[PATCH 19/39] mtd: nand: denali: perform erased check against raw transferred page
Masahiro Yamada
yamada.masahiro at socionext.com
Tue Nov 29 21:36:13 PST 2016
Hi Boris
2016-11-28 1:12 GMT+09:00 Boris Brezillon <boris.brezillon at free-electrons.com>:
> On Sun, 27 Nov 2016 03:06:05 +0900
> Masahiro Yamada <yamada.masahiro at socionext.com> wrote:
>
>> The erased page check must be done against the raw transferred data.
>> The current first call of is_erase() is against the data after ECC
>> correction. I saw cases where not all of the data in the page are
>> 0xFF after they are manipulated by the ECC correction engine.
>
> Hm, that's surprising. Usually ECC engines leaves data unchanged when
> uncorrectable errors are detected. Do you have examples where this
> happens? How did you trigger this case?
It always happens on some of my boards.
At the bottom of this mail, I attached a dump of an erased page
after it was manipulated by the ECC engine.
See offset 0x2c1, 0x6c1
The data is 0xfd, not 0xff.
I think basically two ways for erased page checking.
[1] Read the whole of page + oob in raw mode transfer,
then check if all the data are 0xFF.
[2] Read the ECC-corrected page + oob,
then check if *most* of the data are 0xFF.
bit-flips less than ecc.strength are allowed.
I think [2] is equivalent to calling nand_check_erased_ecc_chunk()
with ecc.strength for threshold,
as you suggested in 09/39
But, the current Denali driver does:
[3] Read the ECC-corrected page + oob,
then check if all the data are 0xFF.
(no bit-flips are allowed)
I think this is wrong
because this erased page checking is false negative.
This patches adopts [1] to solve my problem, but [2] will work as well.
In my case, only one bit-flip (0xff -> 0xfd) in each ECC section.
[ 19.194200] 0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.200275] 10: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.206355] 20: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.212430] 30: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.218511] 40: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.224586] 50: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.230659] 60: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.236733] 70: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.242807] 80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.248881] 90: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.254955] a0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.261030] b0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.267102] c0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.273177] d0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.279254] e0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.285326] f0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.291407] 100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.297481] 110: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.303555] 120: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.309630] 130: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.315702] 140: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.321778] 150: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.327850] 160: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.333927] 170: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.340006] 180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.346082] 190: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.352154] 1a0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.358230] 1b0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.364303] 1c0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.370377] 1d0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.376451] 1e0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.382525] 1f0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.388598] 200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.394674] 210: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.400754] 220: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.406829] 230: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.412903] 240: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.418977] 250: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.425049] 260: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.431124] 270: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.437199] 280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.443274] 290: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.449354] 2a0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.455431] 2b0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.461503] 2c0: ff fd ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.467578] 2d0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.473651] 2e0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.479727] 2f0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.485812] 300: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.491883] 310: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.497963] 320: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.504040] 330: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.510120] 340: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.516195] 350: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.522267] 360: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.528343] 370: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.534416] 380: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.540490] 390: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.546565] 3a0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.552638] 3b0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.558711] 3c0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.564787] 3d0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.570868] 3e0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.576944] 3f0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.583024] 400: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.589100] 410: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.595172] 420: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.601247] 430: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.607319] 440: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.613395] 450: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.619467] 460: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.625542] 470: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.631615] 480: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.637690] 490: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.643764] 4a0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.649839] 4b0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.655911] 4c0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.661986] 4d0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.668058] 4e0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.674133] 4f0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.680208] 500: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.686282] 510: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.692356] 520: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.698431] 530: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.704510] 540: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.710586] 550: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.716659] 560: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.722734] 570: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.728806] 580: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.734881] 590: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.740954] 5a0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.747030] 5b0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.753103] 5c0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.759178] 5d0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.765250] 5e0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.771326] 5f0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.777398] 600: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.783473] 610: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.789547] 620: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.795621] 630: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.801698] 640: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.807770] 650: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.813850] 660: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.819925] 670: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.825997] 680: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.832074] 690: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.838154] 6a0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.844230] 6b0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.850303] 6c0: ff fd ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.856378] 6d0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.862450] 6e0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.868525] 6f0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.874597] 700: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.880673] 710: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.886746] 720: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.892821] 730: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.898894] 740: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.904969] 750: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.911042] 760: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.917118] 770: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.923198] 780: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.929274] 790: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.935346] 7a0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.941421] 7b0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.947493] 7c0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.953569] 7d0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.959642] 7e0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
[ 19.965717] 7f0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
--
Best Regards
Masahiro Yamada
More information about the linux-mtd
mailing list