/* * Calculate Error-correcting Codes. Used by NAND Flash controllers * (not by NAND chips). * * Copyright (c) 2006 Openedhand Ltd. * Written by Andrzej Zaborowski <balrog@zabor.org> * * This code is licensed under the GNU GPL v2. */#include "hw.h"#include "flash.h"/* * Pre-calculated 256-way 1 byte column parity.  Table borrowed from Linux. */static const uint8_t nand_ecc_precalc_table[] = {    0x00, 0x55, 0x56, 0x03, 0x59, 0x0c, 0x0f, 0x5a,    0x5a, 0x0f, 0x0c, 0x59, 0x03, 0x56, 0x55, 0x00,    0x65, 0x30, 0x33, 0x66, 0x3c, 0x69, 0x6a, 0x3f,    0x3f, 0x6a, 0x69, 0x3c, 0x66, 0x33, 0x30, 0x65,    0x66, 0x33, 0x30, 0x65, 0x3f, 0x6a, 0x69, 0x3c,    0x3c, 0x69, 0x6a, 0x3f, 0x65, 0x30, 0x33, 0x66,    0x03, 0x56, 0x55, 0x00, 0x5a, 0x0f, 0x0c, 0x59,    0x59, 0x0c, 0x0f, 0x5a, 0x00, 0x55, 0x56, 0x03,    0x69, 0x3c, 0x3f, 0x6a, 0x30, 0x65, 0x66, 0x33,    0x33, 0x66, 0x65, 0x30, 0x6a, 0x3f, 0x3c, 0x69,    0x0c, 0x59, 0x5a, 0x0f, 0x55, 0x00, 0x03, 0x56,    0x56, 0x03, 0x00, 0x55, 0x0f, 0x5a, 0x59, 0x0c,    0x0f, 0x5a, 0x59, 0x0c, 0x56, 0x03, 0x00, 0x55,    0x55, 0x00, 0x03, 0x56, 0x0c, 0x59, 0x5a, 0x0f,    0x6a, 0x3f, 0x3c, 0x69, 0x33, 0x66, 0x65, 0x30,    0x30, 0x65, 0x66, 0x33, 0x69, 0x3c, 0x3f, 0x6a,    0x6a, 0x3f, 0x3c, 0x69, 0x33, 0x66, 0x65, 0x30,    0x30, 0x65, 0x66, 0x33, 0x69, 0x3c, 0x3f, 0x6a,    0x0f, 0x5a, 0x59, 0x0c, 0x56, 0x03, 0x00, 0x55,    0x55, 0x00, 0x03, 0x56, 0x0c, 0x59, 0x5a, 0x0f,    0x0c, 0x59, 0x5a, 0x0f, 0x55, 0x00, 0x03, 0x56,    0x56, 0x03, 0x00, 0x55, 0x0f, 0x5a, 0x59, 0x0c,    0x69, 0x3c, 0x3f, 0x6a, 0x30, 0x65, 0x66, 0x33,    0x33, 0x66, 0x65, 0x30, 0x6a, 0x3f, 0x3c, 0x69,    0x03, 0x56, 0x55, 0x00, 0x5a, 0x0f, 0x0c, 0x59,    0x59, 0x0c, 0x0f, 0x5a, 0x00, 0x55, 0x56, 0x03,    0x66, 0x33, 0x30, 0x65, 0x3f, 0x6a, 0x69, 0x3c,    0x3c, 0x69, 0x6a, 0x3f, 0x65, 0x30, 0x33, 0x66,    0x65, 0x30, 0x33, 0x66, 0x3c, 0x69, 0x6a, 0x3f,    0x3f, 0x6a, 0x69, 0x3c, 0x66, 0x33, 0x30, 0x65,    0x00, 0x55, 0x56, 0x03, 0x59, 0x0c, 0x0f, 0x5a,    0x5a, 0x0f, 0x0c, 0x59, 0x03, 0x56, 0x55, 0x00,};/* Update ECC parity count.  */uint8_t ecc_digest(struct ecc_state_s *s, uint8_t sample){    uint8_t idx = nand_ecc_precalc_table[sample];    s->cp ^= idx & 0x3f;    if (idx & 0x40) {        s->lp[0] ^= ~s->count;        s->lp[1] ^= s->count;    }    s->count ++;    return sample;}/* Reinitialise the counters.  */void ecc_reset(struct ecc_state_s *s){    s->lp[0] = 0x0000;    s->lp[1] = 0x0000;    s->cp = 0x00;    s->count = 0;}/* Save/restore */void ecc_put(QEMUFile *f, struct ecc_state_s *s){    qemu_put_8s(f, &s->cp);    qemu_put_be16s(f, &s->lp[0]);    qemu_put_be16s(f, &s->lp[1]);    qemu_put_be16s(f, &s->count);}void ecc_get(QEMUFile *f, struct ecc_state_s *s){    qemu_get_8s(f, &s->cp);    qemu_get_be16s(f, &s->lp[0]);    qemu_get_be16s(f, &s->lp[1]);    qemu_get_be16s(f, &s->count);}