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>
[Linux commit: 75eb2cec251fda33c9bb716ecc372819abb9278a]
[masahiro:
 cherry-pick more code from adbbc3bc827eb1f43a932d783f09ba55c8ec8379]
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

1 files changed, 57 insertions, 0 deletions

diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h
index 4bde2513223..ba4cbba949a 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;