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* NAND + YAFFS2 - bad blocks
@ 2009-04-28 16:03 Stanislav Popov
  0 siblings, 0 replies; 6+ messages in thread
From: Stanislav Popov @ 2009-04-28 16:03 UTC (permalink / raw)
  To: linux-mtd

Hi,

I have 64 MB NAND flash on Jacinto (ARM) board.
I am using the device formatted as one YAFFS2 partition.
My SW ECC from NAND is enabled in the kernel and "useNANDECC" in YAFFS 
is set to 0
(If this is non-zero, then YAFFS will not perform ECC and it is assumed 
that the hardware ECC or specified NAND access functions will perform EC 
checks.)

I found that I have 1000-2000 eraseblocks that were reported as "bad block".
I can see them in u-boot with "nand bad" command and when laoding my 
nand_jacinto driver.
When using the NAND they are getting much more.
Actually they are NOT bad blocks!

I edited the kernel and remove is_bad checking when erasing.
Also I edited the mtd-utils (flash_eraseall) and removed is_bad checking 
when erasing.
So I was able to make low-level format of my NAND flash which also erase 
the bad blocks.
(like 'nand erase scrub' command in u-boot, but I currently I do not 
have such command)
After that I had NO bad blocks.

I made some tests:
I formatted Nand with YAFFS2 FS
-  YAFFS2 ECC + NO NAND ECC - when using fs appeared bad blocks and 
getting more.
-  YAFFS2 NO ECC + NAND SW ECC - when using fs appeared bad blocks and 
getting more.

I formatted Nand with EXT2 FS (ext2 fs is not writing into oob)
-  NAND SW ECC ENABLE - NO bad blocks appeared in the time!!!

So the result is that the issue is in using YAFFS2 + NAND.

Maybe the source of the issue is some YAFFS2 configurations?
Do you have any idea?
It's very critical issue for me.

Thanks and Regards,
Stanislav

^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2009-05-04 20:00 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
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2009-04-29  7:03 ` NAND + YAFFS2 - bad blocks Stanislav Popov
2009-04-30  7:37   ` Stanislav Popov
2009-05-04 20:00   ` Subramani
2009-04-29 14:25 ` Stanislav Popov
2009-05-04 19:58   ` Subramani
2009-04-28 16:03 Stanislav Popov

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