mtd: nand: fix incorrect ecc strength values

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Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=44df4d11b8f573e9efcba94d63e6a1ad148c76d0
Commit:     44df4d11b8f573e9efcba94d63e6a1ad148c76d0
Parent:     86c2072be6f3c2150cc35f00233f2c31bdba2745
Author:     Mike Dunn <mikedunn at newsguy.com>
AuthorDate: Wed Apr 25 12:06:06 2012 -0700
Committer:  David Woodhouse <David.Woodhouse at intel.com>
CommitDate: Sun May 13 23:10:28 2012 -0500

    mtd: nand: fix incorrect ecc strength values
    
    This fixes a couple of ecc strength values for which I earlier made conservative
    guesses, but whose correct values were later determined¹ (thanks Ivan).  Also
    sets strength for fsl_ifc_nand, which was merged to mainline after the original
    patch that set the strength for all drivers.
    
    ¹ http://lists.infradead.org/pipermail/linux-mtd/2012-March/040325.html
    
    Signed-off-by: Mike Dunn <mikedunn at newsguy.com>
    Signed-off-by: Artem Bityutskiy <artem.bityutskiy at linux.intel.com>
    Signed-off-by: David Woodhouse <David.Woodhouse at intel.com>
---
 drivers/mtd/nand/bcm_umi_nand.c |    7 +------
 drivers/mtd/nand/fsl_ifc_nand.c |    1 +
 drivers/mtd/nand/jz4740_nand.c  |    6 +-----
 3 files changed, 3 insertions(+), 11 deletions(-)

diff --git a/drivers/mtd/nand/bcm_umi_nand.c b/drivers/mtd/nand/bcm_umi_nand.c
index 6908cdd..7134adf 100644
--- a/drivers/mtd/nand/bcm_umi_nand.c
+++ b/drivers/mtd/nand/bcm_umi_nand.c
@@ -476,12 +476,7 @@ static int __devinit bcm_umi_nand_probe(struct platform_device *pdev)
 		this->badblock_pattern = &largepage_bbt;
 	}
 
-	/*
-	 * FIXME: ecc strength value of 6 bits per 512 bytes of data is a
-	 * conservative guess, given 13 ecc bytes and using bch alg.
-	 * (Assume Galois field order m=15 to allow a margin of error.)
-	 */
-	this->ecc.strength = 6;
+	this->ecc.strength = 8;
 
 #endif
 
diff --git a/drivers/mtd/nand/fsl_ifc_nand.c b/drivers/mtd/nand/fsl_ifc_nand.c
index 5387cec..872cc96 100644
--- a/drivers/mtd/nand/fsl_ifc_nand.c
+++ b/drivers/mtd/nand/fsl_ifc_nand.c
@@ -821,6 +821,7 @@ static int fsl_ifc_chip_init(struct fsl_ifc_mtd *priv)
 	/* Hardware generates ECC per 512 Bytes */
 	chip->ecc.size = 512;
 	chip->ecc.bytes = 8;
+	chip->ecc.strength = 4;
 
 	switch (csor & CSOR_NAND_PGS_MASK) {
 	case CSOR_NAND_PGS_512:
diff --git a/drivers/mtd/nand/jz4740_nand.c b/drivers/mtd/nand/jz4740_nand.c
index e4147e8..a6fa884 100644
--- a/drivers/mtd/nand/jz4740_nand.c
+++ b/drivers/mtd/nand/jz4740_nand.c
@@ -332,11 +332,7 @@ static int __devinit jz_nand_probe(struct platform_device *pdev)
 	chip->ecc.mode		= NAND_ECC_HW_OOB_FIRST;
 	chip->ecc.size		= 512;
 	chip->ecc.bytes		= 9;
-	chip->ecc.strength	= 2;
-	/*
-	 * FIXME: ecc_strength value of 2 bits per 512 bytes of data is a
-	 * conservative guess, given 9 ecc bytes and reed-solomon alg.
-	 */
+	chip->ecc.strength	= 4;
 
 	if (pdata)
 		chip->ecc.layout = pdata->ecc_layout;