/*
* Calls SD_read until SD_read doesn't fail
* because of the random errors.
*/
int
safe_read(int sector, void* buf)
{
int success = SD_read(sector, buf);
if (success == -1 && sderrno == E_READING_FILE)
success = safe_read(sector, buf);
return success;
}
char SD_read(unsigned char bytes) {
SD_read(sd_sector, sd_pos, fat16_buffer, bytes);
sd_pos+=(unsigned short)bytes;
if(sd_pos == 512) {
sd_pos = 0;
sd_sector++;
}
return bytes;
}
// find the start address in sdcard for this new logging session
// and set the common log index for eeprom and sdcard
static void LOG_find_sdcard_start(u8 eeprom_index)
{
u8 buf[2];
// scan the whole eeprom
while (1) {
// read the 2 first octets of the log at LOG.addr
SD_read(LOG.sdcard_addr, buf, sizeof(buf));
while ( !SD_is_fini() )
;
// if the read octets are erased eeprom
if ( (buf[0] == 0xff) && (buf[1] == 0xff) ) {
// the new log session start address is found (here)
//
// the previous index is known from the previous read (see below)
// so increment it
LOG.index++;
// index found during eeprom scanning is higher
if ( eeprom_index > LOG.index ) {
// use the eeprom index
LOG.index = eeprom_index;
}
// finally the scan is over
return;
}
// extract index
LOG.index = buf[0];
// check the next log block
LOG.sdcard_addr += sizeof(log_t);
// if address is out of range
if ( LOG.sdcard_addr >= SDCARD_END_ADDR ) {
// sdcard is full
// so give up
// the log thread protection will prevent overwriting
LOG.index = 0xff;
}
}
}
