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author | Felix Fietkau <nbd@openwrt.org> | 2010-06-26 20:42:58 +0000 |
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committer | Felix Fietkau <nbd@openwrt.org> | 2010-06-26 20:42:58 +0000 |
commit | a082943b09f4f707990ad0ac6326df8480507f02 (patch) | |
tree | de32e4def600e56134cd085a7447cb6620542078 /target/linux/generic-2.6/files/fs/yaffs2/yaffs_ecc.c | |
parent | 67fbcc7bd42cc07b1f3c6b5c9f2db37647178f25 (diff) | |
download | master-187ad058-a082943b09f4f707990ad0ac6326df8480507f02.tar.gz master-187ad058-a082943b09f4f707990ad0ac6326df8480507f02.tar.bz2 master-187ad058-a082943b09f4f707990ad0ac6326df8480507f02.zip |
rename target/linux/generic-2.6 to generic
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@21952 3c298f89-4303-0410-b956-a3cf2f4a3e73
Diffstat (limited to 'target/linux/generic-2.6/files/fs/yaffs2/yaffs_ecc.c')
-rw-r--r-- | target/linux/generic-2.6/files/fs/yaffs2/yaffs_ecc.c | 331 |
1 files changed, 0 insertions, 331 deletions
diff --git a/target/linux/generic-2.6/files/fs/yaffs2/yaffs_ecc.c b/target/linux/generic-2.6/files/fs/yaffs2/yaffs_ecc.c deleted file mode 100644 index e2860393d3..0000000000 --- a/target/linux/generic-2.6/files/fs/yaffs2/yaffs_ecc.c +++ /dev/null @@ -1,331 +0,0 @@ -/* - * YAFFS: Yet Another Flash File System. A NAND-flash specific file system. - * - * Copyright (C) 2002-2007 Aleph One Ltd. - * for Toby Churchill Ltd and Brightstar Engineering - * - * Created by Charles Manning <charles@aleph1.co.uk> - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License version 2 as - * published by the Free Software Foundation. - */ - -/* - * This code implements the ECC algorithm used in SmartMedia. - * - * The ECC comprises 22 bits of parity information and is stuffed into 3 bytes. - * The two unused bit are set to 1. - * The ECC can correct single bit errors in a 256-byte page of data. Thus, two such ECC - * blocks are used on a 512-byte NAND page. - * - */ - -/* Table generated by gen-ecc.c - * Using a table means we do not have to calculate p1..p4 and p1'..p4' - * for each byte of data. These are instead provided in a table in bits7..2. - * Bit 0 of each entry indicates whether the entry has an odd or even parity, and therefore - * this bytes influence on the line parity. - */ - -const char *yaffs_ecc_c_version = - "$Id: yaffs_ecc.c,v 1.9 2007-02-14 01:09:06 wookey Exp $"; - -#include "yportenv.h" - -#include "yaffs_ecc.h" - -static const unsigned char column_parity_table[] = { - 0x00, 0x55, 0x59, 0x0c, 0x65, 0x30, 0x3c, 0x69, - 0x69, 0x3c, 0x30, 0x65, 0x0c, 0x59, 0x55, 0x00, - 0x95, 0xc0, 0xcc, 0x99, 0xf0, 0xa5, 0xa9, 0xfc, - 0xfc, 0xa9, 0xa5, 0xf0, 0x99, 0xcc, 0xc0, 0x95, - 0x99, 0xcc, 0xc0, 0x95, 0xfc, 0xa9, 0xa5, 0xf0, - 0xf0, 0xa5, 0xa9, 0xfc, 0x95, 0xc0, 0xcc, 0x99, - 0x0c, 0x59, 0x55, 0x00, 0x69, 0x3c, 0x30, 0x65, - 0x65, 0x30, 0x3c, 0x69, 0x00, 0x55, 0x59, 0x0c, - 0xa5, 0xf0, 0xfc, 0xa9, 0xc0, 0x95, 0x99, 0xcc, - 0xcc, 0x99, 0x95, 0xc0, 0xa9, 0xfc, 0xf0, 0xa5, - 0x30, 0x65, 0x69, 0x3c, 0x55, 0x00, 0x0c, 0x59, - 0x59, 0x0c, 0x00, 0x55, 0x3c, 0x69, 0x65, 0x30, - 0x3c, 0x69, 0x65, 0x30, 0x59, 0x0c, 0x00, 0x55, - 0x55, 0x00, 0x0c, 0x59, 0x30, 0x65, 0x69, 0x3c, - 0xa9, 0xfc, 0xf0, 0xa5, 0xcc, 0x99, 0x95, 0xc0, - 0xc0, 0x95, 0x99, 0xcc, 0xa5, 0xf0, 0xfc, 0xa9, - 0xa9, 0xfc, 0xf0, 0xa5, 0xcc, 0x99, 0x95, 0xc0, - 0xc0, 0x95, 0x99, 0xcc, 0xa5, 0xf0, 0xfc, 0xa9, - 0x3c, 0x69, 0x65, 0x30, 0x59, 0x0c, 0x00, 0x55, - 0x55, 0x00, 0x0c, 0x59, 0x30, 0x65, 0x69, 0x3c, - 0x30, 0x65, 0x69, 0x3c, 0x55, 0x00, 0x0c, 0x59, - 0x59, 0x0c, 0x00, 0x55, 0x3c, 0x69, 0x65, 0x30, - 0xa5, 0xf0, 0xfc, 0xa9, 0xc0, 0x95, 0x99, 0xcc, - 0xcc, 0x99, 0x95, 0xc0, 0xa9, 0xfc, 0xf0, 0xa5, - 0x0c, 0x59, 0x55, 0x00, 0x69, 0x3c, 0x30, 0x65, - 0x65, 0x30, 0x3c, 0x69, 0x00, 0x55, 0x59, 0x0c, - 0x99, 0xcc, 0xc0, 0x95, 0xfc, 0xa9, 0xa5, 0xf0, - 0xf0, 0xa5, 0xa9, 0xfc, 0x95, 0xc0, 0xcc, 0x99, - 0x95, 0xc0, 0xcc, 0x99, 0xf0, 0xa5, 0xa9, 0xfc, - 0xfc, 0xa9, 0xa5, 0xf0, 0x99, 0xcc, 0xc0, 0x95, - 0x00, 0x55, 0x59, 0x0c, 0x65, 0x30, 0x3c, 0x69, - 0x69, 0x3c, 0x30, 0x65, 0x0c, 0x59, 0x55, 0x00, -}; - -/* Count the bits in an unsigned char or a U32 */ - -static int yaffs_CountBits(unsigned char x) -{ - int r = 0; - while (x) { - if (x & 1) - r++; - x >>= 1; - } - return r; -} - -static int yaffs_CountBits32(unsigned x) -{ - int r = 0; - while (x) { - if (x & 1) - r++; - x >>= 1; - } - return r; -} - -/* Calculate the ECC for a 256-byte block of data */ -void yaffs_ECCCalculate(const unsigned char *data, unsigned char *ecc) -{ - unsigned int i; - - unsigned char col_parity = 0; - unsigned char line_parity = 0; - unsigned char line_parity_prime = 0; - unsigned char t; - unsigned char b; - - for (i = 0; i < 256; i++) { - b = column_parity_table[*data++]; - col_parity ^= b; - - if (b & 0x01) // odd number of bits in the byte - { - line_parity ^= i; - line_parity_prime ^= ~i; - } - - } - - ecc[2] = (~col_parity) | 0x03; - - t = 0; - if (line_parity & 0x80) - t |= 0x80; - if (line_parity_prime & 0x80) - t |= 0x40; - if (line_parity & 0x40) - t |= 0x20; - if (line_parity_prime & 0x40) - t |= 0x10; - if (line_parity & 0x20) - t |= 0x08; - if (line_parity_prime & 0x20) - t |= 0x04; - if (line_parity & 0x10) - t |= 0x02; - if (line_parity_prime & 0x10) - t |= 0x01; - ecc[1] = ~t; - - t = 0; - if (line_parity & 0x08) - t |= 0x80; - if (line_parity_prime & 0x08) - t |= 0x40; - if (line_parity & 0x04) - t |= 0x20; - if (line_parity_prime & 0x04) - t |= 0x10; - if (line_parity & 0x02) - t |= 0x08; - if (line_parity_prime & 0x02) - t |= 0x04; - if (line_parity & 0x01) - t |= 0x02; - if (line_parity_prime & 0x01) - t |= 0x01; - ecc[0] = ~t; - -#ifdef CONFIG_YAFFS_ECC_WRONG_ORDER - // Swap the bytes into the wrong order - t = ecc[0]; - ecc[0] = ecc[1]; - ecc[1] = t; -#endif -} - - -/* Correct the ECC on a 256 byte block of data */ - -int yaffs_ECCCorrect(unsigned char *data, unsigned char *read_ecc, - const unsigned char *test_ecc) -{ - unsigned char d0, d1, d2; /* deltas */ - - d0 = read_ecc[0] ^ test_ecc[0]; - d1 = read_ecc[1] ^ test_ecc[1]; - d2 = read_ecc[2] ^ test_ecc[2]; - - if ((d0 | d1 | d2) == 0) - return 0; /* no error */ - - if (((d0 ^ (d0 >> 1)) & 0x55) == 0x55 && - ((d1 ^ (d1 >> 1)) & 0x55) == 0x55 && - ((d2 ^ (d2 >> 1)) & 0x54) == 0x54) { - /* Single bit (recoverable) error in data */ - - unsigned byte; - unsigned bit; - -#ifdef CONFIG_YAFFS_ECC_WRONG_ORDER - // swap the bytes to correct for the wrong order - unsigned char t; - - t = d0; - d0 = d1; - d1 = t; -#endif - - bit = byte = 0; - - if (d1 & 0x80) - byte |= 0x80; - if (d1 & 0x20) - byte |= 0x40; - if (d1 & 0x08) - byte |= 0x20; - if (d1 & 0x02) - byte |= 0x10; - if (d0 & 0x80) - byte |= 0x08; - if (d0 & 0x20) - byte |= 0x04; - if (d0 & 0x08) - byte |= 0x02; - if (d0 & 0x02) - byte |= 0x01; - - if (d2 & 0x80) - bit |= 0x04; - if (d2 & 0x20) - bit |= 0x02; - if (d2 & 0x08) - bit |= 0x01; - - data[byte] ^= (1 << bit); - - return 1; /* Corrected the error */ - } - - if ((yaffs_CountBits(d0) + - yaffs_CountBits(d1) + - yaffs_CountBits(d2)) == 1) { - /* Reccoverable error in ecc */ - - read_ecc[0] = test_ecc[0]; - read_ecc[1] = test_ecc[1]; - read_ecc[2] = test_ecc[2]; - - return 1; /* Corrected the error */ - } - - /* Unrecoverable error */ - - return -1; - -} - - -/* - * ECCxxxOther does ECC calcs on arbitrary n bytes of data - */ -void yaffs_ECCCalculateOther(const unsigned char *data, unsigned nBytes, - yaffs_ECCOther * eccOther) -{ - unsigned int i; - - unsigned char col_parity = 0; - unsigned line_parity = 0; - unsigned line_parity_prime = 0; - unsigned char b; - - for (i = 0; i < nBytes; i++) { - b = column_parity_table[*data++]; - col_parity ^= b; - - if (b & 0x01) { - /* odd number of bits in the byte */ - line_parity ^= i; - line_parity_prime ^= ~i; - } - - } - - eccOther->colParity = (col_parity >> 2) & 0x3f; - eccOther->lineParity = line_parity; - eccOther->lineParityPrime = line_parity_prime; -} - -int yaffs_ECCCorrectOther(unsigned char *data, unsigned nBytes, - yaffs_ECCOther * read_ecc, - const yaffs_ECCOther * test_ecc) -{ - unsigned char cDelta; /* column parity delta */ - unsigned lDelta; /* line parity delta */ - unsigned lDeltaPrime; /* line parity delta */ - unsigned bit; - - cDelta = read_ecc->colParity ^ test_ecc->colParity; - lDelta = read_ecc->lineParity ^ test_ecc->lineParity; - lDeltaPrime = read_ecc->lineParityPrime ^ test_ecc->lineParityPrime; - - if ((cDelta | lDelta | lDeltaPrime) == 0) - return 0; /* no error */ - - if (lDelta == ~lDeltaPrime && - (((cDelta ^ (cDelta >> 1)) & 0x15) == 0x15)) - { - /* Single bit (recoverable) error in data */ - - bit = 0; - - if (cDelta & 0x20) - bit |= 0x04; - if (cDelta & 0x08) - bit |= 0x02; - if (cDelta & 0x02) - bit |= 0x01; - - if(lDelta >= nBytes) - return -1; - - data[lDelta] ^= (1 << bit); - - return 1; /* corrected */ - } - - if ((yaffs_CountBits32(lDelta) + yaffs_CountBits32(lDeltaPrime) + - yaffs_CountBits(cDelta)) == 1) { - /* Reccoverable error in ecc */ - - *read_ecc = *test_ecc; - return 1; /* corrected */ - } - - /* Unrecoverable error */ - - return -1; - -} - |