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>

2 files changed, 75 insertions, 7 deletions

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 @@ typedef enum {
 	NAND_ECC_HW,
 	NAND_ECC_HW_SYNDROME,
 	NAND_ECC_HW_OOB_FIRST,
+	NAND_ECC_SOFT_BCH,
 } nand_ecc_modes_t;
 
 /*
@@ -308,6 +302,7 @@ struct nand_hw_control {
  * @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 @@ struct nand_ecc_ctrl {
 	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__ */