Root/lm32/logic/sakc/firmware/cain_loader/xmodem.c

1/*
2    Copyright 2001, 2002 Georges Menie (www.menie.org)
3    Copyright 2004 Darrell Harmon modified to work in a bootloader
4
5    This program is free software; you can redistribute it and/or modify
6    it under the terms of the GNU Lesser General Public License as published by
7    the Free Software Foundation; either version 2 of the License, or
8    (at your option) any later version.
9
10    This program is distributed in the hope that it will be useful,
11    but WITHOUT ANY WARRANTY; without even the implied warranty of
12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13    GNU Lesser General Public License for more details.
14
15    You should have received a copy of the GNU Lesser General Public License
16    along with this program; if not, write to the Free Software
17    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18*/
19
20#include "soc-hw.h"
21
22#define SOH 0x01
23#define EOT 0x04
24#define ACK 0x06
25#define NAK 0x15
26
27
28/* CRC16 implementation acording to CCITT standards */
29
30static const unsigned short crc16tab[256]= {
31    0x0000,0x1021,0x2042,0x3063,0x4084,0x50a5,0x60c6,0x70e7,
32    0x8108,0x9129,0xa14a,0xb16b,0xc18c,0xd1ad,0xe1ce,0xf1ef,
33    0x1231,0x0210,0x3273,0x2252,0x52b5,0x4294,0x72f7,0x62d6,
34    0x9339,0x8318,0xb37b,0xa35a,0xd3bd,0xc39c,0xf3ff,0xe3de,
35    0x2462,0x3443,0x0420,0x1401,0x64e6,0x74c7,0x44a4,0x5485,
36    0xa56a,0xb54b,0x8528,0x9509,0xe5ee,0xf5cf,0xc5ac,0xd58d,
37    0x3653,0x2672,0x1611,0x0630,0x76d7,0x66f6,0x5695,0x46b4,
38    0xb75b,0xa77a,0x9719,0x8738,0xf7df,0xe7fe,0xd79d,0xc7bc,
39    0x48c4,0x58e5,0x6886,0x78a7,0x0840,0x1861,0x2802,0x3823,
40    0xc9cc,0xd9ed,0xe98e,0xf9af,0x8948,0x9969,0xa90a,0xb92b,
41    0x5af5,0x4ad4,0x7ab7,0x6a96,0x1a71,0x0a50,0x3a33,0x2a12,
42    0xdbfd,0xcbdc,0xfbbf,0xeb9e,0x9b79,0x8b58,0xbb3b,0xab1a,
43    0x6ca6,0x7c87,0x4ce4,0x5cc5,0x2c22,0x3c03,0x0c60,0x1c41,
44    0xedae,0xfd8f,0xcdec,0xddcd,0xad2a,0xbd0b,0x8d68,0x9d49,
45    0x7e97,0x6eb6,0x5ed5,0x4ef4,0x3e13,0x2e32,0x1e51,0x0e70,
46    0xff9f,0xefbe,0xdfdd,0xcffc,0xbf1b,0xaf3a,0x9f59,0x8f78,
47    0x9188,0x81a9,0xb1ca,0xa1eb,0xd10c,0xc12d,0xf14e,0xe16f,
48    0x1080,0x00a1,0x30c2,0x20e3,0x5004,0x4025,0x7046,0x6067,
49    0x83b9,0x9398,0xa3fb,0xb3da,0xc33d,0xd31c,0xe37f,0xf35e,
50    0x02b1,0x1290,0x22f3,0x32d2,0x4235,0x5214,0x6277,0x7256,
51    0xb5ea,0xa5cb,0x95a8,0x8589,0xf56e,0xe54f,0xd52c,0xc50d,
52    0x34e2,0x24c3,0x14a0,0x0481,0x7466,0x6447,0x5424,0x4405,
53    0xa7db,0xb7fa,0x8799,0x97b8,0xe75f,0xf77e,0xc71d,0xd73c,
54    0x26d3,0x36f2,0x0691,0x16b0,0x6657,0x7676,0x4615,0x5634,
55    0xd94c,0xc96d,0xf90e,0xe92f,0x99c8,0x89e9,0xb98a,0xa9ab,
56    0x5844,0x4865,0x7806,0x6827,0x18c0,0x08e1,0x3882,0x28a3,
57    0xcb7d,0xdb5c,0xeb3f,0xfb1e,0x8bf9,0x9bd8,0xabbb,0xbb9a,
58    0x4a75,0x5a54,0x6a37,0x7a16,0x0af1,0x1ad0,0x2ab3,0x3a92,
59    0xfd2e,0xed0f,0xdd6c,0xcd4d,0xbdaa,0xad8b,0x9de8,0x8dc9,
60    0x7c26,0x6c07,0x5c64,0x4c45,0x3ca2,0x2c83,0x1ce0,0x0cc1,
61    0xef1f,0xff3e,0xcf5d,0xdf7c,0xaf9b,0xbfba,0x8fd9,0x9ff8,
62    0x6e17,0x7e36,0x4e55,0x5e74,0x2e93,0x3eb2,0x0ed1,0x1ef0
63};
64  
65unsigned short crc16_ccitt(const void *buf, int len)
66{
67    int counter;
68    unsigned short crc = 0;
69    for( counter = 0; counter < len; counter++)
70        crc = (crc<<8) ^ crc16tab[((crc>>8) ^ *(char *)buf++)&0x00FF];
71    return crc;
72}
73
74int rxmodem(unsigned char *dest)
75{
76    unsigned short crc, tcrc;
77    int i, len = 0;
78        unsigned char pid = 1;
79
80    uart_getchar();
81        for(i = 0; i < 0x4000000; i++) { asm("nop;"); }
82    uart_putchar('C');
83
84    while(1)
85    {
86        unsigned char c, pid1, pid2;
87
88        c = uart_getchar() & 0xFF;
89
90        if (c != SOH)
91        {
92            if (c == EOT)
93            {
94                uart_putchar(ACK);
95                return len;
96            }
97            else
98                return 0;
99        }
100
101        pid1 = uart_getchar() & 0xFF;
102        pid2 = uart_getchar() & 0xFF;
103
104        if ((pid1 & 0xFF) != (~pid2 & 0xFF))
105            return 0;
106
107        if (pid1 != pid)
108            return 0;
109
110        for (i = 0; i < 130; i++)
111            *dest++ = uart_getchar();
112
113        crc = crc16_ccitt (dest - 130, 128);
114        tcrc = (*(dest - 2)<<8) + *(dest - 1);
115        if (crc != tcrc)
116            return 0;
117        else
118        {
119            pid = (pid + 1) & 0xFF;
120            dest -= 2;
121            len += 128;
122            uart_putchar(ACK);
123        }
124    }
125}
126
127

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