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 */
diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
index 1cdc7ae..527d9ae 100644
--- a/include/linux/mtd/nand.h
+++ b/include/linux/mtd/nand.h
@@ -18,13 +18,6 @@
#ifndef __LINUX_MTD_NAND_H
#define __LINUX_MTD_NAND_H
-/* XXX U-BOOT XXX */
-#if 0
-#include <linux/wait.h>
-#include <linux/spinlock.h>
-#include <linux/mtd/mtd.h>
-#endif
-
#include "config.h"
#include "linux/mtd/compat.h"
@@ -132,6 +125,7 @@
NAND_ECC_HW,
NAND_ECC_HW_SYNDROME,
NAND_ECC_HW_OOB_FIRST,
+ NAND_ECC_SOFT_BCH,
} nand_ecc_modes_t;
/*
@@ -308,6 +302,7 @@
* @prepad: padding information for syndrome based ecc generators
* @postpad: padding information for syndrome based ecc generators
* @layout: ECC layout control struct pointer
+ * @priv: pointer to private ecc control data
* @hwctl: function to control hardware ecc generator. Must only
* be provided if an hardware ECC is available
* @calculate: function for ecc calculation or readback from ecc hardware
@@ -328,6 +323,7 @@
int prepad;
int postpad;
struct nand_ecclayout *layout;
+ void *priv;
void (*hwctl)(struct mtd_info *mtd, int mode);
int (*calculate)(struct mtd_info *mtd,
const uint8_t *dat,
diff --git a/include/linux/mtd/nand_bch.h b/include/linux/mtd/nand_bch.h
new file mode 100644
index 0000000..d8754dd
--- /dev/null
+++ b/include/linux/mtd/nand_bch.h
@@ -0,0 +1,72 @@
+/*
+ * Copyright © 2011 Ivan Djelic <ivan.djelic@parrot.com>
+ *
+ * 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 file is the header for the NAND BCH ECC implementation.
+ */
+
+#ifndef __MTD_NAND_BCH_H__
+#define __MTD_NAND_BCH_H__
+
+struct mtd_info;
+struct nand_bch_control;
+
+#if defined(CONFIG_NAND_ECC_BCH)
+
+static inline int mtd_nand_has_bch(void) { return 1; }
+
+/*
+ * Calculate BCH ecc code
+ */
+int nand_bch_calculate_ecc(struct mtd_info *mtd, const u_char *dat,
+ u_char *ecc_code);
+
+/*
+ * Detect and correct bit errors
+ */
+int nand_bch_correct_data(struct mtd_info *mtd, u_char *dat, u_char *read_ecc,
+ u_char *calc_ecc);
+/*
+ * Initialize BCH encoder/decoder
+ */
+struct nand_bch_control *
+nand_bch_init(struct mtd_info *mtd, unsigned int eccsize,
+ unsigned int eccbytes, struct nand_ecclayout **ecclayout);
+/*
+ * Release BCH encoder/decoder resources
+ */
+void nand_bch_free(struct nand_bch_control *nbc);
+
+#else /* !CONFIG_NAND_ECC_BCH */
+
+static inline int mtd_nand_has_bch(void) { return 0; }
+
+static inline int
+nand_bch_calculate_ecc(struct mtd_info *mtd, const u_char *dat,
+ u_char *ecc_code)
+{
+ return -1;
+}
+
+static inline int
+nand_bch_correct_data(struct mtd_info *mtd, unsigned char *buf,
+ unsigned char *read_ecc, unsigned char *calc_ecc)
+{
+ return -1;
+}
+
+static inline struct nand_bch_control *
+nand_bch_init(struct mtd_info *mtd, unsigned int eccsize,
+ unsigned int eccbytes, struct nand_ecclayout **ecclayout)
+{
+ return NULL;
+}
+
+static inline void nand_bch_free(struct nand_bch_control *nbc) {}
+
+#endif /* CONFIG_NAND_ECC_BCH */
+
+#endif /* __MTD_NAND_BCH_H__ */