releases/3.16.3/mtd-nand-omap-fix-1-bit-hamming-code-scheme-omap_calculate_ecc.patch

   1 From 40ddbf5069bd4e11447c0088fc75318e0aac53f0 Mon Sep 17 00:00:00 2001
   2 From: Roger Quadros <rogerq@ti.com>
   3 Date: Mon, 25 Aug 2014 16:15:33 -0700
   4 Subject: mtd: nand: omap: Fix 1-bit Hamming code scheme, omap_calculate_ecc()
   5
   6 From: Roger Quadros <rogerq@ti.com>
   7
   8 commit 40ddbf5069bd4e11447c0088fc75318e0aac53f0 upstream.
   9
  10 commit 65b97cf6b8de introduced in v3.7 caused a regression
  11 by using a reversed CS_MASK thus causing omap_calculate_ecc to
  12 always fail. As the NAND base driver never checks for .calculate()'s
  13 return value, the zeroed ECC values are used as is without showing
  14 any error to the user. However, this won't work and the NAND device
  15 won't be guarded by any error code.
  16
  17 Fix the issue by using the correct mask.
  18
  19 Code was tested on omap3beagle using the following procedure
  20 - flash the primary bootloader (MLO) from the kernel to the first
  21 NAND partition using nandwrite.
  22 - boot the board from NAND. This utilizes OMAP ROM loader that
  23 relies on 1-bit Hamming code ECC.
  24
  25 Fixes: 65b97cf6b8de (mtd: nand: omap2: handle nand on gpmc)
  26
  27 Signed-off-by: Roger Quadros <rogerq@ti.com>
  28 Signed-off-by: Tony Lindgren <tony@atomide.com>
  29 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  30
  31 ---
  32  drivers/mtd/nand/omap2.c |    2 +-
  33  1 file changed, 1 insertion(+), 1 deletion(-)
  34
  35 --- a/drivers/mtd/nand/omap2.c
  36 +++ b/drivers/mtd/nand/omap2.c
  37 @@ -931,7 +931,7 @@ static int omap_calculate_ecc(struct mtd
  38         u32 val;
  39
  40         val = readl(info->reg.gpmc_ecc_config);
  41 -       if (((val >> ECC_CONFIG_CS_SHIFT)  & ~CS_MASK) != info->gpmc_cs)
  42 +       if (((val >> ECC_CONFIG_CS_SHIFT) & CS_MASK) != info->gpmc_cs)
  43                 return -EINVAL;
  44
  45         /* read ecc result */