[3.13.y.z extended stable] Patch "mtd: nand: omap: Fix 1-bit Hamming code scheme, omap_calculate_ecc()" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    mtd: nand: omap: Fix 1-bit Hamming code scheme, omap_calculate_ecc()

to the linux-3.13.y-queue branch of the 3.13.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11.8.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From e748662251b340a915ca48c9dfb3389225951141 Mon Sep 17 00:00:00 2001
From: Roger Quadros <rogerq at ti.com>
Date: Mon, 25 Aug 2014 16:15:33 -0700
Subject: mtd: nand: omap: Fix 1-bit Hamming code scheme, omap_calculate_ecc()

commit 40ddbf5069bd4e11447c0088fc75318e0aac53f0 upstream.

commit 65b97cf6b8de introduced in v3.7 caused a regression
by using a reversed CS_MASK thus causing omap_calculate_ecc to
always fail. As the NAND base driver never checks for .calculate()'s
return value, the zeroed ECC values are used as is without showing
any error to the user. However, this won't work and the NAND device
won't be guarded by any error code.

Fix the issue by using the correct mask.

Code was tested on omap3beagle using the following procedure
- flash the primary bootloader (MLO) from the kernel to the first
NAND partition using nandwrite.
- boot the board from NAND. This utilizes OMAP ROM loader that
relies on 1-bit Hamming code ECC.

Fixes: 65b97cf6b8de (mtd: nand: omap2: handle nand on gpmc)

Signed-off-by: Roger Quadros <rogerq at ti.com>
Signed-off-by: Tony Lindgren <tony at atomide.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/mtd/nand/omap2.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c
index b594e61..a858904 100644
--- a/drivers/mtd/nand/omap2.c
+++ b/drivers/mtd/nand/omap2.c
@@ -933,7 +933,7 @@ static int omap_calculate_ecc(struct mtd_info *mtd, const u_char *dat,
 	u32 val;

 	val = readl(info->reg.gpmc_ecc_config);
-	if (((val >> ECC_CONFIG_CS_SHIFT)  & ~CS_MASK) != info->gpmc_cs)
+	if (((val >> ECC_CONFIG_CS_SHIFT) & CS_MASK) != info->gpmc_cs)
 		return -EINVAL;

 	/* read ecc result */
--
1.9.1