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mtd: nand: Added a device flag for subpage read support 

Added a NAND device flag for subpage read support. Previously this was
hard coded based on large page and soft ECC.
Updated base NAND driver to use the new subpage read flag if the NAND is
large page and soft ECC.

Signed-off-by: Jeff Westfahl <jeff.westfahl@ni.com>
Reviewed-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
This commit is contained in:
Jeff Westfahl 2012-08-13 16:35:30 -05:00 committed by David Woodhouse
parent 32098f6af0
commit a5ff4f1029
2 changed files with 11 additions and 5 deletions
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9
drivers/mtd/nand/nand_base.c
View File

@ -1484,7 +1484,8 @@ static int nand_do_read_ops(struct mtd_info *mtd, loff_t from,
ret = chip->ecc.read_page_raw(mtd, chip, bufpoi,
oob_required,
page);
else if (!aligned && NAND_SUBPAGE_READ(chip) && !oob)
else if (!aligned && NAND_HAS_SUBPAGE_READ(chip) &&
!oob)
ret = chip->ecc.read_subpage(mtd, chip,
col, bytes, bufpoi);
else
@ -1501,7 +1502,7 @@ static int nand_do_read_ops(struct mtd_info *mtd, loff_t from,
/* Transfer not aligned data */
if (!aligned) {
if (!NAND_SUBPAGE_READ(chip) && !oob &&
if (!NAND_HAS_SUBPAGE_READ(chip) && !oob &&
!(mtd->ecc_stats.failed - stats.failed) &&
(ops->mode != MTD_OPS_RAW)) {
chip->pagebuf = realpage;
@ -3415,6 +3416,10 @@ int nand_scan_tail(struct mtd_info *mtd)
/* Invalidate the pagebuffer reference */
chip->pagebuf = -1;
/* Large page NAND with SOFT_ECC should support subpage reads */
if ((chip->ecc.mode == NAND_ECC_SOFT) && (chip->page_shift > 9))
chip->options |= NAND_SUBPAGE_READ;
/* Fill in remaining MTD driver data */
mtd->type = MTD_NANDFLASH;
mtd->flags = (chip->options & NAND_ROM) ? MTD_CAP_ROM :

7
include/linux/mtd/nand.h
View File

@ -194,6 +194,9 @@ typedef enum {
/* Device behaves just like nand, but is readonly */
#define NAND_ROM 0x00000800
/* Device supports subpage reads */
#define NAND_SUBPAGE_READ 0x00001000
/* Options valid for Samsung large page devices */
#define NAND_SAMSUNG_LP_OPTIONS \
(NAND_NO_PADDING | NAND_CACHEPRG | NAND_COPYBACK)
@ -202,9 +205,7 @@ 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))
/* 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))
#define NAND_HAS_SUBPAGE_READ(chip) ((chip->options & NAND_SUBPAGE_READ))
/* Non chip related options */
/* This option skips the bbt scan during initialization. */