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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 <balrog@zabor.org> | |
7 | * | |
8 | * This code is licensed under the GNU GPL v2. | |
9 | */ | |
10 | ||
87ecb68b PB |
11 | #include "hw.h" |
12 | #include "flash.h" | |
3e3d5815 AZ |
13 | |
14 | /* | |
15 | * Pre-calculated 256-way 1 byte column parity. Table borrowed from Linux. | |
16 | */ | |
17 | static const uint8_t nand_ecc_precalc_table[] = { | |
18 | 0x00, 0x55, 0x56, 0x03, 0x59, 0x0c, 0x0f, 0x5a, | |
19 | 0x5a, 0x0f, 0x0c, 0x59, 0x03, 0x56, 0x55, 0x00, | |
20 | 0x65, 0x30, 0x33, 0x66, 0x3c, 0x69, 0x6a, 0x3f, | |
21 | 0x3f, 0x6a, 0x69, 0x3c, 0x66, 0x33, 0x30, 0x65, | |
22 | 0x66, 0x33, 0x30, 0x65, 0x3f, 0x6a, 0x69, 0x3c, | |
23 | 0x3c, 0x69, 0x6a, 0x3f, 0x65, 0x30, 0x33, 0x66, | |
24 | 0x03, 0x56, 0x55, 0x00, 0x5a, 0x0f, 0x0c, 0x59, | |
25 | 0x59, 0x0c, 0x0f, 0x5a, 0x00, 0x55, 0x56, 0x03, | |
26 | 0x69, 0x3c, 0x3f, 0x6a, 0x30, 0x65, 0x66, 0x33, | |
27 | 0x33, 0x66, 0x65, 0x30, 0x6a, 0x3f, 0x3c, 0x69, | |
28 | 0x0c, 0x59, 0x5a, 0x0f, 0x55, 0x00, 0x03, 0x56, | |
29 | 0x56, 0x03, 0x00, 0x55, 0x0f, 0x5a, 0x59, 0x0c, | |
30 | 0x0f, 0x5a, 0x59, 0x0c, 0x56, 0x03, 0x00, 0x55, | |
31 | 0x55, 0x00, 0x03, 0x56, 0x0c, 0x59, 0x5a, 0x0f, | |
32 | 0x6a, 0x3f, 0x3c, 0x69, 0x33, 0x66, 0x65, 0x30, | |
33 | 0x30, 0x65, 0x66, 0x33, 0x69, 0x3c, 0x3f, 0x6a, | |
34 | 0x6a, 0x3f, 0x3c, 0x69, 0x33, 0x66, 0x65, 0x30, | |
35 | 0x30, 0x65, 0x66, 0x33, 0x69, 0x3c, 0x3f, 0x6a, | |
36 | 0x0f, 0x5a, 0x59, 0x0c, 0x56, 0x03, 0x00, 0x55, | |
37 | 0x55, 0x00, 0x03, 0x56, 0x0c, 0x59, 0x5a, 0x0f, | |
38 | 0x0c, 0x59, 0x5a, 0x0f, 0x55, 0x00, 0x03, 0x56, | |
39 | 0x56, 0x03, 0x00, 0x55, 0x0f, 0x5a, 0x59, 0x0c, | |
40 | 0x69, 0x3c, 0x3f, 0x6a, 0x30, 0x65, 0x66, 0x33, | |
41 | 0x33, 0x66, 0x65, 0x30, 0x6a, 0x3f, 0x3c, 0x69, | |
42 | 0x03, 0x56, 0x55, 0x00, 0x5a, 0x0f, 0x0c, 0x59, | |
43 | 0x59, 0x0c, 0x0f, 0x5a, 0x00, 0x55, 0x56, 0x03, | |
44 | 0x66, 0x33, 0x30, 0x65, 0x3f, 0x6a, 0x69, 0x3c, | |
45 | 0x3c, 0x69, 0x6a, 0x3f, 0x65, 0x30, 0x33, 0x66, | |
46 | 0x65, 0x30, 0x33, 0x66, 0x3c, 0x69, 0x6a, 0x3f, | |
47 | 0x3f, 0x6a, 0x69, 0x3c, 0x66, 0x33, 0x30, 0x65, | |
48 | 0x00, 0x55, 0x56, 0x03, 0x59, 0x0c, 0x0f, 0x5a, | |
49 | 0x5a, 0x0f, 0x0c, 0x59, 0x03, 0x56, 0x55, 0x00, | |
50 | }; | |
51 | ||
52 | /* Update ECC parity count. */ | |
bc24a225 | 53 | uint8_t ecc_digest(ECCState *s, uint8_t sample) |
3e3d5815 AZ |
54 | { |
55 | uint8_t idx = nand_ecc_precalc_table[sample]; | |
56 | ||
57 | s->cp ^= idx & 0x3f; | |
58 | if (idx & 0x40) { | |
59 | s->lp[0] ^= ~s->count; | |
60 | s->lp[1] ^= s->count; | |
61 | } | |
62 | s->count ++; | |
63 | ||
64 | return sample; | |
65 | } | |
66 | ||
67 | /* Reinitialise the counters. */ | |
bc24a225 | 68 | void ecc_reset(ECCState *s) |
3e3d5815 AZ |
69 | { |
70 | s->lp[0] = 0x0000; | |
71 | s->lp[1] = 0x0000; | |
72 | s->cp = 0x00; | |
73 | s->count = 0; | |
74 | } | |
aa941b94 AZ |
75 | |
76 | /* Save/restore */ | |
34f9f0b5 DES |
77 | VMStateDescription vmstate_ecc_state = { |
78 | .name = "ecc-state", | |
79 | .version_id = 0, | |
80 | .minimum_version_id = 0, | |
81 | .minimum_version_id_old = 0, | |
82 | .fields = (VMStateField []) { | |
83 | VMSTATE_UINT8(cp, ECCState), | |
84 | VMSTATE_UINT16_ARRAY(lp, ECCState, 2), | |
85 | VMSTATE_UINT16(count, ECCState), | |
86 | VMSTATE_END_OF_LIST(), | |
87 | }, | |
88 | }; |