From: Boris Brezillon boris.brezillon@free-electrons.com
In order to make the ecclayout definition completely dynamic we need to rework the way the OOB layout are defined and iterated.
Create a few mtd_ooblayout_xxx() helpers to ease OOB bytes manipulation and hide ecclayout internals to their users.
Signed-off-by: Boris Brezillon boris.brezillon@free-electrons.com [Linux commit: 75eb2cec251fda33c9bb716ecc372819abb9278a] [masahiro: cherry-pick more code from adbbc3bc827eb1f43a932d783f09ba55c8ec8379] Signed-off-by: Masahiro Yamada yamada.masahiro@socionext.com
---
drivers/mtd/mtdcore.c | 360 ++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/mtd/mtd.h | 57 ++++++++ 2 files changed, 417 insertions(+)
diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c index e3f56e5..2cda051 100644 --- a/drivers/mtd/mtdcore.c +++ b/drivers/mtd/mtdcore.c @@ -1005,6 +1005,366 @@ int mtd_read_oob(struct mtd_info *mtd, loff_t from, struct mtd_oob_ops *ops) } EXPORT_SYMBOL_GPL(mtd_read_oob);
+/** + * mtd_ooblayout_ecc - Get the OOB region definition of a specific ECC section + * @mtd: MTD device structure + * @section: ECC section. Depending on the layout you may have all the ECC + * bytes stored in a single contiguous section, or one section + * per ECC chunk (and sometime several sections for a single ECC + * ECC chunk) + * @oobecc: OOB region struct filled with the appropriate ECC position + * information + * + * This function returns ECC section information in the OOB area. If you want + * to get all the ECC bytes information, then you should call + * mtd_ooblayout_ecc(mtd, section++, oobecc) until it returns -ERANGE. + * + * Returns zero on success, a negative error code otherwise. + */ +int mtd_ooblayout_ecc(struct mtd_info *mtd, int section, + struct mtd_oob_region *oobecc) +{ + memset(oobecc, 0, sizeof(*oobecc)); + + if (!mtd || section < 0) + return -EINVAL; + + if (!mtd->ooblayout || !mtd->ooblayout->ecc) + return -ENOTSUPP; + + return mtd->ooblayout->ecc(mtd, section, oobecc); +} +EXPORT_SYMBOL_GPL(mtd_ooblayout_ecc); + +/** + * mtd_ooblayout_free - Get the OOB region definition of a specific free + * section + * @mtd: MTD device structure + * @section: Free section you are interested in. Depending on the layout + * you may have all the free bytes stored in a single contiguous + * section, or one section per ECC chunk plus an extra section + * for the remaining bytes (or other funky layout). + * @oobfree: OOB region struct filled with the appropriate free position + * information + * + * This function returns free bytes position in the OOB area. If you want + * to get all the free bytes information, then you should call + * mtd_ooblayout_free(mtd, section++, oobfree) until it returns -ERANGE. + * + * Returns zero on success, a negative error code otherwise. + */ +int mtd_ooblayout_free(struct mtd_info *mtd, int section, + struct mtd_oob_region *oobfree) +{ + memset(oobfree, 0, sizeof(*oobfree)); + + if (!mtd || section < 0) + return -EINVAL; + + if (!mtd->ooblayout || !mtd->ooblayout->free) + return -ENOTSUPP; + + return mtd->ooblayout->free(mtd, section, oobfree); +} +EXPORT_SYMBOL_GPL(mtd_ooblayout_free); + +/** + * mtd_ooblayout_find_region - Find the region attached to a specific byte + * @mtd: mtd info structure + * @byte: the byte we are searching for + * @sectionp: pointer where the section id will be stored + * @oobregion: used to retrieve the ECC position + * @iter: iterator function. Should be either mtd_ooblayout_free or + * mtd_ooblayout_ecc depending on the region type you're searching for + * + * This function returns the section id and oobregion information of a + * specific byte. For example, say you want to know where the 4th ECC byte is + * stored, you'll use: + * + * mtd_ooblayout_find_region(mtd, 3, §ion, &oobregion, mtd_ooblayout_ecc); + * + * Returns zero on success, a negative error code otherwise. + */ +static int mtd_ooblayout_find_region(struct mtd_info *mtd, int byte, + int *sectionp, struct mtd_oob_region *oobregion, + int (*iter)(struct mtd_info *, + int section, + struct mtd_oob_region *oobregion)) +{ + int pos = 0, ret, section = 0; + + memset(oobregion, 0, sizeof(*oobregion)); + + while (1) { + ret = iter(mtd, section, oobregion); + if (ret) + return ret; + + if (pos + oobregion->length > byte) + break; + + pos += oobregion->length; + section++; + } + + /* + * Adjust region info to make it start at the beginning at the + * 'start' ECC byte. + */ + oobregion->offset += byte - pos; + oobregion->length -= byte - pos; + *sectionp = section; + + return 0; +} + +/** + * mtd_ooblayout_find_eccregion - Find the ECC region attached to a specific + * ECC byte + * @mtd: mtd info structure + * @eccbyte: the byte we are searching for + * @sectionp: pointer where the section id will be stored + * @oobregion: OOB region information + * + * Works like mtd_ooblayout_find_region() except it searches for a specific ECC + * byte. + * + * Returns zero on success, a negative error code otherwise. + */ +int mtd_ooblayout_find_eccregion(struct mtd_info *mtd, int eccbyte, + int *section, + struct mtd_oob_region *oobregion) +{ + return mtd_ooblayout_find_region(mtd, eccbyte, section, oobregion, + mtd_ooblayout_ecc); +} +EXPORT_SYMBOL_GPL(mtd_ooblayout_find_eccregion); + +/** + * mtd_ooblayout_get_bytes - Extract OOB bytes from the oob buffer + * @mtd: mtd info structure + * @buf: destination buffer to store OOB bytes + * @oobbuf: OOB buffer + * @start: first byte to retrieve + * @nbytes: number of bytes to retrieve + * @iter: section iterator + * + * Extract bytes attached to a specific category (ECC or free) + * from the OOB buffer and copy them into buf. + * + * Returns zero on success, a negative error code otherwise. + */ +static int mtd_ooblayout_get_bytes(struct mtd_info *mtd, u8 *buf, + const u8 *oobbuf, int start, int nbytes, + int (*iter)(struct mtd_info *, + int section, + struct mtd_oob_region *oobregion)) +{ + struct mtd_oob_region oobregion; + int section, ret; + + ret = mtd_ooblayout_find_region(mtd, start, §ion, + &oobregion, iter); + + while (!ret) { + int cnt; + + cnt = min_t(int, nbytes, oobregion.length); + memcpy(buf, oobbuf + oobregion.offset, cnt); + buf += cnt; + nbytes -= cnt; + + if (!nbytes) + break; + + ret = iter(mtd, ++section, &oobregion); + } + + return ret; +} + +/** + * mtd_ooblayout_set_bytes - put OOB bytes into the oob buffer + * @mtd: mtd info structure + * @buf: source buffer to get OOB bytes from + * @oobbuf: OOB buffer + * @start: first OOB byte to set + * @nbytes: number of OOB bytes to set + * @iter: section iterator + * + * Fill the OOB buffer with data provided in buf. The category (ECC or free) + * is selected by passing the appropriate iterator. + * + * Returns zero on success, a negative error code otherwise. + */ +static int mtd_ooblayout_set_bytes(struct mtd_info *mtd, const u8 *buf, + u8 *oobbuf, int start, int nbytes, + int (*iter)(struct mtd_info *, + int section, + struct mtd_oob_region *oobregion)) +{ + struct mtd_oob_region oobregion; + int section, ret; + + ret = mtd_ooblayout_find_region(mtd, start, §ion, + &oobregion, iter); + + while (!ret) { + int cnt; + + cnt = min_t(int, nbytes, oobregion.length); + memcpy(oobbuf + oobregion.offset, buf, cnt); + buf += cnt; + nbytes -= cnt; + + if (!nbytes) + break; + + ret = iter(mtd, ++section, &oobregion); + } + + return ret; +} + +/** + * mtd_ooblayout_count_bytes - count the number of bytes in a OOB category + * @mtd: mtd info structure + * @iter: category iterator + * + * Count the number of bytes in a given category. + * + * Returns a positive value on success, a negative error code otherwise. + */ +static int mtd_ooblayout_count_bytes(struct mtd_info *mtd, + int (*iter)(struct mtd_info *, + int section, + struct mtd_oob_region *oobregion)) +{ + struct mtd_oob_region oobregion; + int section = 0, ret, nbytes = 0; + + while (1) { + ret = iter(mtd, section++, &oobregion); + if (ret) { + if (ret == -ERANGE) + ret = nbytes; + break; + } + + nbytes += oobregion.length; + } + + return ret; +} + +/** + * mtd_ooblayout_get_eccbytes - extract ECC bytes from the oob buffer + * @mtd: mtd info structure + * @eccbuf: destination buffer to store ECC bytes + * @oobbuf: OOB buffer + * @start: first ECC byte to retrieve + * @nbytes: number of ECC bytes to retrieve + * + * Works like mtd_ooblayout_get_bytes(), except it acts on ECC bytes. + * + * Returns zero on success, a negative error code otherwise. + */ +int mtd_ooblayout_get_eccbytes(struct mtd_info *mtd, u8 *eccbuf, + const u8 *oobbuf, int start, int nbytes) +{ + return mtd_ooblayout_get_bytes(mtd, eccbuf, oobbuf, start, nbytes, + mtd_ooblayout_ecc); +} +EXPORT_SYMBOL_GPL(mtd_ooblayout_get_eccbytes); + +/** + * mtd_ooblayout_set_eccbytes - set ECC bytes into the oob buffer + * @mtd: mtd info structure + * @eccbuf: source buffer to get ECC bytes from + * @oobbuf: OOB buffer + * @start: first ECC byte to set + * @nbytes: number of ECC bytes to set + * + * Works like mtd_ooblayout_set_bytes(), except it acts on ECC bytes. + * + * Returns zero on success, a negative error code otherwise. + */ +int mtd_ooblayout_set_eccbytes(struct mtd_info *mtd, const u8 *eccbuf, + u8 *oobbuf, int start, int nbytes) +{ + return mtd_ooblayout_set_bytes(mtd, eccbuf, oobbuf, start, nbytes, + mtd_ooblayout_ecc); +} +EXPORT_SYMBOL_GPL(mtd_ooblayout_set_eccbytes); + +/** + * mtd_ooblayout_get_databytes - extract data bytes from the oob buffer + * @mtd: mtd info structure + * @databuf: destination buffer to store ECC bytes + * @oobbuf: OOB buffer + * @start: first ECC byte to retrieve + * @nbytes: number of ECC bytes to retrieve + * + * Works like mtd_ooblayout_get_bytes(), except it acts on free bytes. + * + * Returns zero on success, a negative error code otherwise. + */ +int mtd_ooblayout_get_databytes(struct mtd_info *mtd, u8 *databuf, + const u8 *oobbuf, int start, int nbytes) +{ + return mtd_ooblayout_get_bytes(mtd, databuf, oobbuf, start, nbytes, + mtd_ooblayout_free); +} +EXPORT_SYMBOL_GPL(mtd_ooblayout_get_databytes); + +/** + * mtd_ooblayout_get_eccbytes - set data bytes into the oob buffer + * @mtd: mtd info structure + * @eccbuf: source buffer to get data bytes from + * @oobbuf: OOB buffer + * @start: first ECC byte to set + * @nbytes: number of ECC bytes to set + * + * Works like mtd_ooblayout_get_bytes(), except it acts on free bytes. + * + * Returns zero on success, a negative error code otherwise. + */ +int mtd_ooblayout_set_databytes(struct mtd_info *mtd, const u8 *databuf, + u8 *oobbuf, int start, int nbytes) +{ + return mtd_ooblayout_set_bytes(mtd, databuf, oobbuf, start, nbytes, + mtd_ooblayout_free); +} +EXPORT_SYMBOL_GPL(mtd_ooblayout_set_databytes); + +/** + * mtd_ooblayout_count_freebytes - count the number of free bytes in OOB + * @mtd: mtd info structure + * + * Works like mtd_ooblayout_count_bytes(), except it count free bytes. + * + * Returns zero on success, a negative error code otherwise. + */ +int mtd_ooblayout_count_freebytes(struct mtd_info *mtd) +{ + return mtd_ooblayout_count_bytes(mtd, mtd_ooblayout_free); +} +EXPORT_SYMBOL_GPL(mtd_ooblayout_count_freebytes); + +/** + * mtd_ooblayout_count_freebytes - count the number of ECC bytes in OOB + * @mtd: mtd info structure + * + * Works like mtd_ooblayout_count_bytes(), except it count ECC bytes. + * + * Returns zero on success, a negative error code otherwise. + */ +int mtd_ooblayout_count_eccbytes(struct mtd_info *mtd) +{ + return mtd_ooblayout_count_bytes(mtd, mtd_ooblayout_ecc); +} +EXPORT_SYMBOL_GPL(mtd_ooblayout_count_eccbytes); + /* * Method to access the protection register area, present in some flash * devices. The user data is one time programmable but the factory data is read diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h index 4bde251..ba4cbba 100644 --- a/include/linux/mtd/mtd.h +++ b/include/linux/mtd/mtd.h @@ -103,6 +103,36 @@ struct mtd_oob_ops { #else #define MTD_MAX_ECCPOS_ENTRIES_LARGE 680 #endif +/** + * struct mtd_oob_region - oob region definition + * @offset: region offset + * @length: region length + * + * This structure describes a region of the OOB area, and is used + * to retrieve ECC or free bytes sections. + * Each section is defined by an offset within the OOB area and a + * length. + */ +struct mtd_oob_region { + u32 offset; + u32 length; +}; + +/* + * struct mtd_ooblayout_ops - NAND OOB layout operations + * @ecc: function returning an ECC region in the OOB area. + * Should return -ERANGE if %section exceeds the total number of + * ECC sections. + * @free: function returning a free region in the OOB area. + * Should return -ERANGE if %section exceeds the total number of + * free sections. + */ +struct mtd_ooblayout_ops { + int (*ecc)(struct mtd_info *mtd, int section, + struct mtd_oob_region *oobecc); + int (*free)(struct mtd_info *mtd, int section, + struct mtd_oob_region *oobfree); +};
/* * Internal ECC layout control structure. For historical reasons, there is a @@ -179,6 +209,9 @@ struct mtd_info { #endif int index;
+ /* OOB layout description */ + const struct mtd_ooblayout_ops *ooblayout; + /* ECC layout structure pointer - read only! */ struct nand_ecclayout *ecclayout;
@@ -278,6 +311,30 @@ struct mtd_info { int usecount; };
+int mtd_ooblayout_ecc(struct mtd_info *mtd, int section, + struct mtd_oob_region *oobecc); +int mtd_ooblayout_find_eccregion(struct mtd_info *mtd, int eccbyte, + int *section, + struct mtd_oob_region *oobregion); +int mtd_ooblayout_get_eccbytes(struct mtd_info *mtd, u8 *eccbuf, + const u8 *oobbuf, int start, int nbytes); +int mtd_ooblayout_set_eccbytes(struct mtd_info *mtd, const u8 *eccbuf, + u8 *oobbuf, int start, int nbytes); +int mtd_ooblayout_free(struct mtd_info *mtd, int section, + struct mtd_oob_region *oobfree); +int mtd_ooblayout_get_databytes(struct mtd_info *mtd, u8 *databuf, + const u8 *oobbuf, int start, int nbytes); +int mtd_ooblayout_set_databytes(struct mtd_info *mtd, const u8 *databuf, + u8 *oobbuf, int start, int nbytes); +int mtd_ooblayout_count_freebytes(struct mtd_info *mtd); +int mtd_ooblayout_count_eccbytes(struct mtd_info *mtd); + +static inline void mtd_set_ooblayout(struct mtd_info *mtd, + const struct mtd_ooblayout_ops *ooblayout) +{ + mtd->ooblayout = ooblayout; +} + static inline int mtd_oobavail(struct mtd_info *mtd, struct mtd_oob_ops *ops) { return ops->mode == MTD_OPS_AUTO_OOB ? mtd->oobavail : mtd->oobsize;