return NOTIFY_DONE;
}
+/**
+ * mtd_wunit_to_pairing_info - get pairing information of a wunit
+ * @mtd: pointer to new MTD device info structure
+ * @wunit: write unit we are interested in
+ * @info: returned pairing information
+ *
+ * Retrieve pairing information associated to the wunit.
+ * This is mainly useful when dealing with MLC/TLC NANDs where pages can be
+ * paired together, and where programming a page may influence the page it is
+ * paired with.
+ * The notion of page is replaced by the term wunit (write-unit) to stay
+ * consistent with the ->writesize field.
+ *
+ * The @wunit argument can be extracted from an absolute offset using
+ * mtd_offset_to_wunit(). @info is filled with the pairing information attached
+ * to @wunit.
+ *
+ * From the pairing info the MTD user can find all the wunits paired with
+ * @wunit using the following loop:
+ *
+ * for (i = 0; i < mtd_pairing_groups(mtd); i++) {
+ * info.pair = i;
+ * mtd_pairing_info_to_wunit(mtd, &info);
+ * ...
+ * }
+ */
+int mtd_wunit_to_pairing_info(struct mtd_info *mtd, int wunit,
+ struct mtd_pairing_info *info)
+{
+ int npairs = mtd_wunit_per_eb(mtd) / mtd_pairing_groups(mtd);
+
+ if (wunit < 0 || wunit >= npairs)
+ return -EINVAL;
+
+ if (mtd->pairing && mtd->pairing->get_info)
+ return mtd->pairing->get_info(mtd, wunit, info);
+
+ info->group = 0;
+ info->pair = wunit;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(mtd_wunit_to_pairing_info);
+
+/**
+ * mtd_wunit_to_pairing_info - get wunit from pairing information
+ * @mtd: pointer to new MTD device info structure
+ * @info: pairing information struct
+ *
+ * Returns a positive number representing the wunit associated to the info
+ * struct, or a negative error code.
+ *
+ * This is the reverse of mtd_wunit_to_pairing_info(), and can help one to
+ * iterate over all wunits of a given pair (see mtd_wunit_to_pairing_info()
+ * doc).
+ *
+ * It can also be used to only program the first page of each pair (i.e.
+ * page attached to group 0), which allows one to use an MLC NAND in
+ * software-emulated SLC mode:
+ *
+ * info.group = 0;
+ * npairs = mtd_wunit_per_eb(mtd) / mtd_pairing_groups(mtd);
+ * for (info.pair = 0; info.pair < npairs; info.pair++) {
+ * wunit = mtd_pairing_info_to_wunit(mtd, &info);
+ * mtd_write(mtd, mtd_wunit_to_offset(mtd, blkoffs, wunit),
+ * mtd->writesize, &retlen, buf + (i * mtd->writesize));
+ * }
+ */
+int mtd_pairing_info_to_wunit(struct mtd_info *mtd,
+ const struct mtd_pairing_info *info)
+{
+ int ngroups = mtd_pairing_groups(mtd);
+ int npairs = mtd_wunit_per_eb(mtd) / ngroups;
+
+ if (!info || info->pair < 0 || info->pair >= npairs ||
+ info->group < 0 || info->group >= ngroups)
+ return -EINVAL;
+
+ if (mtd->pairing && mtd->pairing->get_wunit)
+ return mtd->pairing->get_wunit(mtd, info);
+
+ return info->pair;
+}
+EXPORT_SYMBOL_GPL(mtd_pairing_info_to_wunit);
+
+/**
+ * mtd_pairing_groups - get the number of pairing groups
+ * @mtd: pointer to new MTD device info structure
+ *
+ * Returns the number of pairing groups.
+ *
+ * This number is usually equal to the number of bits exposed by a single
+ * cell, and can be used in conjunction with mtd_pairing_info_to_wunit()
+ * to iterate over all pages of a given pair.
+ */
+int mtd_pairing_groups(struct mtd_info *mtd)
+{
+ if (!mtd->pairing || !mtd->pairing->ngroups)
+ return 1;
+
+ return mtd->pairing->ngroups;
+}
+EXPORT_SYMBOL_GPL(mtd_pairing_groups);
+
/**
* add_mtd_device - register an MTD device
* @mtd: pointer to new MTD device info structure
struct mtd_oob_region *oobfree);
};
+/**
+ * struct mtd_pairing_info - page pairing information
+ *
+ * @pair: pair id
+ * @group: group id
+ *
+ * The term "pair" is used here, even though TLC NANDs might group pages by 3
+ * (3 bits in a single cell). A pair should regroup all pages that are sharing
+ * the same cell. Pairs are then indexed in ascending order.
+ *
+ * @group is defining the position of a page in a given pair. It can also be
+ * seen as the bit position in the cell: page attached to bit 0 belongs to
+ * group 0, page attached to bit 1 belongs to group 1, etc.
+ *
+ * Example:
+ * The H27UCG8T2BTR-BC datasheet describes the following pairing scheme:
+ *
+ * group-0 group-1
+ *
+ * pair-0 page-0 page-4
+ * pair-1 page-1 page-5
+ * pair-2 page-2 page-8
+ * ...
+ * pair-127 page-251 page-255
+ *
+ *
+ * Note that the "group" and "pair" terms were extracted from Samsung and
+ * Hynix datasheets, and might be referenced under other names in other
+ * datasheets (Micron is describing this concept as "shared pages").
+ */
+struct mtd_pairing_info {
+ int pair;
+ int group;
+};
+
+/**
+ * struct mtd_pairing_scheme - page pairing scheme description
+ *
+ * @ngroups: number of groups. Should be related to the number of bits
+ * per cell.
+ * @get_info: converts a write-unit (page number within an erase block) into
+ * mtd_pairing information (pair + group). This function should
+ * fill the info parameter based on the wunit index or return
+ * -EINVAL if the wunit parameter is invalid.
+ * @get_wunit: converts pairing information into a write-unit (page) number.
+ * This function should return the wunit index pointed by the
+ * pairing information described in the info argument. It should
+ * return -EINVAL, if there's no wunit corresponding to the
+ * passed pairing information.
+ *
+ * See mtd_pairing_info documentation for a detailed explanation of the
+ * pair and group concepts.
+ *
+ * The mtd_pairing_scheme structure provides a generic solution to represent
+ * NAND page pairing scheme. Instead of exposing two big tables to do the
+ * write-unit <-> (pair + group) conversions, we ask the MTD drivers to
+ * implement the ->get_info() and ->get_wunit() functions.
+ *
+ * MTD users will then be able to query these information by using the
+ * mtd_pairing_info_to_wunit() and mtd_wunit_to_pairing_info() helpers.
+ *
+ * @ngroups is here to help MTD users iterating over all the pages in a
+ * given pair. This value can be retrieved by MTD users using the
+ * mtd_pairing_groups() helper.
+ *
+ * Examples are given in the mtd_pairing_info_to_wunit() and
+ * mtd_wunit_to_pairing_info() documentation.
+ */
+struct mtd_pairing_scheme {
+ int ngroups;
+ int (*get_info)(struct mtd_info *mtd, int wunit,
+ struct mtd_pairing_info *info);
+ int (*get_wunit)(struct mtd_info *mtd,
+ const struct mtd_pairing_info *info);
+};
+
struct module; /* only needed for owner field in mtd_info */
struct mtd_info {
/* OOB layout description */
const struct mtd_ooblayout_ops *ooblayout;
+ /* NAND pairing scheme, only provided for MLC/TLC NANDs */
+ const struct mtd_pairing_scheme *pairing;
+
/* the ecc step size. */
unsigned int ecc_step_size;
mtd->ooblayout = ooblayout;
}
+static inline void mtd_set_pairing_scheme(struct mtd_info *mtd,
+ const struct mtd_pairing_scheme *pairing)
+{
+ mtd->pairing = pairing;
+}
+
static inline void mtd_set_of_node(struct mtd_info *mtd,
struct device_node *np)
{
return ops->mode == MTD_OPS_AUTO_OOB ? mtd->oobavail : mtd->oobsize;
}
+int mtd_wunit_to_pairing_info(struct mtd_info *mtd, int wunit,
+ struct mtd_pairing_info *info);
+int mtd_pairing_info_to_wunit(struct mtd_info *mtd,
+ const struct mtd_pairing_info *info);
+int mtd_pairing_groups(struct mtd_info *mtd);
int mtd_erase(struct mtd_info *mtd, struct erase_info *instr);
int mtd_point(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen,
void **virt, resource_size_t *phys);
return do_div(sz, mtd->writesize);
}
+static inline int mtd_wunit_per_eb(struct mtd_info *mtd)
+{
+ return mtd->erasesize / mtd->writesize;
+}
+
+static inline int mtd_offset_to_wunit(struct mtd_info *mtd, loff_t offs)
+{
+ return mtd_div_by_ws(mtd_mod_by_eb(offs, mtd), mtd);
+}
+
+static inline loff_t mtd_wunit_to_offset(struct mtd_info *mtd, loff_t base,
+ int wunit)
+{
+ return base + (wunit * mtd->writesize);
+}
+
+
static inline int mtd_has_oob(const struct mtd_info *mtd)
{
return mtd->_read_oob && mtd->_write_oob;
projects / cascardo / linux.git / commitdiff