Messages in this thread | | | Date | Mon, 23 Aug 2021 16:21:48 +0200 | From | Miquel Raynal <> | Subject | Re: [PATCH v3] mtd: spinand: add support for Foresee FS35ND0*G parts |
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Hi Daniel,
Daniel Palmer <daniel@0x0f.com> wrote on Mon, 23 Aug 2021 23:19:02 +0900:
> Hi Miquel, > > > > + /* > > > + * The datasheet says *successful* with 4 bits flipped. > > > + * nandbiterrs always complains that the read reported > > > + * successful but the data is incorrect. > > > + */ > > > + case FS35ND01G_S1Y2_STATUS_ECC_4_BITFLIPS: > > > + return 4; > > > > This is a real issue. Can you use the nandflipbits tool from the > > mtd-utils package (you should take a recent version of the package) and > > try to observe what happens when you insert a 4th bitflip in a section? > > > > I generally believe the tool more than the datasheet :) > > Maybe I'm using it incorrectly but I can't get a 4 bit flipped > situation to happen. > > I erased the paged so it's all 0xFF: > > # flash_erase /dev/mtd0 0x8000000 1 > Erasing 128 Kibyte @ 8000000 -- 100 % complete > # nanddump --bb=dumpbad -s 0x8000000 -l 1 -c -p /dev/mtd0 > ECC failed: 0 > ECC corrected: 6234 > Number of bad blocks: 0 > Number of bbt blocks: 0 > Block size 131072, page size 2048, OOB size 64 > Dumping data starting at 0x08000000 and ending at 0x08000001... > ECC: 3 corrected bitflip(s) at offset 0x08000000 > 0x08000000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| > 0x08000010: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| > 0x08000020: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| > 0x08000030: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| > 0x08000040: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| > 0x08000050: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| > 0x08000060: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| > > Then used nandflipbits to flip a bunch of bits in the first byte and > then a few other bytes: > > # nanddump --bb=dumpbad -s 0x8000000 -l 1 -c -p /dev/mtd0 > ECC failed: 0 > ECC corrected: 6246 > Number of bad blocks: 0 > Number of bbt blocks: 0 > Block size 131072, page size 2048, OOB size 64 > Dumping data starting at 0x08000000 and ending at 0x08000001... > ECC: 3 corrected bitflip(s) at offset 0x08000000 > 0x08000000: f0 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| > 0x08000010: eb ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| > 0x08000020: ef ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| > 0x08000030: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| > 0x08000040: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| > 0x08000050: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| > 0x08000060: ef ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................| > > Anyhow, > I think we should probably return -EBADMSG if the 4 bit flips status > appears as nandbiterrs always complains that the data is wrong.
I am not sure to follow, above the software says "3 corrected bf" while I thought the problem was when getting 4 bf, but the dump show many more. Can you show me how it behaves: * erase (like you did) * insert {1, 2, 3, 4, 5} bf and show the dump each time?
Thanks, Miquèl
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