mtd: nand: add software BCH ECC support

This patch adds software BCH ECC support to mtd, in order to handle recent NAND device ecc requirements (4 bits or more). It does so by adding a new ecc mode (NAND_ECC_SOFT_BCH) for use by board drivers, and a new Kconfig option to enable BCH support. It relies on the generic BCH library introduced in a previous patch. When a board driver uses mode NAND_ECC_SOFT_BCH, it should also set fields chip->ecc.size and chip->ecc.bytes to select BCH ecc data size and required error correction capability. See nand_bch_init() documentation for details. It has been tested on the following platforms using mtd-utils, UBI and UBIFS: x86 (with nandsim), arm926ejs. Signed-off-by: Ivan Djelic <ivan.djelic@parrot.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
author: Ivan Djelic <ivan.djelic@parrot.com> 2011-03-11 05:05:33 -0500
committer: David Woodhouse <David.Woodhouse@intel.com> 2011-03-11 12:49:08 -0500
commit: 193bd40026443835e1b96c79d5efe559d01509ae (patch)
tree: 979bace7cd9806753c95867c6df89fe2de98fc73 /include/linux/mtd
parent: 89d8d32060de17c23f761df74799c7c07b79dd01 (diff)
2 files changed, 75 insertions, 0 deletions
diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
index 1f489b247a29..ae67ef56a8f5 100644
--- a/include/linux/mtd/nand.h
+++ b/include/linux/mtd/nand.h
@@ -140,6 +140,7 @@ typedef enum {
        NAND_ECC_HW,
        NAND_ECC_HW_SYNDROME,
        NAND_ECC_HW_OOB_FIRST,
+        NAND_ECC_SOFT_BCH,
 } nand_ecc_modes_t;
 /*
@@ -339,6 +340,7 @@ 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
@@ -362,6 +364,7 @@ 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,
                        uint8_t *ecc_code);
diff --git a/include/linux/mtd/nand_bch.h b/include/linux/mtd/nand_bch.h
new file mode 100644
index 000000000000..74acf5367556
--- /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_MTD_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_MTD_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_MTD_NAND_ECC_BCH */
+#endif /* __MTD_NAND_BCH_H__ */
author	Ivan Djelic <ivan.djelic@parrot.com>	2011-03-11 05:05:33 -0500
committer	David Woodhouse <David.Woodhouse@intel.com>	2011-03-11 12:49:08 -0500
commit	193bd40026443835e1b96c79d5efe559d01509ae (patch)
tree	979bace7cd9806753c95867c6df89fe2de98fc73 /include/linux/mtd
parent	89d8d32060de17c23f761df74799c7c07b79dd01 (diff)

diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h index 1f489b247a29..ae67ef56a8f5 100644 --- a/include/linux/mtd/nand.h +++ b/include/linux/mtd/nand.h
@@ -140,6 +140,7 @@ typedef enum {
140	NAND_ECC_HW,	140	NAND_ECC_HW,
141	NAND_ECC_HW_SYNDROME,	141	NAND_ECC_HW_SYNDROME,
142	NAND_ECC_HW_OOB_FIRST,	142	NAND_ECC_HW_OOB_FIRST,
		143	NAND_ECC_SOFT_BCH,
143	} nand_ecc_modes_t;	144	} nand_ecc_modes_t;
144		145
145	/*	146	/*
@@ -339,6 +340,7 @@ struct nand_hw_control {
339	* @prepad: padding information for syndrome based ecc generators	340	* @prepad: padding information for syndrome based ecc generators
340	* @postpad: padding information for syndrome based ecc generators	341	* @postpad: padding information for syndrome based ecc generators
341	* @layout: ECC layout control struct pointer	342	* @layout: ECC layout control struct pointer
		343	* @priv: pointer to private ecc control data
342	* @hwctl: function to control hardware ecc generator. Must only	344	* @hwctl: function to control hardware ecc generator. Must only
343	* be provided if an hardware ECC is available	345	* be provided if an hardware ECC is available
344	* @calculate: function for ecc calculation or readback from ecc hardware	346	* @calculate: function for ecc calculation or readback from ecc hardware
@@ -362,6 +364,7 @@ struct nand_ecc_ctrl {
362	int prepad;	364	int prepad;
363	int postpad;	365	int postpad;
364	struct nand_ecclayout *layout;	366	struct nand_ecclayout *layout;
		367	void *priv;
365	void (hwctl)(struct mtd_info mtd, int mode);	368	void (hwctl)(struct mtd_info mtd, int mode);
366	int (calculate)(struct mtd_info mtd, const uint8_t *dat,	369	int (calculate)(struct mtd_info mtd, const uint8_t *dat,
367	uint8_t *ecc_code);	370	uint8_t *ecc_code);


diff --git a/include/linux/mtd/nand_bch.h b/include/linux/mtd/nand_bch.h new file mode 100644 index 000000000000..74acf5367556 --- /dev/null +++ b/include/linux/mtd/nand_bch.h
@@ -0,0 +1,72 @@
		1	/*
		2	* Copyright © 2011 Ivan Djelic <ivan.djelic@parrot.com>
		3	*
		4	* This program is free software; you can redistribute it and/or modify
		5	* it under the terms of the GNU General Public License version 2 as
		6	* published by the Free Software Foundation.
		7	*
		8	* This file is the header for the NAND BCH ECC implementation.
		9	*/
		10
		11	#ifndef __MTD_NAND_BCH_H__
		12	#define __MTD_NAND_BCH_H__
		13
		14	struct mtd_info;
		15	struct nand_bch_control;
		16
		17	#if defined(CONFIG_MTD_NAND_ECC_BCH)
		18
		19	static inline int mtd_nand_has_bch(void) { return 1; }
		20
		21	/*
		22	* Calculate BCH ecc code
		23	*/
		24	int nand_bch_calculate_ecc(struct mtd_info mtd, const u_char dat,
		25	u_char *ecc_code);
		26
		27	/*
		28	* Detect and correct bit errors
		29	*/
		30	int nand_bch_correct_data(struct mtd_info mtd, u_char dat, u_char *read_ecc,
		31	u_char *calc_ecc);
		32	/*
		33	* Initialize BCH encoder/decoder
		34	*/
		35	struct nand_bch_control *
		36	nand_bch_init(struct mtd_info *mtd, unsigned int eccsize,
		37	unsigned int eccbytes, struct nand_ecclayout **ecclayout);
		38	/*
		39	* Release BCH encoder/decoder resources
		40	*/
		41	void nand_bch_free(struct nand_bch_control *nbc);
		42
		43	#else /* !CONFIG_MTD_NAND_ECC_BCH */
		44
		45	static inline int mtd_nand_has_bch(void) { return 0; }
		46
		47	static inline int
		48	nand_bch_calculate_ecc(struct mtd_info mtd, const u_char dat,
		49	u_char *ecc_code)
		50	{
		51	return -1;
		52	}
		53
		54	static inline int
		55	nand_bch_correct_data(struct mtd_info mtd, unsigned char buf,
		56	unsigned char read_ecc, unsigned char calc_ecc)
		57	{
		58	return -1;
		59	}
		60
		61	static inline struct nand_bch_control *
		62	nand_bch_init(struct mtd_info *mtd, unsigned int eccsize,
		63	unsigned int eccbytes, struct nand_ecclayout **ecclayout)
		64	{
		65	return NULL;
		66	}
		67
		68	static inline void nand_bch_free(struct nand_bch_control *nbc) {}
		69
		70	#endif /* CONFIG_MTD_NAND_ECC_BCH */
		71
		72	#endif /* __MTD_NAND_BCH_H__ */