174 lines
6.8 KiB
C
174 lines
6.8 KiB
C
/* packet.c - an elf and spin binary loader for the Parallax Propeller microcontroller
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Copyright (c) 2011 David Michael Betz
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See license at the end of the file
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*/
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#include <stdio.h>
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#include <string.h>
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#include "packet.h"
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#include "osint.h"
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/* packet format: SOH pkt# type length-lo length-hi hdrchk length*data crc1 crc2 */
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#define HDR_SOH 0
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#define HDR_TYPE 1
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#define HDR_LEN_HI 2
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#define HDR_LEN_LO 3
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#define HDR_CHK 4
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/* packet header and crc lengths */
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#define PKTHDRLEN 5
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#define PKTCRCLEN 2
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/* maximum length of a frame */
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#define FRAMELEN (PKTHDRLEN + PKTMAXLEN + PKTCRCLEN)
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/* protocol characters */
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#define SOH 0x01 /* start of a packet */
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#define updcrc(crc, ch) (crctab[((crc) >> 8) & 0xff] ^ ((crc) << 8) ^ (ch))
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static const uint16_t crctab[256] = {
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0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7,
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0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef,
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0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6,
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0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de,
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0x2462, 0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485,
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0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d,
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0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4,
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0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc,
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0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823,
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0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b,
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0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12,
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0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a,
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0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41,
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0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49,
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0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70,
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0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78,
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0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f,
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0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067,
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0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e,
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0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256,
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0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d,
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0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
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0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c,
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0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634,
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0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab,
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0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3,
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0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a,
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0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92,
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0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9,
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0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1,
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0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8,
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0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0
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};
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int SendPacket(int type, uint8_t *buf, int len)
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{
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uint8_t hdr[PKTHDRLEN], crc[PKTCRCLEN], *p;
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uint16_t crc16 = 0;
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int cnt;
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/* setup the frame header */
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hdr[HDR_SOH] = SOH; /* SOH */
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hdr[HDR_TYPE] = type; /* type type */
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hdr[HDR_LEN_HI] = (uint8_t)(len >> 8); /* data length - high byte */
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hdr[HDR_LEN_LO] = (uint8_t)len; /* data length - low byte */
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hdr[HDR_CHK] = hdr[1] + hdr[2] + hdr[3]; /* header checksum */
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printf("tx length %d\n", len);
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printf("%02x %02x %02x\n", hdr[1], hdr[2], hdr[3]);
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/* compute the crc */
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for (p = buf, cnt = len; --cnt >= 0; ++p)
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crc16 = updcrc(crc16, *p);
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crc16 = updcrc(crc16, '\0');
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crc16 = updcrc(crc16, '\0');
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/* add the crc to the frame */
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crc[0] = (uint8_t)(crc16 >> 8);
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crc[1] = (uint8_t)crc16;
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/* send the packet */
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tx(hdr, PKTHDRLEN);
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if (len > 0)
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tx(buf, len);
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tx(crc, PKTCRCLEN);
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return 0;
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}
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int ReceivePacket(int *pType, uint8_t *buf, int len)
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{
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uint8_t hdr[PKTHDRLEN], crc[PKTCRCLEN];
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int actual_len, chk;
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uint16_t crc16 = 0;
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int retries = 10;
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printf("Looking for SOH\n");
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/* look for start of packet */
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do {
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rx_timeout(&hdr[HDR_SOH], 1, 100);
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} while (hdr[HDR_SOH] != SOH && --retries >= 0);
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printf(" retries %d\n", retries);
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/* check for a timeout waiting for the packet */
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if (retries < 0)
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return -1;
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/* receive the rest of the header */
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rx(&hdr[HDR_TYPE], PKTHDRLEN - 1);
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printf("%02x %02x %02x %02x %02x\n", hdr[0], hdr[1], hdr[2], hdr[3], hdr[4]);
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/* check the header checksum */
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chk = (hdr[1] + hdr[2] + hdr[3]) & 0xff;
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if (hdr[HDR_CHK] != chk)
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return -1;
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printf("checksum okay\n");
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/* make sure the buffer is big enough for the payload */
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actual_len = (hdr[HDR_LEN_HI] << 8) | hdr[HDR_LEN_LO];
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printf("rx length %d\n", actual_len);
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if (actual_len > len)
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return -1;
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printf("length okay\n");
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/* receive the packet payload */
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rx(buf, actual_len);
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/* compute the crc */
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for (len = actual_len; --len >= 0; )
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crc16 = updcrc(crc16, *buf++);
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/* receive the crc */
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rx(crc, PKTCRCLEN);
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/* check the crc */
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crc16 = updcrc(crc16, crc[0]);
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crc16 = updcrc(crc16, crc[1]);
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if (crc16 != 0)
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return -1;
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printf("crc okay\n");
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/* return packet type and the length of the payload */
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*pType = hdr[HDR_TYPE];
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return actual_len;
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}
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/*
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Permission is hereby granted, free of charge, to any person obtaining a copy of this software
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and associated documentation files (the "Software"), to deal in the Software without restriction,
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including without limitation the rights to use, copy, modify, merge, publish, distribute,
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sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in all copies or
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substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
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BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
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DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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