[PATCH v2 0/3] mtd: nand: omap: fix ecc-layout

[PATCH v2 0/3] mtd: nand: omap: fix ecc-layout

[Pekon Gupta]

*changes v1 -> v2*
[PATCH 1/3] fix oobfree->offset calculation + adjust for reserved-marker of last sector
[PATCH 2/3] <new patch>
[PATCH 3/3] refactor code as suggested by Brian Norris <computersforpeace@gmail.com>

 
*original v1*
[PATCH 1/2] http://lists.infradead.org/pipermail/linux-mtd/2013-December/050946.html
[PATCH 2/2] http://lists.infradead.org/pipermail/linux-mtd/2013-December/050945.html

This patch-set is tested on AM335x-EVM using following end-to-end boot sequence
with appropriate u-boot configs [1]

    (BCH8_HW)      (BCH8_SW)         (BCH8_SW)         (BCH8_SW)  (UBIFS)
ROM ---------> SPL ---------> U-Boot ---------> Kernel ---------> File-System

    (BCH8_HW)      (BCH8_HW)         (BCH8_HW)         (BCH8_HW)  (UBIFS)
ROM ---------> SPL ---------> U-Boot ---------> Kernel ---------> File-System


Test1: flash ubi image from u-boot and boot the kernel
   u-boot> mw 0x82000000 0xff <u-boot.img size aligned to NAND block boundary>
   u-boot> fatload mmc 0 0x82000000 u-boot.img
   u-boot> nand erase <u-boot_offset> <u-boot.img size>
   u-boot> nand write 0x82000000  <u-boot_offset> <u-boot.img size>
   u-boot> setenv bootargs 'console=ttyO0,115200n8 noinitrd mem=256M \
                root=ubi0 rw rootfstype=ubifs ubi.mtd=<mtdpart-of-rootfs>,\
                <page-size> ip=off init=/init'
   u-boot> bootm <kernel_offset>

Test2: update u-boot.img from kernel and re-boot
   kernel> flash_erase /dev/<mtdpart-of-u-boot>  0 0
   kernel> nandwrite -s 0  /dev/<mtdpart-of-u-boot>   u-boot.img
   kernel> reboot

[1] u-boot configurations to match above ecc-layout are documented at
    https://processors.wiki.ti.com/index.php/Linux_Core_NAND_User%27s_Guide


Pekon Gupta (3):
  mtd: nand: omap: fix ecclayout->oobfree->offset
  mtd: nand: omap: fix ecclayout->oobfree->length
  mtd: nand: omap: fix ecclayout to be in sync with u-boot NAND driver

 drivers/mtd/nand/omap2.c | 61 +++++++++++++++++++++++++++++++-----------------
 1 file changed, 40 insertions(+), 21 deletions(-)

-- 
1.8.5.1.163.gd7aced9

[PATCH v2 1/3] mtd: nand: omap: fix ecclayout->oobfree->offset

[Pekon Gupta]

1) In current implementation, ecclayout->oobfree->offset is calculated with
 respect to ecclayout->eccpos[0] which is incorrect because ECC bytes may not
 be stored contiguously in OOB.
 So, this patch calculates ecclayout->oobfree->offset with respect to last
 ECC byte-position 'eccpos[ecclayout->eccbytes-1]'.

2) ECC layout of some ecc-schemes expects reserved-markers at specific eccpos[]
 which should not be over-written by any file-system metadata.
 So this patch aligns oobfree->offset taking into account of such markers.

Tested-by: Enric Balletbo i Serra <eballetbo@gmail.com>
Tested-by: Stefan Roese <sr@denx.de>
Signed-off-by: Pekon Gupta <pekon@ti.com>
---
 drivers/mtd/nand/omap2.c | 25 +++++++++++++++----------
 1 file changed, 15 insertions(+), 10 deletions(-)

diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c
index ef4190a..874fd9d 100644
--- a/drivers/mtd/nand/omap2.c
+++ b/drivers/mtd/nand/omap2.c
@@ -1829,8 +1829,9 @@ static int omap_nand_probe(struct platform_device *pdev)
 			ecclayout->eccpos[0]	= BADBLOCK_MARKER_LENGTH;
 		else
 			ecclayout->eccpos[0]	= 1;
-		ecclayout->oobfree->offset	= ecclayout->eccpos[0] +
-							ecclayout->eccbytes;
+		/* no reserved-marker in ecclayout for this ecc-scheme */
+		ecclayout->oobfree->offset	=
+				ecclayout->eccpos[ecclayout->eccbytes - 1] + 1;
 		break;
 
 	case OMAP_ECC_BCH4_CODE_HW_DETECTION_SW:
@@ -1848,8 +1849,9 @@ static int omap_nand_probe(struct platform_device *pdev)
 							(mtd->writesize /
 							nand_chip->ecc.size);
 		ecclayout->eccpos[0]		= BADBLOCK_MARKER_LENGTH;
-		ecclayout->oobfree->offset	= ecclayout->eccpos[0] +
-							ecclayout->eccbytes;
+		/* include reserved-marker in ecclayout->oobfree calculation */
+		ecclayout->oobfree->offset	= 1 +
+				ecclayout->eccpos[ecclayout->eccbytes - 1] + 1;
 		/* software bch library is used for locating errors */
 		nand_chip->ecc.priv		= nand_bch_init(mtd,
 							nand_chip->ecc.size,
@@ -1884,8 +1886,9 @@ static int omap_nand_probe(struct platform_device *pdev)
 							(mtd->writesize /
 							nand_chip->ecc.size);
 		ecclayout->eccpos[0]		= BADBLOCK_MARKER_LENGTH;
-		ecclayout->oobfree->offset	= ecclayout->eccpos[0] +
-							ecclayout->eccbytes;
+		/* reserved marker already included in ecclayout->eccbytes */
+		ecclayout->oobfree->offset	=
+				ecclayout->eccpos[ecclayout->eccbytes - 1] + 1;
 		/* This ECC scheme requires ELM H/W block */
 		if (is_elm_present(info, pdata->elm_of_node, BCH4_ECC) < 0) {
 			pr_err("nand: error: could not initialize ELM\n");
@@ -1914,8 +1917,9 @@ static int omap_nand_probe(struct platform_device *pdev)
 							(mtd->writesize /
 							nand_chip->ecc.size);
 		ecclayout->eccpos[0]		= BADBLOCK_MARKER_LENGTH;
-		ecclayout->oobfree->offset	= ecclayout->eccpos[0] +
-							ecclayout->eccbytes;
+		/* include reserved-marker in ecclayout->oobfree calculation */
+		ecclayout->oobfree->offset	= 1 +
+				ecclayout->eccpos[ecclayout->eccbytes - 1] + 1;
 		/* software bch library is used for locating errors */
 		nand_chip->ecc.priv		= nand_bch_init(mtd,
 							nand_chip->ecc.size,
@@ -1957,8 +1961,9 @@ static int omap_nand_probe(struct platform_device *pdev)
 							(mtd->writesize /
 							nand_chip->ecc.size);
 		ecclayout->eccpos[0]		= BADBLOCK_MARKER_LENGTH;
-		ecclayout->oobfree->offset	= ecclayout->eccpos[0] +
-							ecclayout->eccbytes;
+		/* reserved marker already included in ecclayout->eccbytes */
+		ecclayout->oobfree->offset	=
+				ecclayout->eccpos[ecclayout->eccbytes - 1] + 1;
 		break;
 #else
 		pr_err("nand: error: CONFIG_MTD_NAND_OMAP_BCH not enabled\n");
-- 
1.8.5.1.163.gd7aced9

Re: [PATCH v2 1/3] mtd: nand: omap: fix ecclayout->oobfree->offset

[Brian Norris]

Hi Pekon,

On Fri, Feb 14, 2014 at 10:31:46PM +0530, Pekon Gupta wrote:
> 1) In current implementation, ecclayout->oobfree->offset is calculated with
>  respect to ecclayout->eccpos[0] which is incorrect because ECC bytes may not
>  be stored contiguously in OOB.
>  So, this patch calculates ecclayout->oobfree->offset with respect to last
>  ECC byte-position 'eccpos[ecclayout->eccbytes-1]'.
> 
> 2) ECC layout of some ecc-schemes expects reserved-markers at specific eccpos[]
>  which should not be over-written by any file-system metadata.
>  So this patch aligns oobfree->offset taking into account of such markers.

This is a much better description, and this series is looking a lot more
straightforward now. Thanks. A quick comment below, and I'll spend some
more time looking later.

(BTW, can you mark these for -stable, version 3.13+ if/when you resend?
Or else I'll mark it myself, I think.)

> Tested-by: Enric Balletbo i Serra <eballetbo@gmail.com>
> Tested-by: Stefan Roese <sr@denx.de>
> Signed-off-by: Pekon Gupta <pekon@ti.com>
> ---
>  drivers/mtd/nand/omap2.c | 25 +++++++++++++++----------
>  1 file changed, 15 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c
> index ef4190a..874fd9d 100644
> --- a/drivers/mtd/nand/omap2.c
> +++ b/drivers/mtd/nand/omap2.c
> @@ -1829,8 +1829,9 @@ static int omap_nand_probe(struct platform_device *pdev)
>  			ecclayout->eccpos[0]	= BADBLOCK_MARKER_LENGTH;
>  		else
>  			ecclayout->eccpos[0]	= 1;
> -		ecclayout->oobfree->offset	= ecclayout->eccpos[0] +
> -							ecclayout->eccbytes;
> +		/* no reserved-marker in ecclayout for this ecc-scheme */
> +		ecclayout->oobfree->offset	=
> +				ecclayout->eccpos[ecclayout->eccbytes - 1] + 1;

Thanks for adjusting for 'eccbytes - 1'. This diff *would* be correct,
except that you're only initializing eccpos[1 .. eccbytes-1] in a for
loop after the switch-case block. It seems like this first patch
actually depends on patch 3, where you move the initialization of the
entire eccpos[] array into each 'case' block. e.g.:

@@ -1826,9 +1827,11 @@ static int omap_nand_probe(struct platform_device *pdev)
                                                        (mtd->writesize /
                                                        nand_chip->ecc.size);
                if (nand_chip->options & NAND_BUSWIDTH_16)
-                       ecclayout->eccpos[0]    = BADBLOCK_MARKER_LENGTH;
+                       oob_index               = BADBLOCK_MARKER_LENGTH;
                else
-                       ecclayout->eccpos[0]    = 1;
+                       oob_index               = 1;
+               for (i = 0; i < ecclayout->eccbytes; i++, oob_index++)
+                       ecclayout->eccpos[i]    = oob_index;

So, can you rearrange this series so patch 3 comes first?

> @@ -1848,8 +1849,9 @@ static int omap_nand_probe(struct platform_device *pdev)
>  							(mtd->writesize /
>  							nand_chip->ecc.size);
>  		ecclayout->eccpos[0]		= BADBLOCK_MARKER_LENGTH;
> -		ecclayout->oobfree->offset	= ecclayout->eccpos[0] +
> -							ecclayout->eccbytes;
> +		/* include reserved-marker in ecclayout->oobfree calculation */
> +		ecclayout->oobfree->offset	= 1 +
> +				ecclayout->eccpos[ecclayout->eccbytes - 1] + 1;
>  		/* software bch library is used for locating errors */
>  		nand_chip->ecc.priv		= nand_bch_init(mtd,
>  							nand_chip->ecc.size,
> @@ -1884,8 +1886,9 @@ static int omap_nand_probe(struct platform_device *pdev)
>  							(mtd->writesize /
>  							nand_chip->ecc.size);
>  		ecclayout->eccpos[0]		= BADBLOCK_MARKER_LENGTH;
> -		ecclayout->oobfree->offset	= ecclayout->eccpos[0] +
> -							ecclayout->eccbytes;
> +		/* reserved marker already included in ecclayout->eccbytes */
> +		ecclayout->oobfree->offset	=
> +				ecclayout->eccpos[ecclayout->eccbytes - 1] + 1;
>  		/* This ECC scheme requires ELM H/W block */
>  		if (is_elm_present(info, pdata->elm_of_node, BCH4_ECC) < 0) {
>  			pr_err("nand: error: could not initialize ELM\n");
> @@ -1914,8 +1917,9 @@ static int omap_nand_probe(struct platform_device *pdev)
>  							(mtd->writesize /
>  							nand_chip->ecc.size);
>  		ecclayout->eccpos[0]		= BADBLOCK_MARKER_LENGTH;
> -		ecclayout->oobfree->offset	= ecclayout->eccpos[0] +
> -							ecclayout->eccbytes;
> +		/* include reserved-marker in ecclayout->oobfree calculation */
> +		ecclayout->oobfree->offset	= 1 +
> +				ecclayout->eccpos[ecclayout->eccbytes - 1] + 1;
>  		/* software bch library is used for locating errors */
>  		nand_chip->ecc.priv		= nand_bch_init(mtd,
>  							nand_chip->ecc.size,
> @@ -1957,8 +1961,9 @@ static int omap_nand_probe(struct platform_device *pdev)
>  							(mtd->writesize /
>  							nand_chip->ecc.size);
>  		ecclayout->eccpos[0]		= BADBLOCK_MARKER_LENGTH;
> -		ecclayout->oobfree->offset	= ecclayout->eccpos[0] +
> -							ecclayout->eccbytes;
> +		/* reserved marker already included in ecclayout->eccbytes */
> +		ecclayout->oobfree->offset	=
> +				ecclayout->eccpos[ecclayout->eccbytes - 1] + 1;
>  		break;
>  #else
>  		pr_err("nand: error: CONFIG_MTD_NAND_OMAP_BCH not enabled\n");

Brian

[PATCH v2 2/3] mtd: nand: omap: fix ecclayout->oobfree->length

[Pekon Gupta]

ECC layout of some ecc-schemes expect a 'reserve-marker' as specific
byte-position in OOB. But current calculation of oobfree->length does not
consider that for all ecc-schemes.
But in general, for all ecc-schems, OOB bytes from oobfree->offset till end of
OOB region are unused. So this patch fixes oobfree->length calculation.

Signed-off-by: Pekon Gupta <pekon@ti.com>
---
 drivers/mtd/nand/omap2.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c
index 874fd9d..433e58a 100644
--- a/drivers/mtd/nand/omap2.c
+++ b/drivers/mtd/nand/omap2.c
@@ -1977,9 +1977,8 @@ static int omap_nand_probe(struct platform_device *pdev)
 		goto return_error;
 	}
 
-	/* populate remaining ECC layout data */
-	ecclayout->oobfree->length = mtd->oobsize - (BADBLOCK_MARKER_LENGTH +
-							ecclayout->eccbytes);
+	/* all OOB bytes from oobfree->offset till end off OOB are free */
+	ecclayout->oobfree->length = mtd->oobsize - ecclayout->oobfree->offset;
 	for (i = 1; i < ecclayout->eccbytes; i++)
 		ecclayout->eccpos[i] = ecclayout->eccpos[0] + i;
 	/* check if NAND device's OOB is enough to store ECC signatures */
-- 
1.8.5.1.163.gd7aced9

[PATCH v2 3/3] mtd: nand: omap: fix ecclayout to be in sync with u-boot NAND driver

[Pekon Gupta]

Fixes: commit a919e51161b58ed7e6e663daba99ab7d558808f3
       mtd: nand: omap2: clean-up BCHx_HW and BCHx_SW ECC configurations in device_probe

Fixes ecclayout mismatch introduced in above commit for following ecc-schemes:
 - OMAP_ECC_BCH4_CODE_HW_DETECTION_SW
 - OMAP_ECC_BCH8_CODE_HW_DETECTION_SW
 However, this patch also touches other ecc-schemes as the fix required
 refactoring common code, into ecc-scheme specific code.

This patch aligns ecc-layout for below ecc-schemes as per reference [1],[2],[3]

 +---+------------+-------------++-------------+-------------+
 |OOB|BCH8_CODE_HW|BCH8_CODE_HW_||HAM1_CODE_HW |HAM1_CODE_HW |
 |pos|            | DETECTION_SW||(x8 device)  |(x16 device) |
 +---+------------+-------------++-------------+-------------+
 | 0 |BADBLK_MARK | BADBLK_MARK || BADBLK_MARK | BADBLK_MARK |
 | 1 |BADBLK_MARK | BADBLK_MARK || eccpos[0]   | BADBLK_MARK |
 | 2 | eccpos[0]  | eccpos[0]   || eccpos[1]   | eccpos[0]   |
 | 3 | eccpos[1]  | eccpos[1]   || eccpos[2]   | eccpos[1]   |
 | 4 | eccpos[2]  | eccpos[2]   || eccpos[3]   | eccpos[2]   |
 | 5 | eccpos[3]  | eccpos[3]   || eccpos[4]   | eccpos[3]   |
 | 6 | eccpos[4]  | eccpos[4]   || eccpos[5]   | eccpos[4]   |
 | 7 | eccpos[5]  | eccpos[5]   || eccpos[6]   | eccpos[5]   |
 | 8 | eccpos[6]  | eccpos[6]   || eccpos[7]   | eccpos[6]   |
 | 9 | eccpos[7]  | eccpos[7]   || eccpos[8]   | eccpos[7]   |
 |10 | eccpos[8]  | eccpos[8]   || eccpos[9]   | eccpos[8]   |
 |11 | eccpos[9]  | eccpos[9]   || eccpos[10]  | eccpos[9]   |
 |12 | eccpos[10] | eccpos[10]  || eccpos[11]  | eccpos[10]  |
 |13 | eccpos[11] | eccpos[11]  || oobfree[0]  | eccpos[11]  |
 |14 | eccpos[12] | eccpos[12]  || oobfree[1]  | oobfree[0]  |
 |15 | eccpos[13] | <reserved>  || oobfree[2]  | oobfree[1]  |
 +---+------------+-------------++-------------+-------------+
 |16 | eccpos[14] | eccpos[13]  || oobfree[3]  | oobfree[2]  |
 |...| [...]      | [...]       || [...]       | [...]       |
 |56 | eccpos[54] | eccpos[51]  || oobfree[43] | oobfree[42] |
 |57 | eccpos[55] | <reserved>  || oobfree[44] | oobfree[43] |
 +===+============+=============+==============+=============+
 |58 | oobfree[0] | oobfree[0]  || oobfree[45] | oobfree[44] |
 |59 | oobfree[1] | oobfree[1]  || oobfree[46] | oobfree[45] |
 |60 | oobfree[2] | oobfree[2]  || oobfree[47] | oobfree[46] |
 |61 | oobfree[3] | oobfree[3]  || oobfree[48] | oobfree[47] |
 |62 | oobfree[4] | oobfree[4]  || oobfree[49] | oobfree[48] |
 |63 | oobfree[5] | oobfree[5]  || oobfree[50] | oobfree[49] |
 +---+------------+-------------+--------------+-------------+

[1] ecc-layout expected by ROM code, as specified in SoC TRM under:
      Chapter="Initialization"
        Section="Device Initialization by ROM code"
            Sub-Section="Memory Booting"
                Heading="NAND"
                Figure="ECC Locations in NAND Spare Areas"

[2] ecc-layout updates in u-boot
    http://lists.denx.de/pipermail/u-boot/2013-November/167551.html

[3] u-boot configurations to match above ecc-layout are documented at
    https://processors.wiki.ti.com/index.php/Linux_Core_NAND_User%27s_Guide

Reported-by: Enric Balletbo Serra <eballetbo@iseebcn.com>
Tested-by: Enric Balletbo i Serra <eballetbo@gmail.com>
Tested-by: Stefan Roese <sr@denx.de>
Signed-off-by: Pekon Gupta <pekon@ti.com>
---
 drivers/mtd/nand/omap2.c | 31 +++++++++++++++++++++++--------
 1 file changed, 23 insertions(+), 8 deletions(-)

diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c
index 433e58a..bf642ce 100644
--- a/drivers/mtd/nand/omap2.c
+++ b/drivers/mtd/nand/omap2.c
@@ -1633,6 +1633,7 @@ static int omap_nand_probe(struct platform_device *pdev)
 	int				i;
 	dma_cap_mask_t			mask;
 	unsigned			sig;
+	unsigned			oob_index;
 	struct resource			*res;
 	struct mtd_part_parser_data	ppdata = {};
 
@@ -1826,9 +1827,11 @@ static int omap_nand_probe(struct platform_device *pdev)
 							(mtd->writesize /
 							nand_chip->ecc.size);
 		if (nand_chip->options & NAND_BUSWIDTH_16)
-			ecclayout->eccpos[0]	= BADBLOCK_MARKER_LENGTH;
+			oob_index		= BADBLOCK_MARKER_LENGTH;
 		else
-			ecclayout->eccpos[0]	= 1;
+			oob_index		= 1;
+		for (i = 0; i < ecclayout->eccbytes; i++, oob_index++)
+			ecclayout->eccpos[i]	= oob_index;
 		/* no reserved-marker in ecclayout for this ecc-scheme */
 		ecclayout->oobfree->offset	=
 				ecclayout->eccpos[ecclayout->eccbytes - 1] + 1;
@@ -1848,7 +1851,12 @@ static int omap_nand_probe(struct platform_device *pdev)
 		ecclayout->eccbytes		= nand_chip->ecc.bytes *
 							(mtd->writesize /
 							nand_chip->ecc.size);
-		ecclayout->eccpos[0]		= BADBLOCK_MARKER_LENGTH;
+		oob_index			= BADBLOCK_MARKER_LENGTH;
+		for (i = 0; i < ecclayout->eccbytes; i++, oob_index++) {
+			ecclayout->eccpos[i] = oob_index;
+			if (((i + 1) % nand_chip->ecc.bytes) == 0)
+				oob_index++;
+		}
 		/* include reserved-marker in ecclayout->oobfree calculation */
 		ecclayout->oobfree->offset	= 1 +
 				ecclayout->eccpos[ecclayout->eccbytes - 1] + 1;
@@ -1885,7 +1893,9 @@ static int omap_nand_probe(struct platform_device *pdev)
 		ecclayout->eccbytes		= nand_chip->ecc.bytes *
 							(mtd->writesize /
 							nand_chip->ecc.size);
-		ecclayout->eccpos[0]		= BADBLOCK_MARKER_LENGTH;
+		oob_index			= BADBLOCK_MARKER_LENGTH;
+		for (i = 0; i < ecclayout->eccbytes; i++, oob_index++)
+			ecclayout->eccpos[i]	= oob_index;
 		/* reserved marker already included in ecclayout->eccbytes */
 		ecclayout->oobfree->offset	=
 				ecclayout->eccpos[ecclayout->eccbytes - 1] + 1;
@@ -1916,7 +1926,12 @@ static int omap_nand_probe(struct platform_device *pdev)
 		ecclayout->eccbytes		= nand_chip->ecc.bytes *
 							(mtd->writesize /
 							nand_chip->ecc.size);
-		ecclayout->eccpos[0]		= BADBLOCK_MARKER_LENGTH;
+		oob_index			= BADBLOCK_MARKER_LENGTH;
+		for (i = 0; i < ecclayout->eccbytes; i++, oob_index++) {
+			ecclayout->eccpos[i] = oob_index;
+			if (((i + 1) % nand_chip->ecc.bytes) == 0)
+				oob_index++;
+		}
 		/* include reserved-marker in ecclayout->oobfree calculation */
 		ecclayout->oobfree->offset	= 1 +
 				ecclayout->eccpos[ecclayout->eccbytes - 1] + 1;
@@ -1960,7 +1975,9 @@ static int omap_nand_probe(struct platform_device *pdev)
 		ecclayout->eccbytes		= nand_chip->ecc.bytes *
 							(mtd->writesize /
 							nand_chip->ecc.size);
-		ecclayout->eccpos[0]		= BADBLOCK_MARKER_LENGTH;
+		oob_index			= BADBLOCK_MARKER_LENGTH;
+		for (i = 0; i < ecclayout->eccbytes; i++, oob_index++)
+			ecclayout->eccpos[i]	= oob_index;
 		/* reserved marker already included in ecclayout->eccbytes */
 		ecclayout->oobfree->offset	=
 				ecclayout->eccpos[ecclayout->eccbytes - 1] + 1;
@@ -1979,8 +1996,6 @@ static int omap_nand_probe(struct platform_device *pdev)
 
 	/* all OOB bytes from oobfree->offset till end off OOB are free */
 	ecclayout->oobfree->length = mtd->oobsize - ecclayout->oobfree->offset;
-	for (i = 1; i < ecclayout->eccbytes; i++)
-		ecclayout->eccpos[i] = ecclayout->eccpos[0] + i;
 	/* check if NAND device's OOB is enough to store ECC signatures */
 	if (mtd->oobsize < (ecclayout->eccbytes + BADBLOCK_MARKER_LENGTH)) {
 		pr_err("not enough OOB bytes required = %d, available=%d\n",
-- 
1.8.5.1.163.gd7aced9