diff options
Diffstat (limited to 'drivers/nand/nand_ecc.c')
| -rw-r--r-- | drivers/nand/nand_ecc.c | 45 |
1 files changed, 22 insertions, 23 deletions
diff --git a/drivers/nand/nand_ecc.c b/drivers/nand/nand_ecc.c index dc9db4b..6e11c22 100644 --- a/drivers/nand/nand_ecc.c +++ b/drivers/nand/nand_ecc.c @@ -13,16 +13,16 @@ * under the terms of the GNU General Public License as published by the * Free Software Foundation; either version 2 or (at your option) any * later version. - * + * * This file is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * for more details. - * + * * You should have received a copy of the GNU General Public License along * with this file; if not, write to the Free Software Foundation, Inc., * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. - * + * * As a special exception, if other files instantiate templates or use * macros or inline functions from these files, or you compile these * files and link them with other works to produce a work based on these @@ -30,7 +30,7 @@ * covered by the GNU General Public License. However the source code for * these files must still be made available in accordance with section (3) * of the GNU General Public License. - * + * * This exception does not invalidate any other reasons why a work based on * this file might be covered by the GNU General Public License. */ @@ -66,7 +66,7 @@ static const u_char nand_ecc_precalc_table[] = { * nand_trans_result - [GENERIC] create non-inverted ECC * @reg2: line parity reg 2 * @reg3: line parity reg 3 - * @ecc_code: ecc + * @ecc_code: ecc * * Creates non-inverted ECC code from line parity */ @@ -74,11 +74,11 @@ static void nand_trans_result(u_char reg2, u_char reg3, u_char *ecc_code) { u_char a, b, i, tmp1, tmp2; - + /* Initialize variables */ a = b = 0x80; tmp1 = tmp2 = 0; - + /* Calculate first ECC byte */ for (i = 0; i < 4; i++) { if (reg3 & a) /* LP15,13,11,9 --> ecc_code[0] */ @@ -89,7 +89,7 @@ static void nand_trans_result(u_char reg2, u_char reg3, b >>= 1; a >>= 1; } - + /* Calculate second ECC byte */ b = 0x80; for (i = 0; i < 4; i++) { @@ -101,7 +101,7 @@ static void nand_trans_result(u_char reg2, u_char reg3, b >>= 1; a >>= 1; } - + /* Store two of the ECC bytes */ ecc_code[0] = tmp1; ecc_code[1] = tmp2; @@ -117,28 +117,28 @@ int nand_calculate_ecc(struct mtd_info *mtd, const u_char *dat, u_char *ecc_code { u_char 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 */ + + /* 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 ^= (u_char) j; reg2 ^= ~((u_char) 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]; @@ -158,12 +158,12 @@ int nand_calculate_ecc(struct mtd_info *mtd, const u_char *dat, u_char *ecc_code int nand_correct_data(struct mtd_info *mtd, u_char *dat, u_char *read_ecc, u_char *calc_ecc) { u_char a, b, c, d1, d2, d3, add, bit, i; - - /* Do error detection */ + + /* Do error detection */ d1 = calc_ecc[0] ^ read_ecc[0]; d2 = calc_ecc[1] ^ read_ecc[1]; d3 = calc_ecc[2] ^ read_ecc[2]; - + if ((d1 | d2 | d3) == 0) { /* No errors */ return 0; @@ -172,7 +172,7 @@ int nand_correct_data(struct mtd_info *mtd, u_char *dat, u_char *read_ecc, u_cha a = (d1 ^ (d1 >> 1)) & 0x55; b = (d2 ^ (d2 >> 1)) & 0x55; c = (d3 ^ (d3 >> 1)) & 0x54; - + /* Found and will correct single bit error in the data */ if ((a == 0x55) && (b == 0x55) && (c == 0x54)) { c = 0x80; @@ -205,8 +205,7 @@ int nand_correct_data(struct mtd_info *mtd, u_char *dat, u_char *read_ecc, u_cha a ^= (b << bit); dat[add] = a; return 1; - } - else { + } else { i = 0; while (d1) { if (d1 & 0x01) @@ -236,7 +235,7 @@ int nand_correct_data(struct mtd_info *mtd, u_char *dat, u_char *read_ecc, u_cha } } } - + /* Should never happen */ return -1; } |