TRANS 0x20         /* Asynchronous transparency modifier */

#define INIT_FCS  0xffff        /* Initial FCS value */
#define GOOD_FCS  0xf0b8

#define BUFSIZE 500

Byte tx_buf[BUFSIZE];
Byte rx_buf[BUFSIZE];
int rx_ptr = 0;
Word rx_fcs;

static __u16 const irda_crc16_table[256] = {
  0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,
  0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,
  0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e,
  0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876,
  0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd,
  0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,
  0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c,
  0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974,
  0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb,
  0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3,
  0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a,
  0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,
  0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9,
  0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,
  0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738,
  0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70,
  0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7,
  0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,
  0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036,
  0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e,
  0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5,
  0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd,
  0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134,
  0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,
  0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3,
  0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb,
  0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232,
  0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a,
  0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1,
  0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,
  0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330,
  0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78
};

static inline Word
irda_fcs (Word fcs, Byte c)
{
  return (((fcs) >> 8) ^ irda_crc16_table[((fcs) ^ (c)) & 0xff]);
}

static inline int
stuff_byte (Byte byte, Byte * buf)
{
  switch (byte)
    {
    case BOF:                  /* FALLTHROUGH */
    case EOF:                  /* FALLTHROUGH */
    case CE:
      /* Insert transparently coded */
      buf[0] = CE;              /* Send link escape */
      buf[1] = byte ^ IRDA_TRANS; /* Complement bit 5 */
      return 2;
      /* break; */
    default:
      /* Non-special value, no transparency required */
      buf[0] = byte;
      return 1;
      /* break; */
    }
}


void
irda_new_frame (Byte * ptr, int len)
{



  if ((ptr[0] != 0xff) || (ptr[1] != 0x13))
    {
      moan ("Rejected packet %02x %02x\n", ptr[0], ptr[1]);
      return;
    }

  hifi_new_packet (NULL, ptr + 2, len - 2, hifi_valid_cmd);


}

int
irda_send_data (Byte * packet, int len)
{
  int xbofs;
  int i;
  int n;

  union
  {
    Word value;
    Byte bytes[2];
  }
  fcs;

  /* Initialize variables */
  fcs.value = INIT_FCS;
  n = 0;

  xbofs = 10;                   /*Really ought to negociate this */

  if (xbofs > 163)
    {
      xbofs = 163;
    }

  MemSet (tx_buf + n, xbofs, XBOF);
  n += xbofs;

  /* Start of packet character BOF */
  tx_buf[n++] = BOF;

  /* Address is Broadcast/Command */

  n += stuff_byte (0xfe, tx_buf + n);
  fcs.value = irda_fcs (fcs.value, 0xfe);

  /* UI/P=0 */
  n += stuff_byte (0x13, tx_buf + n);
  fcs.value = irda_fcs (fcs.value, 0x13);

  /* Insert frame and calc CRC */
  for (i = 0; i < len; i++)
    {

      if (n >= (BUFSIZE - 5))
        {
          CRASH_AND_BURN ("TX buffer too small");
          return 0;
        }

      n += stuff_byte (packet[i], tx_buf + n);
      fcs.value = irda_fcs (fcs.value, packet[i]);
    }

  /* Insert CRC in little endian format (LSB first) */
  fcs.value = ~fcs.value;

  n += stuff_byte (fcs.bytes[1], tx_buf + n);
  n += stuff_byte (fcs.bytes[0], tx_buf + n);

  tx_buf[n++] = EOF;

  serial_send (tx_buf, n);
  return 1;
}

typedef enum
{
  irda_outside_frame,
  irda_begin_frame,
  irda_link_escape,
  irda_inside_frame
}
irda_rx_stat;

static irda_rx_stat rx_state;

int
irda_parse (Byte * ptr, int len)
{
  while (len--)
    {
      switch (rx_state)
        {
        case irda_outside_frame:

          switch (*ptr)
            {
            case BOF:
              rx_state = irda_begin_frame;
              break;
            case XBOF:         /*Hmmm */
              break;
            case EOF:
              break;
            default:
              break;
            }
          break;
        case irda_begin_frame:

          rx_ptr = 0;
          rx_fcs = INIT_FCS;

          switch (*ptr)
            {
            case BOF:
              /*yadiyadiya... */
              break;
            case CE:           /*Escape next char */
              rx_state = irda_link_escape;
              break;
            case EOF:          /* Avort Frame */
              rx_state = irda_outside_frame;
              break;
            default:           /*Add char to buffer */
              rx_buf[rx_ptr++] = *ptr;
              rx_fcs = irda_fcs (rx_fcs, *ptr);
              rx_state = irda_inside_frame;
              break;
            }
          break;
        case irda_link_escape:
          switch (*ptr)
            {
            case BOF:          /*New frame? */
              rx_state = irda_begin_frame;
              break;
            case CE:           /*Escape next char -- this not meant to happen */
              moan ("CE'd CE oops...\n");
              break;
            case EOF:          /* Abort Frame */
              rx_state = irda_outside_frame;
              break;
            default:           /*Add char to buffer after de-escaping */
              if (rx_ptr < BUFSIZE)
                {
                  *ptr ^= IRDA_TRANS;
                  rx_buf[rx_ptr++] = *ptr;
                  rx_fcs = irda_fcs (rx_fcs, *ptr);

                  rx_state = irda_inside_frame;
                }
              else
                {
                  /*Jump out */
                  rx_state = irda_outside_frame;
                  moan ("Frame to big...\n");
                }
              break;
            }
          break;
        case irda_inside_frame:
          switch (*ptr)
            {
            case BOF:          /*New frame? */
              rx_state = irda_begin_frame;
              break;
            case CE:           /*Escape next char */
              rx_state = irda_link_escape;
              break;
            case EOF:          /* Deliver Frame */

              if (rx_fcs == GOOD_FCS)
                irda_new_frame (rx_buf, rx_ptr - 2);

              rx_state = irda_outside_frame;
              break;
            default:           /*Add char to buffer */
              if (rx_ptr < BUFSIZE)
                {
                  rx_buf[rx_ptr++] = *ptr;
                  rx_fcs = irda_fcs (rx_fcs, *ptr);
                }
              else
                {
                  rx_ptr = 0;   /*Jump out */
                  rx_state = irda_outside_frame;
                  moan ("Frame to big...\n");
                }
              break;
            }
          break;
        }
      ptr++;
    }
}




void
irda_init (void)
{
  rx_state = irda_outside_frame;
}

void
irda_flush (void)
{
  serial_flush ();
}

void
irda_dispatch (void)
{
  serial_dispatch ();
}
