target/linux/pistachio/patches-4.9/411-mtd-nand-Check-length-of-ID-before-reading-bits-per-.patch

   1 From 42ebff638003be18fab503b37de4ad7853244e95 Mon Sep 17 00:00:00 2001
   2 From: Ezequiel Garcia <ezequiel.garcia@imgtec.com>
   3 Date: Sat, 25 Feb 2017 15:58:22 +0000
   4 Subject: mtd: nand: Check length of ID before reading bits per cell
   5
   6 The table-based NAND identification currently reads the number
   7 of bits per cell from the 3rd byte of the extended ID. This is done
   8 for the so-called 'full ID' devices; i.e. devices that have a known
   9 length ID.
  10
  11 However, if the ID length is shorter than three, there's no 3rd byte,
  12 and so it's wrong to read the bits per cell from there. Fix this by
  13 adding a check for the ID length.
  14
  15 (picked from http://lists.infradead.org/pipermail/linux-mtd/2014-December/056764.html)
  16
  17 Signed-off-by: Ezequiel Garcia <ezequiel.garcia@imgtec.com>
  18 ---
  19  drivers/mtd/nand/nand_base.c | 3 ++-
  20  1 file changed, 2 insertions(+), 1 deletion(-)
  21
  22 --- a/drivers/mtd/nand/nand_base.c
  23 +++ b/drivers/mtd/nand/nand_base.c
  24 @@ -4040,7 +4040,8 @@ static bool find_full_id_nand(struct mtd
  25                 mtd->erasesize = type->erasesize;
  26                 mtd->oobsize = type->oobsize;
  27
  28 -               chip->bits_per_cell = nand_get_bits_per_cell(id_data[2]);
  29 +               if (type->id_len > 2)
  30 +                       chip->bits_per_cell = nand_get_bits_per_cell(id_data[2]);
  31                 chip->chipsize = (uint64_t)type->chipsize << 20;
  32                 chip->options |= type->options;
  33                 chip->ecc_strength_ds = NAND_ECC_STRENGTH(type);