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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /include/linux/rslib.h
Initial import
Diffstat (limited to 'include/linux/rslib.h')
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diff --git a/include/linux/rslib.h b/include/linux/rslib.h
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+/*
+ * include/linux/rslib.h
+ *
+ * Overview:
+ * Generic Reed Solomon encoder / decoder library
+ *
+ * Copyright (C) 2004 Thomas Gleixner (tglx@linutronix.de)
+ *
+ * RS code lifted from reed solomon library written by Phil Karn
+ * Copyright 2002 Phil Karn, KA9Q
+ *
+ * $Id: rslib.h,v 1.4 2005/11/07 11:14:52 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.
+ */
+
+#ifndef _RSLIB_H_
+#define _RSLIB_H_
+
+#include <linux/list.h>
+
+/**
+ * struct rs_control - rs control structure
+ *
+ * @mm: Bits per symbol
+ * @nn: Symbols per block (= (1<<mm)-1)
+ * @alpha_to: log lookup table
+ * @index_of: Antilog lookup table
+ * @genpoly: Generator polynomial
+ * @nroots: Number of generator roots = number of parity symbols
+ * @fcr: First consecutive root, index form
+ * @prim: Primitive element, index form
+ * @iprim: prim-th root of 1, index form
+ * @gfpoly: The primitive generator polynominal
+ * @gffunc: Function to generate the field, if non-canonical representation
+ * @users: Users of this structure
+ * @list: List entry for the rs control list
+*/
+struct rs_control {
+ int mm;
+ int nn;
+ uint16_t *alpha_to;
+ uint16_t *index_of;
+ uint16_t *genpoly;
+ int nroots;
+ int fcr;
+ int prim;
+ int iprim;
+ int gfpoly;
+ int (*gffunc)(int);
+ int users;
+ struct list_head list;
+};
+
+/* General purpose RS codec, 8-bit data width, symbol width 1-15 bit */
+#ifdef CONFIG_REED_SOLOMON_ENC8
+int encode_rs8(struct rs_control *rs, uint8_t *data, int len, uint16_t *par,
+ uint16_t invmsk);
+#endif
+#ifdef CONFIG_REED_SOLOMON_DEC8
+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);
+#endif
+
+/* General purpose RS codec, 16-bit data width, symbol width 1-15 bit */
+#ifdef CONFIG_REED_SOLOMON_ENC16
+int encode_rs16(struct rs_control *rs, uint16_t *data, int len, uint16_t *par,
+ uint16_t invmsk);
+#endif
+#ifdef CONFIG_REED_SOLOMON_DEC16
+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);
+#endif
+
+/* Create or get a matching rs control structure */
+struct rs_control *init_rs(int symsize, int gfpoly, int fcr, int prim,
+ int nroots);
+struct rs_control *init_rs_non_canonical(int symsize, int (*func)(int),
+ int fcr, int prim, int nroots);
+
+/* Release a rs control structure */
+void free_rs(struct rs_control *rs);
+
+/** modulo replacement for galois field arithmetics
+ *
+ * @rs: the rs control structure
+ * @x: the value to reduce
+ *
+ * where
+ * rs->mm = number of bits per symbol
+ * rs->nn = (2^rs->mm) - 1
+ *
+ * Simple arithmetic modulo would return a wrong result for values
+ * >= 3 * rs->nn
+*/
+static inline int rs_modnn(struct rs_control *rs, int x)
+{
+ while (x >= rs->nn) {
+ x -= rs->nn;
+ x = (x >> rs->mm) + (x & rs->nn);
+ }
+ return x;
+}
+
+#endif