nand: Merge BCH code from Linux nand driver
[backport from linux commit 02f8c6aee8df3cdc935e9bdd4f2d020306035dbe]
This patch merges the BCH ECC algorithm from the 3.0 Linux kernel.
This enables U-Boot to support modern NAND flash chips that
require more than 1-bit of ECC in software.
Signed-off-by: Christian Hitz <christian.hitz@aizo.com>
Cc: Scott Wood <scottwood@freescale.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>
diff --git a/include/linux/bch.h b/include/linux/bch.h
new file mode 100644
index 0000000..295b4ef
--- /dev/null
+++ b/include/linux/bch.h
@@ -0,0 +1,79 @@
+/*
+ * Generic binary BCH encoding/decoding library
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 51
+ * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Copyright © 2011 Parrot S.A.
+ *
+ * Author: Ivan Djelic <ivan.djelic@parrot.com>
+ *
+ * Description:
+ *
+ * This library provides runtime configurable encoding/decoding of binary
+ * Bose-Chaudhuri-Hocquenghem (BCH) codes.
+*/
+#ifndef _BCH_H
+#define _BCH_H
+
+#include <linux/types.h>
+
+/**
+ * struct bch_control - BCH control structure
+ * @m: Galois field order
+ * @n: maximum codeword size in bits (= 2^m-1)
+ * @t: error correction capability in bits
+ * @ecc_bits: ecc exact size in bits, i.e. generator polynomial degree (<=m*t)
+ * @ecc_bytes: ecc max size (m*t bits) in bytes
+ * @a_pow_tab: Galois field GF(2^m) exponentiation lookup table
+ * @a_log_tab: Galois field GF(2^m) log lookup table
+ * @mod8_tab: remainder generator polynomial lookup tables
+ * @ecc_buf: ecc parity words buffer
+ * @ecc_buf2: ecc parity words buffer
+ * @xi_tab: GF(2^m) base for solving degree 2 polynomial roots
+ * @syn: syndrome buffer
+ * @cache: log-based polynomial representation buffer
+ * @elp: error locator polynomial
+ * @poly_2t: temporary polynomials of degree 2t
+ */
+struct bch_control {
+ unsigned int m;
+ unsigned int n;
+ unsigned int t;
+ unsigned int ecc_bits;
+ unsigned int ecc_bytes;
+/* private: */
+ uint16_t *a_pow_tab;
+ uint16_t *a_log_tab;
+ uint32_t *mod8_tab;
+ uint32_t *ecc_buf;
+ uint32_t *ecc_buf2;
+ unsigned int *xi_tab;
+ unsigned int *syn;
+ int *cache;
+ struct gf_poly *elp;
+ struct gf_poly *poly_2t[4];
+};
+
+struct bch_control *init_bch(int m, int t, unsigned int prim_poly);
+
+void free_bch(struct bch_control *bch);
+
+void encode_bch(struct bch_control *bch, const uint8_t *data,
+ unsigned int len, uint8_t *ecc);
+
+int decode_bch(struct bch_control *bch, const uint8_t *data, unsigned int len,
+ const uint8_t *recv_ecc, const uint8_t *calc_ecc,
+ const unsigned int *syn, unsigned int *errloc);
+
+#endif /* _BCH_H */