4 files changed, 667 insertions, 0 deletions

diff --git a/lib/reed_solomon/Makefile b/lib/reed_solomon/Makefile
new file mode 100644
index 000000000000..747a2de29346
--- /dev/null
+++ b/lib/reed_solomon/Makefile
@@ -0,0 +1,6 @@
+#
+# This is a modified version of reed solomon lib, 
+#
+
+obj-$(CONFIG_REED_SOLOMON) += reed_solomon.o
+
diff --git a/lib/reed_solomon/decode_rs.c b/lib/reed_solomon/decode_rs.c
new file mode 100644
index 000000000000..d401decd6289
--- /dev/null
+++ b/lib/reed_solomon/decode_rs.c
@@ -0,0 +1,272 @@
+/* 
+ * 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;
+
+}
diff --git a/lib/reed_solomon/encode_rs.c b/lib/reed_solomon/encode_rs.c
new file mode 100644
index 000000000000..237bf65ae886
--- /dev/null
+++ b/lib/reed_solomon/encode_rs.c
@@ -0,0 +1,54 @@
+/* 
+ * 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;
+}
diff --git a/lib/reed_solomon/reed_solomon.c b/lib/reed_solomon/reed_solomon.c
new file mode 100644
index 000000000000..6604e3b1940c
--- /dev/null
+++ b/lib/reed_solomon/reed_solomon.c
@@ -0,0 +1,335 @@
+/* 
+ * 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");
+