GPMI-NAND Status?

Hi,

Ivan Djelic writes:

On Mon, Aug 15, 2011 at 10:31:34AM +0100, Lothar Wa?mann wrote:

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It's not a problem of the device (Samsung K9F1G08U0B in my case)! The
problem is that the controller generates an ECC code that is non-FF
for all-FF data, which JFFS2 cannot handle properly.

JFFS2 has nothing to do with it. JFFS2 does not assume it can program empty
pages and then reprogram them on a NAND flash device. You flashing method does.

AFAICT JFFS2 checks the flash for areas that contain only FF and
treats them like erased flash. At least it tries to overwrite such
areas in flash without erasing it beforehand.

Hmmm, again, JFFS2 simply "writes" to an erased block. You say "it tries to
overwrite", but that's only because you programmed an empty page in the first

Which will happen most of the time (unless the image file size is near
a multiple of the eraseblock size), if you create an jffs2 image with
mkfs.jffs2 and the '-p' option.

Unfortunately the data written by U-Boot must be page aligned and
mkfs.jffs2 cannot generate images that fulfill that constraint (unless
you know the exact image file size beforehand and specify the
rounded-up file size with the '-p' option).

place! And it cannot "erase such areas beforehand" (think of a partially
programmed block with tailing empty pages).

I know, that it cannot simply erase such blocks.

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Therefore... it is simply a matter of avoiding empty page programming, which
only happens in your flasher. See also the flashing guidelines [1] as per Artem
suggestion.

"Your flasher" is the standard mtd-utils mkfs.jffs2 to create an image
file and the U-Boot commands 'nand erase/nand write' or
the mtd-utils 'flash_eraseall/nandwrite' to write it to flash.

OK, maybe you could submit a patch to fix this issue then ?
Thanks,

I have no idea how and where it should be fixed.
- at driver level, creating an all-FF ECC for all-FF data?
- in the bootloader and mtd-utils preventing stretches of all-FF data
  to be written?
- in mkfs.jffs2, enabling it to generate images that are padded to
  page size instead of eraseblock size?


Lothar Wa?mann
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