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    SubjectRe: [PATCH v3] mtd: spinand: add support for Foresee FS35ND0*G parts
    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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