| yuezonghe | 824eb0c | 2024-06-27 02:32:26 -0700 | [diff] [blame] | 1 | #include <linux/mtd/zftl_ecc.h> |
| 2 | #include <linux/bitops.h> |
| 3 | |
| 4 | |
| 5 | |
| 6 | static const unsigned char column_parity_table[] = { |
| 7 | 0x00, 0x55, 0x59, 0x0c, 0x65, 0x30, 0x3c, 0x69, |
| 8 | 0x69, 0x3c, 0x30, 0x65, 0x0c, 0x59, 0x55, 0x00, |
| 9 | 0x95, 0xc0, 0xcc, 0x99, 0xf0, 0xa5, 0xa9, 0xfc, |
| 10 | 0xfc, 0xa9, 0xa5, 0xf0, 0x99, 0xcc, 0xc0, 0x95, |
| 11 | 0x99, 0xcc, 0xc0, 0x95, 0xfc, 0xa9, 0xa5, 0xf0, |
| 12 | 0xf0, 0xa5, 0xa9, 0xfc, 0x95, 0xc0, 0xcc, 0x99, |
| 13 | 0x0c, 0x59, 0x55, 0x00, 0x69, 0x3c, 0x30, 0x65, |
| 14 | 0x65, 0x30, 0x3c, 0x69, 0x00, 0x55, 0x59, 0x0c, |
| 15 | 0xa5, 0xf0, 0xfc, 0xa9, 0xc0, 0x95, 0x99, 0xcc, |
| 16 | 0xcc, 0x99, 0x95, 0xc0, 0xa9, 0xfc, 0xf0, 0xa5, |
| 17 | 0x30, 0x65, 0x69, 0x3c, 0x55, 0x00, 0x0c, 0x59, |
| 18 | 0x59, 0x0c, 0x00, 0x55, 0x3c, 0x69, 0x65, 0x30, |
| 19 | 0x3c, 0x69, 0x65, 0x30, 0x59, 0x0c, 0x00, 0x55, |
| 20 | 0x55, 0x00, 0x0c, 0x59, 0x30, 0x65, 0x69, 0x3c, |
| 21 | 0xa9, 0xfc, 0xf0, 0xa5, 0xcc, 0x99, 0x95, 0xc0, |
| 22 | 0xc0, 0x95, 0x99, 0xcc, 0xa5, 0xf0, 0xfc, 0xa9, |
| 23 | 0xa9, 0xfc, 0xf0, 0xa5, 0xcc, 0x99, 0x95, 0xc0, |
| 24 | 0xc0, 0x95, 0x99, 0xcc, 0xa5, 0xf0, 0xfc, 0xa9, |
| 25 | 0x3c, 0x69, 0x65, 0x30, 0x59, 0x0c, 0x00, 0x55, |
| 26 | 0x55, 0x00, 0x0c, 0x59, 0x30, 0x65, 0x69, 0x3c, |
| 27 | 0x30, 0x65, 0x69, 0x3c, 0x55, 0x00, 0x0c, 0x59, |
| 28 | 0x59, 0x0c, 0x00, 0x55, 0x3c, 0x69, 0x65, 0x30, |
| 29 | 0xa5, 0xf0, 0xfc, 0xa9, 0xc0, 0x95, 0x99, 0xcc, |
| 30 | 0xcc, 0x99, 0x95, 0xc0, 0xa9, 0xfc, 0xf0, 0xa5, |
| 31 | 0x0c, 0x59, 0x55, 0x00, 0x69, 0x3c, 0x30, 0x65, |
| 32 | 0x65, 0x30, 0x3c, 0x69, 0x00, 0x55, 0x59, 0x0c, |
| 33 | 0x99, 0xcc, 0xc0, 0x95, 0xfc, 0xa9, 0xa5, 0xf0, |
| 34 | 0xf0, 0xa5, 0xa9, 0xfc, 0x95, 0xc0, 0xcc, 0x99, |
| 35 | 0x95, 0xc0, 0xcc, 0x99, 0xf0, 0xa5, 0xa9, 0xfc, |
| 36 | 0xfc, 0xa9, 0xa5, 0xf0, 0x99, 0xcc, 0xc0, 0x95, |
| 37 | 0x00, 0x55, 0x59, 0x0c, 0x65, 0x30, 0x3c, 0x69, |
| 38 | 0x69, 0x3c, 0x30, 0x65, 0x0c, 0x59, 0x55, 0x00, |
| 39 | }; |
| 40 | |
| 41 | |
| 42 | void zftl_ecc_calc_other(const unsigned char *data, unsigned n_bytes, |
| 43 | struct zftl_ecc_other *ecc_other) |
| 44 | { |
| 45 | unsigned int i; |
| 46 | |
| 47 | unsigned char col_parity = 0; |
| 48 | unsigned line_parity = 0; |
| 49 | unsigned line_parity_prime = 0; |
| 50 | unsigned char b; |
| 51 | |
| 52 | for (i = 0; i < n_bytes; i++) { |
| 53 | b = column_parity_table[*data++]; |
| 54 | col_parity ^= b; |
| 55 | |
| 56 | if (b & 0x01) { |
| 57 | /* odd number of bits in the byte */ |
| 58 | line_parity ^= i; |
| 59 | line_parity_prime ^= ~i; |
| 60 | } |
| 61 | |
| 62 | } |
| 63 | |
| 64 | ecc_other->col_parity = (col_parity >> 2) & 0x3f; |
| 65 | ecc_other->line_parity = line_parity; |
| 66 | ecc_other->line_parity_prime = line_parity_prime; |
| 67 | } |
| 68 | |
| 69 | int zftl_ecc_correct_other(unsigned char *data, unsigned n_bytes, |
| 70 | struct zftl_ecc_other *read_ecc, |
| 71 | const struct zftl_ecc_other *test_ecc) |
| 72 | { |
| 73 | unsigned char delta_col; /* column parity delta */ |
| 74 | unsigned delta_line; /* line parity delta */ |
| 75 | unsigned delta_line_prime; /* line parity delta */ |
| 76 | unsigned bit; |
| 77 | |
| 78 | delta_col = read_ecc->col_parity ^ test_ecc->col_parity; |
| 79 | delta_line = read_ecc->line_parity ^ test_ecc->line_parity; |
| 80 | delta_line_prime = |
| 81 | read_ecc->line_parity_prime ^ test_ecc->line_parity_prime; |
| 82 | |
| 83 | if ((delta_col | delta_line | delta_line_prime) == 0) |
| 84 | return 0; /* no error */ |
| 85 | |
| 86 | if (delta_line == ~delta_line_prime && |
| 87 | (((delta_col ^ (delta_col >> 1)) & 0x15) == 0x15)) { |
| 88 | /* Single bit (recoverable) error in data */ |
| 89 | |
| 90 | bit = 0; |
| 91 | |
| 92 | if (delta_col & 0x20) |
| 93 | bit |= 0x04; |
| 94 | if (delta_col & 0x08) |
| 95 | bit |= 0x02; |
| 96 | if (delta_col & 0x02) |
| 97 | bit |= 0x01; |
| 98 | |
| 99 | if (delta_line >= n_bytes) |
| 100 | return -1; |
| 101 | |
| 102 | data[delta_line] ^= (1 << bit); |
| 103 | |
| 104 | return 1; /* corrected */ |
| 105 | } |
| 106 | |
| 107 | if ((hweight32(delta_line) + |
| 108 | hweight32(delta_line_prime) + |
| 109 | hweight8(delta_col)) == 1) { |
| 110 | /* Reccoverable error in ecc */ |
| 111 | |
| 112 | *read_ecc = *test_ecc; |
| 113 | return 1; /* corrected */ |
| 114 | } |
| 115 | |
| 116 | /* Unrecoverable error */ |
| 117 | |
| 118 | return -1; |
| 119 | } |