MT7621 NAND OOB misdetect

[Chuanhong Guo]

Hi!

On Sat, Feb 11, 2023 at 8:41 PM Peter Naulls <peter at chocky.org> wrote:
>
> On 2/10/23 22:41, Chuanhong Guo wrote:
> > Hi!
> >
> 16.163318] 8 fixed-partitions partitions found on MTD device mt7621-nand
> >
> >  From the datasheet here:
> > https://www.mxic.com.tw/Lists/Datasheet/Attachments/8858/MX30LF1G28AD,%203V,%201Gb,%20v1.3.pdf
> > The MX30LF1G28AD actually have 2K+128 flash layout, so it's the old driver
> > which is incorrectly detecting OOB size.
> >
> >> Suffice to that accessing the device (nanddump) does not go well.
> >
> > Could you describe what exactly goes wrong?
> >
>
> Thanks for your reply. Sorry, yes, I should have included that output.
>
> In particular, this fails:
>
> [   28.070690] mt76x2e 0000:02:00.0: reading EEPROM from mtd factory failed: -77
> [   28.717408] mt76x2e 0000:02:00.0: Invalid MAC address, using random address
> 02:73:0b:95:75:d9
>
> I have verified that the correct MAC address does in fact exist in flash at the
> same location as it did on the NOR under the legacy kernel.
>
> And then also at the end of boot (mtd6 is rootfs):
>
> [   33.335299] blk_update_request: I/O error, dev mtdblock6, sector 0 op
> 0x0:(READ) flags 0x80700 phys_seg 4 prio class 0
> [   33.359479] blk_update_request: I/O error, dev mtdblock6, sector 8 op
> 0x0:(READ) flags 0x80700 phys_seg 3 prio class 0
> [   33.383345] blk_update_request: I/O error, dev mtdblock6, sector 16 op
> 0x0:(READ) flags 0x80700 phys_seg 2 prio class 0
> [   33.407643] blk_update_request: I/O error, dev mtdblock6, sector 24 op
> 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0
> [   33.431898] blk_update_request: I/O error, dev mtdblock6, sector 0 op
> 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
> [   33.452624] Buffer I/O error on dev mtdblock6, logical block 0, async page read
> [   33.476059] blk_update_request: I/O error, dev mtdblock6, sector 36736 op
> 0x0:(READ) flags 0x80700 phys_seg 1 prio class 0
> [   33.501107] blk_update_request: I/O error, dev mtdblock6, sector 36736 op
> 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
> [   33.522557] Buffer I/O error on dev mtdblock6, logical block 4592, async page
> read
>
> And then for example:
>
>
> # nanddump -a /dev/mtd2
> ECC failed: 8
> ECC corrected: 0
> Number of bad blocks: 0
> Number of bbt blocks: 0
> Block size 131072, page size 2048, OOB size 128
> Dumping data starting at 0x00000000 and ending at 0x00040000...
> libmtd: error!: MEMGETBADBLOCK ioctl failed for eraseblock 0 (mtd2)
>          error 77 (Bad message)
> nanddump: error!: libmtd: mtd_is_bad
>
> I haven't been able to find anything on what this error means in practice.

You could try printing the spare size and ecc strength used in the
old driver, replacing the calculation in the new driver with
hard-coded values and see if that works. If it works, you can
implement the ecc strength override in our driver.

-- 
Regards,
Chuanhong Guo