Re: mtd_oobtest fails with GPMI-NAND

[Stefan Roese <sr@denx.de>]

On 05/13/2013 04:51 AM, Huang Shijie wrote:
>>> Also, I don't have enough spare boards to sacrifice it for mtd_torture test.
>> Yes, I can understand this.
>>
>> Huang, do you have any idea on how to proceed here? What else
>> could/should we test? Any ideas/hints?
> 
> Currently, the kernel supports three imx6 boards for the gpmi-nand:
>     imx6q-arm2, imx6q-sabreauto, imx6dl-sabareauto.
> 
> I am afraid your board is none of them. I doubt your board is not 
> correctly configrated with
> some timing or signals.

Correct, our board is a custom imx6 board. Basically NAND is working
just fine (UBI/UBIFS works basically). This board even boots from NAND.
So at least the pin muxing has to be correct.

Please correct me if I'm wrong, but from my understanding the Linux GPMI
NAND driver configures the timings. So this is not board platform code
related but NAND driver related.

Do you have any hints where to "tune/change" some values (timing or
signal related) to fix this error?

> The key issue (i want to emphosis ) is that the current gpmi-nand does 
> not support the
> subpage operations.

Yes. And this is disabled via setting NAND_NO_SUBPAGE_WRITE in the
options variable in the GPMI NAND driver.

BTW: I just tested with the "mtd_nandbiterrs" test. This fails directly.
I would have expected the ECC to being able to at least correct the
errors for some loops:

# insmod mtd_nandbiterrs.ko dev=3 mode=0
[  831.622694]
[  831.624198] ==================================================
[  831.630071] mtd_nandbiterrs: MTD device: 3
[  831.634259] mtd_nandbiterrs: MTD device size 519045120,
eraseblock=131072, page=2048, oob=64
[  831.642796] mtd_nandbiterrs: Device uses 1 subpages of 2048 bytes
[  831.648920] mtd_nandbiterrs: Using page=0, offset=0, eraseblock=0
[  831.655026] mtd_nandbiterrs: erase_block
[  831.659502] mtd_nandbiterrs: incremental biterrors test
[  831.664805] mtd_nandbiterrs: write_page
[  831.669028] mtd_nandbiterrs: rewrite page
[  831.673413] mtd_nandbiterrs: read_page
[  831.691729] mtd_nandbiterrs: error: read failed at 0x0
[  831.696887] mtd_nandbiterrs: After 0 biterrors per subpage, read
reported error -74
[  831.704546] mtd_nandbiterrs: erase_block
[  831.708997] mtd_nandbiterrs: finished successfully.
[  831.713880] ==================================================
insmod: error inserting 'mtd_nandbiterrs.ko': -1 Input/output error

Huang, is this to be expected? How does this look on one of your
officially "supported" imx6 boards with NAND support?

BTW: I'm using Linux v3.9.1 for theses tests.

>> Here the infos for our NAND device:
>>
>> [    0.917552] ONFI param page 0 valid
>> [    0.921053] ONFI flash detected
>> [    0.924206] NAND device: Manufacturer ID: 0x2c, Chip ID: 0xdc (Micron MT29F4G08ABADAH4), 512MiB, page size: 2048, OOB size: 64
>> [
> It's a SLC ,or a MLC?

SLC. Why do you ask?

Thanks,
Stefan