target/linux/xburst/patches-3.10/003-NAND-Add-support-for-subpage-reads-for-NAND_ECC_HW_O.patch

   1 From 90e325c5e16db262818bca442b00f5ac10b9c852 Mon Sep 17 00:00:00 2001
   2 From: Lars-Peter Clausen <lars@metafoo.de>
   3 Date: Tue, 15 Mar 2011 12:33:41 +0100
   4 Subject: [PATCH 03/16] NAND: Add support for subpage reads for
   5  NAND_ECC_HW_OOB_FIRST
   6
   7 Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
   8 ---
   9  drivers/mtd/nand/nand_base.c |   80 ++++++++++++++++++++++++++++++++++++++++--
  10  include/linux/mtd/nand.h     |    2 +-
  11  2 files changed, 78 insertions(+), 4 deletions(-)
  12
  13 diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
  14 index 287c433..0fd6f2e 100644
  15 --- a/drivers/mtd/nand/nand_base.c
  16 +++ b/drivers/mtd/nand/nand_base.c
  17 @@ -1118,7 +1118,7 @@ static int nand_read_page_swecc(struct mtd_info *mtd, struct nand_chip *chip,
  18   * @bufpoi: buffer to store read data
  19   */
  20  static int nand_read_subpage(struct mtd_info *mtd, struct nand_chip *chip,
  21 -                       uint32_t data_offs, uint32_t readlen, uint8_t *bufpoi)
  22 +                       uint32_t data_offs, uint32_t readlen, uint8_t *bufpoi, int page)
  23  {
  24         int start_step, end_step, num_steps;
  25         uint32_t *eccpos = chip->ecc.layout->eccpos;
  26 @@ -1311,6 +1311,75 @@ static int nand_read_page_hwecc_oob_first(struct mtd_info *mtd,
  27  }
  28
  29  /**
  30 + * nand_read_subpage_hwecc_oob_first - [REPLACABLE] hw ecc based sub-page read function
  31 + * @mtd:       mtd info structure
  32 + * @chip:      nand chip info structure
  33 + * @data_offs: offset of requested data within the page
  34 + * @readlen:   data length
  35 + * @bufpoi:    buffer to store read data
  36 + * @page:      page number to read
  37 + *
  38 + * Hardware ECC for large page chips, require OOB to be read first.
  39 + * For this ECC mode, the write_page method is re-used from ECC_HW.
  40 + * These methods read/write ECC from the OOB area, unlike the
  41 + * ECC_HW_SYNDROME support with multiple ECC steps, follows the
  42 + * "infix ECC" scheme and reads/writes ECC from the data area, by
  43 + * overwriting the NAND manufacturer bad block markings.
  44 + */
  45 +static int nand_read_subpage_hwecc_oob_first(struct mtd_info *mtd, struct nand_chip *chip,
  46 +                       uint32_t data_offs, uint32_t readlen, uint8_t *bufpoi, int page)
  47 +{
  48 +       int start_step, end_step, num_steps;
  49 +       uint32_t *eccpos = chip->ecc.layout->eccpos;
  50 +       uint8_t *p;
  51 +       int data_col_addr;
  52 +       int eccsize = chip->ecc.size;
  53 +       int eccbytes = chip->ecc.bytes;
  54 +       uint8_t *ecc_code = chip->buffers->ecccode;
  55 +       uint8_t *ecc_calc = chip->buffers->ecccalc;
  56 +       int i;
  57 +
  58 +       /* Column address wihin the page aligned to ECC size */
  59 +       start_step = data_offs / chip->ecc.size;
  60 +       end_step = (data_offs + readlen - 1) / chip->ecc.size;
  61 +       num_steps = end_step - start_step + 1;
  62 +
  63 +       data_col_addr = start_step * chip->ecc.size;
  64 +
  65 +       /* Read the OOB area first */
  66 +       if (mtd->writesize > 512) {
  67 +               chip->cmdfunc(mtd, NAND_CMD_READ0, mtd->writesize, page);
  68 +               chip->read_buf(mtd, chip->oob_poi, mtd->oobsize);
  69 +               chip->cmdfunc(mtd, NAND_CMD_RNDOUT, data_col_addr, -1);
  70 +       } else {
  71 +               chip->cmdfunc(mtd, NAND_CMD_READOOB, 0, page);
  72 +               chip->read_buf(mtd, chip->oob_poi, mtd->oobsize);
  73 +               chip->cmdfunc(mtd, NAND_CMD_READ0, data_col_addr, page);
  74 +       }
  75 +
  76 +       for (i = 0; i < chip->ecc.total; i++)
  77 +               ecc_code[i] = chip->oob_poi[eccpos[i]];
  78 +
  79 +       p = bufpoi + data_col_addr;
  80 +
  81 +       for (i = eccbytes * start_step; num_steps; num_steps--, i += eccbytes, p += eccsize) {
  82 +               int stat;
  83 +
  84 +               chip->ecc.hwctl(mtd, NAND_ECC_READ);
  85 +               chip->read_buf(mtd, p, eccsize);
  86 +               chip->ecc.calculate(mtd, p, &ecc_calc[i]);
  87 +
  88 +               stat = chip->ecc.correct(mtd, p, &ecc_code[i], NULL);
  89 +               if (stat < 0)
  90 +                       mtd->ecc_stats.failed++;
  91 +               else
  92 +                       mtd->ecc_stats.corrected += stat;
  93 +       }
  94 +
  95 +       return 0;
  96 +}
  97 +
  98 +/**
  99   * nand_read_page_syndrome - [REPLACEABLE] hardware ECC syndrome based page read
 100   * @mtd: mtd info structure
 101   * @chip: nand chip info structure
 102 @@ -1477,7 +1546,7 @@ static int nand_do_read_ops(struct mtd_info *mtd, loff_t from,
 103                         else if (!aligned && NAND_HAS_SUBPAGE_READ(chip) &&
 104                                  !oob)
 105                                 ret = chip->ecc.read_subpage(mtd, chip,
 106 -                                                       col, bytes, bufpoi);
 107 +                                                       col, bytes, bufpoi, page);
 108                         else
 109                                 ret = chip->ecc.read_page(mtd, chip, bufpoi,
 110                                                           oob_required, page);
 111 @@ -3475,8 +3544,13 @@ int nand_scan_tail(struct mtd_info *mtd)
 112                                    "hardware ECC not possible\n");
 113                         BUG();
 114                 }
 115 -               if (!chip->ecc.read_page)
 116 +               if (!chip->ecc.read_page) {
 117                         chip->ecc.read_page = nand_read_page_hwecc_oob_first;
 118 +                       if (!chip->ecc.read_subpage) {
 119 +                               chip->ecc.read_subpage = nand_read_subpage_hwecc_oob_first;
 120 +                               chip->options |= NAND_SUBPAGE_READ;
 121 +                       }
 122 +               }
 123
 124         case NAND_ECC_HW:
 125                 /* Use standard hwecc read page function? */
 126 diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
 127 index ab63634..ff5b62e 100644
 128 --- a/include/linux/mtd/nand.h
 129 +++ b/include/linux/mtd/nand.h
 130 @@ -349,7 +349,7 @@ struct nand_ecc_ctrl {
 131         int (*read_page)(struct mtd_info *mtd, struct nand_chip *chip,
 132                         uint8_t *buf, int oob_required, int page);
 133         int (*read_subpage)(struct mtd_info *mtd, struct nand_chip *chip,
 134 -                       uint32_t offs, uint32_t len, uint8_t *buf);
 135 +                       uint32_t offs, uint32_t len, uint8_t *buf, int page);
 136         int (*write_subpage)(struct mtd_info *mtd, struct nand_chip *chip,
 137                         uint32_t offset, uint32_t data_len,
 138                         const uint8_t *data_buf, int oob_required);
 139 --
 140 1.7.10.4
 141