e06ca69b2f
via xmodem to the DBGU port when the AT91 comes up in recovery mode. The recovery loader will then load your program via xmodem into SDRAM at 1MB which can do its things. It needs to be tweaked to the specific board one is using, but it fits in < 1kB (all of Atmel's ARM products have at least 8kb of SRAM that I can tell, so this should work for them all). Parts of this code were provided by Kwikbyte with copyright specifically disclaimed. I heavily modified it to act as a recovery loader (before it was a bootstrap loader) and to optimize for size (before I started the size was closer to 8k). Bootstrap loaders for SPI and IIC to follow.
128 lines
3.4 KiB
C
128 lines
3.4 KiB
C
/*-
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* Copyright (c) 2006 M. Warner Losh. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* This software is derived from software provide by Kwikbyte who specifically
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* disclaimed copyright on the code. This version of xmodem has been nearly
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* completely rewritten, but the CRC is from the original.
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*
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* $FreeBSD$
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*/
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#include "lib.h"
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#define PACKET_SIZE 128
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/* Line control codes */
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#define SOH 0x01 /* start of header */
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#define ACK 0x06 /* Acknowledge */
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#define NAK 0x15 /* Negative acknowledge */
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#define CAN 0x18 /* Cancel */
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#define EOT 0x04 /* end of text */
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/*
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* int GetRecord(char , char *)
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* This private function receives a x-modem record to the pointer and
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* returns non-zero on success.
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*/
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static int
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GetRecord(char blocknum, char *dest)
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{
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int size;
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int ch;
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unsigned chk, j;
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chk = 0;
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if ((ch = getc(1)) == -1)
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goto err;
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if (ch != blocknum)
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goto err;
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if ((ch = getc(1)) == -1)
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goto err;
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if (ch != (~blocknum & 0xff))
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goto err;
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for (size = 0; size < PACKET_SIZE; ++size) {
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if ((ch = getc(1)) == -1)
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goto err;
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chk = chk ^ ch << 8;
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for (j = 0; j < 8; ++j) {
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if (chk & 0x8000)
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chk = chk << 1 ^ 0x1021;
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else
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chk = chk << 1;
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}
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*dest++ = ch;
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}
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chk &= 0xFFFF;
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if (((ch = getc(1)) == -1) || ((ch & 0xff) != ((chk >> 8) & 0xFF)))
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goto err;
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if (((ch = getc(1)) == -1) || ((ch & 0xff) != (chk & 0xFF)))
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goto err;
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putc(ACK);
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return (1);
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err:;
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putc(CAN);
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// We should allow for resend, but we don't.
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return (0);
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}
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/*
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* int xmodem_rx(char *)
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* This global function receives a x-modem transmission consisting of
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* (potentially) several blocks. Returns the number of bytes received or
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* -1 on error.
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*/
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int
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xmodem_rx(char *dest)
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{
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int starting, ch;
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char packetNumber, *startAddress = dest;
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packetNumber = 1;
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starting = 1;
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while (1) {
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if (starting)
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putc('C');
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if (((ch = getc(1)) == -1) || (ch != SOH && ch != EOT))
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continue;
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if (ch == EOT) {
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putc(ACK);
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return (dest - startAddress);
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}
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starting = 0;
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// Xmodem packets: SOH PKT# ~PKT# 128-bytes CRC16
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if (!GetRecord(packetNumber, dest))
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return (-1);
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dest += PACKET_SIZE;
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packetNumber++;
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}
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// the loop above should return in all cases
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return (-1);
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}
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