common/s_record.c

   1 /*
   2  * (C) Copyright 2000
   3  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
   4  *
   5  * SPDX-License-Identifier:     GPL-2.0+
   6  */
   7
   8 #include <common.h>
   9 #include <s_record.h>
  10
  11 static int hex1_bin (char  c);
  12 static int hex2_bin (char *s);
  13
  14 int srec_decode (char *input, int *count, ulong *addr, char *data)
  15 {
  16         int     i;
  17         int     v;                              /* conversion buffer    */
  18         int     srec_type;                      /* S-Record type        */
  19         unsigned char chksum;                   /* buffer for checksum  */
  20
  21         chksum = 0;
  22
  23         /* skip anything before 'S', and the 'S' itself.
  24          * Return error if not found
  25          */
  26
  27         for (; *input; ++input) {
  28                 if (*input == 'S') {            /* skip 'S' */
  29                         ++input;
  30                         break;
  31                 }
  32         }
  33         if (*input == '\0') {                   /* no more data?        */
  34                 return (SREC_EMPTY);
  35         }
  36
  37         v = *input++;                           /* record type          */
  38
  39         if ((*count = hex2_bin(input)) < 0) {
  40                 return (SREC_E_NOSREC);
  41         }
  42
  43         chksum += *count;
  44         input  += 2;
  45
  46         switch (v) {                            /* record type          */
  47
  48         case '0':                               /* start record         */
  49                 srec_type = SREC_START;         /* 2 byte addr field    */
  50                 *count   -= 3;                  /* - checksum and addr  */
  51                 break;
  52         case '1':
  53                 srec_type = SREC_DATA2;         /* 2 byte addr field    */
  54                 *count   -= 3;                  /* - checksum and addr  */
  55                 break;
  56         case '2':
  57                 srec_type = SREC_DATA3;         /* 3 byte addr field    */
  58                 *count   -= 4;                  /* - checksum and addr  */
  59                 break;
  60         case '3':                               /* data record with a   */
  61                 srec_type = SREC_DATA4;         /* 4 byte addr field    */
  62                 *count   -= 5;                  /* - checksum and addr  */
  63                 break;
  64 /***    case '4'  ***/
  65         case '5':                       /* count record, addr field contains */
  66                 srec_type = SREC_COUNT; /* a 2 byte record counter      */
  67                 *count    = 0;                  /* no data              */
  68                 break;
  69 /***    case '6' -- not used  ***/
  70         case '7':                               /* end record with a    */
  71                 srec_type = SREC_END4;          /* 4 byte addr field    */
  72                 *count   -= 5;                  /* - checksum and addr  */
  73                 break;
  74         case '8':                               /* end record with a    */
  75                 srec_type = SREC_END3;          /* 3 byte addr field    */
  76                 *count   -= 4;                  /* - checksum and addr  */
  77                 break;
  78         case '9':                               /* end record with a    */
  79                 srec_type = SREC_END2;          /* 2 byte addr field    */
  80                 *count   -= 3;                  /* - checksum and addr  */
  81                 break;
  82         default:
  83                 return (SREC_E_BADTYPE);
  84         }
  85
  86         /* read address field */
  87         *addr = 0;
  88
  89         switch (v) {
  90         case '3':                               /* 4 byte addr field    */
  91         case '7':
  92                 if ((v = hex2_bin(input)) < 0) {
  93                         return (SREC_E_NOSREC);
  94                 }
  95                 *addr  += v;
  96                 chksum += v;
  97                 input  += 2;
  98                 /* FALL THRU */
  99         case '2':                               /* 3 byte addr field    */
 100         case '8':
 101                 if ((v = hex2_bin(input)) < 0) {
 102                         return (SREC_E_NOSREC);
 103                 }
 104                 *addr <<= 8;
 105                 *addr  += v;
 106                 chksum += v;
 107                 input  += 2;
 108                 /* FALL THRU */
 109         case '0':                               /* 2 byte addr field    */
 110         case '1':
 111         case '5':
 112         case '9':
 113                 if ((v = hex2_bin(input)) < 0) {
 114                         return (SREC_E_NOSREC);
 115                 }
 116                 *addr <<= 8;
 117                 *addr  += v;
 118                 chksum += v;
 119                 input  += 2;
 120
 121                 if ((v = hex2_bin(input)) < 0) {
 122                         return (SREC_E_NOSREC);
 123                 }
 124                 *addr <<= 8;
 125                 *addr  += v;
 126                 chksum += v;
 127                 input  += 2;
 128
 129                 break;
 130         default:
 131                 return (SREC_E_BADTYPE);
 132         }
 133
 134         /* convert data and calculate checksum */
 135         for (i=0; i < *count; ++i) {
 136                 if ((v = hex2_bin(input)) < 0) {
 137                         return (SREC_E_NOSREC);
 138                 }
 139                 data[i] = v;
 140                 chksum += v;
 141                 input  += 2;
 142         }
 143
 144         /* read anc check checksum */
 145         if ((v = hex2_bin(input)) < 0) {
 146                 return (SREC_E_NOSREC);
 147         }
 148
 149         if ((unsigned char)v != (unsigned char)~chksum) {
 150                 return (SREC_E_BADCHKS);
 151         }
 152
 153         return (srec_type);
 154 }
 155
 156 static int hex1_bin (char c)
 157 {
 158         if (c >= '0' && c <= '9')
 159                 return (c - '0');
 160         if (c >= 'a' && c <= 'f')
 161                 return (c + 10 - 'a');
 162         if (c >= 'A' && c <= 'F')
 163                 return (c + 10 - 'A');
 164         return (-1);
 165 }
 166
 167 static int hex2_bin (char *s)
 168 {
 169         int i, j;
 170
 171         if ((i = hex1_bin(*s++)) < 0) {
 172                 return (-1);
 173         }
 174         if ((j = hex1_bin(*s)) < 0) {
 175                 return (-1);
 176         }
 177
 178         return ((i<<4) + j);
 179 }