mtd: add mtd_ooblayout_xxx() helper functions
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>
This commit is contained in:
Boris Brezillon
Родитель
c4f3ef2c6c
Коммит
75eb2cec25
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@ -1016,6 +1016,406 @@ int mtd_write_oob(struct mtd_info *mtd, loff_t to,
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}
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EXPORT_SYMBOL_GPL(mtd_write_oob);
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/**
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* mtd_ooblayout_ecc - Get the OOB region definition of a specific ECC section
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* @mtd: MTD device structure
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* @section: ECC section. Depending on the layout you may have all the ECC
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* bytes stored in a single contiguous section, or one section
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* per ECC chunk (and sometime several sections for a single ECC
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* ECC chunk)
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* @oobecc: OOB region struct filled with the appropriate ECC position
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* information
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*
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* This functions return ECC section information in the OOB area. I you want
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* to get all the ECC bytes information, then you should call
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* mtd_ooblayout_ecc(mtd, section++, oobecc) until it returns -ERANGE.
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*
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* Returns zero on success, a negative error code otherwise.
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*/
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int mtd_ooblayout_ecc(struct mtd_info *mtd, int section,
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struct mtd_oob_region *oobecc)
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{
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int eccbyte = 0, cursection = 0, length = 0, eccpos = 0;
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memset(oobecc, 0, sizeof(*oobecc));
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if (!mtd || section < 0)
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return -EINVAL;
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if (!mtd->ecclayout)
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return -ENOTSUPP;
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/*
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* This logic allows us to reuse the ->ecclayout information and
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* expose them as ECC regions (as done for the OOB free regions).
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*
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* TODO: this should be dropped as soon as we get rid of the
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* ->ecclayout field.
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*/
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for (eccbyte = 0; eccbyte < mtd->ecclayout->eccbytes; eccbyte++) {
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eccpos = mtd->ecclayout->eccpos[eccbyte];
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if (eccbyte < mtd->ecclayout->eccbytes - 1) {
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int neccpos = mtd->ecclayout->eccpos[eccbyte + 1];
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if (eccpos + 1 == neccpos) {
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length++;
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continue;
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}
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}
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if (section == cursection)
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break;
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length = 0;
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cursection++;
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}
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if (cursection != section || eccbyte >= mtd->ecclayout->eccbytes)
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return -ERANGE;
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oobecc->length = length + 1;
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oobecc->offset = eccpos - length;
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return 0;
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}
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EXPORT_SYMBOL_GPL(mtd_ooblayout_ecc);
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/**
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* mtd_ooblayout_free - Get the OOB region definition of a specific free
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* section
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* @mtd: MTD device structure
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* @section: Free section you are interested in. Depending on the layout
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* you may have all the free bytes stored in a single contiguous
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* section, or one section per ECC chunk plus an extra section
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* for the remaining bytes (or other funky layout).
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* @oobfree: OOB region struct filled with the appropriate free position
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* information
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*
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* This functions return free bytes position in the OOB area. I you want
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* to get all the free bytes information, then you should call
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* mtd_ooblayout_free(mtd, section++, oobfree) until it returns -ERANGE.
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*
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* Returns zero on success, a negative error code otherwise.
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*/
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int mtd_ooblayout_free(struct mtd_info *mtd, int section,
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struct mtd_oob_region *oobfree)
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{
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memset(oobfree, 0, sizeof(*oobfree));
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if (!mtd || section < 0)
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return -EINVAL;
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if (!mtd->ecclayout)
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return -ENOTSUPP;
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if (section >= MTD_MAX_OOBFREE_ENTRIES_LARGE)
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return -ERANGE;
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oobfree->offset = mtd->ecclayout->oobfree[section].offset;
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oobfree->length = mtd->ecclayout->oobfree[section].length;
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return 0;
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}
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EXPORT_SYMBOL_GPL(mtd_ooblayout_free);
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/**
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* mtd_ooblayout_find_region - Find the region attached to a specific byte
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* @mtd: mtd info structure
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* @byte: the byte we are searching for
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* @sectionp: pointer where the section id will be stored
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* @oobregion: used to retrieve the ECC position
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* @iter: iterator function. Should be either mtd_ooblayout_free or
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* mtd_ooblayout_ecc depending on the region type you're searching for
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*
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* This functions returns the section id and oobregion information of a
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* specific byte. For example, say you want to know where the 4th ECC byte is
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* stored, you'll use:
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*
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* mtd_ooblayout_find_region(mtd, 3, §ion, &oobregion, mtd_ooblayout_ecc);
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*
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* Returns zero on success, a negative error code otherwise.
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*/
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static int mtd_ooblayout_find_region(struct mtd_info *mtd, int byte,
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int *sectionp, struct mtd_oob_region *oobregion,
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int (*iter)(struct mtd_info *,
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int section,
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struct mtd_oob_region *oobregion))
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{
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int pos = 0, ret, section = 0;
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memset(oobregion, 0, sizeof(*oobregion));
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while (1) {
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ret = iter(mtd, section, oobregion);
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if (ret)
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return ret;
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if (pos + oobregion->length > byte)
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break;
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pos += oobregion->length;
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section++;
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}
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/*
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* Adjust region info to make it start at the beginning at the
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* 'start' ECC byte.
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*/
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oobregion->offset += byte - pos;
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oobregion->length -= byte - pos;
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*sectionp = section;
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return 0;
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}
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/**
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* mtd_ooblayout_find_eccregion - Find the ECC region attached to a specific
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* ECC byte
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* @mtd: mtd info structure
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* @eccbyte: the byte we are searching for
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* @sectionp: pointer where the section id will be stored
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* @oobregion: OOB region information
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*
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* Works like mtd_ooblayout_find_region() except it searches for a specific ECC
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* byte.
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*
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* Returns zero on success, a negative error code otherwise.
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*/
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int mtd_ooblayout_find_eccregion(struct mtd_info *mtd, int eccbyte,
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int *section,
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struct mtd_oob_region *oobregion)
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{
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return mtd_ooblayout_find_region(mtd, eccbyte, section, oobregion,
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mtd_ooblayout_ecc);
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}
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EXPORT_SYMBOL_GPL(mtd_ooblayout_find_eccregion);
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/**
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* mtd_ooblayout_get_bytes - Extract OOB bytes from the oob buffer
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* @mtd: mtd info structure
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* @buf: destination buffer to store OOB bytes
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* @oobbuf: OOB buffer
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* @start: first byte to retrieve
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* @nbytes: number of bytes to retrieve
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* @iter: section iterator
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*
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* Extract bytes attached to a specific category (ECC or free)
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* from the OOB buffer and copy them into buf.
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*
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* Returns zero on success, a negative error code otherwise.
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*/
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static int mtd_ooblayout_get_bytes(struct mtd_info *mtd, u8 *buf,
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const u8 *oobbuf, int start, int nbytes,
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int (*iter)(struct mtd_info *,
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int section,
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struct mtd_oob_region *oobregion))
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{
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struct mtd_oob_region oobregion = { };
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int section = 0, ret;
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ret = mtd_ooblayout_find_region(mtd, start, §ion,
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&oobregion, iter);
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while (!ret) {
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int cnt;
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cnt = oobregion.length > nbytes ? nbytes : oobregion.length;
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memcpy(buf, oobbuf + oobregion.offset, cnt);
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buf += cnt;
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nbytes -= cnt;
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if (!nbytes)
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break;
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ret = iter(mtd, ++section, &oobregion);
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}
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return ret;
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}
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/**
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* mtd_ooblayout_set_bytes - put OOB bytes into the oob buffer
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* @mtd: mtd info structure
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* @buf: source buffer to get OOB bytes from
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* @oobbuf: OOB buffer
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* @start: first OOB byte to set
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* @nbytes: number of OOB bytes to set
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* @iter: section iterator
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*
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* Fill the OOB buffer with data provided in buf. The category (ECC or free)
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* is selected by passing the appropriate iterator.
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*
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* Returns zero on success, a negative error code otherwise.
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*/
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static int mtd_ooblayout_set_bytes(struct mtd_info *mtd, const u8 *buf,
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u8 *oobbuf, int start, int nbytes,
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int (*iter)(struct mtd_info *,
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int section,
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struct mtd_oob_region *oobregion))
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{
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struct mtd_oob_region oobregion = { };
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int section = 0, ret;
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ret = mtd_ooblayout_find_region(mtd, start, §ion,
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&oobregion, iter);
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while (!ret) {
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int cnt;
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cnt = oobregion.length > nbytes ? nbytes : oobregion.length;
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memcpy(oobbuf + oobregion.offset, buf, cnt);
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buf += cnt;
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nbytes -= cnt;
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if (!nbytes)
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break;
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ret = iter(mtd, ++section, &oobregion);
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}
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return ret;
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}
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/**
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* mtd_ooblayout_count_bytes - count the number of bytes in a OOB category
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* @mtd: mtd info structure
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* @iter: category iterator
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*
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* Count the number of bytes in a given category.
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*
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* Returns a positive value on success, a negative error code otherwise.
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*/
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static int mtd_ooblayout_count_bytes(struct mtd_info *mtd,
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int (*iter)(struct mtd_info *,
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int section,
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struct mtd_oob_region *oobregion))
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{
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struct mtd_oob_region oobregion = { };
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int section = 0, ret, nbytes = 0;
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while (1) {
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ret = iter(mtd, section++, &oobregion);
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if (ret) {
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if (ret == -ERANGE)
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ret = nbytes;
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break;
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}
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nbytes += oobregion.length;
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}
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return ret;
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}
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/**
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* mtd_ooblayout_get_eccbytes - extract ECC bytes from the oob buffer
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* @mtd: mtd info structure
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* @eccbuf: destination buffer to store ECC bytes
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* @oobbuf: OOB buffer
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* @start: first ECC byte to retrieve
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* @nbytes: number of ECC bytes to retrieve
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*
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* Works like mtd_ooblayout_get_bytes(), except it acts on ECC bytes.
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*
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* Returns zero on success, a negative error code otherwise.
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*/
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int mtd_ooblayout_get_eccbytes(struct mtd_info *mtd, u8 *eccbuf,
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const u8 *oobbuf, int start, int nbytes)
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{
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return mtd_ooblayout_get_bytes(mtd, eccbuf, oobbuf, start, nbytes,
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mtd_ooblayout_ecc);
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}
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EXPORT_SYMBOL_GPL(mtd_ooblayout_get_eccbytes);
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/**
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* mtd_ooblayout_set_eccbytes - set ECC bytes into the oob buffer
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* @mtd: mtd info structure
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* @eccbuf: source buffer to get ECC bytes from
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* @oobbuf: OOB buffer
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* @start: first ECC byte to set
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* @nbytes: number of ECC bytes to set
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*
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* Works like mtd_ooblayout_set_bytes(), except it acts on ECC bytes.
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*
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* Returns zero on success, a negative error code otherwise.
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*/
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int mtd_ooblayout_set_eccbytes(struct mtd_info *mtd, const u8 *eccbuf,
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u8 *oobbuf, int start, int nbytes)
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{
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return mtd_ooblayout_set_bytes(mtd, eccbuf, oobbuf, start, nbytes,
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mtd_ooblayout_ecc);
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}
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EXPORT_SYMBOL_GPL(mtd_ooblayout_set_eccbytes);
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/**
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* mtd_ooblayout_get_databytes - extract data bytes from the oob buffer
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* @mtd: mtd info structure
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* @databuf: destination buffer to store ECC bytes
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* @oobbuf: OOB buffer
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* @start: first ECC byte to retrieve
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* @nbytes: number of ECC bytes to retrieve
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*
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* Works like mtd_ooblayout_get_bytes(), except it acts on free bytes.
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*
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* Returns zero on success, a negative error code otherwise.
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*/
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int mtd_ooblayout_get_databytes(struct mtd_info *mtd, u8 *databuf,
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const u8 *oobbuf, int start, int nbytes)
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{
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return mtd_ooblayout_get_bytes(mtd, databuf, oobbuf, start, nbytes,
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mtd_ooblayout_free);
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}
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EXPORT_SYMBOL_GPL(mtd_ooblayout_get_databytes);
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/**
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* mtd_ooblayout_get_eccbytes - set data bytes into the oob buffer
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* @mtd: mtd info structure
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* @eccbuf: source buffer to get data bytes from
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* @oobbuf: OOB buffer
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* @start: first ECC byte to set
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* @nbytes: number of ECC bytes to set
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*
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* Works like mtd_ooblayout_get_bytes(), except it acts on free bytes.
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*
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* Returns zero on success, a negative error code otherwise.
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*/
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int mtd_ooblayout_set_databytes(struct mtd_info *mtd, const u8 *databuf,
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u8 *oobbuf, int start, int nbytes)
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{
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return mtd_ooblayout_set_bytes(mtd, databuf, oobbuf, start, nbytes,
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mtd_ooblayout_free);
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}
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EXPORT_SYMBOL_GPL(mtd_ooblayout_set_databytes);
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/**
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* mtd_ooblayout_count_freebytes - count the number of free bytes in OOB
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* @mtd: mtd info structure
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*
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* Works like mtd_ooblayout_count_bytes(), except it count free bytes.
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*
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* Returns zero on success, a negative error code otherwise.
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*/
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int mtd_ooblayout_count_freebytes(struct mtd_info *mtd)
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{
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return mtd_ooblayout_count_bytes(mtd, mtd_ooblayout_free);
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}
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EXPORT_SYMBOL_GPL(mtd_ooblayout_count_freebytes);
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/**
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* mtd_ooblayout_count_freebytes - count the number of ECC bytes in OOB
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* @mtd: mtd info structure
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*
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* Works like mtd_ooblayout_count_bytes(), except it count ECC bytes.
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*
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* Returns zero on success, a negative error code otherwise.
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*/
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int mtd_ooblayout_count_eccbytes(struct mtd_info *mtd)
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{
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return mtd_ooblayout_count_bytes(mtd, mtd_ooblayout_ecc);
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}
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EXPORT_SYMBOL_GPL(mtd_ooblayout_count_eccbytes);
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/*
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* Method to access the protection register area, present in some flash
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* devices. The user data is one time programmable but the factory data is read
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@ -108,6 +108,21 @@ struct nand_ecclayout {
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struct nand_oobfree oobfree[MTD_MAX_OOBFREE_ENTRIES_LARGE];
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};
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/**
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* struct mtd_oob_region - oob region definition
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* @offset: region offset
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* @length: region length
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*
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* This structure describes a region of the OOB area, and is used
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* to retrieve ECC or free bytes sections.
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* Each section is defined by an offset within the OOB area and a
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* length.
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*/
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struct mtd_oob_region {
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u32 offset;
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u32 length;
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};
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struct module; /* only needed for owner field in mtd_info */
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struct mtd_info {
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@ -253,6 +268,24 @@ struct mtd_info {
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int usecount;
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};
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int mtd_ooblayout_ecc(struct mtd_info *mtd, int section,
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struct mtd_oob_region *oobecc);
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int mtd_ooblayout_find_eccregion(struct mtd_info *mtd, int eccbyte,
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int *section,
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struct mtd_oob_region *oobregion);
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int mtd_ooblayout_get_eccbytes(struct mtd_info *mtd, u8 *eccbuf,
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const u8 *oobbuf, int start, int nbytes);
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int mtd_ooblayout_set_eccbytes(struct mtd_info *mtd, const u8 *eccbuf,
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u8 *oobbuf, int start, int nbytes);
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int mtd_ooblayout_free(struct mtd_info *mtd, int section,
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struct mtd_oob_region *oobfree);
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int mtd_ooblayout_get_databytes(struct mtd_info *mtd, u8 *databuf,
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const u8 *oobbuf, int start, int nbytes);
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int mtd_ooblayout_set_databytes(struct mtd_info *mtd, const u8 *databuf,
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u8 *oobbuf, int start, int nbytes);
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int mtd_ooblayout_count_freebytes(struct mtd_info *mtd);
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int mtd_ooblayout_count_eccbytes(struct mtd_info *mtd);
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static inline void mtd_set_of_node(struct mtd_info *mtd,
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struct device_node *np)
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{
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