target/linux/xburst/patches-3.10/002-NAND-Optimize-NAND_ECC_HW_OOB_FIRST-read.patch

   1 From f2b7099d3986e59aab5792cecc052e440caf2cdd Mon Sep 17 00:00:00 2001
   2 From: Lars-Peter Clausen <lars@metafoo.de>
   3 Date: Sat, 26 Feb 2011 15:30:07 +0100
   4 Subject: [PATCH 02/16] NAND: Optimize NAND_ECC_HW_OOB_FIRST read
   5
   6 Avoid sending unnecessary READ commands to the chip.
   7
   8 Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
   9 ---
  10  drivers/mtd/nand/nand_base.c |   17 +++++++++++++----
  11  1 file changed, 13 insertions(+), 4 deletions(-)
  12
  13 diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
  14 index dfcd0a5..287c433 100644
  15 --- a/drivers/mtd/nand/nand_base.c
  16 +++ b/drivers/mtd/nand/nand_base.c
  17 @@ -1278,9 +1278,16 @@ static int nand_read_page_hwecc_oob_first(struct mtd_info *mtd,
  18         unsigned int max_bitflips = 0;
  19
  20         /* Read the OOB area first */
  21 -       chip->cmdfunc(mtd, NAND_CMD_READOOB, 0, page);
  22 -       chip->read_buf(mtd, chip->oob_poi, mtd->oobsize);
  23 -       chip->cmdfunc(mtd, NAND_CMD_READ0, 0, page);
  24 +       /* Read the OOB area first */
  25 +       if (mtd->writesize > 512) {
  26 +               chip->cmdfunc(mtd, NAND_CMD_READ0, mtd->writesize, page);
  27 +               chip->read_buf(mtd, chip->oob_poi, mtd->oobsize);
  28 +               chip->cmdfunc(mtd, NAND_CMD_RNDOUT, 0, -1);
  29 +       } else {
  30 +               chip->cmdfunc(mtd, NAND_CMD_READOOB, 0, page);
  31 +               chip->read_buf(mtd, chip->oob_poi, mtd->oobsize);
  32 +               chip->cmdfunc(mtd, NAND_CMD_READ0, 0, page);
  33 +       }
  34
  35         for (i = 0; i < chip->ecc.total; i++)
  36                 ecc_code[i] = chip->oob_poi[eccpos[i]];
  37 @@ -1455,7 +1462,9 @@ static int nand_do_read_ops(struct mtd_info *mtd, loff_t from,
  38                 if (realpage != chip->pagebuf || oob) {
  39                         bufpoi = aligned ? buf : chip->buffers->databuf;
  40
  41 -                       chip->cmdfunc(mtd, NAND_CMD_READ0, 0x00, page);
  42 +                       if (chip->ecc.mode != NAND_ECC_HW_OOB_FIRST) {
  43 +                               chip->cmdfunc(mtd, NAND_CMD_READ0, 0x00, page);
  44 +                       }
  45
  46                         /*
  47                          * Now read the page into the buffer.  Absent an error,
  48 --
  49 1.7.10.4
  50