[net-next-2.6.git] / lib / reed_solomon / reed_solomon.c

/*
 * lib/reed_solomon/reed_solomon.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 1.7 2005/11/07 11:14:59 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 <linux/mutex.h>
#include <asm/semaphore.h>

/* This list holds all currently allocated rs control structures */
static LIST_HEAD (rslist);
/* Protection for the list */
static DEFINE_MUTEX(rslistlock);

/**
 * rs_init - Initialize a Reed-Solomon codec
 * @symsize:	symbol size, bits (1-8)
 * @gfpoly:	Field generator polynomial coefficients
 * @gffunc:	Field generator function
 * @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 (*gffunc)(int),
                                  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;
	rs->gffunc = gffunc;

	/* 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 */
	if (gfpoly) {
		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;
		}
	} else {
		sr = gffunc(0);
		for (i = 0; i < rs->nn; i++) {
			rs->index_of[sr] = i;
			rs->alpha_to[i] = sr;
			sr = gffunc(sr);
		}
	}
	/* If it's not primitive, exit */
	if(sr != rs->alpha_to[0])
		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 it is no longer used
 *  @rs:	the control structure which is not longer used by the
 *		caller
 */
void free_rs(struct rs_control *rs)
{
	mutex_lock(&rslistlock);
	rs->users--;
	if(!rs->users) {
		list_del(&rs->list);
		kfree(rs->alpha_to);
		kfree(rs->index_of);
		kfree(rs->genpoly);
		kfree(rs);
	}
	mutex_unlock(&rslistlock);
}

/**
 * init_rs_internal - 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;
 *  @gffunc:	pointer to function to generate the next field element,
 *		or the multiplicative identity element if given 0.  Used
 *		instead of gfpoly if gfpoly is 0
 *  @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)
 */
static struct rs_control *init_rs_internal(int symsize, int gfpoly,
                                           int (*gffunc)(int), 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))
		return NULL;

	mutex_lock(&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 (gffunc != rs->gffunc)
			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, gffunc, fcr, prim, nroots);
	if (rs) {
		rs->users = 1;
		list_add(&rs->list, &rslist);
	}
out:
	mutex_unlock(&rslistlock);
	return rs;
}

/**
 * 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)
{
	return init_rs_internal(symsize, gfpoly, NULL, fcr, prim, nroots);
}

/**
 * init_rs_non_canonical - Find a matching or allocate a new rs control
 *                         structure, for fields with non-canonical
 *                         representation
 *  @symsize:	the symbol size (number of bits)
 *  @gffunc:	pointer to function to generate the next field element,
 *		or the multiplicative identity element if given 0.  Used
 *		instead of gfpoly if gfpoly is 0
 *  @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_non_canonical(int symsize, int (*gffunc)(int),
                                         int fcr, int prim, int nroots)
{
	return init_rs_internal(symsize, 0, gffunc, fcr, prim, nroots);
}

#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.
 *  Returns the number of corrected bits or -EBADMSG for uncorrectable errors.
 */
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.
 *  Returns the number of corrected bits or -EBADMSG for uncorrectable errors.
 */
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(init_rs_non_canonical);
EXPORT_SYMBOL_GPL(free_rs);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Reed Solomon encoder/decoder");
MODULE_AUTHOR("Phil Karn, Thomas Gleixner");
Commit	Line	Data
03ead842	1	/*
f30c2269	2	* lib/reed_solomon/reed_solomon.c
1da177e4 LT	3	*
	4	* Overview:
	5	* Generic Reed Solomon encoder / decoder library
03ead842	6	*
1da177e4 LT	7	* Copyright (C) 2004 Thomas Gleixner (tglx@linutronix.de)
	8	*
	9	* Reed Solomon code lifted from reed solomon library written by Phil Karn
	10	* Copyright 2002 Phil Karn, KA9Q
	11	*
03ead842	12	* $Id: rslib.c,v 1.7 2005/11/07 11:14:59 gleixner Exp $
1da177e4 LT	13	*
	14	* This program is free software; you can redistribute it and/or modify
	15	* it under the terms of the GNU General Public License version 2 as
	16	* published by the Free Software Foundation.
	17	*
	18	* Description:
03ead842	19	*
1da177e4 LT	20	* The generic Reed Solomon library provides runtime configurable
	21	* encoding / decoding of RS codes.
	22	* Each user must call init_rs to get a pointer to a rs_control
	23	* structure for the given rs parameters. This structure is either
	24	* generated or a already available matching control structure is used.
	25	* If a structure is generated then the polynomial arrays for
	26	* fast encoding / decoding are built. This can take some time so
	27	* make sure not to call this function from a time critical path.
03ead842	28	* Usually a module / driver should initialize the necessary
1da177e4 LT	29	* rs_control structure on module / driver init and release it
1da177e4 LT	30	* on exit.
03ead842 TG	31	* The encoding puts the calculated syndrome into a given syndrome
03ead842 TG	32	* buffer.
1da177e4 LT	33	* The decoding is a two step process. The first step calculates
	34	* the syndrome over the received (data + syndrome) and calls the
	35	* second stage, which does the decoding / error correction itself.
	36	* Many hw encoders provide a syndrome calculation over the received
	37	* data + syndrome and can call the second stage directly.
	38	*
	39	*/
	40
	41	#include <linux/errno.h>
	42	#include <linux/kernel.h>
	43	#include <linux/init.h>
	44	#include <linux/module.h>
	45	#include <linux/rslib.h>
	46	#include <linux/slab.h>
97d1f15b	47	#include <linux/mutex.h>
1da177e4 LT	48	#include <asm/semaphore.h>
	49
	50	/* This list holds all currently allocated rs control structures */
	51	static LIST_HEAD (rslist);
	52	/* Protection for the list */
97d1f15b	53	static DEFINE_MUTEX(rslistlock);
1da177e4	54
03ead842	55	/**
1da177e4	56	* rs_init - Initialize a Reed-Solomon codec
1da177e4 LT	57	* @symsize: symbol size, bits (1-8)
1da177e4 LT	58	* @gfpoly: Field generator polynomial coefficients
d7e5a546	59	* @gffunc: Field generator function
1da177e4 LT	60	* @fcr: first root of RS code generator polynomial, index form
	61	* @prim: primitive element to generate polynomial roots
	62	* @nroots: RS code generator polynomial degree (number of roots)
	63	*
	64	* Allocate a control structure and the polynom arrays for faster
9dc65576	65	* en/decoding. Fill the arrays according to the given parameters.
1da177e4	66	*/
d7e5a546 SB	67	static struct rs_control rs_init(int symsize, int gfpoly, int (gffunc)(int),
d7e5a546 SB	68	int fcr, int prim, int nroots)
1da177e4 LT	69	{
	70	struct rs_control *rs;
	71	int i, j, sr, root, iprim;
	72
	73	/* Allocate the control structure */
	74	rs = kmalloc(sizeof (struct rs_control), GFP_KERNEL);
	75	if (rs == NULL)
	76	return NULL;
	77
	78	INIT_LIST_HEAD(&rs->list);
	79
	80	rs->mm = symsize;
	81	rs->nn = (1 << symsize) - 1;
	82	rs->fcr = fcr;
	83	rs->prim = prim;
	84	rs->nroots = nroots;
	85	rs->gfpoly = gfpoly;
d7e5a546	86	rs->gffunc = gffunc;
1da177e4 LT	87
	88	/* Allocate the arrays */
	89	rs->alpha_to = kmalloc(sizeof(uint16_t) * (rs->nn + 1), GFP_KERNEL);
	90	if (rs->alpha_to == NULL)
	91	goto errrs;
	92
	93	rs->index_of = kmalloc(sizeof(uint16_t) * (rs->nn + 1), GFP_KERNEL);
	94	if (rs->index_of == NULL)
	95	goto erralp;
	96
	97	rs->genpoly = kmalloc(sizeof(uint16_t) * (rs->nroots + 1), GFP_KERNEL);
	98	if(rs->genpoly == NULL)
	99	goto erridx;
	100
	101	/* Generate Galois field lookup tables */
	102	rs->index_of[0] = rs->nn; /* log(zero) = -inf */
	103	rs->alpha_to[rs->nn] = 0; /* alpha*-inf = 0 /
d7e5a546 SB	104	if (gfpoly) {
	105	sr = 1;
	106	for (i = 0; i < rs->nn; i++) {
	107	rs->index_of[sr] = i;
	108	rs->alpha_to[i] = sr;
	109	sr <<= 1;
	110	if (sr & (1 << symsize))
	111	sr ^= gfpoly;
	112	sr &= rs->nn;
	113	}
	114	} else {
	115	sr = gffunc(0);
	116	for (i = 0; i < rs->nn; i++) {
	117	rs->index_of[sr] = i;
	118	rs->alpha_to[i] = sr;
	119	sr = gffunc(sr);
	120	}
1da177e4 LT	121	}
1da177e4 LT	122	/* If it's not primitive, exit */
d7e5a546	123	if(sr != rs->alpha_to[0])
1da177e4 LT	124	goto errpol;
	125
	126	/* Find prim-th root of 1, used in decoding */
	127	for(iprim = 1; (iprim % prim) != 0; iprim += rs->nn);
	128	/* prim-th root of 1, index form */
	129	rs->iprim = iprim / prim;
	130
	131	/* Form RS code generator polynomial from its roots */
	132	rs->genpoly[0] = 1;
	133	for (i = 0, root = fcr * prim; i < nroots; i++, root += prim) {
	134	rs->genpoly[i + 1] = 1;
	135	/* Multiply rs->genpoly[] by @*(root + x) /
	136	for (j = i; j > 0; j--) {
	137	if (rs->genpoly[j] != 0) {
03ead842 TG	138	rs->genpoly[j] = rs->genpoly[j -1] ^
03ead842 TG	139	rs->alpha_to[rs_modnn(rs,
1da177e4 LT	140	rs->index_of[rs->genpoly[j]] + root)];
	141	} else
	142	rs->genpoly[j] = rs->genpoly[j - 1];
	143	}
	144	/* rs->genpoly[0] can never be zero */
03ead842 TG	145	rs->genpoly[0] =
03ead842 TG	146	rs->alpha_to[rs_modnn(rs,
1da177e4 LT	147	rs->index_of[rs->genpoly[0]] + root)];
	148	}
	149	/* convert rs->genpoly[] to index form for quicker encoding */
	150	for (i = 0; i <= nroots; i++)
	151	rs->genpoly[i] = rs->index_of[rs->genpoly[i]];
	152	return rs;
	153
	154	/* Error exit */
	155	errpol:
	156	kfree(rs->genpoly);
	157	erridx:
	158	kfree(rs->index_of);
	159	erralp:
	160	kfree(rs->alpha_to);
	161	errrs:
	162	kfree(rs);
	163	return NULL;
	164	}
	165
	166
03ead842	167	/**
9dc65576	168	* free_rs - Free the rs control structure, if it is no longer used
1da177e4 LT	169	* @rs: the control structure which is not longer used by the
	170	* caller
	171	*/
	172	void free_rs(struct rs_control *rs)
	173	{
97d1f15b	174	mutex_lock(&rslistlock);
1da177e4 LT	175	rs->users--;
	176	if(!rs->users) {
	177	list_del(&rs->list);
	178	kfree(rs->alpha_to);
	179	kfree(rs->index_of);
	180	kfree(rs->genpoly);
	181	kfree(rs);
	182	}
97d1f15b	183	mutex_unlock(&rslistlock);
1da177e4 LT	184	}
1da177e4 LT	185
03ead842	186	/**
d7e5a546	187	* init_rs_internal - Find a matching or allocate a new rs control structure
1da177e4 LT	188	* @symsize: the symbol size (number of bits)
	189	* @gfpoly: the extended Galois field generator polynomial coefficients,
	190	* with the 0th coefficient in the low order bit. The polynomial
	191	* must be primitive;
d7e5a546 SB	192	* @gffunc: pointer to function to generate the next field element,
	193	* or the multiplicative identity element if given 0. Used
	194	* instead of gfpoly if gfpoly is 0
03ead842	195	* @fcr: the first consecutive root of the rs code generator polynomial
1da177e4 LT	196	* in index form
	197	* @prim: primitive element to generate polynomial roots
	198	* @nroots: RS code generator polynomial degree (number of roots)
	199	*/
d7e5a546 SB	200	static struct rs_control *init_rs_internal(int symsize, int gfpoly,
	201	int (*gffunc)(int), int fcr,
	202	int prim, int nroots)
1da177e4 LT	203	{
	204	struct list_head *tmp;
	205	struct rs_control *rs;
	206
	207	/* Sanity checks */
	208	if (symsize < 1)
	209	return NULL;
	210	if (fcr < 0 \|\| fcr >= (1<<symsize))
	211	return NULL;
	212	if (prim <= 0 \|\| prim >= (1<<symsize))
	213	return NULL;
03ead842	214	if (nroots < 0 \|\| nroots >= (1<<symsize))
1da177e4	215	return NULL;
03ead842	216
97d1f15b	217	mutex_lock(&rslistlock);
1da177e4 LT	218
	219	/* Walk through the list and look for a matching entry */
	220	list_for_each(tmp, &rslist) {
	221	rs = list_entry(tmp, struct rs_control, list);
	222	if (symsize != rs->mm)
	223	continue;
	224	if (gfpoly != rs->gfpoly)
	225	continue;
d7e5a546 SB	226	if (gffunc != rs->gffunc)
d7e5a546 SB	227	continue;
1da177e4	228	if (fcr != rs->fcr)
03ead842	229	continue;
1da177e4	230	if (prim != rs->prim)
03ead842	231	continue;
1da177e4 LT	232	if (nroots != rs->nroots)
	233	continue;
	234	/* We have a matching one already */
	235	rs->users++;
	236	goto out;
	237	}
	238
	239	/* Create a new one */
d7e5a546	240	rs = rs_init(symsize, gfpoly, gffunc, fcr, prim, nroots);
1da177e4 LT	241	if (rs) {
	242	rs->users = 1;
	243	list_add(&rs->list, &rslist);
	244	}
03ead842	245	out:
97d1f15b	246	mutex_unlock(&rslistlock);
1da177e4 LT	247	return rs;
	248	}
	249
d7e5a546 SB	250	/**
	251	* init_rs - Find a matching or allocate a new rs control structure
	252	* @symsize: the symbol size (number of bits)
	253	* @gfpoly: the extended Galois field generator polynomial coefficients,
	254	* with the 0th coefficient in the low order bit. The polynomial
	255	* must be primitive;
	256	* @fcr: the first consecutive root of the rs code generator polynomial
	257	* in index form
	258	* @prim: primitive element to generate polynomial roots
	259	* @nroots: RS code generator polynomial degree (number of roots)
	260	*/
	261	struct rs_control *init_rs(int symsize, int gfpoly, int fcr, int prim,
	262	int nroots)
	263	{
	264	return init_rs_internal(symsize, gfpoly, NULL, fcr, prim, nroots);
	265	}
	266
	267	/**
	268	* init_rs_non_canonical - Find a matching or allocate a new rs control
	269	* structure, for fields with non-canonical
	270	* representation
	271	* @symsize: the symbol size (number of bits)
	272	* @gffunc: pointer to function to generate the next field element,
	273	* or the multiplicative identity element if given 0. Used
	274	* instead of gfpoly if gfpoly is 0
	275	* @fcr: the first consecutive root of the rs code generator polynomial
	276	* in index form
	277	* @prim: primitive element to generate polynomial roots
	278	* @nroots: RS code generator polynomial degree (number of roots)
	279	*/
	280	struct rs_control init_rs_non_canonical(int symsize, int (gffunc)(int),
	281	int fcr, int prim, int nroots)
	282	{
	283	return init_rs_internal(symsize, 0, gffunc, fcr, prim, nroots);
	284	}
	285
1da177e4	286	#ifdef CONFIG_REED_SOLOMON_ENC8
03ead842	287	/**
1da177e4	288	* encode_rs8 - Calculate the parity for data values (8bit data width)
1da177e4 LT	289	* @rs: the rs control structure
1da177e4 LT	290	* @data: data field of a given type
03ead842	291	* @len: data length
1da177e4 LT	292	* @par: parity data, must be initialized by caller (usually all 0)
	293	* @invmsk: invert data mask (will be xored on data)
	294	*
	295	* The parity uses a uint16_t data type to enable
	296	* symbol size > 8. The calling code must take care of encoding of the
	297	* syndrome result for storage itself.
	298	*/
03ead842	299	int encode_rs8(struct rs_control rs, uint8_t data, int len, uint16_t *par,
1da177e4 LT	300	uint16_t invmsk)
	301	{
	302	#include "encode_rs.c"
	303	}
	304	EXPORT_SYMBOL_GPL(encode_rs8);
	305	#endif
	306
	307	#ifdef CONFIG_REED_SOLOMON_DEC8
03ead842	308	/**
1da177e4	309	* decode_rs8 - Decode codeword (8bit data width)
1da177e4 LT	310	* @rs: the rs control structure
	311	* @data: data field of a given type
	312	* @par: received parity data field
	313	* @len: data length
	314	* @s: syndrome data field (if NULL, syndrome is calculated)
	315	* @no_eras: number of erasures
	316	* @eras_pos: position of erasures, can be NULL
	317	* @invmsk: invert data mask (will be xored on data, not on parity!)
	318	* @corr: buffer to store correction bitmask on eras_pos
	319	*
	320	* The syndrome and parity uses a uint16_t data type to enable
	321	* symbol size > 8. The calling code must take care of decoding of the
	322	* syndrome result and the received parity before calling this code.
eb684507	323	* Returns the number of corrected bits or -EBADMSG for uncorrectable errors.
1da177e4 LT	324	*/
1da177e4 LT	325	int decode_rs8(struct rs_control rs, uint8_t data, uint16_t *par, int len,
03ead842	326	uint16_t s, int no_eras, int eras_pos, uint16_t invmsk,
1da177e4 LT	327	uint16_t *corr)
	328	{
	329	#include "decode_rs.c"
	330	}
	331	EXPORT_SYMBOL_GPL(decode_rs8);
	332	#endif
	333
	334	#ifdef CONFIG_REED_SOLOMON_ENC16
	335	/**
	336	* encode_rs16 - Calculate the parity for data values (16bit data width)
1da177e4 LT	337	* @rs: the rs control structure
1da177e4 LT	338	* @data: data field of a given type
03ead842	339	* @len: data length
1da177e4 LT	340	* @par: parity data, must be initialized by caller (usually all 0)
	341	* @invmsk: invert data mask (will be xored on data, not on parity!)
	342	*
	343	* Each field in the data array contains up to symbol size bits of valid data.
	344	*/
03ead842	345	int encode_rs16(struct rs_control rs, uint16_t data, int len, uint16_t *par,
1da177e4 LT	346	uint16_t invmsk)
	347	{
	348	#include "encode_rs.c"
	349	}
	350	EXPORT_SYMBOL_GPL(encode_rs16);
	351	#endif
	352
	353	#ifdef CONFIG_REED_SOLOMON_DEC16
03ead842	354	/**
1da177e4	355	* decode_rs16 - Decode codeword (16bit data width)
1da177e4 LT	356	* @rs: the rs control structure
	357	* @data: data field of a given type
	358	* @par: received parity data field
	359	* @len: data length
	360	* @s: syndrome data field (if NULL, syndrome is calculated)
	361	* @no_eras: number of erasures
	362	* @eras_pos: position of erasures, can be NULL
03ead842	363	* @invmsk: invert data mask (will be xored on data, not on parity!)
1da177e4 LT	364	* @corr: buffer to store correction bitmask on eras_pos
	365	*
	366	* Each field in the data array contains up to symbol size bits of valid data.
eb684507	367	* Returns the number of corrected bits or -EBADMSG for uncorrectable errors.
1da177e4 LT	368	*/
1da177e4 LT	369	int decode_rs16(struct rs_control rs, uint16_t data, uint16_t *par, int len,
03ead842	370	uint16_t s, int no_eras, int eras_pos, uint16_t invmsk,
1da177e4 LT	371	uint16_t *corr)
	372	{
	373	#include "decode_rs.c"
	374	}
	375	EXPORT_SYMBOL_GPL(decode_rs16);
	376	#endif
	377
	378	EXPORT_SYMBOL_GPL(init_rs);
d7e5a546	379	EXPORT_SYMBOL_GPL(init_rs_non_canonical);
1da177e4 LT	380	EXPORT_SYMBOL_GPL(free_rs);
	381
	382	MODULE_LICENSE("GPL");
	383	MODULE_DESCRIPTION("Reed Solomon encoder/decoder");
	384	MODULE_AUTHOR("Phil Karn, Thomas Gleixner");
	385