From: Miquel Raynal Date: Tue, 29 Sep 2020 23:01:06 +0000 (+0200) Subject: mtd: nand: ecc-bch: Move BCH code to the generic NAND layer X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=cdbe8df5e28e452c232c0c16b205edfd390d28e5;p=linux.git mtd: nand: ecc-bch: Move BCH code to the generic NAND layer BCH ECC code might be later re-used by the SPI NAND layer. Signed-off-by: Miquel Raynal Link: https://lore.kernel.org/linux-mtd/20200929230124.31491-3-miquel.raynal@bootlin.com --- diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig index 4a9aed4f01042..55c17fb0dee12 100644 --- a/drivers/mtd/nand/Kconfig +++ b/drivers/mtd/nand/Kconfig @@ -15,6 +15,17 @@ config MTD_NAND_ECC bool depends on MTD_NAND_CORE +config MTD_NAND_ECC_SW_BCH + bool "Software BCH ECC engine" + select BCH + select MTD_NAND_ECC + default n + help + This enables support for software BCH error correction. Binary BCH + codes are more powerful and cpu intensive than traditional Hamming + ECC codes. They are used with NAND devices requiring more than 1 bit + of error correction. + endmenu endmenu diff --git a/drivers/mtd/nand/Makefile b/drivers/mtd/nand/Makefile index 981372953b56c..c7179ff237532 100644 --- a/drivers/mtd/nand/Makefile +++ b/drivers/mtd/nand/Makefile @@ -8,3 +8,4 @@ obj-y += raw/ obj-y += spi/ nandcore-$(CONFIG_MTD_NAND_ECC) += ecc.o +nandcore-$(CONFIG_MTD_NAND_ECC_SW_BCH) += ecc-sw-bch.o diff --git a/drivers/mtd/nand/ecc-sw-bch.c b/drivers/mtd/nand/ecc-sw-bch.c new file mode 100644 index 0000000000000..6da14d0263d9c --- /dev/null +++ b/drivers/mtd/nand/ecc-sw-bch.c @@ -0,0 +1,219 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * This file provides ECC correction for more than 1 bit per block of data, + * using binary BCH codes. It relies on the generic BCH library lib/bch.c. + * + * Copyright © 2011 Ivan Djelic + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/** + * struct nand_bch_control - private NAND BCH control structure + * @bch: BCH control structure + * @errloc: error location array + * @eccmask: XOR ecc mask, allows erased pages to be decoded as valid + */ +struct nand_bch_control { + struct bch_control *bch; + unsigned int *errloc; + unsigned char *eccmask; +}; + +/** + * nand_bch_calculate_ecc - [NAND Interface] Calculate ECC for data block + * @chip: NAND chip object + * @buf: input buffer with raw data + * @code: output buffer with ECC + */ +int nand_bch_calculate_ecc(struct nand_chip *chip, const unsigned char *buf, + unsigned char *code) +{ + struct nand_bch_control *nbc = chip->ecc.priv; + unsigned int i; + + memset(code, 0, chip->ecc.bytes); + bch_encode(nbc->bch, buf, chip->ecc.size, code); + + /* apply mask so that an erased page is a valid codeword */ + for (i = 0; i < chip->ecc.bytes; i++) + code[i] ^= nbc->eccmask[i]; + + return 0; +} +EXPORT_SYMBOL(nand_bch_calculate_ecc); + +/** + * nand_bch_correct_data - [NAND Interface] Detect and correct bit error(s) + * @chip: NAND chip object + * @buf: raw data read from the chip + * @read_ecc: ECC from the chip + * @calc_ecc: the ECC calculated from raw data + * + * Detect and correct bit errors for a data byte block + */ +int nand_bch_correct_data(struct nand_chip *chip, unsigned char *buf, + unsigned char *read_ecc, unsigned char *calc_ecc) +{ + struct nand_bch_control *nbc = chip->ecc.priv; + unsigned int *errloc = nbc->errloc; + int i, count; + + count = bch_decode(nbc->bch, NULL, chip->ecc.size, read_ecc, calc_ecc, + NULL, errloc); + if (count > 0) { + for (i = 0; i < count; i++) { + if (errloc[i] < (chip->ecc.size*8)) + /* error is located in data, correct it */ + buf[errloc[i] >> 3] ^= (1 << (errloc[i] & 7)); + /* else error in ecc, no action needed */ + + pr_debug("%s: corrected bitflip %u\n", __func__, + errloc[i]); + } + } else if (count < 0) { + pr_err("ecc unrecoverable error\n"); + count = -EBADMSG; + } + return count; +} +EXPORT_SYMBOL(nand_bch_correct_data); + +/** + * nand_bch_init - [NAND Interface] Initialize NAND BCH error correction + * @mtd: MTD block structure + * + * Returns: + * a pointer to a new NAND BCH control structure, or NULL upon failure + * + * Initialize NAND BCH error correction. Parameters @eccsize and @eccbytes + * are used to compute BCH parameters m (Galois field order) and t (error + * correction capability). @eccbytes should be equal to the number of bytes + * required to store m*t bits, where m is such that 2^m-1 > @eccsize*8. + * + * Example: to configure 4 bit correction per 512 bytes, you should pass + * @eccsize = 512 (thus, m=13 is the smallest integer such that 2^m-1 > 512*8) + * @eccbytes = 7 (7 bytes are required to store m*t = 13*4 = 52 bits) + */ +struct nand_bch_control *nand_bch_init(struct mtd_info *mtd) +{ + struct nand_chip *nand = mtd_to_nand(mtd); + unsigned int m, t, eccsteps, i; + struct nand_bch_control *nbc = NULL; + unsigned char *erased_page; + unsigned int eccsize = nand->ecc.size; + unsigned int eccbytes = nand->ecc.bytes; + unsigned int eccstrength = nand->ecc.strength; + + if (!eccbytes && eccstrength) { + eccbytes = DIV_ROUND_UP(eccstrength * fls(8 * eccsize), 8); + nand->ecc.bytes = eccbytes; + } + + if (!eccsize || !eccbytes) { + pr_warn("ecc parameters not supplied\n"); + goto fail; + } + + m = fls(1+8*eccsize); + t = (eccbytes*8)/m; + + nbc = kzalloc(sizeof(*nbc), GFP_KERNEL); + if (!nbc) + goto fail; + + nbc->bch = bch_init(m, t, 0, false); + if (!nbc->bch) + goto fail; + + /* verify that eccbytes has the expected value */ + if (nbc->bch->ecc_bytes != eccbytes) { + pr_warn("invalid eccbytes %u, should be %u\n", + eccbytes, nbc->bch->ecc_bytes); + goto fail; + } + + eccsteps = mtd->writesize/eccsize; + + /* Check that we have an oob layout description. */ + if (!mtd->ooblayout) { + pr_warn("missing oob scheme"); + goto fail; + } + + /* sanity checks */ + if (8*(eccsize+eccbytes) >= (1 << m)) { + pr_warn("eccsize %u is too large\n", eccsize); + goto fail; + } + + /* + * ecc->steps and ecc->total might be used by mtd->ooblayout->ecc(), + * which is called by mtd_ooblayout_count_eccbytes(). + * Make sure they are properly initialized before calling + * mtd_ooblayout_count_eccbytes(). + * FIXME: we should probably rework the sequencing in nand_scan_tail() + * to avoid setting those fields twice. + */ + nand->ecc.steps = eccsteps; + nand->ecc.total = eccsteps * eccbytes; + nand->base.ecc.ctx.total = nand->ecc.total; + if (mtd_ooblayout_count_eccbytes(mtd) != (eccsteps*eccbytes)) { + pr_warn("invalid ecc layout\n"); + goto fail; + } + + nbc->eccmask = kzalloc(eccbytes, GFP_KERNEL); + nbc->errloc = kmalloc_array(t, sizeof(*nbc->errloc), GFP_KERNEL); + if (!nbc->eccmask || !nbc->errloc) + goto fail; + /* + * compute and store the inverted ecc of an erased ecc block + */ + erased_page = kmalloc(eccsize, GFP_KERNEL); + if (!erased_page) + goto fail; + + memset(erased_page, 0xff, eccsize); + bch_encode(nbc->bch, erased_page, eccsize, nbc->eccmask); + kfree(erased_page); + + for (i = 0; i < eccbytes; i++) + nbc->eccmask[i] ^= 0xff; + + if (!eccstrength) + nand->ecc.strength = (eccbytes * 8) / fls(8 * eccsize); + + return nbc; +fail: + nand_bch_free(nbc); + return NULL; +} +EXPORT_SYMBOL(nand_bch_init); + +/** + * nand_bch_free - [NAND Interface] Release NAND BCH ECC resources + * @nbc: NAND BCH control structure + */ +void nand_bch_free(struct nand_bch_control *nbc) +{ + if (nbc) { + bch_free(nbc->bch); + kfree(nbc->errloc); + kfree(nbc->eccmask); + kfree(nbc); + } +} +EXPORT_SYMBOL(nand_bch_free); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Ivan Djelic "); +MODULE_DESCRIPTION("NAND software BCH ECC support"); diff --git a/drivers/mtd/nand/raw/Kconfig b/drivers/mtd/nand/raw/Kconfig index 6c46f25b57e2a..b73860aa77c64 100644 --- a/drivers/mtd/nand/raw/Kconfig +++ b/drivers/mtd/nand/raw/Kconfig @@ -22,16 +22,6 @@ menuconfig MTD_RAW_NAND if MTD_RAW_NAND -config MTD_NAND_ECC_SW_BCH - bool "Support software BCH ECC" - select BCH - default n - help - This enables support for software BCH error correction. Binary BCH - codes are more powerful and cpu intensive than traditional Hamming - ECC codes. They are used with NAND devices requiring more than 1 bit - of error correction. - comment "Raw/parallel NAND flash controllers" config MTD_NAND_DENALI diff --git a/drivers/mtd/nand/raw/Makefile b/drivers/mtd/nand/raw/Makefile index 2930f5b9015d4..76904305d091f 100644 --- a/drivers/mtd/nand/raw/Makefile +++ b/drivers/mtd/nand/raw/Makefile @@ -2,7 +2,6 @@ obj-$(CONFIG_MTD_RAW_NAND) += nand.o obj-$(CONFIG_MTD_NAND_ECC_SW_HAMMING) += nand_ecc.o -nand-$(CONFIG_MTD_NAND_ECC_SW_BCH) += nand_bch.o obj-$(CONFIG_MTD_SM_COMMON) += sm_common.o obj-$(CONFIG_MTD_NAND_CAFE) += cafe_nand.o diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c index 1f0d542d59230..7edcf08a2e818 100644 --- a/drivers/mtd/nand/raw/nand_base.c +++ b/drivers/mtd/nand/raw/nand_base.c @@ -36,7 +36,7 @@ #include #include #include -#include +#include #include #include #include diff --git a/drivers/mtd/nand/raw/nand_bch.c b/drivers/mtd/nand/raw/nand_bch.c deleted file mode 100644 index 9d19ac14c1960..0000000000000 --- a/drivers/mtd/nand/raw/nand_bch.c +++ /dev/null @@ -1,219 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0-or-later -/* - * This file provides ECC correction for more than 1 bit per block of data, - * using binary BCH codes. It relies on the generic BCH library lib/bch.c. - * - * Copyright © 2011 Ivan Djelic - */ - -#include -#include -#include -#include -#include -#include -#include -#include -#include - -/** - * struct nand_bch_control - private NAND BCH control structure - * @bch: BCH control structure - * @errloc: error location array - * @eccmask: XOR ecc mask, allows erased pages to be decoded as valid - */ -struct nand_bch_control { - struct bch_control *bch; - unsigned int *errloc; - unsigned char *eccmask; -}; - -/** - * nand_bch_calculate_ecc - [NAND Interface] Calculate ECC for data block - * @chip: NAND chip object - * @buf: input buffer with raw data - * @code: output buffer with ECC - */ -int nand_bch_calculate_ecc(struct nand_chip *chip, const unsigned char *buf, - unsigned char *code) -{ - struct nand_bch_control *nbc = chip->ecc.priv; - unsigned int i; - - memset(code, 0, chip->ecc.bytes); - bch_encode(nbc->bch, buf, chip->ecc.size, code); - - /* apply mask so that an erased page is a valid codeword */ - for (i = 0; i < chip->ecc.bytes; i++) - code[i] ^= nbc->eccmask[i]; - - return 0; -} -EXPORT_SYMBOL(nand_bch_calculate_ecc); - -/** - * nand_bch_correct_data - [NAND Interface] Detect and correct bit error(s) - * @chip: NAND chip object - * @buf: raw data read from the chip - * @read_ecc: ECC from the chip - * @calc_ecc: the ECC calculated from raw data - * - * Detect and correct bit errors for a data byte block - */ -int nand_bch_correct_data(struct nand_chip *chip, unsigned char *buf, - unsigned char *read_ecc, unsigned char *calc_ecc) -{ - struct nand_bch_control *nbc = chip->ecc.priv; - unsigned int *errloc = nbc->errloc; - int i, count; - - count = bch_decode(nbc->bch, NULL, chip->ecc.size, read_ecc, calc_ecc, - NULL, errloc); - if (count > 0) { - for (i = 0; i < count; i++) { - if (errloc[i] < (chip->ecc.size*8)) - /* error is located in data, correct it */ - buf[errloc[i] >> 3] ^= (1 << (errloc[i] & 7)); - /* else error in ecc, no action needed */ - - pr_debug("%s: corrected bitflip %u\n", __func__, - errloc[i]); - } - } else if (count < 0) { - pr_err("ecc unrecoverable error\n"); - count = -EBADMSG; - } - return count; -} -EXPORT_SYMBOL(nand_bch_correct_data); - -/** - * nand_bch_init - [NAND Interface] Initialize NAND BCH error correction - * @mtd: MTD block structure - * - * Returns: - * a pointer to a new NAND BCH control structure, or NULL upon failure - * - * Initialize NAND BCH error correction. Parameters @eccsize and @eccbytes - * are used to compute BCH parameters m (Galois field order) and t (error - * correction capability). @eccbytes should be equal to the number of bytes - * required to store m*t bits, where m is such that 2^m-1 > @eccsize*8. - * - * Example: to configure 4 bit correction per 512 bytes, you should pass - * @eccsize = 512 (thus, m=13 is the smallest integer such that 2^m-1 > 512*8) - * @eccbytes = 7 (7 bytes are required to store m*t = 13*4 = 52 bits) - */ -struct nand_bch_control *nand_bch_init(struct mtd_info *mtd) -{ - struct nand_chip *nand = mtd_to_nand(mtd); - unsigned int m, t, eccsteps, i; - struct nand_bch_control *nbc = NULL; - unsigned char *erased_page; - unsigned int eccsize = nand->ecc.size; - unsigned int eccbytes = nand->ecc.bytes; - unsigned int eccstrength = nand->ecc.strength; - - if (!eccbytes && eccstrength) { - eccbytes = DIV_ROUND_UP(eccstrength * fls(8 * eccsize), 8); - nand->ecc.bytes = eccbytes; - } - - if (!eccsize || !eccbytes) { - pr_warn("ecc parameters not supplied\n"); - goto fail; - } - - m = fls(1+8*eccsize); - t = (eccbytes*8)/m; - - nbc = kzalloc(sizeof(*nbc), GFP_KERNEL); - if (!nbc) - goto fail; - - nbc->bch = bch_init(m, t, 0, false); - if (!nbc->bch) - goto fail; - - /* verify that eccbytes has the expected value */ - if (nbc->bch->ecc_bytes != eccbytes) { - pr_warn("invalid eccbytes %u, should be %u\n", - eccbytes, nbc->bch->ecc_bytes); - goto fail; - } - - eccsteps = mtd->writesize/eccsize; - - /* Check that we have an oob layout description. */ - if (!mtd->ooblayout) { - pr_warn("missing oob scheme"); - goto fail; - } - - /* sanity checks */ - if (8*(eccsize+eccbytes) >= (1 << m)) { - pr_warn("eccsize %u is too large\n", eccsize); - goto fail; - } - - /* - * ecc->steps and ecc->total might be used by mtd->ooblayout->ecc(), - * which is called by mtd_ooblayout_count_eccbytes(). - * Make sure they are properly initialized before calling - * mtd_ooblayout_count_eccbytes(). - * FIXME: we should probably rework the sequencing in nand_scan_tail() - * to avoid setting those fields twice. - */ - nand->ecc.steps = eccsteps; - nand->ecc.total = eccsteps * eccbytes; - nand->base.ecc.ctx.total = nand->ecc.total; - if (mtd_ooblayout_count_eccbytes(mtd) != (eccsteps*eccbytes)) { - pr_warn("invalid ecc layout\n"); - goto fail; - } - - nbc->eccmask = kzalloc(eccbytes, GFP_KERNEL); - nbc->errloc = kmalloc_array(t, sizeof(*nbc->errloc), GFP_KERNEL); - if (!nbc->eccmask || !nbc->errloc) - goto fail; - /* - * compute and store the inverted ecc of an erased ecc block - */ - erased_page = kmalloc(eccsize, GFP_KERNEL); - if (!erased_page) - goto fail; - - memset(erased_page, 0xff, eccsize); - bch_encode(nbc->bch, erased_page, eccsize, nbc->eccmask); - kfree(erased_page); - - for (i = 0; i < eccbytes; i++) - nbc->eccmask[i] ^= 0xff; - - if (!eccstrength) - nand->ecc.strength = (eccbytes * 8) / fls(8 * eccsize); - - return nbc; -fail: - nand_bch_free(nbc); - return NULL; -} -EXPORT_SYMBOL(nand_bch_init); - -/** - * nand_bch_free - [NAND Interface] Release NAND BCH ECC resources - * @nbc: NAND BCH control structure - */ -void nand_bch_free(struct nand_bch_control *nbc) -{ - if (nbc) { - bch_free(nbc->bch); - kfree(nbc->errloc); - kfree(nbc->eccmask); - kfree(nbc); - } -} -EXPORT_SYMBOL(nand_bch_free); - -MODULE_LICENSE("GPL"); -MODULE_AUTHOR("Ivan Djelic "); -MODULE_DESCRIPTION("NAND software BCH ECC support"); diff --git a/drivers/mtd/nand/raw/nandsim.c b/drivers/mtd/nand/raw/nandsim.c index a8048cb8d2205..9c940ead66fdf 100644 --- a/drivers/mtd/nand/raw/nandsim.c +++ b/drivers/mtd/nand/raw/nandsim.c @@ -23,7 +23,7 @@ #include #include #include -#include +#include #include #include #include diff --git a/drivers/mtd/nand/raw/omap2.c b/drivers/mtd/nand/raw/omap2.c index 512f60780a501..0ef209e1cd87a 100644 --- a/drivers/mtd/nand/raw/omap2.c +++ b/drivers/mtd/nand/raw/omap2.c @@ -23,7 +23,7 @@ #include #include -#include +#include #include #include diff --git a/include/linux/mtd/nand-ecc-sw-bch.h b/include/linux/mtd/nand-ecc-sw-bch.h new file mode 100644 index 0000000000000..1e1ee3af82b14 --- /dev/null +++ b/include/linux/mtd/nand-ecc-sw-bch.h @@ -0,0 +1,66 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright © 2011 Ivan Djelic + * + * This file is the header for the NAND BCH ECC implementation. + */ + +#ifndef __MTD_NAND_ECC_SW_BCH_H__ +#define __MTD_NAND_ECC_SW_BCH_H__ + +struct mtd_info; +struct nand_chip; +struct nand_bch_control; + +#if IS_ENABLED(CONFIG_MTD_NAND_ECC_SW_BCH) + +static inline int mtd_nand_has_bch(void) { return 1; } + +/* + * Calculate BCH ecc code + */ +int nand_bch_calculate_ecc(struct nand_chip *chip, const u_char *dat, + u_char *ecc_code); + +/* + * Detect and correct bit errors + */ +int nand_bch_correct_data(struct nand_chip *chip, 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); +/* + * Release BCH encoder/decoder resources + */ +void nand_bch_free(struct nand_bch_control *nbc); + +#else /* !CONFIG_MTD_NAND_ECC_SW_BCH */ + +static inline int mtd_nand_has_bch(void) { return 0; } + +static inline int +nand_bch_calculate_ecc(struct nand_chip *chip, const u_char *dat, + u_char *ecc_code) +{ + return -1; +} + +static inline int +nand_bch_correct_data(struct nand_chip *chip, unsigned char *buf, + unsigned char *read_ecc, unsigned char *calc_ecc) +{ + return -ENOTSUPP; +} + +static inline struct nand_bch_control *nand_bch_init(struct mtd_info *mtd) +{ + return NULL; +} + +static inline void nand_bch_free(struct nand_bch_control *nbc) {} + +#endif /* CONFIG_MTD_NAND_ECC_SW_BCH */ + +#endif /* __MTD_NAND_ECC_SW_BCH_H__ */ diff --git a/include/linux/mtd/nand_bch.h b/include/linux/mtd/nand_bch.h deleted file mode 100644 index d5956cc48ba96..0000000000000 --- a/include/linux/mtd/nand_bch.h +++ /dev/null @@ -1,66 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0-only */ -/* - * Copyright © 2011 Ivan Djelic - * - * 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_chip; -struct nand_bch_control; - -#if IS_ENABLED(CONFIG_MTD_NAND_ECC_SW_BCH) - -static inline int mtd_nand_has_bch(void) { return 1; } - -/* - * Calculate BCH ecc code - */ -int nand_bch_calculate_ecc(struct nand_chip *chip, const u_char *dat, - u_char *ecc_code); - -/* - * Detect and correct bit errors - */ -int nand_bch_correct_data(struct nand_chip *chip, 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); -/* - * Release BCH encoder/decoder resources - */ -void nand_bch_free(struct nand_bch_control *nbc); - -#else /* !CONFIG_MTD_NAND_ECC_SW_BCH */ - -static inline int mtd_nand_has_bch(void) { return 0; } - -static inline int -nand_bch_calculate_ecc(struct nand_chip *chip, const u_char *dat, - u_char *ecc_code) -{ - return -1; -} - -static inline int -nand_bch_correct_data(struct nand_chip *chip, unsigned char *buf, - unsigned char *read_ecc, unsigned char *calc_ecc) -{ - return -ENOTSUPP; -} - -static inline struct nand_bch_control *nand_bch_init(struct mtd_info *mtd) -{ - return NULL; -} - -static inline void nand_bch_free(struct nand_bch_control *nbc) {} - -#endif /* CONFIG_MTD_NAND_ECC_SW_BCH */ - -#endif /* __MTD_NAND_BCH_H__ */