xyzModem.c 17.7 KB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818
/*
 *==========================================================================
 *
 *      xyzModem.c
 *
 *      RedBoot stream handler for xyzModem protocol
 *
 *==========================================================================
 * SPDX-License-Identifier:	eCos-2.0
 *==========================================================================
 *#####DESCRIPTIONBEGIN####
 *
 * Author(s):    gthomas
 * Contributors: gthomas, tsmith, Yoshinori Sato
 * Date:         2000-07-14
 * Purpose:
 * Description:
 *
 * This code is part of RedBoot (tm).
 *
 *####DESCRIPTIONEND####
 *
 *==========================================================================
 */
#include <common.h>
#include <xyzModem.h>
#include <stdarg.h>
#include <crc.h>

/* Assumption - run xyzModem protocol over the console port */

/* Values magic to the protocol */
#define SOH 0x01
#define STX 0x02
#define EOT 0x04
#define ACK 0x06
#define BSP 0x08
#define NAK 0x15
#define CAN 0x18
#define EOF 0x1A		/* ^Z for DOS officionados */

#define USE_YMODEM_LENGTH

/* Data & state local to the protocol */
static struct
{
#ifdef REDBOOT
  hal_virtual_comm_table_t *__chan;
#else
  int *__chan;
#endif
  unsigned char pkt[1024], *bufp;
  unsigned char blk, cblk, crc1, crc2;
  unsigned char next_blk;	/* Expected block */
  int len, mode, total_retries;
  int total_SOH, total_STX, total_CAN;
  bool crc_mode, at_eof, tx_ack;
#ifdef USE_YMODEM_LENGTH
  unsigned long file_length, read_length;
#endif
} xyz;

#define xyzModem_CHAR_TIMEOUT            2000	/* 2 seconds */
#define xyzModem_MAX_RETRIES             20
#define xyzModem_MAX_RETRIES_WITH_CRC    10
#define xyzModem_CAN_COUNT                3	/* Wait for 3 CAN before quitting */


#ifndef REDBOOT			/*SB */
typedef int cyg_int32;
static int
CYGACC_COMM_IF_GETC_TIMEOUT (char chan, char *c)
{
#define DELAY 20
  unsigned long counter = 0;
  while (!tstc () && (counter < xyzModem_CHAR_TIMEOUT * 1000 / DELAY))
    {
      udelay (DELAY);
      counter++;
    }
  if (tstc ())
    {
      *c = getc ();
      return 1;
    }
  return 0;
}

static void
CYGACC_COMM_IF_PUTC (char x, char y)
{
  putc (y);
}

/* Validate a hex character */
__inline__ static bool
_is_hex (char c)
{
  return (((c >= '0') && (c <= '9')) ||
	  ((c >= 'A') && (c <= 'F')) || ((c >= 'a') && (c <= 'f')));
}

/* Convert a single hex nibble */
__inline__ static int
_from_hex (char c)
{
  int ret = 0;

  if ((c >= '0') && (c <= '9'))
    {
      ret = (c - '0');
    }
  else if ((c >= 'a') && (c <= 'f'))
    {
      ret = (c - 'a' + 0x0a);
    }
  else if ((c >= 'A') && (c <= 'F'))
    {
      ret = (c - 'A' + 0x0A);
    }
  return ret;
}

/* Convert a character to lower case */
__inline__ static char
_tolower (char c)
{
  if ((c >= 'A') && (c <= 'Z'))
    {
      c = (c - 'A') + 'a';
    }
  return c;
}

/* Parse (scan) a number */
static bool
parse_num (char *s, unsigned long *val, char **es, char *delim)
{
  bool first = true;
  int radix = 10;
  char c;
  unsigned long result = 0;
  int digit;

  while (*s == ' ')
    s++;
  while (*s)
    {
      if (first && (s[0] == '0') && (_tolower (s[1]) == 'x'))
	{
	  radix = 16;
	  s += 2;
	}
      first = false;
      c = *s++;
      if (_is_hex (c) && ((digit = _from_hex (c)) < radix))
	{
	  /* Valid digit */
#ifdef CYGPKG_HAL_MIPS
	  /* FIXME: tx49 compiler generates 0x2539018 for MUL which */
	  /* isn't any good. */
	  if (16 == radix)
	    result = result << 4;
	  else
	    result = 10 * result;
	  result += digit;
#else
	  result = (result * radix) + digit;
#endif
	}
      else
	{
	  if (delim != (char *) 0)
	    {
	      /* See if this character is one of the delimiters */
	      char *dp = delim;
	      while (*dp && (c != *dp))
		dp++;
	      if (*dp)
		break;		/* Found a good delimiter */
	    }
	  return false;		/* Malformatted number */
	}
    }
  *val = result;
  if (es != (char **) 0)
    {
      *es = s;
    }
  return true;
}

#endif

#define USE_SPRINTF
#ifdef DEBUG
#ifndef USE_SPRINTF
/*
 * Note: this debug setup only works if the target platform has two serial ports
 * available so that the other one (currently only port 1) can be used for debug
 * messages.
 */
static int
zm_dprintf (char *fmt, ...)
{
  int cur_console;
  va_list args;

  va_start (args, fmt);
#ifdef REDBOOT
  cur_console =
    CYGACC_CALL_IF_SET_CONSOLE_COMM
    (CYGNUM_CALL_IF_SET_COMM_ID_QUERY_CURRENT);
  CYGACC_CALL_IF_SET_CONSOLE_COMM (1);
#endif
  diag_vprintf (fmt, args);
#ifdef REDBOOT
  CYGACC_CALL_IF_SET_CONSOLE_COMM (cur_console);
#endif
}

static void
zm_flush (void)
{
}

#else
/*
 * Note: this debug setup works by storing the strings in a fixed buffer
 */
#define FINAL
#ifdef FINAL
static char *zm_out = (char *) 0x00380000;
static char *zm_out_start = (char *) 0x00380000;
#else
static char zm_buf[8192];
static char *zm_out = zm_buf;
static char *zm_out_start = zm_buf;

#endif
static int
zm_dprintf (char *fmt, ...)
{
  int len;
  va_list args;

  va_start (args, fmt);
  len = diag_vsprintf (zm_out, fmt, args);
  zm_out += len;
  return len;
}

static void
zm_flush (void)
{
#ifdef REDBOOT
  char *p = zm_out_start;
  while (*p)
    mon_write_char (*p++);
#endif
  zm_out = zm_out_start;
}
#endif

static void
zm_dump_buf (void *buf, int len)
{
#ifdef REDBOOT
  diag_vdump_buf_with_offset (zm_dprintf, buf, len, 0);
#else

#endif
}

static unsigned char zm_buf[2048];
static unsigned char *zm_bp;

static void
zm_new (void)
{
  zm_bp = zm_buf;
}

static void
zm_save (unsigned char c)
{
  *zm_bp++ = c;
}

static void
zm_dump (int line)
{
  zm_dprintf ("Packet at line: %d\n", line);
  zm_dump_buf (zm_buf, zm_bp - zm_buf);
}

#define ZM_DEBUG(x) x
#else
#define ZM_DEBUG(x)
#endif

/* Wait for the line to go idle */
static void
xyzModem_flush (void)
{
  int res;
  char c;
  while (true)
    {
      res = CYGACC_COMM_IF_GETC_TIMEOUT (*xyz.__chan, &c);
      if (!res)
	return;
    }
}

static int
xyzModem_get_hdr (void)
{
  char c;
  int res;
  bool hdr_found = false;
  int i, can_total, hdr_chars;
  unsigned short cksum;

  ZM_DEBUG (zm_new ());
  /* Find the start of a header */
  can_total = 0;
  hdr_chars = 0;

  if (xyz.tx_ack)
    {
      CYGACC_COMM_IF_PUTC (*xyz.__chan, ACK);
      xyz.tx_ack = false;
    }
  while (!hdr_found)
    {
      res = CYGACC_COMM_IF_GETC_TIMEOUT (*xyz.__chan, &c);
      ZM_DEBUG (zm_save (c));
      if (res)
	{
	  hdr_chars++;
	  switch (c)
	    {
	    case SOH:
	      xyz.total_SOH++;
	    case STX:
	      if (c == STX)
		xyz.total_STX++;
	      hdr_found = true;
	      break;
	    case CAN:
	      xyz.total_CAN++;
	      ZM_DEBUG (zm_dump (__LINE__));
	      if (++can_total == xyzModem_CAN_COUNT)
		{
		  return xyzModem_cancel;
		}
	      else
		{
		  /* Wait for multiple CAN to avoid early quits */
		  break;
		}
	    case EOT:
	      /* EOT only supported if no noise */
	      if (hdr_chars == 1)
		{
		  CYGACC_COMM_IF_PUTC (*xyz.__chan, ACK);
		  ZM_DEBUG (zm_dprintf ("ACK on EOT #%d\n", __LINE__));
		  ZM_DEBUG (zm_dump (__LINE__));
		  return xyzModem_eof;
		}
	    default:
	      /* Ignore, waiting for start of header */
	      ;
	    }
	}
      else
	{
	  /* Data stream timed out */
	  xyzModem_flush ();	/* Toss any current input */
	  ZM_DEBUG (zm_dump (__LINE__));
	  CYGACC_CALL_IF_DELAY_US ((cyg_int32) 250000);
	  return xyzModem_timeout;
	}
    }

  /* Header found, now read the data */
  res = CYGACC_COMM_IF_GETC_TIMEOUT (*xyz.__chan, (char *) &xyz.blk);
  ZM_DEBUG (zm_save (xyz.blk));
  if (!res)
    {
      ZM_DEBUG (zm_dump (__LINE__));
      return xyzModem_timeout;
    }
  res = CYGACC_COMM_IF_GETC_TIMEOUT (*xyz.__chan, (char *) &xyz.cblk);
  ZM_DEBUG (zm_save (xyz.cblk));
  if (!res)
    {
      ZM_DEBUG (zm_dump (__LINE__));
      return xyzModem_timeout;
    }
  xyz.len = (c == SOH) ? 128 : 1024;
  xyz.bufp = xyz.pkt;
  for (i = 0; i < xyz.len; i++)
    {
      res = CYGACC_COMM_IF_GETC_TIMEOUT (*xyz.__chan, &c);
      ZM_DEBUG (zm_save (c));
      if (res)
	{
	  xyz.pkt[i] = c;
	}
      else
	{
	  ZM_DEBUG (zm_dump (__LINE__));
	  return xyzModem_timeout;
	}
    }
  res = CYGACC_COMM_IF_GETC_TIMEOUT (*xyz.__chan, (char *) &xyz.crc1);
  ZM_DEBUG (zm_save (xyz.crc1));
  if (!res)
    {
      ZM_DEBUG (zm_dump (__LINE__));
      return xyzModem_timeout;
    }
  if (xyz.crc_mode)
    {
      res = CYGACC_COMM_IF_GETC_TIMEOUT (*xyz.__chan, (char *) &xyz.crc2);
      ZM_DEBUG (zm_save (xyz.crc2));
      if (!res)
	{
	  ZM_DEBUG (zm_dump (__LINE__));
	  return xyzModem_timeout;
	}
    }
  ZM_DEBUG (zm_dump (__LINE__));
  /* Validate the message */
  if ((xyz.blk ^ xyz.cblk) != (unsigned char) 0xFF)
    {
      ZM_DEBUG (zm_dprintf
		("Framing error - blk: %x/%x/%x\n", xyz.blk, xyz.cblk,
		 (xyz.blk ^ xyz.cblk)));
      ZM_DEBUG (zm_dump_buf (xyz.pkt, xyz.len));
      xyzModem_flush ();
      return xyzModem_frame;
    }
  /* Verify checksum/CRC */
  if (xyz.crc_mode)
    {
      cksum = cyg_crc16 (xyz.pkt, xyz.len);
      if (cksum != ((xyz.crc1 << 8) | xyz.crc2))
	{
	  ZM_DEBUG (zm_dprintf ("CRC error - recvd: %02x%02x, computed: %x\n",
				xyz.crc1, xyz.crc2, cksum & 0xFFFF));
	  return xyzModem_cksum;
	}
    }
  else
    {
      cksum = 0;
      for (i = 0; i < xyz.len; i++)
	{
	  cksum += xyz.pkt[i];
	}
      if (xyz.crc1 != (cksum & 0xFF))
	{
	  ZM_DEBUG (zm_dprintf
		    ("Checksum error - recvd: %x, computed: %x\n", xyz.crc1,
		     cksum & 0xFF));
	  return xyzModem_cksum;
	}
    }
  /* If we get here, the message passes [structural] muster */
  return 0;
}

int
xyzModem_stream_open (connection_info_t * info, int *err)
{
#ifdef REDBOOT
  int console_chan;
#endif
  int stat = 0;
  int retries = xyzModem_MAX_RETRIES;
  int crc_retries = xyzModem_MAX_RETRIES_WITH_CRC;

/*    ZM_DEBUG(zm_out = zm_out_start); */
#ifdef xyzModem_zmodem
  if (info->mode == xyzModem_zmodem)
    {
      *err = xyzModem_noZmodem;
      return -1;
    }
#endif

#ifdef REDBOOT
  /* Set up the I/O channel.  Note: this allows for using a different port in the future */
  console_chan =
    CYGACC_CALL_IF_SET_CONSOLE_COMM
    (CYGNUM_CALL_IF_SET_COMM_ID_QUERY_CURRENT);
  if (info->chan >= 0)
    {
      CYGACC_CALL_IF_SET_CONSOLE_COMM (info->chan);
    }
  else
    {
      CYGACC_CALL_IF_SET_CONSOLE_COMM (console_chan);
    }
  xyz.__chan = CYGACC_CALL_IF_CONSOLE_PROCS ();

  CYGACC_CALL_IF_SET_CONSOLE_COMM (console_chan);
  CYGACC_COMM_IF_CONTROL (*xyz.__chan, __COMMCTL_SET_TIMEOUT,
			  xyzModem_CHAR_TIMEOUT);
#else
/* TODO: CHECK ! */
  int dummy = 0;
  xyz.__chan = &dummy;
#endif
  xyz.len = 0;
  xyz.crc_mode = true;
  xyz.at_eof = false;
  xyz.tx_ack = false;
  xyz.mode = info->mode;
  xyz.total_retries = 0;
  xyz.total_SOH = 0;
  xyz.total_STX = 0;
  xyz.total_CAN = 0;
#ifdef USE_YMODEM_LENGTH
  xyz.read_length = 0;
  xyz.file_length = 0;
#endif

  CYGACC_COMM_IF_PUTC (*xyz.__chan, (xyz.crc_mode ? 'C' : NAK));

  if (xyz.mode == xyzModem_xmodem)
    {
      /* X-modem doesn't have an information header - exit here */
      xyz.next_blk = 1;
      return 0;
    }

  while (retries-- > 0)
    {
      stat = xyzModem_get_hdr ();
      if (stat == 0)
	{
	  /* Y-modem file information header */
	  if (xyz.blk == 0)
	    {
#ifdef USE_YMODEM_LENGTH
	      /* skip filename */
	      while (*xyz.bufp++);
	      /* get the length */
	      parse_num ((char *) xyz.bufp, &xyz.file_length, NULL, " ");
#endif
	      /* The rest of the file name data block quietly discarded */
	      xyz.tx_ack = true;
	    }
	  xyz.next_blk = 1;
	  xyz.len = 0;
	  return 0;
	}
      else if (stat == xyzModem_timeout)
	{
	  if (--crc_retries <= 0)
	    xyz.crc_mode = false;
	  CYGACC_CALL_IF_DELAY_US (5 * 100000);	/* Extra delay for startup */
	  CYGACC_COMM_IF_PUTC (*xyz.__chan, (xyz.crc_mode ? 'C' : NAK));
	  xyz.total_retries++;
	  ZM_DEBUG (zm_dprintf ("NAK (%d)\n", __LINE__));
	}
      if (stat == xyzModem_cancel)
	{
	  break;
	}
    }
  *err = stat;
  ZM_DEBUG (zm_flush ());
  return -1;
}

int
xyzModem_stream_read (char *buf, int size, int *err)
{
  int stat, total, len;
  int retries;

  total = 0;
  stat = xyzModem_cancel;
  /* Try and get 'size' bytes into the buffer */
  while (!xyz.at_eof && (size > 0))
    {
      if (xyz.len == 0)
	{
	  retries = xyzModem_MAX_RETRIES;
	  while (retries-- > 0)
	    {
	      stat = xyzModem_get_hdr ();
	      if (stat == 0)
		{
		  if (xyz.blk == xyz.next_blk)
		    {
		      xyz.tx_ack = true;
		      ZM_DEBUG (zm_dprintf
				("ACK block %d (%d)\n", xyz.blk, __LINE__));
		      xyz.next_blk = (xyz.next_blk + 1) & 0xFF;

#if defined(xyzModem_zmodem) || defined(USE_YMODEM_LENGTH)
		      if (xyz.mode == xyzModem_xmodem || xyz.file_length == 0)
			{
#else
		      if (1)
			{
#endif
			  /* Data blocks can be padded with ^Z (EOF) characters */
			  /* This code tries to detect and remove them */
			  if ((xyz.bufp[xyz.len - 1] == EOF) &&
			      (xyz.bufp[xyz.len - 2] == EOF) &&
			      (xyz.bufp[xyz.len - 3] == EOF))
			    {
			      while (xyz.len
				     && (xyz.bufp[xyz.len - 1] == EOF))
				{
				  xyz.len--;
				}
			    }
			}

#ifdef USE_YMODEM_LENGTH
		      /*
		       * See if accumulated length exceeds that of the file.
		       * If so, reduce size (i.e., cut out pad bytes)
		       * Only do this for Y-modem (and Z-modem should it ever
		       * be supported since it can fall back to Y-modem mode).
		       */
		      if (xyz.mode != xyzModem_xmodem && 0 != xyz.file_length)
			{
			  xyz.read_length += xyz.len;
			  if (xyz.read_length > xyz.file_length)
			    {
			      xyz.len -= (xyz.read_length - xyz.file_length);
			    }
			}
#endif
		      break;
		    }
		  else if (xyz.blk == ((xyz.next_blk - 1) & 0xFF))
		    {
		      /* Just re-ACK this so sender will get on with it */
		      CYGACC_COMM_IF_PUTC (*xyz.__chan, ACK);
		      continue;	/* Need new header */
		    }
		  else
		    {
		      stat = xyzModem_sequence;
		    }
		}
	      if (stat == xyzModem_cancel)
		{
		  break;
		}
	      if (stat == xyzModem_eof)
		{
		  CYGACC_COMM_IF_PUTC (*xyz.__chan, ACK);
		  ZM_DEBUG (zm_dprintf ("ACK (%d)\n", __LINE__));
		  if (xyz.mode == xyzModem_ymodem)
		    {
		      CYGACC_COMM_IF_PUTC (*xyz.__chan,
					   (xyz.crc_mode ? 'C' : NAK));
		      xyz.total_retries++;
		      ZM_DEBUG (zm_dprintf ("Reading Final Header\n"));
		      stat = xyzModem_get_hdr ();
		      CYGACC_COMM_IF_PUTC (*xyz.__chan, ACK);
		      ZM_DEBUG (zm_dprintf ("FINAL ACK (%d)\n", __LINE__));
		    }
		  xyz.at_eof = true;
		  break;
		}
	      CYGACC_COMM_IF_PUTC (*xyz.__chan, (xyz.crc_mode ? 'C' : NAK));
	      xyz.total_retries++;
	      ZM_DEBUG (zm_dprintf ("NAK (%d)\n", __LINE__));
	    }
	  if (stat < 0)
	    {
	      *err = stat;
	      xyz.len = -1;
	      return total;
	    }
	}
      /* Don't "read" data from the EOF protocol package */
      if (!xyz.at_eof)
	{
	  len = xyz.len;
	  if (size < len)
	    len = size;
	  memcpy (buf, xyz.bufp, len);
	  size -= len;
	  buf += len;
	  total += len;
	  xyz.len -= len;
	  xyz.bufp += len;
	}
    }
  return total;
}

void
xyzModem_stream_close (int *err)
{
  diag_printf
    ("xyzModem - %s mode, %d(SOH)/%d(STX)/%d(CAN) packets, %d retries\n",
     xyz.crc_mode ? "CRC" : "Cksum", xyz.total_SOH, xyz.total_STX,
     xyz.total_CAN, xyz.total_retries);
  ZM_DEBUG (zm_flush ());
}

/* Need to be able to clean out the input buffer, so have to take the */
/* getc */
void
xyzModem_stream_terminate (bool abort, int (*getc) (void))
{
  int c;

  if (abort)
    {
      ZM_DEBUG (zm_dprintf ("!!!! TRANSFER ABORT !!!!\n"));
      switch (xyz.mode)
	{
	case xyzModem_xmodem:
	case xyzModem_ymodem:
	  /* The X/YMODEM Spec seems to suggest that multiple CAN followed by an equal */
	  /* number of Backspaces is a friendly way to get the other end to abort. */
	  CYGACC_COMM_IF_PUTC (*xyz.__chan, CAN);
	  CYGACC_COMM_IF_PUTC (*xyz.__chan, CAN);
	  CYGACC_COMM_IF_PUTC (*xyz.__chan, CAN);
	  CYGACC_COMM_IF_PUTC (*xyz.__chan, CAN);
	  CYGACC_COMM_IF_PUTC (*xyz.__chan, BSP);
	  CYGACC_COMM_IF_PUTC (*xyz.__chan, BSP);
	  CYGACC_COMM_IF_PUTC (*xyz.__chan, BSP);
	  CYGACC_COMM_IF_PUTC (*xyz.__chan, BSP);
	  /* Now consume the rest of what's waiting on the line. */
	  ZM_DEBUG (zm_dprintf ("Flushing serial line.\n"));
	  xyzModem_flush ();
	  xyz.at_eof = true;
	  break;
#ifdef xyzModem_zmodem
	case xyzModem_zmodem:
	  /* Might support it some day I suppose. */
#endif
	  break;
	}
    }
  else
    {
      ZM_DEBUG (zm_dprintf ("Engaging cleanup mode...\n"));
      /*
       * Consume any trailing crap left in the inbuffer from
       * previous received blocks. Since very few files are an exact multiple
       * of the transfer block size, there will almost always be some gunk here.
       * If we don't eat it now, RedBoot will think the user typed it.
       */
      ZM_DEBUG (zm_dprintf ("Trailing gunk:\n"));
      while ((c = (*getc) ()) > -1)
        ;
      ZM_DEBUG (zm_dprintf ("\n"));
      /*
       * Make a small delay to give terminal programs like minicom
       * time to get control again after their file transfer program
       * exits.
       */
      CYGACC_CALL_IF_DELAY_US ((cyg_int32) 250000);
    }
}

char *
xyzModem_error (int err)
{
  switch (err)
    {
    case xyzModem_access:
      return "Can't access file";
      break;
    case xyzModem_noZmodem:
      return "Sorry, zModem not available yet";
      break;
    case xyzModem_timeout:
      return "Timed out";
      break;
    case xyzModem_eof:
      return "End of file";
      break;
    case xyzModem_cancel:
      return "Cancelled";
      break;
    case xyzModem_frame:
      return "Invalid framing";
      break;
    case xyzModem_cksum:
      return "CRC/checksum error";
      break;
    case xyzModem_sequence:
      return "Block sequence error";
      break;
    default:
      return "Unknown error";
      break;
    }
}

/*
 * RedBoot interface
 */
#if 0				/* SB */
GETC_IO_FUNCS (xyzModem_io, xyzModem_stream_open, xyzModem_stream_close,
	       xyzModem_stream_terminate, xyzModem_stream_read,
	       xyzModem_error);
RedBoot_load (xmodem, xyzModem_io, false, false, xyzModem_xmodem);
RedBoot_load (ymodem, xyzModem_io, false, false, xyzModem_ymodem);
#endif