Commit b5a6c309 authored by Artem Bityutskiy's avatar Artem Bityutskiy Committed by David Woodhouse

mtd: doc: remove support for DoC 2000/2001/2001+

These drivers are deprecated for very long time, and we have a different driver
for these called "diskonchip". Thus, kill the ancient cruft.
Signed-off-by: default avatarArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
parent 8e12b474
......@@ -205,69 +205,6 @@ config MTD_BLOCK2MTD
comment "Disk-On-Chip Device Drivers"
config MTD_DOC2000
tristate "M-Systems Disk-On-Chip 2000 and Millennium (DEPRECATED)"
depends on MTD_NAND
select MTD_DOCPROBE
select MTD_NAND_IDS
---help---
This provides an MTD device driver for the M-Systems DiskOnChip
2000 and Millennium devices. Originally designed for the DiskOnChip
2000, it also now includes support for the DiskOnChip Millennium.
If you have problems with this driver and the DiskOnChip Millennium,
you may wish to try the alternative Millennium driver below. To use
the alternative driver, you will need to undefine DOC_SINGLE_DRIVER
in the <file:drivers/mtd/devices/docprobe.c> source code.
If you use this device, you probably also want to enable the NFTL
'NAND Flash Translation Layer' option below, which is used to
emulate a block device by using a kind of file system on the flash
chips.
NOTE: This driver is deprecated and will probably be removed soon.
Please try the new DiskOnChip driver under "NAND Flash Device
Drivers".
config MTD_DOC2001
tristate "M-Systems Disk-On-Chip Millennium-only alternative driver (DEPRECATED)"
depends on MTD_NAND
select MTD_DOCPROBE
select MTD_NAND_IDS
---help---
This provides an alternative MTD device driver for the M-Systems
DiskOnChip Millennium devices. Use this if you have problems with
the combined DiskOnChip 2000 and Millennium driver above. To get
the DiskOnChip probe code to load and use this driver instead of
the other one, you will need to undefine DOC_SINGLE_DRIVER near
the beginning of <file:drivers/mtd/devices/docprobe.c>.
If you use this device, you probably also want to enable the NFTL
'NAND Flash Translation Layer' option below, which is used to
emulate a block device by using a kind of file system on the flash
chips.
NOTE: This driver is deprecated and will probably be removed soon.
Please try the new DiskOnChip driver under "NAND Flash Device
Drivers".
config MTD_DOC2001PLUS
tristate "M-Systems Disk-On-Chip Millennium Plus"
depends on MTD_NAND
select MTD_DOCPROBE
select MTD_NAND_IDS
---help---
This provides an MTD device driver for the M-Systems DiskOnChip
Millennium Plus devices.
If you use this device, you probably also want to enable the INFTL
'Inverse NAND Flash Translation Layer' option below, which is used
to emulate a block device by using a kind of file system on the
flash chips.
NOTE: This driver will soon be replaced by the new DiskOnChip driver
under "NAND Flash Device Drivers" (currently that driver does not
support all Millennium Plus devices).
config MTD_DOCG3
tristate "M-Systems Disk-On-Chip G3"
select BCH
......
......@@ -2,12 +2,7 @@
# linux/drivers/mtd/devices/Makefile
#
obj-$(CONFIG_MTD_DOC2000) += doc2000.o
obj-$(CONFIG_MTD_DOC2001) += doc2001.o
obj-$(CONFIG_MTD_DOC2001PLUS) += doc2001plus.o
obj-$(CONFIG_MTD_DOCG3) += docg3.o
obj-$(CONFIG_MTD_DOCPROBE) += docprobe.o
obj-$(CONFIG_MTD_DOCECC) += docecc.o
obj-$(CONFIG_MTD_SLRAM) += slram.o
obj-$(CONFIG_MTD_PHRAM) += phram.o
obj-$(CONFIG_MTD_PMC551) += pmc551.o
......
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/*
* ECC algorithm for M-systems disk on chip. We use the excellent Reed
* Solmon code of Phil Karn (karn@ka9q.ampr.org) available under the
* GNU GPL License. The rest is simply to convert the disk on chip
* syndrome into a standard syndome.
*
* Author: Fabrice Bellard (fabrice.bellard@netgem.com)
* Copyright (C) 2000 Netgem S.A.
*
* 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
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <asm/errno.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/doc2000.h>
#define DEBUG_ECC 0
/* need to undef it (from asm/termbits.h) */
#undef B0
#define MM 10 /* Symbol size in bits */
#define KK (1023-4) /* Number of data symbols per block */
#define B0 510 /* First root of generator polynomial, alpha form */
#define PRIM 1 /* power of alpha used to generate roots of generator poly */
#define NN ((1 << MM) - 1)
typedef unsigned short dtype;
/* 1+x^3+x^10 */
static const int Pp[MM+1] = { 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1 };
/* This defines the type used to store an element of the Galois Field
* used by the code. Make sure this is something larger than a char if
* if anything larger than GF(256) is used.
*
* Note: unsigned char will work up to GF(256) but int seems to run
* faster on the Pentium.
*/
typedef int gf;
/* No legal value in index form represents zero, so
* we need a special value for this purpose
*/
#define A0 (NN)
/* Compute x % NN, where NN is 2**MM - 1,
* without a slow divide
*/
static inline gf
modnn(int x)
{
while (x >= NN) {
x -= NN;
x = (x >> MM) + (x & NN);
}
return x;
}
#define CLEAR(a,n) {\
int ci;\
for(ci=(n)-1;ci >=0;ci--)\
(a)[ci] = 0;\
}
#define COPY(a,b,n) {\
int ci;\
for(ci=(n)-1;ci >=0;ci--)\
(a)[ci] = (b)[ci];\
}
#define COPYDOWN(a,b,n) {\
int ci;\
for(ci=(n)-1;ci >=0;ci--)\
(a)[ci] = (b)[ci];\
}
#define Ldec 1
/* generate GF(2**m) from the irreducible polynomial p(X) in Pp[0]..Pp[m]
lookup tables: index->polynomial form alpha_to[] contains j=alpha**i;
polynomial form -> index form index_of[j=alpha**i] = i
alpha=2 is the primitive element of GF(2**m)
HARI's COMMENT: (4/13/94) alpha_to[] can be used as follows:
Let @ represent the primitive element commonly called "alpha" that
is the root of the primitive polynomial p(x). Then in GF(2^m), for any
0 <= i <= 2^m-2,
@^i = a(0) + a(1) @ + a(2) @^2 + ... + a(m-1) @^(m-1)
where the binary vector (a(0),a(1),a(2),...,a(m-1)) is the representation
of the integer "alpha_to[i]" with a(0) being the LSB and a(m-1) the MSB. Thus for
example the polynomial representation of @^5 would be given by the binary
representation of the integer "alpha_to[5]".
Similarly, index_of[] can be used as follows:
As above, let @ represent the primitive element of GF(2^m) that is
the root of the primitive polynomial p(x). In order to find the power
of @ (alpha) that has the polynomial representation
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
representation is (a(0),a(1),a(2),...,a(m-1)).
NOTE:
The element alpha_to[2^m-1] = 0 always signifying that the
representation of "@^infinity" = 0 is (0,0,0,...,0).
Similarly, 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
generate_gf(dtype Alpha_to[NN + 1], dtype Index_of[NN + 1])
{
register int i, mask;
mask = 1;
Alpha_to[MM] = 0;
for (i = 0; i < MM; i++) {
Alpha_to[i] = mask;
Index_of[Alpha_to[i]] = i;
/* If Pp[i] == 1 then, term @^i occurs in poly-repr of @^MM */
if (Pp[i] != 0)
Alpha_to[MM] ^= mask; /* Bit-wise EXOR operation */
mask <<= 1; /* single left-shift */
}
Index_of[Alpha_to[MM]] = MM;
/*
* Have obtained poly-repr of @^MM. Poly-repr of @^(i+1) is given by
* poly-repr of @^i shifted left one-bit and accounting for any @^MM
* term that may occur when poly-repr of @^i is shifted.
*/
mask >>= 1;
for (i = MM + 1; i < NN; i++) {
if (Alpha_to[i - 1] >= mask)
Alpha_to[i] = Alpha_to[MM] ^ ((Alpha_to[i - 1] ^ mask) << 1);
else
Alpha_to[i] = Alpha_to[i - 1] << 1;
Index_of[Alpha_to[i]] = i;
}
Index_of[0] = A0;
Alpha_to[NN] = 0;
}
/*
* Performs ERRORS+ERASURES decoding of RS codes. bb[] is the content
* of the feedback shift register after having processed the data and
* the ECC.
*
* Return number of symbols corrected, or -1 if codeword is illegal
* or uncorrectable. If eras_pos is non-null, the detected error locations
* 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
* transmitted codeword will be recovered. Details of algorithm can be found
* in R. Blahut's "Theory ... of Error-Correcting Codes".
* Warning: the eras_pos[] array must not contain duplicate entries; decoder failure
* will result. The decoder *could* check for this condition, but it would involve
* extra time on every decoding operation.
* */
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],
int no_eras)
{
int deg_lambda, el, deg_omega;
int i, j, r,k;
gf u,q,tmp,num1,num2,den,discr_r;
gf lambda[NN-KK + 1], s[NN-KK + 1]; /* Err+Eras Locator poly
* and syndrome poly */
gf b[NN-KK + 1], t[NN-KK + 1], omega[NN-KK + 1];
gf root[NN-KK], reg[NN-KK + 1], loc[NN-KK];
int syn_error, count;
syn_error = 0;
for(i=0;i<NN-KK;i++)
syn_error |= bb[i];
if (!syn_error) {
/* if remainder is zero, data[] is a codeword and there are no
* errors to correct. So return data[] unmodified
*/
count = 0;
goto finish;
}
for(i=1;i<=NN-KK;i++){
s[i] = bb[0];
}
for(j=1;j<NN-KK;j++){
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)];
}
/* undo the feedback register implicit multiplication and convert
syndromes to index form */
for(i=1;i<=NN-KK;i++) {
tmp = Index_of[s[i]];
if (tmp != A0)
tmp = modnn(tmp + 2 * KK * (B0+i-1)*PRIM);
s[i] = tmp;
}
CLEAR(&lambda[1],NN-KK);
lambda[0] = 1;
if (no_eras > 0) {
/* Init lambda to be the erasure locator polynomial */
lambda[1] = Alpha_to[modnn(PRIM * eras_pos[0])];
for (i = 1; i < no_eras; i++) {
u = modnn(PRIM*eras_pos[i]);
for (j = i+1; j > 0; j--) {
tmp = Index_of[lambda[j - 1]];
if(tmp != A0)
lambda[j] ^= Alpha_to[modnn(u + tmp)];
}
}
#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]];
count = 0;
for (i = 1,k=NN-Ldec; i <= NN; i++,k = modnn(NN+k-Ldec)) {
q = 1;
for (j = 1; j <= no_eras; j++)
if (reg[j] != A0) {
reg[j] = modnn(reg[j] + j);
q ^= Alpha_to[reg[j]];
}
if (q != 0)
continue;
/* store root and error location number indices */
root[count] = i;
loc[count] = k;
count++;
}
if (count != no_eras) {
printf("\n lambda(x) is WRONG\n");
count = -1;
goto finish;
}
#if DEBUG_ECC >= 2
printf("\n Erasure positions as determined by roots of Eras Loc Poly:\n");
for (i = 0; i < count; i++)
printf("%d ", loc[i]);
printf("\n");
#endif
#endif
}
for(i=0;i<NN-KK+1;i++)
b[i] = Index_of[lambda[i]];
/*
* Begin Berlekamp-Massey algorithm to determine error+erasure
* locator polynomial
*/
r = no_eras;
el = no_eras;
while (++r <= NN-KK) { /* r is the step number */
/* Compute discrepancy at the r-th step in poly-form */
discr_r = 0;
for (i = 0; i < r; i++){
if ((lambda[i] != 0) && (s[r - i] != A0)) {
discr_r ^= Alpha_to[modnn(Index_of[lambda[i]] + s[r - i])];
}
}
discr_r = Index_of[discr_r]; /* Index form */
if (discr_r == A0) {
/* 2 lines below: B(x) <-- x*B(x) */
COPYDOWN(&b[1],b,NN-KK);
b[0] = A0;
} else {
/* 7 lines below: T(x) <-- lambda(x) - discr_r*x*b(x) */
t[0] = lambda[0];
for (i = 0 ; i < NN-KK; i++) {
if(b[i] != A0)
t[i+1] = lambda[i+1] ^ Alpha_to[modnn(discr_r + b[i])];
else
t[i+1] = lambda[i+1];
}
if (2 * el <= r + no_eras - 1) {
el = r + no_eras - el;
/*
* 2 lines below: B(x) <-- inv(discr_r) *
* lambda(x)
*/
for (i = 0; i <= NN-KK; i++)
b[i] = (lambda[i] == 0) ? A0 : modnn(Index_of[lambda[i]] - discr_r + NN);
} else {
/* 2 lines below: B(x) <-- x*B(x) */
COPYDOWN(&b[1],b,NN-KK);
b[0] = A0;
}
COPY(lambda,t,NN-KK+1);
}
}
/* Convert lambda to index form and compute deg(lambda(x)) */
deg_lambda = 0;
for(i=0;i<NN-KK+1;i++){
lambda[i] = Index_of[lambda[i]];
if(lambda[i] != A0)
deg_lambda = i;
}
/*
* Find roots of the error+erasure locator polynomial by Chien
* Search
*/
COPY(&reg[1],&lambda[1],NN-KK);
count = 0; /* Number of roots of lambda(x) */
for (i = 1,k=NN-Ldec; i <= NN; i++,k = modnn(NN+k-Ldec)) {
q = 1;
for (j = deg_lambda; j > 0; j--){
if (reg[j] != A0) {
reg[j] = modnn(reg[j] + j);
q ^= Alpha_to[reg[j]];
}
}
if (q != 0)
continue;
/* store root (index-form) and error location number */
root[count] = i;
loc[count] = k;
/* If we've already found max possible roots,
* abort the search to save time
*/
if(++count == deg_lambda)
break;
}
if (deg_lambda != count) {
/*
* deg(lambda) unequal to number of roots => uncorrectable
* error detected
*/
count = -1;
goto finish;
}
/*
* Compute err+eras evaluator poly omega(x) = s(x)*lambda(x) (modulo
* x**(NN-KK)). in index form. Also find deg(omega).
*/
deg_omega = 0;
for (i = 0; i < NN-KK;i++){
tmp = 0;
j = (deg_lambda < i) ? deg_lambda : i;
for(;j >= 0; j--){
if ((s[i + 1 - j] != A0) && (lambda[j] != A0))
tmp ^= Alpha_to[modnn(s[i + 1 - j] + lambda[j])];
}
if(tmp != 0)
deg_omega = i;
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
*/
for (j = count-1; j >=0; j--) {
num1 = 0;
for (i = deg_omega; i >= 0; i--) {
if (omega[i] != A0)
num1 ^= Alpha_to[modnn(omega[i] + i * root[j])];
}
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)
den ^= Alpha_to[modnn(lambda[i+1] + i * root[j])];
}
if (den == 0) {
#if DEBUG_ECC >= 1
printf("\n ERROR: denominator = 0\n");
#endif
/* Convert to dual- basis */
count = -1;
goto finish;
}
/* Apply error to data */
if (num1 != 0) {
eras_val[j] = Alpha_to[modnn(Index_of[num1] + Index_of[num2] + NN - Index_of[den])];
} else {
eras_val[j] = 0;
}
}
finish:
for(i=0;i<count;i++)
eras_pos[i] = loc[i];
return count;
}
/***************************************************************************/
/* The DOC specific code begins here */
#define SECTOR_SIZE 512
/* 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
*/
int doc_decode_ecc(unsigned char sector[SECTOR_SIZE], unsigned char ecc1[6])
{
int parity, i, nb_errors;
gf bb[NN - KK + 1];
gf error_val[NN-KK];
int error_pos[NN-KK], pos, bitpos, index, val;
dtype *Alpha_to, *Index_of;
/* init log and exp tables here to save memory. However, it is slower */
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);
return -1;
}
generate_gf(Alpha_to, Index_of);
parity = ecc1[1];
bb[0] = (ecc1[4] & 0xff) | ((ecc1[5] & 0x03) << 8);
bb[1] = ((ecc1[5] & 0xfc) >> 2) | ((ecc1[2] & 0x0f) << 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,
error_val, error_pos, 0);
if (nb_errors <= 0)
goto the_end;
/* correct the errors */
for(i=0;i<nb_errors;i++) {
pos = error_pos[i];
if (pos >= NB_DATA && pos < KK) {
nb_errors = -1;
goto the_end;
}
if (pos < NB_DATA) {
/* extract bit position (MSB first) */
pos = 10 * (NB_DATA - 1 - pos) - 6;
/* now correct the following 10 bits. At most two bytes
can be modified since pos is even */
index = (pos >> 3) ^ 1;
bitpos = pos & 7;
if ((index >= 0 && index < SECTOR_SIZE) ||
index == (SECTOR_SIZE + 1)) {
val = error_val[i] >> (2 + bitpos);
parity ^= val;
if (index < SECTOR_SIZE)
sector[index] ^= val;
}
index = ((pos >> 3) + 1) ^ 1;
bitpos = (bitpos + 10) & 7;
if (bitpos == 0)
bitpos = 8;
if ((index >= 0 && index < SECTOR_SIZE) ||
index == (SECTOR_SIZE + 1)) {
val = error_val[i] << (8 - bitpos);
parity ^= val;
if (index < SECTOR_SIZE)
sector[index] ^= val;
}
}
}
/* use parity to test extra errors */
if ((parity & 0xff) != 0)
nb_errors = -1;
the_end:
kfree(Alpha_to);
kfree(Index_of);
return nb_errors;
}
EXPORT_SYMBOL_GPL(doc_decode_ecc);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Fabrice Bellard <fabrice.bellard@netgem.com>");
MODULE_DESCRIPTION("ECC code for correcting errors detected by DiskOnChip 2000 and Millennium ECC hardware");