Messages in this thread | | | From | Daniel Palmer <> | Date | Mon, 22 Mar 2021 21:44:40 +0900 | Subject | Re: [PATCH v2] mtd: spinand: add support for Foresee FS35ND01G-S1Y2 |
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Hi Miquel,
Sorry for the resend. Gmail randomly switched to HTML email so the original version seems to have bounced.
On Mon, 15 Feb 2021 at 20:16, Miquel Raynal <miquel.raynal@bootlin.com> wrote: > > "2. Spare area 800H to 83FH is all available for user. > > ECC parity codes are programmed in > > additional space and not user accessible." > > > > It would seem that the pages are actually bigger than 2K + 64 or there > > is some other place they keep the ECC. > > Or both datasheets are lying. Somewhere else in the datasheets it says > > that writes to the ECC area will be ignored but that doesn't make a > > lot of sense if the ECC area isn't user accessible in the first place. > > > > I didn't think about it at the time but I can take a dump of the OOB > > area of my FS35ND01G-S1Y2 to confirm it's all 0xff except for any > > factory marked bad blocks. > > I see. Can you please try the following: > > nandwrite -o /dev/mtdx /dev/zero > nanddump -ol1 /dev/mtdx > If the entire area is effectively free to be used, you should see 0's > everywhere. Otherwise you should have ff's somewhere.
Sorry I didn't follow up sooner on this. I needed to order another of this flash chip to test with as I couldn't destroy the data on the one I have.
Anyhow:
Erased the page with flash erase (I'm forcing it to erase bad blocks here as I mess up the marker, I have a hack to allow erasing bad blocks..) Everything is 0xFF for that page.
# flash_erase -N /dev/mtd1 0 1 Erasing 128 Kibyte @ 0 -- 100 % complete # nanddump --bb=dumpbad -n -l2048 -o -c -s 0x0 /dev/mtd1 Block size 131072, page size 2048, OOB size 64 Dumping data starting at 0x00000000 and ending at 0x00000800... 0x00000000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| .... 0x000007f0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| OOB Data: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| OOB Data: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| OOB Data: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| OOB Data: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
Write zeros into the page and OOB. Get all zeros back including the OOB.
# nandwrite -o /dev/mtd1 /dev/zero Writing data to block 0 at offset 0x0 Bad block at 0, 1 block(s) will be skipped Writing data to block 1 at offset 0x20000 # nandwrite -N -o /dev/mtd1 /dev/zero Writing data to block 0 at offset 0x0 # nanddump --bb=dumpbad -n -l2048 -o -c -s 0x0 /dev/mtd1 Block size 131072, page size 2048, OOB size 64 Dumping data starting at 0x00000000 and ending at 0x00000800... 0x00000000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| ... 0x000007f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| OOB Data: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| OOB Data: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| OOB Data: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| OOB Data: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
Erase the page again and writing random junk into it. Seeing random junk everywhere including the OOB.
# flash_erase -N /dev/mtd1 0 1 Erasing 128 Kibyte @ 0 -- 100 % complete # nandwrite -N -o /dev/mtd1 /dev/urandom Writing data to [ 230.506260] random: nandwrite: uninitialized urandom read (2048 bytes read) block 0 at offse[ 230.514705] random: nandwrite: uninitialized urandom read (64 bytes read) t 0x0 # nanddump --bb=dumpbad -n -l2048 -o -c -s 0x0 /dev/mtd1 Block size 131072, page size 2048, OOB size 64 Dumping data starting at 0x00000000 and ending at 0x00000800... 0x00000000: 5e 24 bd 5f d9 c6 ce c5 b1 85 52 4d 27 94 c9 98 |^$._......RM'...| ... 0x000007f0: fa 9f 7f 7d ce 99 33 88 d6 9f 99 7d 84 e7 0c 4d |...}..3....}...M| OOB Data: b1 81 07 6a 8d 47 8b ed 89 88 ac 62 e8 ae 48 54 |...j.G.....b..HT| OOB Data: 7d b2 ea 73 f3 29 ba 65 e6 45 cb 8b 1a c6 5b dc |}..s.).e.E....[.| OOB Data: b2 2e 77 56 e0 e1 04 59 86 31 7a e5 bd 43 f9 48 |..wV...Y.1z..C.H| OOB Data: 52 05 b2 f1 65 64 59 22 79 50 ec 89 55 6b 6e 23 |R...edY"yP..Ukn#|
I think this shows that the datasheet is right in that the complete 64 bytes of "spare area" is usable. I have no idea where it puts the ECC though. :)
Thanks,
Daniel
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