Messages in this thread | | | From | Daniel Palmer <> | Date | Mon, 23 Aug 2021 23:19:02 +0900 | Subject | Re: [PATCH v3] mtd: spinand: add support for Foresee FS35ND0*G parts |
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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.
Cheers,
Daniel
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