nand: davinci: add support for 4K page size nand devices

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Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=a11244c0b25b79d2a3b07df429268d66736e5b45
Commit:     a11244c0b25b79d2a3b07df429268d66736e5b45
Parent:     906b1f536d5b1a26e549c78a07b664f22340b7df
Author:     Sandeep Paulraj <s-paulraj at ti.com>
AuthorDate: Tue Aug 19 15:31:54 2014 +0300
Committer:  Brian Norris <computersforpeace at gmail.com>
CommitDate: Mon Jul 20 09:58:15 2015 -0700

    nand: davinci: add support for 4K page size nand devices
    
    It is needed for k2l keystone2 EVM which uses NAND flash with 4K page
    size, hence add support for 4K page size nand devices.
    
    [Brian: similar work submitted by Murali Karicheri <m-karicheri2 at ti.com>
    and Hao Zhang <hzhang at ti.com>]
    
    Signed-off-by: Sandeep Paulraj <s-paulraj at ti.com>
    Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk at ti.com>
    Signed-off-by: Brian Norris <computersforpeace at gmail.com>
---
 drivers/mtd/nand/davinci_nand.c | 42 ++++++++++++++++++++++++++++++-----------
 1 file changed, 31 insertions(+), 11 deletions(-)

diff --git a/drivers/mtd/nand/davinci_nand.c b/drivers/mtd/nand/davinci_nand.c
index feb6d18..b9080130 100644
--- a/drivers/mtd/nand/davinci_nand.c
+++ b/drivers/mtd/nand/davinci_nand.c
@@ -520,6 +520,32 @@ static struct nand_ecclayout hwecc4_2048 = {
 	},
 };
 
+/*
+ * An ECC layout for using 4-bit ECC with large-page (4096bytes) 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_4096 = {
+	.eccbytes = 80,
+	.eccpos = {
+		/* at the end of spare sector */
+		48, 49, 50, 51, 52, 53, 54, 55, 56, 57,
+		58, 59, 60, 61, 62, 63, 64, 65, 66, 67,
+		68, 69, 70, 71, 72, 73, 74, 75, 76, 77,
+		78, 79, 80, 81, 82, 83, 84, 85, 86, 87,
+		88, 89, 90, 91, 92, 93, 94, 95, 96, 97,
+		98, 99, 100, 101, 102, 103, 104, 105, 106, 107,
+		108, 109, 110, 111, 112, 113, 114, 115, 116, 117,
+		118, 119, 120, 121, 122, 123, 124, 125, 126, 127,
+	},
+	.oobfree = {
+		/* 2 bytes at offset 0 hold manufacturer badblock markers */
+		{.offset = 2, .length = 46, },
+		/* 5 bytes at offset 8 hold BBT markers */
+		/* 8 bytes at offset 16 hold JFFS2 clean markers */
+	},
+};
+
 #if defined(CONFIG_OF)
 static const struct of_device_id davinci_nand_of_match[] = {
 	{.compatible = "ti,davinci-nand", },
@@ -796,18 +822,12 @@ static int nand_davinci_probe(struct platform_device *pdev)
 			info->chip.ecc.mode = NAND_ECC_HW_OOB_FIRST;
 			goto syndrome_done;
 		}
+		if (chunks == 8) {
+			info->ecclayout = hwecc4_4096;
+			info->chip.ecc.mode = NAND_ECC_HW_OOB_FIRST;
+			goto syndrome_done;
+		}
 
-		/* 4KiB 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 4KiB page chips.
-		 *
-		 * TODO: Note that nand_ecclayout has now been expanded and can
-		 *  hold plenty of OOB entries.
-		 */
-		dev_warn(&pdev->dev, "no 4-bit ECC support yet "
-				"for 4KiB-page NAND\n");
 		ret = -EIO;
 		goto err;