projects / mirror_qemu.git / blame
| Commit | Line | Data |
|---|---|---|
| 3e3d5815 AZ |
1 | /* |
| 2 | * Calculate Error-correcting Codes. Used by NAND Flash controllers | |
| 3 | * (not by NAND chips). | |
| 4 | * | |
| 5 | * Copyright (c) 2006 Openedhand Ltd. | |
| 6 | * Written by Andrzej Zaborowski <balrog@zabor.org> | |
| 7 | * | |
| 8 | * This code is licensed under the GNU GPL v2. | |
| 9 | */ | |
| 10 | ||
| 11 | struct ecc_state_s { | |
| 12 | uint8_t cp; /* Column parity */ | |
| 13 | uint16_t lp[2]; /* Line parity */ | |
| 14 | uint16_t count; | |
| 15 | }; | |
| 16 | ||
| 17 | /* | |
| 18 | * Pre-calculated 256-way 1 byte column parity. Table borrowed from Linux. | |
| 19 | */ | |
| 20 | static const uint8_t nand_ecc_precalc_table[] = { | |
| 21 | 0x00, 0x55, 0x56, 0x03, 0x59, 0x0c, 0x0f, 0x5a, | |
| 22 | 0x5a, 0x0f, 0x0c, 0x59, 0x03, 0x56, 0x55, 0x00, | |
| 23 | 0x65, 0x30, 0x33, 0x66, 0x3c, 0x69, 0x6a, 0x3f, | |
| 24 | 0x3f, 0x6a, 0x69, 0x3c, 0x66, 0x33, 0x30, 0x65, | |
| 25 | 0x66, 0x33, 0x30, 0x65, 0x3f, 0x6a, 0x69, 0x3c, | |
| 26 | 0x3c, 0x69, 0x6a, 0x3f, 0x65, 0x30, 0x33, 0x66, | |
| 27 | 0x03, 0x56, 0x55, 0x00, 0x5a, 0x0f, 0x0c, 0x59, | |
| 28 | 0x59, 0x0c, 0x0f, 0x5a, 0x00, 0x55, 0x56, 0x03, | |
| 29 | 0x69, 0x3c, 0x3f, 0x6a, 0x30, 0x65, 0x66, 0x33, | |
| 30 | 0x33, 0x66, 0x65, 0x30, 0x6a, 0x3f, 0x3c, 0x69, | |
| 31 | 0x0c, 0x59, 0x5a, 0x0f, 0x55, 0x00, 0x03, 0x56, | |
| 32 | 0x56, 0x03, 0x00, 0x55, 0x0f, 0x5a, 0x59, 0x0c, | |
| 33 | 0x0f, 0x5a, 0x59, 0x0c, 0x56, 0x03, 0x00, 0x55, | |
| 34 | 0x55, 0x00, 0x03, 0x56, 0x0c, 0x59, 0x5a, 0x0f, | |
| 35 | 0x6a, 0x3f, 0x3c, 0x69, 0x33, 0x66, 0x65, 0x30, | |
| 36 | 0x30, 0x65, 0x66, 0x33, 0x69, 0x3c, 0x3f, 0x6a, | |
| 37 | 0x6a, 0x3f, 0x3c, 0x69, 0x33, 0x66, 0x65, 0x30, | |
| 38 | 0x30, 0x65, 0x66, 0x33, 0x69, 0x3c, 0x3f, 0x6a, | |
| 39 | 0x0f, 0x5a, 0x59, 0x0c, 0x56, 0x03, 0x00, 0x55, | |
| 40 | 0x55, 0x00, 0x03, 0x56, 0x0c, 0x59, 0x5a, 0x0f, | |
| 41 | 0x0c, 0x59, 0x5a, 0x0f, 0x55, 0x00, 0x03, 0x56, | |
| 42 | 0x56, 0x03, 0x00, 0x55, 0x0f, 0x5a, 0x59, 0x0c, | |
| 43 | 0x69, 0x3c, 0x3f, 0x6a, 0x30, 0x65, 0x66, 0x33, | |
| 44 | 0x33, 0x66, 0x65, 0x30, 0x6a, 0x3f, 0x3c, 0x69, | |
| 45 | 0x03, 0x56, 0x55, 0x00, 0x5a, 0x0f, 0x0c, 0x59, | |
| 46 | 0x59, 0x0c, 0x0f, 0x5a, 0x00, 0x55, 0x56, 0x03, | |
| 47 | 0x66, 0x33, 0x30, 0x65, 0x3f, 0x6a, 0x69, 0x3c, | |
| 48 | 0x3c, 0x69, 0x6a, 0x3f, 0x65, 0x30, 0x33, 0x66, | |
| 49 | 0x65, 0x30, 0x33, 0x66, 0x3c, 0x69, 0x6a, 0x3f, | |
| 50 | 0x3f, 0x6a, 0x69, 0x3c, 0x66, 0x33, 0x30, 0x65, | |
| 51 | 0x00, 0x55, 0x56, 0x03, 0x59, 0x0c, 0x0f, 0x5a, | |
| 52 | 0x5a, 0x0f, 0x0c, 0x59, 0x03, 0x56, 0x55, 0x00, | |
| 53 | }; | |
| 54 | ||
| 55 | /* Update ECC parity count. */ | |
| 56 | static inline uint8_t ecc_digest(struct ecc_state_s *s, uint8_t sample) | |
| 57 | { | |
| 58 | uint8_t idx = nand_ecc_precalc_table[sample]; | |
| 59 | ||
| 60 | s->cp ^= idx & 0x3f; | |
| 61 | if (idx & 0x40) { | |
| 62 | s->lp[0] ^= ~s->count; | |
| 63 | s->lp[1] ^= s->count; | |
| 64 | } | |
| 65 | s->count ++; | |
| 66 | ||
| 67 | return sample; | |
| 68 | } | |
| 69 | ||
| 70 | /* Reinitialise the counters. */ | |
| 71 | static inline void ecc_reset(struct ecc_state_s *s) | |
| 72 | { | |
| 73 | s->lp[0] = 0x0000; | |
| 74 | s->lp[1] = 0x0000; | |
| 75 | s->cp = 0x00; | |
| 76 | s->count = 0; | |
| 77 | } |