Re: [PATCH - v1] mtd: nand: davinci: add support for 4K page size nand devices.

From: Murali Karicheri
Date: Mon Jun 29 2015 - 13:49:18 EST


On 06/10/2015 05:02 AM, Murali Karicheri wrote:
K2L EVM uses NAND with 4K page size. This patch add support for
ECC layout requires to enable Micron MT29F16G08ADBCAH4 NAND available
on this EVM.

Signed-off-by: Murali Karicheri <m-karicheri2@xxxxxx>
Signed-off-by: Hao Zhang <hzhang@xxxxxx>
---
- v1 - Remove the comment as well from the code as now 4K page
is supported
drivers/mtd/nand/davinci_nand.c | 42 +++++++++++++++++++++++++++++------------
1 file changed, 30 insertions(+), 12 deletions(-)

diff --git a/drivers/mtd/nand/davinci_nand.c b/drivers/mtd/nand/davinci_nand.c
index feb6d18..90b177b 100644
--- a/drivers/mtd/nand/davinci_nand.c
+++ b/drivers/mtd/nand/davinci_nand.c
@@ -520,6 +520,31 @@ 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 +821,11 @@ static int nand_davinci_probe(struct platform_device *pdev)
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");
+ if (chunks == 8) {
+ info->ecclayout = hwecc4_4096;
+ info->chip.ecc.mode = NAND_ECC_HW_OOB_FIRST;
+ goto syndrome_done;
+ }
ret = -EIO;
goto err;


MTD Maintainers,

Can you please review and queue this to next?

Thanks
--
Murali Karicheri
Linux Kernel, Keystone
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