Use a flag instead of a hard-coded macro so that sub-page reads can be enabled in other cases (such as on-die ecc).

This is the same as a5ff4f102937a3492bca4a9ff0c341d78813414c in Linux

Signed-off-by: Joe Hershberger joe.hershberger@ni.com --- Changes in v2: - Added Linux commit ID to commit message

drivers/mtd/nand/nand_base.c | 9 +++++++-- include/linux/mtd/nand.h | 7 ++++--- 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c index 71f5027..4f2963b 100644 --- a/drivers/mtd/nand/nand_base.c +++ b/drivers/mtd/nand/nand_base.c @@ -1245,7 +1245,8 @@ static int nand_do_read_ops(struct mtd_info *mtd, loff_t from, if (unlikely(ops->mode == MTD_OOB_RAW)) ret = chip->ecc.read_page_raw(mtd, chip, bufpoi, 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 @@ -1256,7 +1257,7 @@ 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)) chip->pagebuf = realpage; memcpy(buf, chip->buffers->databuf + col, bytes); @@ -3149,6 +3150,10 @@ 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 : diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h index f63e04b..e9e9045 100644 --- a/include/linux/mtd/nand.h +++ b/include/linux/mtd/nand.h @@ -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) @@ -203,9 +206,7 @@ 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 */ /*

On 11/05/2012 05:46 PM, Joe Hershberger wrote:

If sub-page reads are supported, this will save reading unneeded data

Signed-off-by: Joe Hershberger joe.hershberger@ni.com

drivers/mtd/ubi/io.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mtd/ubi/io.c b/drivers/mtd/ubi/io.c index 8423894..23660e3 100644 --- a/drivers/mtd/ubi/io.c +++ b/drivers/mtd/ubi/io.c @@ -916,7 +916,7 @@ int ubi_io_read_vid_hdr(struct ubi_device *ubi, int pnum,

p = (char *)vid_hdr - ubi->vid_hdr_shift; err = ubi_io_read(ubi, p, pnum, ubi->vid_hdr_aloffset,

• 	  ubi->vid_hdr_alsize);
  

• 	  UBI_VID_HDR_SIZE);
  

  if (err) { if (err != UBI_IO_BITFLIPS && err != -EBADMSG) return err;

Joe, are you pushing this change to Linux as well? I would really like to see Artem commenting on this.

Thanks, Stefan