common/s_record.c

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