Add support for ymodem protocol (loady command).

Patch by Stefano Babic, 29 Mar 2006

1 files changed, 739 insertions, 0 deletions

diff --git a/common/xyzModem.c b/common/xyzModem.c
new file mode 100644
index 0000000..3c86b13
--- /dev/null
+++ b/common/xyzModem.c
@@ -0,0 +1,739 @@
+//==========================================================================
+//
+//      xyzModem.c
+//
+//      RedBoot stream handler for xyzModem protocol
+//
+//==========================================================================
+//####ECOSGPLCOPYRIGHTBEGIN####
+// -------------------------------------------
+// This file is part of eCos, the Embedded Configurable Operating System.
+// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.
+// Copyright (C) 2002 Gary Thomas
+//
+// eCos 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 or (at your option) any later version.
+//
+// eCos 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 eCos; if not, write to the Free Software Foundation, Inc.,
+// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+//
+// As a special exception, if other files instantiate templates or use macros
+// or inline functions from this file, or you compile this file and link it
+// with other works to produce a work based on this file, this file does not
+// by itself cause the resulting work to be covered by the GNU General Public
+// License. However the source code for this file must still be made available
+// in accordance with section (3) of the GNU General Public License.
+//
+// This exception does not invalidate any other reasons why a work based on
+// this file might be covered by the GNU General Public License.
+//
+// Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.
+// at http://sources.redhat.com/ecos/ecos-license/
+// -------------------------------------------
+//####ECOSGPLCOPYRIGHTEND####
+//==========================================================================
+//#####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;
+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;
+}
+
+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
+//
+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)
+{
+    char *p = zm_out_start;
+#ifdef REDBOOT
+    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, &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, &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, &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, &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)
+{
+    int console_chan, 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;
+    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(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 recieved 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