Patchwork [2/7] mtd: nand: fix incorrect ecc strength values

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Submitter Mike Dunn
Date April 25, 2012, 7:06 p.m.
Message ID <1335380771-27805-3-git-send-email-mikedunn@newsguy.com>
Download mbox | patch
Permalink /patch/155063/
State New
Headers show

Comments

Mike Dunn - April 25, 2012, 7:06 p.m.
This fixes a couple of ecc strength values for which I earlier made conservative
guesses, but whose correct values were later determined [1] (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@newsguy.com>
---

This v2 is actually unchanged from the original set.

 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(-)

Patch

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;