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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 <[email protected]> | |
7 | * | |
8 | * This code is licensed under the GNU GPL v2. | |
6b620ca3 PB |
9 | * |
10 | * Contributions after 2012-01-13 are licensed under the terms of the | |
11 | * GNU GPL, version 2 or (at your option) any later version. | |
3e3d5815 AZ |
12 | */ |
13 | ||
87ecb68b PB |
14 | #include "hw.h" |
15 | #include "flash.h" | |
3e3d5815 AZ |
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. */ | |
bc24a225 | 56 | uint8_t ecc_digest(ECCState *s, uint8_t sample) |
3e3d5815 AZ |
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. */ | |
bc24a225 | 71 | void ecc_reset(ECCState *s) |
3e3d5815 AZ |
72 | { |
73 | s->lp[0] = 0x0000; | |
74 | s->lp[1] = 0x0000; | |
75 | s->cp = 0x00; | |
76 | s->count = 0; | |
77 | } | |
aa941b94 AZ |
78 | |
79 | /* Save/restore */ | |
34f9f0b5 DES |
80 | VMStateDescription vmstate_ecc_state = { |
81 | .name = "ecc-state", | |
82 | .version_id = 0, | |
83 | .minimum_version_id = 0, | |
84 | .minimum_version_id_old = 0, | |
85 | .fields = (VMStateField []) { | |
86 | VMSTATE_UINT8(cp, ECCState), | |
87 | VMSTATE_UINT16_ARRAY(lp, ECCState, 2), | |
88 | VMSTATE_UINT16(count, ECCState), | |
89 | VMSTATE_END_OF_LIST(), | |
90 | }, | |
91 | }; |