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authorBrian Norris <computersforpeace@gmail.com>2016-10-08 12:23:37 -0700
committerBrian Norris <computersforpeace@gmail.com>2016-10-08 20:56:54 -0700
commit69db4aa44fdd8befc2eccd1313d841c5128c385c (patch)
tree1b84be76e9497231ed8027cf2a22b79fab64a87c /include/linux/mtd
parentf5b88de284932def6850e976c18d25940c1b2c3d (diff)
parent477b0229ac9bc275f6f8d2c27a2d08b246fccd0e (diff)
downloadop-kernel-dev-69db4aa44fdd8befc2eccd1313d841c5128c385c.zip
op-kernel-dev-69db4aa44fdd8befc2eccd1313d841c5128c385c.tar.gz
Merge tag '4.9/mtd-pairing-scheme' of github.com:linux-nand/linux
Introduction of the MTD pairing scheme concept.
Diffstat (limited to 'include/linux/mtd')
-rw-r--r--include/linux/mtd/mtd.h107
1 files changed, 107 insertions, 0 deletions
diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h
index 29a1706..13f8052 100644
--- a/include/linux/mtd/mtd.h
+++ b/include/linux/mtd/mtd.h
@@ -127,6 +127,82 @@ struct mtd_ooblayout_ops {
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 {
@@ -188,6 +264,9 @@ 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;
@@ -296,6 +375,12 @@ static inline void mtd_set_ooblayout(struct mtd_info *mtd,
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)
{
@@ -312,6 +397,11 @@ 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;
}
+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);
@@ -397,6 +487,23 @@ static inline uint32_t mtd_mod_by_ws(uint64_t sz, struct mtd_info *mtd)
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;
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