target/linux/xburst/patches-3.3/0003-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 --- a/drivers/mtd/nand/nand_base.c
  12 +++ b/drivers/mtd/nand/nand_base.c
  13 @@ -1294,9 +1294,15 @@ static int nand_read_page_hwecc_oob_firs
  14         uint8_t *ecc_calc = chip->buffers->ecccalc;
  15
  16         /* Read the OOB area first */
  17 -       chip->cmdfunc(mtd, NAND_CMD_READOOB, 0, page);
  18 -       chip->read_buf(mtd, chip->oob_poi, mtd->oobsize);
  19 -       chip->cmdfunc(mtd, NAND_CMD_READ0, 0, page);
  20 +       if (mtd->writesize > 512) {
  21 +               chip->cmdfunc(mtd, NAND_CMD_READ0, mtd->writesize, page);
  22 +               chip->read_buf(mtd, chip->oob_poi, mtd->oobsize);
  23 +               chip->cmdfunc(mtd, NAND_CMD_RNDOUT, 0, -1);
  24 +       } else {
  25 +               chip->cmdfunc(mtd, NAND_CMD_READOOB, 0, page);
  26 +               chip->read_buf(mtd, chip->oob_poi, mtd->oobsize);
  27 +               chip->cmdfunc(mtd, NAND_CMD_READ0, 0, page);
  28 +       }
  29
  30         for (i = 0; i < chip->ecc.total; i++)
  31                 ecc_code[i] = chip->oob_poi[eccpos[i]];
  32 @@ -1465,7 +1471,7 @@ static int nand_do_read_ops(struct mtd_i
  33                 if (realpage != chip->pagebuf || oob) {
  34                         bufpoi = aligned ? buf : chip->buffers->databuf;
  35
  36 -                       if (likely(sndcmd)) {
  37 +                       if (likely(sndcmd) && chip->ecc.mode != NAND_ECC_HW_OOB_FIRST) {
  38                                 chip->cmdfunc(mtd, NAND_CMD_READ0, 0x00, page);
  39                                 sndcmd = 0;
  40                         }