target/linux/bcm63xx/patches-5.4/021-v5.8-mtd-rawnand-brcmnand-improve-hamming-oob-layout.patch

   1 From d00358d7a1c50718232799e1ee10955bcd73795a Mon Sep 17 00:00:00 2001
   2 From: =?UTF-8?q?=C3=81lvaro=20Fern=C3=A1ndez=20Rojas?= <noltari@gmail.com>
   3 Date: Tue, 12 May 2020 09:57:33 +0200
   4 Subject: [PATCH] mtd: rawnand: brcmnand: improve hamming oob layout
   5 MIME-Version: 1.0
   6 Content-Type: text/plain; charset=UTF-8
   7 Content-Transfer-Encoding: 8bit
   8
   9 The current code generates 8 oob sections:
  10 S1      1-5
  11 ECC     6-8
  12 S2      9-15
  13 S3      16-21
  14 ECC     22-24
  15 S4      25-31
  16 S5      32-37
  17 ECC     38-40
  18 S6      41-47
  19 S7      48-53
  20 ECC     54-56
  21 S8      57-63
  22
  23 Change it by merging continuous sections:
  24 S1      1-5
  25 ECC     6-8
  26 S2      9-21
  27 ECC     22-24
  28 S3      25-37
  29 ECC     38-40
  30 S4      41-53
  31 ECC     54-56
  32 S5      57-63
  33
  34 Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
  35 Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
  36 Link: https://lore.kernel.org/linux-mtd/20200512075733.745374-3-noltari@gmail.com
  37 ---
  38  drivers/mtd/nand/raw/brcmnand/brcmnand.c | 35 +++++++++++-------------
  39  1 file changed, 16 insertions(+), 19 deletions(-)
  40
  41 --- a/drivers/mtd/nand/raw/brcmnand/brcmnand.c
  42 +++ b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
  43 @@ -1004,33 +1004,30 @@ static int brcmnand_hamming_ooblayout_fr
  44         struct brcmnand_cfg *cfg = &host->hwcfg;
  45         int sas = cfg->spare_area_size << cfg->sector_size_1k;
  46         int sectors = cfg->page_size / (512 << cfg->sector_size_1k);
  47 +       u32 next;
  48
  49 -       if (section >= sectors * 2)
  50 +       if (section > sectors)
  51                 return -ERANGE;
  52
  53 -       oobregion->offset = (section / 2) * sas;
  54 +       next = (section * sas);
  55 +       if (section < sectors)
  56 +               next += 6;
  57
  58 -       if (section & 1) {
  59 -               oobregion->offset += 9;
  60 -               oobregion->length = 7;
  61 +       if (section) {
  62 +               oobregion->offset = ((section - 1) * sas) + 9;
  63         } else {
  64 -               oobregion->length = 6;
  65 -
  66 -               /* First sector of each page may have BBI */
  67 -               if (!section) {
  68 -                       /*
  69 -                        * Small-page NAND use byte 6 for BBI while large-page
  70 -                        * NAND use bytes 0 and 1.
  71 -                        */
  72 -                       if (cfg->page_size > 512) {
  73 -                               oobregion->offset += 2;
  74 -                               oobregion->length -= 2;
  75 -                       } else {
  76 -                               oobregion->length--;
  77 -                       }
  78 +               if (cfg->page_size > 512) {
  79 +                       /* Large page NAND uses first 2 bytes for BBI */
  80 +                       oobregion->offset = 2;
  81 +               } else {
  82 +                       /* Small page NAND uses last byte before ECC for BBI */
  83 +                       oobregion->offset = 0;
  84 +                       next--;
  85                 }
  86         }
  87
  88 +       oobregion->length = next - oobregion->offset;
  89 +
  90         return 0;
  91  }
  92