target/linux/xburst/patches-3.8/0004-NAND-Add-support-for-subpage-reads-for-NAND_ECC_HW_O.patch

   1 From 297d8a7bdfb755778d4189ca2861dd2a6125e972 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 04/21] NAND: Add support for subpage reads for
   5  NAND_ECC_HW_OOB_FIRST
   6
   7 ---
   8  drivers/mtd/nand/nand_base.c |   78 ++++++++++++++++++++++++++++++++++++++++--
   9  include/linux/mtd/nand.h     |    8 ++--
  10  2 files changed, 79 insertions(+), 7 deletions(-)
  11
  12 --- a/drivers/mtd/nand/nand_base.c
  13 +++ b/drivers/mtd/nand/nand_base.c
  14 @@ -1139,7 +1139,7 @@ static int nand_read_page_swecc(struct m
  15   * @bufpoi: buffer to store read data
  16   */
  17  static int nand_read_subpage(struct mtd_info *mtd, struct nand_chip *chip,
  18 -                       uint32_t data_offs, uint32_t readlen, uint8_t *bufpoi)
  19 +                       uint32_t data_offs, uint32_t readlen, uint8_t *bufpoi, int page)
  20  {
  21         int start_step, end_step, num_steps;
  22         uint32_t *eccpos = chip->ecc.layout->eccpos;
  23 @@ -1331,6 +1331,75 @@ static int nand_read_page_hwecc_oob_firs
  24  }
  25
  26  /**
  27 + * nand_read_subpage_hwecc_oob_first - [REPLACABLE] hw ecc based sub-page read function
  28 + * @mtd:       mtd info structure
  29 + * @chip:      nand chip info structure
  30 + * @data_offs: offset of requested data within the page
  31 + * @readlen:   data length
  32 + * @bufpoi:    buffer to store read data
  33 + * @page:      page number to read
  34 + *
  35 + * Hardware ECC for large page chips, require OOB to be read first.
  36 + * For this ECC mode, the write_page method is re-used from ECC_HW.
  37 + * These methods read/write ECC from the OOB area, unlike the
  38 + * ECC_HW_SYNDROME support with multiple ECC steps, follows the
  39 + * "infix ECC" scheme and reads/writes ECC from the data area, by
  40 + * overwriting the NAND manufacturer bad block markings.
  41 + */
  42 +static int nand_read_subpage_hwecc_oob_first(struct mtd_info *mtd, struct nand_chip *chip,
  43 +                       uint32_t data_offs, uint32_t readlen, uint8_t *bufpoi, int page)
  44 +{
  45 +       int start_step, end_step, num_steps;
  46 +       uint32_t *eccpos = chip->ecc.layout->eccpos;
  47 +       uint8_t *p;
  48 +       int data_col_addr;
  49 +       int eccsize = chip->ecc.size;
  50 +       int eccbytes = chip->ecc.bytes;
  51 +       uint8_t *ecc_code = chip->buffers->ecccode;
  52 +       uint8_t *ecc_calc = chip->buffers->ecccalc;
  53 +       int i;
  54 +
  55 +       /* Column address wihin the page aligned to ECC size */
  56 +       start_step = data_offs / chip->ecc.size;
  57 +       end_step = (data_offs + readlen - 1) / chip->ecc.size;
  58 +       num_steps = end_step - start_step + 1;
  59 +
  60 +       data_col_addr = start_step * chip->ecc.size;
  61 +
  62 +       /* Read the OOB area first */
  63 +       if (mtd->writesize > 512) {
  64 +               chip->cmdfunc(mtd, NAND_CMD_READ0, mtd->writesize, page);
  65 +               chip->read_buf(mtd, chip->oob_poi, mtd->oobsize);
  66 +               chip->cmdfunc(mtd, NAND_CMD_RNDOUT, data_col_addr, -1);
  67 +       } else {
  68 +               chip->cmdfunc(mtd, NAND_CMD_READOOB, 0, page);
  69 +               chip->read_buf(mtd, chip->oob_poi, mtd->oobsize);
  70 +               chip->cmdfunc(mtd, NAND_CMD_READ0, data_col_addr, page);
  71 +       }
  72 +
  73 +       for (i = 0; i < chip->ecc.total; i++)
  74 +               ecc_code[i] = chip->oob_poi[eccpos[i]];
  75 +
  76 +       p = bufpoi + data_col_addr;
  77 +
  78 +       for (i = eccbytes * start_step; num_steps; num_steps--, i += eccbytes, p += eccsize) {
  79 +               int stat;
  80 +
  81 +               chip->ecc.hwctl(mtd, NAND_ECC_READ);
  82 +               chip->read_buf(mtd, p, eccsize);
  83 +               chip->ecc.calculate(mtd, p, &ecc_calc[i]);
  84 +
  85 +               stat = chip->ecc.correct(mtd, p, &ecc_code[i], NULL);
  86 +               if (stat < 0)
  87 +                       mtd->ecc_stats.failed++;
  88 +               else
  89 +                       mtd->ecc_stats.corrected += stat;
  90 +       }
  91 +
  92 +       return 0;
  93 +}
  94 +
  95 +/**
  96   * nand_read_page_syndrome - [REPLACEABLE] hardware ECC syndrome based page read
  97   * @mtd: mtd info structure
  98   * @chip: nand chip info structure
  99 @@ -1495,7 +1564,7 @@ static int nand_do_read_ops(struct mtd_i
 100                         else if (!aligned && NAND_HAS_SUBPAGE_READ(chip) &&
 101                                  !oob)
 102                                 ret = chip->ecc.read_subpage(mtd, chip,
 103 -                                                       col, bytes, bufpoi);
 104 +                                                       col, bytes, bufpoi, page);
 105                         else
 106                                 ret = chip->ecc.read_page(mtd, chip, bufpoi,
 107                                                           oob_required, page);
 108 @@ -3451,8 +3520,11 @@ int nand_scan_tail(struct mtd_info *mtd)
 109                                    "hardware ECC not possible\n");
 110                         BUG();
 111                 }
 112 -               if (!chip->ecc.read_page)
 113 +               if (!chip->ecc.read_page) {
 114                         chip->ecc.read_page = nand_read_page_hwecc_oob_first;
 115 +                       if (!chip->ecc.read_subpage)
 116 +                               chip->ecc.read_subpage = nand_read_subpage_hwecc_oob_first;
 117 +               }
 118
 119         case NAND_ECC_HW:
 120                 /* Use standard hwecc read page function? */
 121 --- a/include/linux/mtd/nand.h
 122 +++ b/include/linux/mtd/nand.h
 123 @@ -384,7 +384,7 @@ struct nand_ecc_ctrl {
 124         int (*read_page)(struct mtd_info *mtd, struct nand_chip *chip,
 125                         uint8_t *buf, int oob_required, int page);
 126         int (*read_subpage)(struct mtd_info *mtd, struct nand_chip *chip,
 127 -                       uint32_t offs, uint32_t len, uint8_t *buf);
 128 +                       uint32_t offs, uint32_t len, uint8_t *buf, int page);
 129         int (*write_page)(struct mtd_info *mtd, struct nand_chip *chip,
 130                         const uint8_t *buf, int oob_required);
 131         int (*write_oob_raw)(struct mtd_info *mtd, struct nand_chip *chip,