From 96d8b647cfff90c8ff07863866aacdcd9d13cead Mon Sep 17 00:00:00 2001 From: Alexey Korolev Date: Tue, 29 Jul 2008 13:54:11 +0100 Subject: [PATCH] [MTD] [NAND] fix subpage read for small page NAND Current implementation of subpage read feature for NAND has issues with small page devices. Small page NAND do not support RNDOUT command. So subpage feature is not applicable for them. This patch disables support of subpage for small page NAND. The code is verified on nandsim(SP NAND simulation) and on LP NAND devices. Thanks a lot to Artem for finding this issue. Signed-off-by: Alexey Korolev Signed-off-by: Artem Bityutskiy Signed-off-by: David Woodhouse --- include/linux/mtd/nand.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h index 83f678702dff..81774e5facf4 100644 --- a/include/linux/mtd/nand.h +++ b/include/linux/mtd/nand.h @@ -177,7 +177,9 @@ 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)) +/* Large page NAND with SOFT_ECC should support subpage reads */ +#define NAND_SUBPAGE_READ(chip) ((chip->ecc.mode == NAND_ECC_SOFT) \ + && (chip->page_shift > 9)) /* Mask to zero out the chip options, which come from the id table */ #define NAND_CHIPOPTIONS_MSK (0x0000ffff & ~NAND_NO_AUTOINCR) -- 2.20.1