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!

1 files changed, 335 insertions, 0 deletions

diff --git a/lib/reed_solomon/reed_solomon.c b/lib/reed_solomon/reed_solomon.c
new file mode 100644
index 0000000000000..6604e3b1940c1
--- /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");
+