Linux-2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
This commit is contained in:
Linus Torvalds
2005-04-16 15:20:36 -07:00
commit 1da177e4c3
17291 changed files with 6718755 additions and 0 deletions

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#
# This is a modified version of reed solomon lib,
#
obj-$(CONFIG_REED_SOLOMON) += reed_solomon.o

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/*
* lib/reed_solomon/decode_rs.c
*
* Overview:
* Generic Reed Solomon encoder / decoder library
*
* Copyright 2002, Phil Karn, KA9Q
* May be used under the terms of the GNU General Public License (GPL)
*
* Adaption to the kernel by Thomas Gleixner (tglx@linutronix.de)
*
* $Id: decode_rs.c,v 1.6 2004/10/22 15:41:47 gleixner Exp $
*
*/
/* Generic data width independent code which is included by the
* wrappers.
*/
{
int deg_lambda, el, deg_omega;
int i, j, r, k, pad;
int nn = rs->nn;
int nroots = rs->nroots;
int fcr = rs->fcr;
int prim = rs->prim;
int iprim = rs->iprim;
uint16_t *alpha_to = rs->alpha_to;
uint16_t *index_of = rs->index_of;
uint16_t u, q, tmp, num1, num2, den, discr_r, syn_error;
/* Err+Eras Locator poly and syndrome poly The maximum value
* of nroots is 8. So the necessary stack size will be about
* 220 bytes max.
*/
uint16_t lambda[nroots + 1], syn[nroots];
uint16_t b[nroots + 1], t[nroots + 1], omega[nroots + 1];
uint16_t root[nroots], reg[nroots + 1], loc[nroots];
int count = 0;
uint16_t msk = (uint16_t) rs->nn;
/* Check length parameter for validity */
pad = nn - nroots - len;
if (pad < 0 || pad >= nn)
return -ERANGE;
/* Does the caller provide the syndrome ? */
if (s != NULL)
goto decode;
/* form the syndromes; i.e., evaluate data(x) at roots of
* g(x) */
for (i = 0; i < nroots; i++)
syn[i] = (((uint16_t) data[0]) ^ invmsk) & msk;
for (j = 1; j < len; j++) {
for (i = 0; i < nroots; i++) {
if (syn[i] == 0) {
syn[i] = (((uint16_t) data[j]) ^
invmsk) & msk;
} else {
syn[i] = ((((uint16_t) data[j]) ^
invmsk) & msk) ^
alpha_to[rs_modnn(rs, index_of[syn[i]] +
(fcr + i) * prim)];
}
}
}
for (j = 0; j < nroots; j++) {
for (i = 0; i < nroots; i++) {
if (syn[i] == 0) {
syn[i] = ((uint16_t) par[j]) & msk;
} else {
syn[i] = (((uint16_t) par[j]) & msk) ^
alpha_to[rs_modnn(rs, index_of[syn[i]] +
(fcr+i)*prim)];
}
}
}
s = syn;
/* Convert syndromes to index form, checking for nonzero condition */
syn_error = 0;
for (i = 0; i < nroots; i++) {
syn_error |= s[i];
s[i] = index_of[s[i]];
}
if (!syn_error) {
/* if syndrome is zero, data[] is a codeword and there are no
* errors to correct. So return data[] unmodified
*/
count = 0;
goto finish;
}
decode:
memset(&lambda[1], 0, nroots * sizeof(lambda[0]));
lambda[0] = 1;
if (no_eras > 0) {
/* Init lambda to be the erasure locator polynomial */
lambda[1] = alpha_to[rs_modnn(rs,
prim * (nn - 1 - eras_pos[0]))];
for (i = 1; i < no_eras; i++) {
u = rs_modnn(rs, prim * (nn - 1 - eras_pos[i]));
for (j = i + 1; j > 0; j--) {
tmp = index_of[lambda[j - 1]];
if (tmp != nn) {
lambda[j] ^=
alpha_to[rs_modnn(rs, u + tmp)];
}
}
}
}
for (i = 0; i < nroots + 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 <= nroots) { /* 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 - 1] != nn)) {
discr_r ^=
alpha_to[rs_modnn(rs,
index_of[lambda[i]] +
s[r - i - 1])];
}
}
discr_r = index_of[discr_r]; /* Index form */
if (discr_r == nn) {
/* 2 lines below: B(x) <-- x*B(x) */
memmove (&b[1], b, nroots * sizeof (b[0]));
b[0] = nn;
} else {
/* 7 lines below: T(x) <-- lambda(x)-discr_r*x*b(x) */
t[0] = lambda[0];
for (i = 0; i < nroots; i++) {
if (b[i] != nn) {
t[i + 1] = lambda[i + 1] ^
alpha_to[rs_modnn(rs, 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 <= nroots; i++) {
b[i] = (lambda[i] == 0) ? nn :
rs_modnn(rs, index_of[lambda[i]]
- discr_r + nn);
}
} else {
/* 2 lines below: B(x) <-- x*B(x) */
memmove(&b[1], b, nroots * sizeof(b[0]));
b[0] = nn;
}
memcpy(lambda, t, (nroots + 1) * sizeof(t[0]));
}
}
/* Convert lambda to index form and compute deg(lambda(x)) */
deg_lambda = 0;
for (i = 0; i < nroots + 1; i++) {
lambda[i] = index_of[lambda[i]];
if (lambda[i] != nn)
deg_lambda = i;
}
/* Find roots of error+erasure locator polynomial by Chien search */
memcpy(&reg[1], &lambda[1], nroots * sizeof(reg[0]));
count = 0; /* Number of roots of lambda(x) */
for (i = 1, k = iprim - 1; i <= nn; i++, k = rs_modnn(rs, k + iprim)) {
q = 1; /* lambda[0] is always 0 */
for (j = deg_lambda; j > 0; j--) {
if (reg[j] != nn) {
reg[j] = rs_modnn(rs, reg[j] + j);
q ^= alpha_to[reg[j]];
}
}
if (q != 0)
continue; /* Not a root */
/* 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**nroots). in index form. Also find deg(omega).
*/
deg_omega = deg_lambda - 1;
for (i = 0; i <= deg_omega; i++) {
tmp = 0;
for (j = i; j >= 0; j--) {
if ((s[i - j] != nn) && (lambda[j] != nn))
tmp ^=
alpha_to[rs_modnn(rs, s[i - j] + lambda[j])];
}
omega[i] = index_of[tmp];
}
/*
* Compute error values in poly-form. num1 = omega(inv(X(l))), num2 =
* inv(X(l))**(fcr-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] != nn)
num1 ^= alpha_to[rs_modnn(rs, omega[i] +
i * root[j])];
}
num2 = alpha_to[rs_modnn(rs, root[j] * (fcr - 1) + nn)];
den = 0;
/* lambda[i+1] for i even is the formal derivative
* lambda_pr of lambda[i] */
for (i = min(deg_lambda, nroots - 1) & ~1; i >= 0; i -= 2) {
if (lambda[i + 1] != nn) {
den ^= alpha_to[rs_modnn(rs, lambda[i + 1] +
i * root[j])];
}
}
/* Apply error to data */
if (num1 != 0 && loc[j] >= pad) {
uint16_t cor = alpha_to[rs_modnn(rs,index_of[num1] +
index_of[num2] +
nn - index_of[den])];
/* Store the error correction pattern, if a
* correction buffer is available */
if (corr) {
corr[j] = cor;
} else {
/* If a data buffer is given and the
* error is inside the message,
* correct it */
if (data && (loc[j] < (nn - nroots)))
data[loc[j] - pad] ^= cor;
}
}
}
finish:
if (eras_pos != NULL) {
for (i = 0; i < count; i++)
eras_pos[i] = loc[i] - pad;
}
return count;
}

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/*
* lib/reed_solomon/encode_rs.c
*
* Overview:
* Generic Reed Solomon encoder / decoder library
*
* Copyright 2002, Phil Karn, KA9Q
* May be used under the terms of the GNU General Public License (GPL)
*
* Adaption to the kernel by Thomas Gleixner (tglx@linutronix.de)
*
* $Id: encode_rs.c,v 1.4 2004/10/22 15:41:47 gleixner Exp $
*
*/
/* Generic data width independent code which is included by the
* wrappers.
* int encode_rsX (struct rs_control *rs, uintX_t *data, int len, uintY_t *par)
*/
{
int i, j, pad;
int nn = rs->nn;
int nroots = rs->nroots;
uint16_t *alpha_to = rs->alpha_to;
uint16_t *index_of = rs->index_of;
uint16_t *genpoly = rs->genpoly;
uint16_t fb;
uint16_t msk = (uint16_t) rs->nn;
/* Check length parameter for validity */
pad = nn - nroots - len;
if (pad < 0 || pad >= nn)
return -ERANGE;
for (i = 0; i < len; i++) {
fb = index_of[((((uint16_t) data[i])^invmsk) & msk) ^ par[0]];
/* feedback term is non-zero */
if (fb != nn) {
for (j = 1; j < nroots; j++) {
par[j] ^= alpha_to[rs_modnn(rs, fb +
genpoly[nroots - j])];
}
}
/* Shift */
memmove(&par[0], &par[1], sizeof(uint16_t) * (nroots - 1));
if (fb != nn) {
par[nroots - 1] = alpha_to[rs_modnn(rs,
fb + genpoly[0])];
} else {
par[nroots - 1] = 0;
}
}
return 0;
}

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/*
* lib/reed_solomon/rslib.c
*
* Overview:
* Generic Reed Solomon encoder / decoder library
*
* Copyright (C) 2004 Thomas Gleixner (tglx@linutronix.de)
*
* Reed Solomon code lifted from reed solomon library written by Phil Karn
* Copyright 2002 Phil Karn, KA9Q
*
* $Id: rslib.c,v 1.5 2004/10/22 15:41:47 gleixner Exp $
*
* 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.
*
* Description:
*
* The generic Reed Solomon library provides runtime configurable
* encoding / decoding of RS codes.
* Each user must call init_rs to get a pointer to a rs_control
* structure for the given rs parameters. This structure is either
* generated or a already available matching control structure is used.
* If a structure is generated then the polynomial arrays for
* fast encoding / decoding are built. This can take some time so
* make sure not to call this function from a time critical path.
* Usually a module / driver should initialize the necessary
* rs_control structure on module / driver init and release it
* on exit.
* The encoding puts the calculated syndrome into a given syndrome
* buffer.
* The decoding is a two step process. The first step calculates
* the syndrome over the received (data + syndrome) and calls the
* second stage, which does the decoding / error correction itself.
* Many hw encoders provide a syndrome calculation over the received
* data + syndrome and can call the second stage directly.
*
*/
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/rslib.h>
#include <linux/slab.h>
#include <asm/semaphore.h>
/* This list holds all currently allocated rs control structures */
static LIST_HEAD (rslist);
/* Protection for the list */
static DECLARE_MUTEX(rslistlock);
/**
* rs_init - Initialize a Reed-Solomon codec
*
* @symsize: symbol size, bits (1-8)
* @gfpoly: Field generator polynomial coefficients
* @fcr: first root of RS code generator polynomial, index form
* @prim: primitive element to generate polynomial roots
* @nroots: RS code generator polynomial degree (number of roots)
*
* Allocate a control structure and the polynom arrays for faster
* en/decoding. Fill the arrays according to the given parameters
*/
static struct rs_control *rs_init(int symsize, int gfpoly, int fcr,
int prim, int nroots)
{
struct rs_control *rs;
int i, j, sr, root, iprim;
/* Allocate the control structure */
rs = kmalloc(sizeof (struct rs_control), GFP_KERNEL);
if (rs == NULL)
return NULL;
INIT_LIST_HEAD(&rs->list);
rs->mm = symsize;
rs->nn = (1 << symsize) - 1;
rs->fcr = fcr;
rs->prim = prim;
rs->nroots = nroots;
rs->gfpoly = gfpoly;
/* Allocate the arrays */
rs->alpha_to = kmalloc(sizeof(uint16_t) * (rs->nn + 1), GFP_KERNEL);
if (rs->alpha_to == NULL)
goto errrs;
rs->index_of = kmalloc(sizeof(uint16_t) * (rs->nn + 1), GFP_KERNEL);
if (rs->index_of == NULL)
goto erralp;
rs->genpoly = kmalloc(sizeof(uint16_t) * (rs->nroots + 1), GFP_KERNEL);
if(rs->genpoly == NULL)
goto erridx;
/* Generate Galois field lookup tables */
rs->index_of[0] = rs->nn; /* log(zero) = -inf */
rs->alpha_to[rs->nn] = 0; /* alpha**-inf = 0 */
sr = 1;
for (i = 0; i < rs->nn; i++) {
rs->index_of[sr] = i;
rs->alpha_to[i] = sr;
sr <<= 1;
if (sr & (1 << symsize))
sr ^= gfpoly;
sr &= rs->nn;
}
/* If it's not primitive, exit */
if(sr != 1)
goto errpol;
/* Find prim-th root of 1, used in decoding */
for(iprim = 1; (iprim % prim) != 0; iprim += rs->nn);
/* prim-th root of 1, index form */
rs->iprim = iprim / prim;
/* Form RS code generator polynomial from its roots */
rs->genpoly[0] = 1;
for (i = 0, root = fcr * prim; i < nroots; i++, root += prim) {
rs->genpoly[i + 1] = 1;
/* Multiply rs->genpoly[] by @**(root + x) */
for (j = i; j > 0; j--) {
if (rs->genpoly[j] != 0) {
rs->genpoly[j] = rs->genpoly[j -1] ^
rs->alpha_to[rs_modnn(rs,
rs->index_of[rs->genpoly[j]] + root)];
} else
rs->genpoly[j] = rs->genpoly[j - 1];
}
/* rs->genpoly[0] can never be zero */
rs->genpoly[0] =
rs->alpha_to[rs_modnn(rs,
rs->index_of[rs->genpoly[0]] + root)];
}
/* convert rs->genpoly[] to index form for quicker encoding */
for (i = 0; i <= nroots; i++)
rs->genpoly[i] = rs->index_of[rs->genpoly[i]];
return rs;
/* Error exit */
errpol:
kfree(rs->genpoly);
erridx:
kfree(rs->index_of);
erralp:
kfree(rs->alpha_to);
errrs:
kfree(rs);
return NULL;
}
/**
* free_rs - Free the rs control structure, if its not longer used
*
* @rs: the control structure which is not longer used by the
* caller
*/
void free_rs(struct rs_control *rs)
{
down(&rslistlock);
rs->users--;
if(!rs->users) {
list_del(&rs->list);
kfree(rs->alpha_to);
kfree(rs->index_of);
kfree(rs->genpoly);
kfree(rs);
}
up(&rslistlock);
}
/**
* init_rs - Find a matching or allocate a new rs control structure
*
* @symsize: the symbol size (number of bits)
* @gfpoly: the extended Galois field generator polynomial coefficients,
* with the 0th coefficient in the low order bit. The polynomial
* must be primitive;
* @fcr: the first consecutive root of the rs code generator polynomial
* in index form
* @prim: primitive element to generate polynomial roots
* @nroots: RS code generator polynomial degree (number of roots)
*/
struct rs_control *init_rs(int symsize, int gfpoly, int fcr, int prim,
int nroots)
{
struct list_head *tmp;
struct rs_control *rs;
/* Sanity checks */
if (symsize < 1)
return NULL;
if (fcr < 0 || fcr >= (1<<symsize))
return NULL;
if (prim <= 0 || prim >= (1<<symsize))
return NULL;
if (nroots < 0 || nroots >= (1<<symsize) || nroots > 8)
return NULL;
down(&rslistlock);
/* Walk through the list and look for a matching entry */
list_for_each(tmp, &rslist) {
rs = list_entry(tmp, struct rs_control, list);
if (symsize != rs->mm)
continue;
if (gfpoly != rs->gfpoly)
continue;
if (fcr != rs->fcr)
continue;
if (prim != rs->prim)
continue;
if (nroots != rs->nroots)
continue;
/* We have a matching one already */
rs->users++;
goto out;
}
/* Create a new one */
rs = rs_init(symsize, gfpoly, fcr, prim, nroots);
if (rs) {
rs->users = 1;
list_add(&rs->list, &rslist);
}
out:
up(&rslistlock);
return rs;
}
#ifdef CONFIG_REED_SOLOMON_ENC8
/**
* encode_rs8 - Calculate the parity for data values (8bit data width)
*
* @rs: the rs control structure
* @data: data field of a given type
* @len: data length
* @par: parity data, must be initialized by caller (usually all 0)
* @invmsk: invert data mask (will be xored on data)
*
* The parity uses a uint16_t data type to enable
* symbol size > 8. The calling code must take care of encoding of the
* syndrome result for storage itself.
*/
int encode_rs8(struct rs_control *rs, uint8_t *data, int len, uint16_t *par,
uint16_t invmsk)
{
#include "encode_rs.c"
}
EXPORT_SYMBOL_GPL(encode_rs8);
#endif
#ifdef CONFIG_REED_SOLOMON_DEC8
/**
* decode_rs8 - Decode codeword (8bit data width)
*
* @rs: the rs control structure
* @data: data field of a given type
* @par: received parity data field
* @len: data length
* @s: syndrome data field (if NULL, syndrome is calculated)
* @no_eras: number of erasures
* @eras_pos: position of erasures, can be NULL
* @invmsk: invert data mask (will be xored on data, not on parity!)
* @corr: buffer to store correction bitmask on eras_pos
*
* The syndrome and parity uses a uint16_t data type to enable
* symbol size > 8. The calling code must take care of decoding of the
* syndrome result and the received parity before calling this code.
*/
int decode_rs8(struct rs_control *rs, uint8_t *data, uint16_t *par, int len,
uint16_t *s, int no_eras, int *eras_pos, uint16_t invmsk,
uint16_t *corr)
{
#include "decode_rs.c"
}
EXPORT_SYMBOL_GPL(decode_rs8);
#endif
#ifdef CONFIG_REED_SOLOMON_ENC16
/**
* encode_rs16 - Calculate the parity for data values (16bit data width)
*
* @rs: the rs control structure
* @data: data field of a given type
* @len: data length
* @par: parity data, must be initialized by caller (usually all 0)
* @invmsk: invert data mask (will be xored on data, not on parity!)
*
* Each field in the data array contains up to symbol size bits of valid data.
*/
int encode_rs16(struct rs_control *rs, uint16_t *data, int len, uint16_t *par,
uint16_t invmsk)
{
#include "encode_rs.c"
}
EXPORT_SYMBOL_GPL(encode_rs16);
#endif
#ifdef CONFIG_REED_SOLOMON_DEC16
/**
* decode_rs16 - Decode codeword (16bit data width)
*
* @rs: the rs control structure
* @data: data field of a given type
* @par: received parity data field
* @len: data length
* @s: syndrome data field (if NULL, syndrome is calculated)
* @no_eras: number of erasures
* @eras_pos: position of erasures, can be NULL
* @invmsk: invert data mask (will be xored on data, not on parity!)
* @corr: buffer to store correction bitmask on eras_pos
*
* Each field in the data array contains up to symbol size bits of valid data.
*/
int decode_rs16(struct rs_control *rs, uint16_t *data, uint16_t *par, int len,
uint16_t *s, int no_eras, int *eras_pos, uint16_t invmsk,
uint16_t *corr)
{
#include "decode_rs.c"
}
EXPORT_SYMBOL_GPL(decode_rs16);
#endif
EXPORT_SYMBOL_GPL(init_rs);
EXPORT_SYMBOL_GPL(free_rs);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Reed Solomon encoder/decoder");
MODULE_AUTHOR("Phil Karn, Thomas Gleixner");