/**
* \brief 16-bit checksum of data block test
*
* This test does a checksum of a data block with a known checksum,
* and verifies that they are equal. It then appends the 16-bit CRC
* to the end of the data, and does another checksum operation, which
* should result in the zero flag being set.
*
* \param test Current test case
*/
static void run_16bit_io_test(const struct test_case *test)
{
uint8_t tmp_buffer[LENGTH(data_8bit) + sizeof(uint16_t)];
int i;
uint16_t checksum;
crc_io_checksum_byte_start(CRC_16BIT);
for(i = 0;i < LENGTH(data_8bit); ++i)
crc_io_checksum_byte_add(data_8bit[i]);
checksum = crc_io_checksum_byte_stop();
test_assert_true(test, checksum == CRC_CHECKSUM_16BIT,
"Checksum mismatch on IO CRC-16 test");
memcpy(tmp_buffer, data_8bit, LENGTH(data_8bit));
crc16_append_value(checksum,
&tmp_buffer[LENGTH(tmp_buffer) - sizeof(uint16_t)]);
checksum = crc_io_checksum(tmp_buffer, LENGTH(tmp_buffer), CRC_16BIT);
test_assert_true(test, checksum == 0,
"Checksum fail check failed on IO CRC-16 test");
}
/**
* \brief Calculate the CRC checksum for data in a buffer
*
* This function initializes the CRC module, calculates the checksum for the
* selected number of bytes in a data buffer, disables the module and returns
* the calculated checksum.
*
* \param data Data buffer to perform CRC on
* \param len The number of bytes to perform CRC on
* \param crc_16_32 Indicator for whether CRC-32 or CRC-16 shall be used
*
* \return checksum checksum
*/
uint32_t crc_io_checksum(void *data, uint16_t len, enum crc_16_32_t crc_16_32)
{
/* Initialize CRC calculations on I/O interface */
crc_io_checksum_byte_start(crc_16_32);
/* Write data to DATAIN register */
while (len--) {
crc_io_checksum_byte_add(*(uint8_t*)data);
data = (uint8_t*)data + 1;
}
/* Return checksum */
return crc_io_checksum_byte_stop();
}
/**
* \brief Compute 16-bit CRC for Flash address range using hardware CRC module.
*
* This function returns the 16-bit CRC of the specified Flash address range.
*
* \param origDataptr Address of Flash location to start CRC computation at.
* \param numBytes Number of bytes of the data.
* \param pchecksum Pointer to the checksum stored in EEPROM.
*
* \note 16-bit flash CRC is much slower than 32-bit for flash checking.
* \note No sanity checking of addresses is done.
*/
uint16_t CLASSB_CRC16_Flash_HW(flashptr_t origDataptr, crcbytenum_t numBytes,
eeprom_uint16ptr_t pchecksum)
{
uint32_t checksum;
flash_uint8ptr_t dataptr = origDataptr;
uint8_t dataTemp;
crc_set_initial_value(CRC16_INITIAL_REMAINDER);
crc_io_checksum_byte_start(CRC_16BIT);
/* Compute CRC for the specified data. */
for (; numBytes != 0; numBytes--) {
#if (PROGMEM_SIZE >= 0x10000UL)
dataTemp = PROGMEM_READ_BYTE(dataptr++);
#else
dataTemp = PROGMEM_READ_BYTE(dataptr++);
#endif
crc_io_checksum_byte_add(dataTemp);
}
checksum = crc_io_checksum_byte_stop();
#if defined(__ICCAVR__)
/* Compare checksums and handle error if necessary. */
if (checksum != *pchecksum) {
CLASSB_ERROR_HANDLER_CRC();
}
#elif defined(__GCC__)
/* Ensure that EEPROM is memory mapped. */
CLASSB_EEMAP_BEGIN();
/* Compare checksums and handle error if necessary. */
if (checksum != (*(eeprom_uint16ptr_t)(MAPPED_EEPROM_START
+ (uintptr_t)pchecksum))) {
CLASSB_ERROR_HANDLER_CRC();
}
/* Disable memory mapping of EEPROM, if necessary. */
CLASSB_EEMAP_END();
#endif
/* Return 16 bits */
return checksum & (uint32_t)0x0000FFFF;
}
