[linux-2.6-block.git] / lib / reed_solomon / reed_solomon.c

// SPDX-License-Identifier: GPL-2.0
/*
 * 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
 *
 * 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>

/* 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)
 * @gfp:	GFP_ flags for allocations
 *
 * 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, gfp_t gfp)
{
	struct rs_control *rs;
	int i, j, sr, root, iprim;

	rs = kzalloc(sizeof(*rs), gfp);
	if (!rs)
		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);
	if (rs->alpha_to == NULL)
		goto err;

	rs->index_of = kmalloc(sizeof(uint16_t) * (rs->nn + 1), gfp);
	if (rs->index_of == NULL)
		goto err;

	rs->genpoly = kmalloc(sizeof(uint16_t) * (rs->nroots + 1), gfp);
	if(rs->genpoly == NULL)
		goto err;

	/* 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 err;

	/* 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;

err:
	kfree(rs->genpoly);
	kfree(rs->index_of);
	kfree(rs->alpha_to);
	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);
}
EXPORT_SYMBOL_GPL(free_rs);

/**
 * 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)
 *  @gfp:	GFP_ flags for allocations
 */
static struct rs_control *init_rs_internal(int symsize, int gfpoly,
					   int (*gffunc)(int), int fcr,
					   int prim, int nroots, gfp_t gfp)
{
	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, gfp);
	if (rs) {
		rs->users = 1;
		list_add(&rs->list, &rslist);
	}
out:
	mutex_unlock(&rslistlock);
	return rs;
}

/**
 * init_rs_gfp - 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)
 *  @gfp:	GFP_ flags for allocations
 */
struct rs_control *init_rs_gfp(int symsize, int gfpoly, int fcr, int prim,
			       int nroots, gfp_t gfp)
{
	return init_rs_internal(symsize, gfpoly, NULL, fcr, prim, nroots, gfp);
}
EXPORT_SYMBOL_GPL(init_rs_gfp);

/**
 * 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,
				GFP_KERNEL);
}
EXPORT_SYMBOL_GPL(init_rs_non_canonical);

#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

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Reed Solomon encoder/decoder");
MODULE_AUTHOR("Phil Karn, Thomas Gleixner");
Commit	Line	Data
dc8f923e	1	// SPDX-License-Identifier: GPL-2.0
03ead842	2	/*
3413e189	3	* Generic Reed Solomon encoder / decoder library
03ead842	4	*
1da177e4 LT	5	* Copyright (C) 2004 Thomas Gleixner (tglx@linutronix.de)
	6	*
	7	* Reed Solomon code lifted from reed solomon library written by Phil Karn
	8	* Copyright 2002 Phil Karn, KA9Q
	9	*
1da177e4	10	* Description:
03ead842	11	*
1da177e4 LT	12	* The generic Reed Solomon library provides runtime configurable
	13	* encoding / decoding of RS codes.
	14	* Each user must call init_rs to get a pointer to a rs_control
	15	* structure for the given rs parameters. This structure is either
	16	* generated or a already available matching control structure is used.
	17	* If a structure is generated then the polynomial arrays for
	18	* fast encoding / decoding are built. This can take some time so
	19	* make sure not to call this function from a time critical path.
03ead842	20	* Usually a module / driver should initialize the necessary
1da177e4 LT	21	* rs_control structure on module / driver init and release it
1da177e4 LT	22	* on exit.
03ead842 TG	23	* The encoding puts the calculated syndrome into a given syndrome
03ead842 TG	24	* buffer.
1da177e4 LT	25	* The decoding is a two step process. The first step calculates
	26	* the syndrome over the received (data + syndrome) and calls the
	27	* second stage, which does the decoding / error correction itself.
	28	* Many hw encoders provide a syndrome calculation over the received
	29	* data + syndrome and can call the second stage directly.
1da177e4	30	*/
1da177e4 LT	31	#include <linux/errno.h>
	32	#include <linux/kernel.h>
	33	#include <linux/init.h>
	34	#include <linux/module.h>
	35	#include <linux/rslib.h>
	36	#include <linux/slab.h>
97d1f15b	37	#include <linux/mutex.h>
1da177e4 LT	38
	39	/* This list holds all currently allocated rs control structures */
	40	static LIST_HEAD (rslist);
	41	/* Protection for the list */
97d1f15b	42	static DEFINE_MUTEX(rslistlock);
1da177e4	43
03ead842	44	/**
1da177e4	45	* rs_init - Initialize a Reed-Solomon codec
1da177e4 LT	46	* @symsize: symbol size, bits (1-8)
1da177e4 LT	47	* @gfpoly: Field generator polynomial coefficients
d7e5a546	48	* @gffunc: Field generator function
1da177e4 LT	49	* @fcr: first root of RS code generator polynomial, index form
	50	* @prim: primitive element to generate polynomial roots
	51	* @nroots: RS code generator polynomial degree (number of roots)
83a530e1	52	* @gfp: GFP_ flags for allocations
1da177e4 LT	53	*
1da177e4 LT	54	* Allocate a control structure and the polynom arrays for faster
9dc65576	55	* en/decoding. Fill the arrays according to the given parameters.
1da177e4	56	*/
d7e5a546	57	static struct rs_control rs_init(int symsize, int gfpoly, int (gffunc)(int),
83a530e1	58	int fcr, int prim, int nroots, gfp_t gfp)
1da177e4 LT	59	{
	60	struct rs_control *rs;
	61	int i, j, sr, root, iprim;
	62
a85e126a	63	rs = kzalloc(sizeof(*rs), gfp);
83a530e1	64	if (!rs)
1da177e4 LT	65	return NULL;
	66
	67	INIT_LIST_HEAD(&rs->list);
	68
	69	rs->mm = symsize;
	70	rs->nn = (1 << symsize) - 1;
	71	rs->fcr = fcr;
	72	rs->prim = prim;
	73	rs->nroots = nroots;
	74	rs->gfpoly = gfpoly;
d7e5a546	75	rs->gffunc = gffunc;
1da177e4 LT	76
1da177e4 LT	77	/* Allocate the arrays */
83a530e1	78	rs->alpha_to = kmalloc(sizeof(uint16_t) * (rs->nn + 1), gfp);
1da177e4	79	if (rs->alpha_to == NULL)
a85e126a	80	goto err;
1da177e4	81
83a530e1	82	rs->index_of = kmalloc(sizeof(uint16_t) * (rs->nn + 1), gfp);
1da177e4	83	if (rs->index_of == NULL)
a85e126a	84	goto err;
1da177e4	85
83a530e1	86	rs->genpoly = kmalloc(sizeof(uint16_t) * (rs->nroots + 1), gfp);
1da177e4	87	if(rs->genpoly == NULL)
a85e126a	88	goto err;
1da177e4 LT	89
	90	/* Generate Galois field lookup tables */
	91	rs->index_of[0] = rs->nn; /* log(zero) = -inf */
	92	rs->alpha_to[rs->nn] = 0; /* alpha*-inf = 0 /
d7e5a546 SB	93	if (gfpoly) {
	94	sr = 1;
	95	for (i = 0; i < rs->nn; i++) {
	96	rs->index_of[sr] = i;
	97	rs->alpha_to[i] = sr;
	98	sr <<= 1;
	99	if (sr & (1 << symsize))
	100	sr ^= gfpoly;
	101	sr &= rs->nn;
	102	}
	103	} else {
	104	sr = gffunc(0);
	105	for (i = 0; i < rs->nn; i++) {
	106	rs->index_of[sr] = i;
	107	rs->alpha_to[i] = sr;
	108	sr = gffunc(sr);
	109	}
1da177e4 LT	110	}
1da177e4 LT	111	/* If it's not primitive, exit */
d7e5a546	112	if(sr != rs->alpha_to[0])
a85e126a	113	goto err;
1da177e4 LT	114
	115	/* Find prim-th root of 1, used in decoding */
	116	for(iprim = 1; (iprim % prim) != 0; iprim += rs->nn);
	117	/* prim-th root of 1, index form */
	118	rs->iprim = iprim / prim;
	119
	120	/* Form RS code generator polynomial from its roots */
	121	rs->genpoly[0] = 1;
	122	for (i = 0, root = fcr * prim; i < nroots; i++, root += prim) {
	123	rs->genpoly[i + 1] = 1;
	124	/* Multiply rs->genpoly[] by @*(root + x) /
	125	for (j = i; j > 0; j--) {
	126	if (rs->genpoly[j] != 0) {
03ead842 TG	127	rs->genpoly[j] = rs->genpoly[j -1] ^
03ead842 TG	128	rs->alpha_to[rs_modnn(rs,
1da177e4 LT	129	rs->index_of[rs->genpoly[j]] + root)];
	130	} else
	131	rs->genpoly[j] = rs->genpoly[j - 1];
	132	}
	133	/* rs->genpoly[0] can never be zero */
03ead842 TG	134	rs->genpoly[0] =
03ead842 TG	135	rs->alpha_to[rs_modnn(rs,
1da177e4 LT	136	rs->index_of[rs->genpoly[0]] + root)];
	137	}
	138	/* convert rs->genpoly[] to index form for quicker encoding */
	139	for (i = 0; i <= nroots; i++)
	140	rs->genpoly[i] = rs->index_of[rs->genpoly[i]];
	141	return rs;
	142
a85e126a	143	err:
1da177e4	144	kfree(rs->genpoly);
1da177e4	145	kfree(rs->index_of);
1da177e4	146	kfree(rs->alpha_to);
1da177e4 LT	147	kfree(rs);
	148	return NULL;
	149	}
	150
	151
03ead842	152	/**
9dc65576	153	* free_rs - Free the rs control structure, if it is no longer used
1da177e4 LT	154	* @rs: the control structure which is not longer used by the
	155	* caller
	156	*/
	157	void free_rs(struct rs_control *rs)
	158	{
97d1f15b	159	mutex_lock(&rslistlock);
1da177e4 LT	160	rs->users--;
	161	if(!rs->users) {
	162	list_del(&rs->list);
	163	kfree(rs->alpha_to);
	164	kfree(rs->index_of);
	165	kfree(rs->genpoly);
	166	kfree(rs);
	167	}
97d1f15b	168	mutex_unlock(&rslistlock);
1da177e4	169	}
83a530e1	170	EXPORT_SYMBOL_GPL(free_rs);
1da177e4	171
03ead842	172	/**
d7e5a546	173	* init_rs_internal - Find a matching or allocate a new rs control structure
1da177e4 LT	174	* @symsize: the symbol size (number of bits)
	175	* @gfpoly: the extended Galois field generator polynomial coefficients,
	176	* with the 0th coefficient in the low order bit. The polynomial
	177	* must be primitive;
d7e5a546 SB	178	* @gffunc: pointer to function to generate the next field element,
	179	* or the multiplicative identity element if given 0. Used
	180	* instead of gfpoly if gfpoly is 0
cc4b86e4	181	* @fcr: the first consecutive root of the rs code generator polynomial
1da177e4 LT	182	* in index form
	183	* @prim: primitive element to generate polynomial roots
	184	* @nroots: RS code generator polynomial degree (number of roots)
83a530e1	185	* @gfp: GFP_ flags for allocations
1da177e4	186	*/
d7e5a546	187	static struct rs_control *init_rs_internal(int symsize, int gfpoly,
83a530e1 TG	188	int (*gffunc)(int), int fcr,
83a530e1 TG	189	int prim, int nroots, gfp_t gfp)
1da177e4	190	{
83a530e1 TG	191	struct list_head *tmp;
83a530e1 TG	192	struct rs_control *rs;
1da177e4 LT	193
	194	/* Sanity checks */
	195	if (symsize < 1)
	196	return NULL;
	197	if (fcr < 0 \|\| fcr >= (1<<symsize))
cc4b86e4	198	return NULL;
1da177e4	199	if (prim <= 0 \|\| prim >= (1<<symsize))
cc4b86e4	200	return NULL;
03ead842	201	if (nroots < 0 \|\| nroots >= (1<<symsize))
1da177e4	202	return NULL;
03ead842	203
97d1f15b	204	mutex_lock(&rslistlock);
1da177e4 LT	205
	206	/* Walk through the list and look for a matching entry */
	207	list_for_each(tmp, &rslist) {
	208	rs = list_entry(tmp, struct rs_control, list);
	209	if (symsize != rs->mm)
	210	continue;
	211	if (gfpoly != rs->gfpoly)
	212	continue;
d7e5a546 SB	213	if (gffunc != rs->gffunc)
d7e5a546 SB	214	continue;
1da177e4	215	if (fcr != rs->fcr)
03ead842	216	continue;
1da177e4	217	if (prim != rs->prim)
03ead842	218	continue;
1da177e4 LT	219	if (nroots != rs->nroots)
	220	continue;
	221	/* We have a matching one already */
	222	rs->users++;
	223	goto out;
	224	}
	225
	226	/* Create a new one */
83a530e1	227	rs = rs_init(symsize, gfpoly, gffunc, fcr, prim, nroots, gfp);
1da177e4 LT	228	if (rs) {
	229	rs->users = 1;
	230	list_add(&rs->list, &rslist);
	231	}
03ead842	232	out:
97d1f15b	233	mutex_unlock(&rslistlock);
1da177e4 LT	234	return rs;
	235	}
	236
d7e5a546	237	/**
83a530e1	238	* init_rs_gfp - Find a matching or allocate a new rs control structure
d7e5a546 SB	239	* @symsize: the symbol size (number of bits)
	240	* @gfpoly: the extended Galois field generator polynomial coefficients,
	241	* with the 0th coefficient in the low order bit. The polynomial
	242	* must be primitive;
cc4b86e4	243	* @fcr: the first consecutive root of the rs code generator polynomial
d7e5a546 SB	244	* in index form
	245	* @prim: primitive element to generate polynomial roots
	246	* @nroots: RS code generator polynomial degree (number of roots)
83a530e1	247	* @gfp: GFP_ flags for allocations
d7e5a546	248	*/
83a530e1 TG	249	struct rs_control *init_rs_gfp(int symsize, int gfpoly, int fcr, int prim,
83a530e1 TG	250	int nroots, gfp_t gfp)
d7e5a546	251	{
83a530e1	252	return init_rs_internal(symsize, gfpoly, NULL, fcr, prim, nroots, gfp);
d7e5a546	253	}
83a530e1	254	EXPORT_SYMBOL_GPL(init_rs_gfp);
d7e5a546 SB	255
	256	/**
	257	* init_rs_non_canonical - Find a matching or allocate a new rs control
	258	* structure, for fields with non-canonical
	259	* representation
	260	* @symsize: the symbol size (number of bits)
	261	* @gffunc: pointer to function to generate the next field element,
	262	* or the multiplicative identity element if given 0. Used
	263	* instead of gfpoly if gfpoly is 0
cc4b86e4	264	* @fcr: the first consecutive root of the rs code generator polynomial
d7e5a546 SB	265	* in index form
	266	* @prim: primitive element to generate polynomial roots
	267	* @nroots: RS code generator polynomial degree (number of roots)
	268	*/
	269	struct rs_control init_rs_non_canonical(int symsize, int (gffunc)(int),
cc4b86e4	270	int fcr, int prim, int nroots)
d7e5a546	271	{
83a530e1 TG	272	return init_rs_internal(symsize, 0, gffunc, fcr, prim, nroots,
83a530e1 TG	273	GFP_KERNEL);
d7e5a546	274	}
83a530e1	275	EXPORT_SYMBOL_GPL(init_rs_non_canonical);
d7e5a546	276
1da177e4	277	#ifdef CONFIG_REED_SOLOMON_ENC8
03ead842	278	/**
1da177e4	279	* encode_rs8 - Calculate the parity for data values (8bit data width)
1da177e4 LT	280	* @rs: the rs control structure
1da177e4 LT	281	* @data: data field of a given type
03ead842	282	* @len: data length
1da177e4 LT	283	* @par: parity data, must be initialized by caller (usually all 0)
	284	* @invmsk: invert data mask (will be xored on data)
	285	*
	286	* The parity uses a uint16_t data type to enable
	287	* symbol size > 8. The calling code must take care of encoding of the
	288	* syndrome result for storage itself.
	289	*/
03ead842	290	int encode_rs8(struct rs_control rs, uint8_t data, int len, uint16_t *par,
1da177e4 LT	291	uint16_t invmsk)
	292	{
	293	#include "encode_rs.c"
	294	}
	295	EXPORT_SYMBOL_GPL(encode_rs8);
	296	#endif
	297
	298	#ifdef CONFIG_REED_SOLOMON_DEC8
03ead842	299	/**
1da177e4	300	* decode_rs8 - Decode codeword (8bit data width)
1da177e4 LT	301	* @rs: the rs control structure
	302	* @data: data field of a given type
	303	* @par: received parity data field
	304	* @len: data length
	305	* @s: syndrome data field (if NULL, syndrome is calculated)
	306	* @no_eras: number of erasures
	307	* @eras_pos: position of erasures, can be NULL
	308	* @invmsk: invert data mask (will be xored on data, not on parity!)
	309	* @corr: buffer to store correction bitmask on eras_pos
	310	*
	311	* The syndrome and parity uses a uint16_t data type to enable
	312	* symbol size > 8. The calling code must take care of decoding of the
	313	* syndrome result and the received parity before calling this code.
eb684507	314	* Returns the number of corrected bits or -EBADMSG for uncorrectable errors.
1da177e4 LT	315	*/
1da177e4 LT	316	int decode_rs8(struct rs_control rs, uint8_t data, uint16_t *par, int len,
03ead842	317	uint16_t s, int no_eras, int eras_pos, uint16_t invmsk,
1da177e4 LT	318	uint16_t *corr)
	319	{
	320	#include "decode_rs.c"
	321	}
	322	EXPORT_SYMBOL_GPL(decode_rs8);
	323	#endif
	324
	325	#ifdef CONFIG_REED_SOLOMON_ENC16
	326	/**
	327	* encode_rs16 - Calculate the parity for data values (16bit data width)
1da177e4 LT	328	* @rs: the rs control structure
1da177e4 LT	329	* @data: data field of a given type
03ead842	330	* @len: data length
1da177e4 LT	331	* @par: parity data, must be initialized by caller (usually all 0)
	332	* @invmsk: invert data mask (will be xored on data, not on parity!)
	333	*
	334	* Each field in the data array contains up to symbol size bits of valid data.
	335	*/
03ead842	336	int encode_rs16(struct rs_control rs, uint16_t data, int len, uint16_t *par,
1da177e4 LT	337	uint16_t invmsk)
	338	{
	339	#include "encode_rs.c"
	340	}
	341	EXPORT_SYMBOL_GPL(encode_rs16);
	342	#endif
	343
	344	#ifdef CONFIG_REED_SOLOMON_DEC16
03ead842	345	/**
1da177e4	346	* decode_rs16 - Decode codeword (16bit data width)
1da177e4 LT	347	* @rs: the rs control structure
	348	* @data: data field of a given type
	349	* @par: received parity data field
	350	* @len: data length
	351	* @s: syndrome data field (if NULL, syndrome is calculated)
	352	* @no_eras: number of erasures
	353	* @eras_pos: position of erasures, can be NULL
03ead842	354	* @invmsk: invert data mask (will be xored on data, not on parity!)
1da177e4 LT	355	* @corr: buffer to store correction bitmask on eras_pos
	356	*
	357	* Each field in the data array contains up to symbol size bits of valid data.
eb684507	358	* Returns the number of corrected bits or -EBADMSG for uncorrectable errors.
1da177e4 LT	359	*/
1da177e4 LT	360	int decode_rs16(struct rs_control rs, uint16_t data, uint16_t *par, int len,
03ead842	361	uint16_t s, int no_eras, int eras_pos, uint16_t invmsk,
1da177e4 LT	362	uint16_t *corr)
	363	{
	364	#include "decode_rs.c"
	365	}
	366	EXPORT_SYMBOL_GPL(decode_rs16);
	367	#endif
	368
1da177e4 LT	369	MODULE_LICENSE("GPL");
	370	MODULE_DESCRIPTION("Reed Solomon encoder/decoder");
	371	MODULE_AUTHOR("Phil Karn, Thomas Gleixner");
	372