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authorAlexey Korolev <akorolev@infradead.org>2008-05-15 17:23:18 +0100
committerDavid Woodhouse <David.Woodhouse@intel.com>2008-07-25 10:49:50 -0400
commit3d45955962496879dead8d4dd70bb9a23b07154b (patch)
treeaf34201ba3bfc195a22ceac43a1c22f2f7c2fbe8 /include/linux/mtd
parentff877ea80efa2015b6263766f78ee42c2a1b32f9 (diff)
[MTD] [NAND] subpage read feature as a way to increase performance.
This patch enables NAND subpage read functionality. If upper layer drivers are requesting to read non page aligned data NAND subpage-read functionality reads the only whose ECC regions which include requested data when original code reads whole page. This significantly improves performance in many cases. Here are some digits : UBI volume mount time No subpage reads: 5.75 seconds Subpage read patch: 2.42 seconds Open/stat time for files on JFFS2 volume: No subpage read 0m 5.36s Subpage read 0m 2.88s Signed-off-by Alexey Korolev <akorolev@infradead.org> Acked-by: Artem Bityutskiy <dedekind@infradead.org> Acked-by: Jörn Engel <joern@logfs.org> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Diffstat (limited to 'include/linux/mtd')
-rw-r--r--include/linux/mtd/nand.h5
1 files changed, 5 insertions, 0 deletions
diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
index 863e22a0ddb5..83f678702dff 100644
--- a/include/linux/mtd/nand.h
+++ b/include/linux/mtd/nand.h
@@ -177,6 +177,7 @@ typedef enum {
#define NAND_MUST_PAD(chip) (!(chip->options & NAND_NO_PADDING))
#define NAND_HAS_CACHEPROG(chip) ((chip->options & NAND_CACHEPRG))
#define NAND_HAS_COPYBACK(chip) ((chip->options & NAND_COPYBACK))
+#define NAND_SUBPAGE_READ(chip) ((chip->ecc.mode == NAND_ECC_SOFT))
/* Mask to zero out the chip options, which come from the id table */
#define NAND_CHIPOPTIONS_MSK (0x0000ffff & ~NAND_NO_AUTOINCR)
@@ -274,6 +275,10 @@ struct nand_ecc_ctrl {
int (*read_page)(struct mtd_info *mtd,
struct nand_chip *chip,
uint8_t *buf);
+ int (*read_subpage)(struct mtd_info *mtd,
+ struct nand_chip *chip,
+ uint32_t offs, uint32_t len,
+ uint8_t *buf);
void (*write_page)(struct mtd_info *mtd,
struct nand_chip *chip,
const uint8_t *buf);