/**
* nand_calculate_ecc - [NAND Interface] Calculate 3 byte ECC code for
* 256 byte block
*
* @dat: raw data
* @ecc_code: buffer for ECC
*/
int nand_calculate_ecc(const uint8_t *dat, uint8_t *ecc_code)
{
uint8_t idx, reg1, reg2, reg3;
int j;
/* Initialize variables */
reg1 = reg2 = reg3 = 0;
ecc_code[0] = ecc_code[1] = ecc_code[2] = 0;
/* Build up column parity */
for(j = 0; j < 256; j++) {
/* Get CP0 - CP5 from table */
idx = nand_ecc_precalc_table[dat[j]];
reg1 ^= (idx & 0x3f);
/* All bit XOR = 1 ? */
if (idx & 0x40) {
reg3 ^= (uint8_t) j;
reg2 ^= ~((uint8_t) j);
}
}
/* Create non-inverted ECC code from line parity */
nand_trans_result(reg2, reg3, ecc_code);
/* Calculate final ECC code */
ecc_code[0] = ~ecc_code[0];
ecc_code[1] = ~ecc_code[1];
ecc_code[2] = ((~reg1) << 2) | 0x03;
return 0;
}
/**
* nand_calculate_ecc - Calc 3 byte ECC code for 512 byte block
* @dat: raw data
* @ecc_code: buffer for ECC
*/
int nand_calculate_ecc(const U8 *dat, U8 *ecc_code)
{
U16 idx, reg1, reg2, reg3;
int j;
/* Initialize variables */
reg1 = reg2 = reg3 = 0;
ecc_code[0] = ecc_code[1] = ecc_code[2] = 0;
/* Build up column parity */
for(j = 0; j < 512; j++) {
/* Get CP0 - CP5 from table */
idx = (U16) nand_ecc_precalc_table[dat[j]];
reg1 ^= (idx & 0x3f);
/* All bit XOR = 1 ? */
if (idx & 0x40) {
reg3 ^= (U16) j;
reg2 ^= ~((U16) j);
reg3 &= 0x1FF ;
reg2 &= 0x1FF ;
}
}
/* Populate the ECC Codes from the parity bits in reg1-3 */
nand_trans_result(reg1, reg2, reg3, ecc_code);
return 0;
}