From 3d45955962496879dead8d4dd70bb9a23b07154b Mon Sep 17 00:00:00 2001 From: Alexey Korolev Date: Thu, 15 May 2008 17:23:18 +0100 Subject: [MTD] [NAND] subpage read feature as a way to increase performance. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Acked-by: Artem Bityutskiy Acked-by: Jörn Engel Signed-off-by: David Woodhouse --- include/linux/mtd/nand.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'include/linux/mtd') diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h index 863e22a0ddb..83f678702df 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); -- cgit v1.2.3