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* [PATCH] txx9ndfmc: limit transfer bytes to 512 (ECC provides 6 bytes max)
@ 2010-12-30  9:30 Ralf Rösch
  2011-01-04  5:13 ` Atsushi Nemoto
  2011-01-05  8:37 ` Artem Bityutskiy
  0 siblings, 2 replies; 3+ messages in thread
From: Ralf Rösch @ 2010-12-30  9:30 UTC (permalink / raw)
  To: linux-mtd; +Cc: Atsushi Nemoto

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(-)

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);
 	}
-- 
1.7.2.3

^ permalink raw reply related	[flat|nested] 3+ messages in thread

* Re: [PATCH] txx9ndfmc: limit transfer bytes to 512 (ECC provides 6 bytes max)
  2010-12-30  9:30 [PATCH] txx9ndfmc: limit transfer bytes to 512 (ECC provides 6 bytes max) Ralf Rösch
@ 2011-01-04  5:13 ` Atsushi Nemoto
  2011-01-05  8:37 ` Artem Bityutskiy
  1 sibling, 0 replies; 3+ messages in thread
From: Atsushi Nemoto @ 2011-01-04  5:13 UTC (permalink / raw)
  To: ralf.roesch; +Cc: linux-mtd

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>

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] txx9ndfmc: limit transfer bytes to 512 (ECC provides 6 bytes max)
  2010-12-30  9:30 [PATCH] txx9ndfmc: limit transfer bytes to 512 (ECC provides 6 bytes max) Ralf Rösch
  2011-01-04  5:13 ` Atsushi Nemoto
@ 2011-01-05  8:37 ` Artem Bityutskiy
  1 sibling, 0 replies; 3+ messages in thread
From: Artem Bityutskiy @ 2011-01-05  8:37 UTC (permalink / raw)
  To: Ralf Rösch; +Cc: Atsushi Nemoto, linux-mtd

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!

-- 
Best Regards,
Artem Bityutskiy (Битюцкий Артём)

^ permalink raw reply	[flat|nested] 3+ messages in thread

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2010-12-30  9:30 [PATCH] txx9ndfmc: limit transfer bytes to 512 (ECC provides 6 bytes max) Ralf Rösch
2011-01-04  5:13 ` Atsushi Nemoto
2011-01-05  8:37 ` Artem Bityutskiy

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