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qemu / qemu / 8ef9ea85a2cc1007eaefa53e6871f1f83bcef22d / . / hw / ecc.c
blob: a75408b9ae84b6b74754352a5a781f51c27644ff [file] [log] [blame]
balrog3e3d5812007-04-30 02:09:25 +0000[diff] [blame]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
pbrook87ecb682007-11-17 17:14:51 +0000[diff] [blame]11#include "hw.h"
12#include "flash.h"
balrog3e3d5812007-04-30 02:09:25 +0000[diff] [blame]13
14/*
15 * Pre-calculated 256-way 1 byte column parity. Table borrowed from Linux.
16 */
17static 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. */
Paul Brookbc24a222009-05-10 01:44:56 +0100[diff] [blame]53uint8_t ecc_digest(ECCState *s, uint8_t sample)
balrog3e3d5812007-04-30 02:09:25 +0000[diff] [blame]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. */
Paul Brookbc24a222009-05-10 01:44:56 +0100[diff] [blame]68void ecc_reset(ECCState *s)
balrog3e3d5812007-04-30 02:09:25 +0000[diff] [blame]69{
70 s->lp[0] = 0x0000;
71 s->lp[1] = 0x0000;
72 s->cp = 0x00;
73 s->count = 0;
74}
balrogaa941b92007-05-24 18:50:09 +0000[diff] [blame]75
76/* Save/restore */
Dmitry Eremin-Solenikov34f9f0b2011-01-21 13:12:11 +0300[diff] [blame]77VMStateDescription 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};