[PATCH v4 3/3] mtd-nand: DaVinci: Add 4-bit ECC support for large page NAND chips

[PATCH v4 3/3] mtd-nand: DaVinci: Add 4-bit ECC support for large page NAND chips

[nsnehaprabha]

From: Sneha Narnakaje <nsnehaprabha@ti.com>

This patch adds 4-bit ECC support for large page NAND chips using the new ECC
mode NAND_ECC_HW_OOB_FIRST. The platform data from board-dm355-evm has been
adjusted to use this mode.

The patches have been verified on DM355 device with 2K Micron devices using
mtd-tests and JFFS2. Error correction upto 4-bits has also been verified using
nandwrite/nanddump utilities.

This patch series applies to linux-mtd next (mmotm) GIT tree.

This version (v4) addresses the review comment to leave 2 bytes at offset 0
for NAND manufacturer badblock markers.

Reviewed-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Sneha Narnakaje <nsnehaprabha@ti.com>
Signed-off-by: Sandeep Paulraj <s-paulraj@ti.com>
---
 drivers/mtd/nand/davinci_nand.c |   45 +++++++++++++++++++++++++++++++++-----
 1 files changed, 39 insertions(+), 6 deletions(-)

diff --git a/drivers/mtd/nand/davinci_nand.c b/drivers/mtd/nand/davinci_nand.c
index 0fad648..14c72d2 100644
--- a/drivers/mtd/nand/davinci_nand.c
+++ b/drivers/mtd/nand/davinci_nand.c
@@ -348,6 +348,12 @@ compare:
 	if (!(syndrome[0] | syndrome[1] | syndrome[2] | syndrome[3]))
 		return 0;
 
+	/*
+	 * Clear any previous address calculation by doing a dummy read of an
+	 * error address register.
+	 */
+	davinci_nand_readl(info, NAND_ERR_ADD1_OFFSET);
+
 	/* Start address calculation, and wait for it to complete.
 	 * We _could_ start reading more data while this is working,
 	 * to speed up the overall page read.
@@ -359,8 +365,10 @@ compare:
 
 		switch ((fsr >> 8) & 0x0f) {
 		case 0:		/* no error, should not happen */
+			davinci_nand_readl(info, NAND_ERR_ERRVAL1_OFFSET);
 			return 0;
 		case 1:		/* five or more errors detected */
+			davinci_nand_readl(info, NAND_ERR_ERRVAL1_OFFSET);
 			return -EIO;
 		case 2:		/* error addresses computed */
 		case 3:
@@ -500,6 +508,26 @@ static struct nand_ecclayout hwecc4_small __initconst = {
 	},
 };
 
+/* An ECC layout for using 4-bit ECC with large-page (2048bytes) flash,
+ * storing ten ECC bytes plus the manufacturer's bad block marker byte,
+ * and not overlapping the default BBT markers.
+ */
+static struct nand_ecclayout hwecc4_2048 __initconst = {
+	.eccbytes = 40,
+	.eccpos = {
+		/* at the end of spare sector */
+		24, 25, 26, 27, 28, 29,	30, 31, 32, 33,
+		34, 35, 36, 37, 38, 39,	40, 41, 42, 43,
+		44, 45, 46, 47, 48, 49, 50, 51, 52, 53,
+		54, 55, 56, 57, 58, 59, 60, 61, 62, 63,
+		},
+	.oobfree = {
+		/* 2 bytes at offset 0 hold manufacturer badblock markers */
+		{.offset = 2, .length = 22, },
+		/* 5 bytes at offset 8 hold BBT markers */
+		/* 8 bytes at offset 16 hold JFFS2 clean markers */
+	},
+};
 
 static int __init nand_davinci_probe(struct platform_device *pdev)
 {
@@ -690,15 +718,20 @@ static int __init nand_davinci_probe(struct platform_device *pdev)
 				info->mtd.oobsize - 16;
 			goto syndrome_done;
 		}
+		if (chunks == 4) {
+			info->ecclayout = hwecc4_2048;
+			info->chip.ecc.mode = NAND_ECC_HW_OOB_FIRST;
+			goto syndrome_done;
+		}
 
-		/* For large page chips we'll be wanting to use a
-		 * not-yet-implemented mode that reads OOB data
-		 * before reading the body of the page, to avoid
-		 * the "infix OOB" model of NAND_ECC_HW_SYNDROME
-		 * (and preserve manufacturer badblock markings).
+		/* 4K page chips are not yet supported. The eccpos from
+		 * nand_ecclayout cannot hold 80 bytes and change to eccpos[]
+		 * breaks userspace ioctl interface with mtd-utils. Once we
+		 * resolve this issue, NAND_ECC_HW_OOB_FIRST mode can be used
+		 * for the 4K page chips.
 		 */
 		dev_warn(&pdev->dev, "no 4-bit ECC support yet "
-				"for large page NAND\n");
+				"for 4K page NAND\n");
 		ret = -EIO;
 		goto err_scan;
 
-- 
1.6.0.4

Re: [PATCH v4 3/3] mtd-nand: DaVinci: Add 4-bit ECC support for large page NAND chips

[Artem Bityutskiy]

On 08/07/2009 11:48 PM, nsnehaprabha@ti.com wrote:
> From: Sneha Narnakaje<nsnehaprabha@ti.com>
>
> This patch adds 4-bit ECC support for large page NAND chips using the new ECC
> mode NAND_ECC_HW_OOB_FIRST. The platform data from board-dm355-evm has been
> adjusted to use this mode.
>
> The patches have been verified on DM355 device with 2K Micron devices using
> mtd-tests and JFFS2. Error correction upto 4-bits has also been verified using
> nandwrite/nanddump utilities.
>
> This patch series applies to linux-mtd next (mmotm) GIT tree.
>
> This version (v4) addresses the review comment to leave 2 bytes at offset 0
> for NAND manufacturer badblock markers.
>
> Reviewed-by: David Brownell<dbrownell@users.sourceforge.net>
> Signed-off-by: Sneha Narnakaje<nsnehaprabha@ti.com>
> Signed-off-by: Sandeep Paulraj<s-paulraj@ti.com>

There are already 3 patches in my l2-mtd-2.6.git tree:

http://git.infradead.org/users/dedekind/l2-mtd-2.6.git/commit/d391d866060d31884c6fc0fe459b3d9ee0a8fd4c
http://git.infradead.org/users/dedekind/l2-mtd-2.6.git/commit/5284a62fc7a526db9db1c922208e07b7fc442e72
http://git.infradead.org/users/dedekind/l2-mtd-2.6.git/commit/8cefbcdbb7d60baddb2db3d8d743b03eb3df619e

Please, verify them and let me know if they are OK or I should drop
them and take other patches.

-- 
Best Regards,
Artem Bityutskiy (Артём Битюцкий)

RE: [PATCH v4 3/3] mtd-nand: DaVinci: Add 4-bit ECC support for large page NAND chips

[Narnakaje, Snehaprabha]

Artem,

The patches on the link below are quite old - v2 version of the patches.

I had sent v3 version of the patches mid July, which Andrew had pulled into the mmotm tree. One of the patches v4, 3/3 was re-submitted last week.

Patch v3 1/3: http://userweb.kernel.org/~akpm/mmotm/broken-out/mtd-nand-add-page-parameter-to-all-read_page-read_page_raw-apis.patch
Patch v3 2/3: http://userweb.kernel.org/~akpm/mmotm/broken-out/mtd-nand-add-new-ecc-mode-ecc_hw_oob_first.patch
Patch v4 3/3: http://lists.infradead.org/pipermail/linux-mtd/2009-August/026832.html

The l2-mtd-2.6.git tree can be updated for the 3 patches above.

Thanks
Sneha

> -----Original Message-----
> From: Artem Bityutskiy [mailto:dedekind1@gmail.com]
> Sent: Monday, August 10, 2009 2:50 AM
> To: Narnakaje, Snehaprabha
> Cc: linux-mtd@lists.infradead.org; davinci-linux-open-
> source@linux.davincidsp.com; dwmw2@infradead.org; tglx@linutronix.de;
> akpm@linux-foundation.org; Paulraj, Sandeep
> Subject: Re: [PATCH v4 3/3] mtd-nand: DaVinci: Add 4-bit ECC support for
> large page NAND chips
> 
> On 08/07/2009 11:48 PM, nsnehaprabha@ti.com wrote:
> > From: Sneha Narnakaje<nsnehaprabha@ti.com>
> >
> > This patch adds 4-bit ECC support for large page NAND chips using the
> new ECC
> > mode NAND_ECC_HW_OOB_FIRST. The platform data from board-dm355-evm has
> been
> > adjusted to use this mode.
> >
> > The patches have been verified on DM355 device with 2K Micron devices
> using
> > mtd-tests and JFFS2. Error correction upto 4-bits has also been verified
> using
> > nandwrite/nanddump utilities.
> >
> > This patch series applies to linux-mtd next (mmotm) GIT tree.
> >
> > This version (v4) addresses the review comment to leave 2 bytes at
> offset 0
> > for NAND manufacturer badblock markers.
> >
> > Reviewed-by: David Brownell<dbrownell@users.sourceforge.net>
> > Signed-off-by: Sneha Narnakaje<nsnehaprabha@ti.com>
> > Signed-off-by: Sandeep Paulraj<s-paulraj@ti.com>
> 
> There are already 3 patches in my l2-mtd-2.6.git tree:
> 
> http://git.infradead.org/users/dedekind/l2-mtd-
> 2.6.git/commit/d391d866060d31884c6fc0fe459b3d9ee0a8fd4c
> http://git.infradead.org/users/dedekind/l2-mtd-
> 2.6.git/commit/5284a62fc7a526db9db1c922208e07b7fc442e72
> http://git.infradead.org/users/dedekind/l2-mtd-
> 2.6.git/commit/8cefbcdbb7d60baddb2db3d8d743b03eb3df619e
> 
> Please, verify them and let me know if they are OK or I should drop
> them and take other patches.
> 
> --
> Best Regards,
> Artem Bityutskiy (Артём Битюцкий)

Re: [PATCH v4 3/3] mtd-nand: DaVinci: Add 4-bit ECC support for large page NAND chips

[Artem Bityutskiy]

On 08/10/2009 04:57 PM, Narnakaje, Snehaprabha wrote:
> Patch v3 1/3: http://userweb.kernel.org/~akpm/mmotm/broken-out/mtd-nand-add-page-parameter-to-all-read_page-read_page_raw-apis.patch
> Patch v3 2/3: http://userweb.kernel.org/~akpm/mmotm/broken-out/mtd-nand-add-new-ecc-mode-ecc_hw_oob_first.patch
> Patch v4 3/3: http://lists.infradead.org/pipermail/linux-mtd/2009-August/026832.html
>
> The l2-mtd-2.6.git tree can be updated for the 3 patches above.

(Could you please avoid top-posting?)

I've picked up these new versions.

-- 
Best Regards,
Artem Bityutskiy (Артём Битюцкий)