target/linux/xburst/patches-3.2/0003-NAND-Optimize-NAND_ECC_HW_OOB_FIRST-read.patch

   1 From b971c50dc50c07f981a1619f977e7509db9c4eac 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 03/21] 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 |   14 ++++++++++----
   9  1 files changed, 10 insertions(+), 4 deletions(-)
  10
  11 diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
  12 index 3ed9c5e..184aa93 100644
  13 --- a/drivers/mtd/nand/nand_base.c
  14 +++ b/drivers/mtd/nand/nand_base.c
  15 @@ -1294,9 +1294,15 @@ static int nand_read_page_hwecc_oob_first(struct mtd_info *mtd,
  16         uint8_t *ecc_calc = chip->buffers->ecccalc;
  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 +       if (mtd->writesize > 512) {
  23 +               chip->cmdfunc(mtd, NAND_CMD_READ0, mtd->writesize, page);
  24 +               chip->read_buf(mtd, chip->oob_poi, mtd->oobsize);
  25 +               chip->cmdfunc(mtd, NAND_CMD_RNDOUT, 0, -1);
  26 +       } else {
  27 +               chip->cmdfunc(mtd, NAND_CMD_READOOB, 0, page);
  28 +               chip->read_buf(mtd, chip->oob_poi, mtd->oobsize);
  29 +               chip->cmdfunc(mtd, NAND_CMD_READ0, 0, page);
  30 +       }
  31
  32         for (i = 0; i < chip->ecc.total; i++)
  33                 ecc_code[i] = chip->oob_poi[eccpos[i]];
  34 @@ -1465,7 +1471,7 @@ static int nand_do_read_ops(struct mtd_info *mtd, loff_t from,
  35                 if (realpage != chip->pagebuf || oob) {
  36                         bufpoi = aligned ? buf : chip->buffers->databuf;
  37
  38 -                       if (likely(sndcmd)) {
  39 +                       if (likely(sndcmd) && chip->ecc.mode != NAND_ECC_HW_OOB_FIRST) {
  40                                 chip->cmdfunc(mtd, NAND_CMD_READ0, 0x00, page);
  41                                 sndcmd = 0;
  42                         }
  43 --
  44 1.7.5.4
  45