Patchwork txx9ndfmc: limit transfer bytes to 512 (ECC provides 6 bytes max)

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Submitter Ralf Rösch
Date Dec. 30, 2010, 9:30 a.m.
Message ID <4D1C5123.4050804@rw-gmbh.de>
Download mbox | patch
Permalink /patch/76964/
State New
Headers show

Comments

Ralf Rösch - Dec. 30, 2010, 9:30 a.m.
See commit: c0cbfd0e81d879a950ba6f0df3f75ea30c5ab16e
Using __nand_correct_data() helper function, this driver can read 512
byte (with 6 byte ECC) at a time.

This is correct, but not more:
With NAND chips providing page sizes > 512 Bytes
chip->ecc.bytes are calculated > 6 in txx9ndfmc_nand_scan.
According the data sheet there are (only) 6 bytes ECC available.

After applying the patch a Hynix 512M*8 with 2k page size could be
successfully formatted and used with an ubifs file system.

Signed-off-by: Ralf Roesch <ralf.roesch@rw-gmbh.de>
---
 drivers/mtd/nand/txx9ndfmc.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)
Atsushi Nemoto - Jan. 4, 2011, 5:13 a.m.
On Thu, 30 Dec 2010 10:30:11 +0100, Ralf Rösch <ralf.roesch@rw-gmbh.de> wrote:
> See commit: c0cbfd0e81d879a950ba6f0df3f75ea30c5ab16e
> Using __nand_correct_data() helper function, this driver can read 512
> byte (with 6 byte ECC) at a time.
> 
> This is correct, but not more:
> With NAND chips providing page sizes > 512 Bytes
> chip->ecc.bytes are calculated > 6 in txx9ndfmc_nand_scan.
> According the data sheet there are (only) 6 bytes ECC available.
> 
> After applying the patch a Hynix 512M*8 with 2k page size could be
> successfully formatted and used with an ubifs file system.
> 
> Signed-off-by: Ralf Roesch <ralf.roesch@rw-gmbh.de>

Thank you for the fix.  It is good news that this controller can work
with large page NAND.

Acked-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Artem Bityutskiy - Jan. 5, 2011, 8:37 a.m.
On Thu, 2010-12-30 at 10:30 +0100, Ralf Rösch wrote:
> See commit: c0cbfd0e81d879a950ba6f0df3f75ea30c5ab16e
> Using __nand_correct_data() helper function, this driver can read 512
> byte (with 6 byte ECC) at a time.
> 
> This is correct, but not more:
> With NAND chips providing page sizes > 512 Bytes
> chip->ecc.bytes are calculated > 6 in txx9ndfmc_nand_scan.
> According the data sheet there are (only) 6 bytes ECC available.
> 
> After applying the patch a Hynix 512M*8 with 2k page size could be
> successfully formatted and used with an ubifs file system.
> 
> Signed-off-by: Ralf Roesch <ralf.roesch@rw-gmbh.de>

Pushed to l2-mtd-2.6.git, thanks!

Patch

diff --git a/drivers/mtd/nand/txx9ndfmc.c b/drivers/mtd/nand/txx9ndfmc.c
index 054a41c..ca270a4 100644
--- a/drivers/mtd/nand/txx9ndfmc.c
+++ b/drivers/mtd/nand/txx9ndfmc.c
@@ -277,8 +277,9 @@  static int txx9ndfmc_nand_scan(struct mtd_info *mtd)
 	ret = nand_scan_ident(mtd, 1, NULL);
 	if (!ret) {
 		if (mtd->writesize >= 512) {
-			chip->ecc.size = mtd->writesize;
-			chip->ecc.bytes = 3 * (mtd->writesize / 256);
+			/* Hardware ECC 6 byte ECC per 512 Byte data */
+			chip->ecc.size = 512;
+			chip->ecc.bytes = 6;
 		}
 		ret = nand_scan_tail(mtd);
 	}