diff options
Diffstat (limited to 'drivers/mtd/devices/docecc.c')
| -rw-r--r-- | drivers/mtd/devices/docecc.c | 40 |
1 files changed, 20 insertions, 20 deletions
diff --git a/drivers/mtd/devices/docecc.c b/drivers/mtd/devices/docecc.c index 24f670b5a4f3..cd3db72bef96 100644 --- a/drivers/mtd/devices/docecc.c +++ b/drivers/mtd/devices/docecc.c @@ -4,10 +4,10 @@ * GNU GPL License. The rest is simply to convert the disk on chip * syndrom into a standard syndom. * - * Author: Fabrice Bellard (fabrice.bellard@netgem.com) + * Author: Fabrice Bellard (fabrice.bellard@netgem.com) * Copyright (C) 2000 Netgem S.A. * - * $Id: docecc.c,v 1.5 2003/05/21 15:15:06 dwmw2 Exp $ + * $Id: docecc.c,v 1.7 2005/11/07 11:14:25 gleixner Exp $ * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by @@ -122,7 +122,7 @@ for(ci=(n)-1;ci >=0;ci--)\ a(0) + a(1) @ + a(2) @^2 + ... + a(m-1) @^(m-1) we consider the integer "i" whose binary representation with a(0) being LSB and a(m-1) MSB is (a(0),a(1),...,a(m-1)) and locate the entry - "index_of[i]". Now, @^index_of[i] is that element whose polynomial + "index_of[i]". Now, @^index_of[i] is that element whose polynomial representation is (a(0),a(1),a(2),...,a(m-1)). NOTE: The element alpha_to[2^m-1] = 0 always signifying that the @@ -130,7 +130,7 @@ for(ci=(n)-1;ci >=0;ci--)\ Similarily, the element index_of[0] = A0 always signifying that the power of alpha which has the polynomial representation (0,0,...,0) is "infinity". - + */ static void @@ -176,7 +176,7 @@ generate_gf(dtype Alpha_to[NN + 1], dtype Index_of[NN + 1]) * are written back. NOTE! This array must be at least NN-KK elements long. * The corrected data are written in eras_val[]. They must be xor with the data * to retrieve the correct data : data[erase_pos[i]] ^= erase_val[i] . - * + * * First "no_eras" erasures are declared by the calling program. Then, the * maximum # of errors correctable is t_after_eras = floor((NN-KK-no_eras)/2). * If the number of channel errors is not greater than "t_after_eras" the @@ -189,7 +189,7 @@ generate_gf(dtype Alpha_to[NN + 1], dtype Index_of[NN + 1]) * */ static int eras_dec_rs(dtype Alpha_to[NN + 1], dtype Index_of[NN + 1], - gf bb[NN - KK + 1], gf eras_val[NN-KK], int eras_pos[NN-KK], + gf bb[NN - KK + 1], gf eras_val[NN-KK], int eras_pos[NN-KK], int no_eras) { int deg_lambda, el, deg_omega; @@ -212,7 +212,7 @@ eras_dec_rs(dtype Alpha_to[NN + 1], dtype Index_of[NN + 1], count = 0; goto finish; } - + for(i=1;i<=NN-KK;i++){ s[i] = bb[0]; } @@ -220,7 +220,7 @@ eras_dec_rs(dtype Alpha_to[NN + 1], dtype Index_of[NN + 1], if(bb[j] == 0) continue; tmp = Index_of[bb[j]]; - + for(i=1;i<=NN-KK;i++) s[i] ^= Alpha_to[modnn(tmp + (B0+i-1)*PRIM*j)]; } @@ -234,7 +234,7 @@ eras_dec_rs(dtype Alpha_to[NN + 1], dtype Index_of[NN + 1], tmp = modnn(tmp + 2 * KK * (B0+i-1)*PRIM); s[i] = tmp; } - + CLEAR(&lambda[1],NN-KK); lambda[0] = 1; @@ -252,7 +252,7 @@ eras_dec_rs(dtype Alpha_to[NN + 1], dtype Index_of[NN + 1], #if DEBUG_ECC >= 1 /* Test code that verifies the erasure locator polynomial just constructed Needed only for decoder debugging. */ - + /* find roots of the erasure location polynomial */ for(i=1;i<=no_eras;i++) reg[i] = Index_of[lambda[i]]; @@ -286,7 +286,7 @@ eras_dec_rs(dtype Alpha_to[NN + 1], dtype Index_of[NN + 1], } for(i=0;i<NN-KK+1;i++) b[i] = Index_of[lambda[i]]; - + /* * Begin Berlekamp-Massey algorithm to determine error+erasure * locator polynomial @@ -389,7 +389,7 @@ eras_dec_rs(dtype Alpha_to[NN + 1], dtype Index_of[NN + 1], omega[i] = Index_of[tmp]; } omega[NN-KK] = A0; - + /* * Compute error values in poly-form. num1 = omega(inv(X(l))), num2 = * inv(X(l))**(B0-1) and den = lambda_pr(inv(X(l))) all in poly-form @@ -402,7 +402,7 @@ eras_dec_rs(dtype Alpha_to[NN + 1], dtype Index_of[NN + 1], } num2 = Alpha_to[modnn(root[j] * (B0 - 1) + NN)]; den = 0; - + /* lambda[i+1] for i even is the formal derivative lambda_pr of lambda[i] */ for (i = min(deg_lambda,NN-KK-1) & ~1; i >= 0; i -=2) { if(lambda[i+1] != A0) @@ -436,11 +436,11 @@ eras_dec_rs(dtype Alpha_to[NN + 1], dtype Index_of[NN + 1], /* The sector bytes are packed into NB_DATA MM bits words */ #define NB_DATA (((SECTOR_SIZE + 1) * 8 + 6) / MM) -/* +/* * Correct the errors in 'sector[]' by using 'ecc1[]' which is the * content of the feedback shift register applyied to the sector and * the ECC. Return the number of errors corrected (and correct them in - * sector), or -1 if error + * sector), or -1 if error */ int doc_decode_ecc(unsigned char sector[SECTOR_SIZE], unsigned char ecc1[6]) { @@ -454,7 +454,7 @@ int doc_decode_ecc(unsigned char sector[SECTOR_SIZE], unsigned char ecc1[6]) Alpha_to = kmalloc((NN + 1) * sizeof(dtype), GFP_KERNEL); if (!Alpha_to) return -1; - + Index_of = kmalloc((NN + 1) * sizeof(dtype), GFP_KERNEL); if (!Index_of) { kfree(Alpha_to); @@ -470,7 +470,7 @@ int doc_decode_ecc(unsigned char sector[SECTOR_SIZE], unsigned char ecc1[6]) bb[2] = ((ecc1[2] & 0xf0) >> 4) | ((ecc1[3] & 0x3f) << 4); bb[3] = ((ecc1[3] & 0xc0) >> 6) | ((ecc1[0] & 0xff) << 2); - nb_errors = eras_dec_rs(Alpha_to, Index_of, bb, + nb_errors = eras_dec_rs(Alpha_to, Index_of, bb, error_val, error_pos, 0); if (nb_errors <= 0) goto the_end; @@ -489,7 +489,7 @@ int doc_decode_ecc(unsigned char sector[SECTOR_SIZE], unsigned char ecc1[6]) can be modified since pos is even */ index = (pos >> 3) ^ 1; bitpos = pos & 7; - if ((index >= 0 && index < SECTOR_SIZE) || + if ((index >= 0 && index < SECTOR_SIZE) || index == (SECTOR_SIZE + 1)) { val = error_val[i] >> (2 + bitpos); parity ^= val; @@ -500,7 +500,7 @@ int doc_decode_ecc(unsigned char sector[SECTOR_SIZE], unsigned char ecc1[6]) bitpos = (bitpos + 10) & 7; if (bitpos == 0) bitpos = 8; - if ((index >= 0 && index < SECTOR_SIZE) || + if ((index >= 0 && index < SECTOR_SIZE) || index == (SECTOR_SIZE + 1)) { val = error_val[i] << (8 - bitpos); parity ^= val; @@ -509,7 +509,7 @@ int doc_decode_ecc(unsigned char sector[SECTOR_SIZE], unsigned char ecc1[6]) } } } - + /* use parity to test extra errors */ if ((parity & 0xff) != 0) nb_errors = -1; |