target/linux/xburst/patches-3.18/002-NAND-Optimize-NAND_ECC_HW_OOB_FIRST-read.patch

   1 From 98d33db1c87e2447b9b203399d2f995e05ecdb52 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 2/7] NAND: Optimize NAND_ECC_HW_OOB_FIRST read
   5
   6 Avoid sending unnecessary READ commands to the chip.
   7 ---
   8  drivers/mtd/nand/nand_base.c |   17 +++++++++++++----
   9  1 file changed, 13 insertions(+), 4 deletions(-)
  10
  11 diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
  12 index 5b5c627..4c8d646 100644
  13 --- a/drivers/mtd/nand/nand_base.c
  14 +++ b/drivers/mtd/nand/nand_base.c
  15 @@ -1360,9 +1360,16 @@ static int nand_read_page_hwecc_oob_first(struct mtd_info *mtd,
  16         unsigned int max_bitflips = 0;
  17
  18         /* Read the OOB area first */
  19 -       chip->cmdfunc(mtd, NAND_CMD_READOOB, 0, page);
  20 -       chip->read_buf(mtd, chip->oob_poi, mtd->oobsize);
  21 -       chip->cmdfunc(mtd, NAND_CMD_READ0, 0, page);
  22 +       /* Read the OOB area first */
  23 +       if (mtd->writesize > 512) {
  24 +               chip->cmdfunc(mtd, NAND_CMD_READ0, mtd->writesize, page);
  25 +               chip->read_buf(mtd, chip->oob_poi, mtd->oobsize);
  26 +               chip->cmdfunc(mtd, NAND_CMD_RNDOUT, 0, -1);
  27 +       } else {
  28 +               chip->cmdfunc(mtd, NAND_CMD_READOOB, 0, page);
  29 +               chip->read_buf(mtd, chip->oob_poi, mtd->oobsize);
  30 +               chip->cmdfunc(mtd, NAND_CMD_READ0, 0, page);
  31 +       }
  32
  33         for (i = 0; i < chip->ecc.total; i++)
  34                 ecc_code[i] = chip->oob_poi[eccpos[i]];
  35 @@ -1575,7 +1582,9 @@ static int nand_do_read_ops(struct mtd_info *mtd, loff_t from,
  36                                                  __func__, buf);
  37
  38  read_retry:
  39 -                       chip->cmdfunc(mtd, NAND_CMD_READ0, 0x00, page);
  40 +                       if (chip->ecc.mode != NAND_ECC_HW_OOB_FIRST) {
  41 +                               chip->cmdfunc(mtd, NAND_CMD_READ0, 0x00, page);
  42 +                       }
  43
  44                         /*
  45                          * Now read the page into the buffer.  Absent an error,
  46 --
  47 1.7.10.4
  48