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| author | Alexey Korolev <akorolev@infradead.org> | 2008-05-15 17:23:18 +0100 |
|---|---|---|
| committer | David Woodhouse <David.Woodhouse@intel.com> | 2008-07-25 10:49:50 -0400 |
| commit | 3d45955962496879dead8d4dd70bb9a23b07154b (patch) | |
| tree | af34201ba3bfc195a22ceac43a1c22f2f7c2fbe8 /include/linux/mtd/nand.h | |
| parent | ff877ea80efa2015b6263766f78ee42c2a1b32f9 (diff) | |
| download | kernel_samsung_smdk4412-3d45955962496879dead8d4dd70bb9a23b07154b.zip kernel_samsung_smdk4412-3d45955962496879dead8d4dd70bb9a23b07154b.tar.gz kernel_samsung_smdk4412-3d45955962496879dead8d4dd70bb9a23b07154b.tar.bz2 | |
[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/nand.h')
| -rw-r--r-- | include/linux/mtd/nand.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h index 863e22a..83f6787 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); |