[PATCH 1/1] mtd: spi-nand: macronix: disable continuous read for MX35LFxGE4AD

[Cheng Ming Lin]

Hi Miquel,

Miquel Raynal <miquel.raynal at bootlin.com> 於 2025年6月20日 週五 上午12:50寫道：
>
> Hello,
>
> + Cheng Ming from Macronix
>
> On 19/06/2025 at 22:00:03 +08, Chukun Pan <amadeus at jmu.edu.cn> wrote:
>
> > Hi,
> >
> >> Please cc linux-mtd at lists.infradead.org for all patches and queries
> >> related to MTD subsystems.
> >> Run ./scripts/get_maintainers.pl on the patch for more information.
> >
> > Sorry, I forgot to add the following mailing list.
> > Do I need to resend this patch?
> >
> >> Why? this datasheet says otherwise [1]:
> >>
> >> Would it be possible that SPI/QSPI controller of GL.iNet GL-MT3000
> >> has a limitation?
> >
> > GL.iNet GL-MT3000 uses MediaTek MT7981 SoC, with SPI controllers
> > based on IPM design. [1]
> >
> > I don't know what the difference is between the SPI controllers of
> > MT7981 and the Zynq used in commit [2].
> >
> > In my case, ubi_io_read and ecc errors occurred when the openwrt
> > attach ubi partition (NMBM has been disabled [3]):
> >
> > [    7.852000] ubi0 warning: ubi_io_read: error -5 while reading 126976 bytes from PEB 517:4096, read only 0 bytes, retry
> > [    7.865374] ubi0 warning: ubi_io_read: error -5 while reading 126976 bytes from PEB 517:4096, read only 0 bytes, retry
> > [    7.878742] ubi0 warning: ubi_io_read: error -5 while reading 126976 bytes from PEB 517:4096, read only 0 bytes, retry
> > [    7.892104] ubi0 error: ubi_io_read: error -5 while reading 126976 bytes from PEB 517:4096, read 0 bytes
> > [    7.901754] UBIFS error (ubi0:2 pid 687): ubifs_leb_read: reading 126976 bytes from LEB 1:0 failed, error -5
> >
> > After disabling continuous read, this flash works fine.
> > So despite the datasheet stating support, I think it would be
> > better to disable it first to avoid bricking MT7981 devices
> > with MX35LFxGE4AD flash.
>
> I am sorry but disabling the feature for every user of the chip does not
> work if the problem comes from the SPI controller.
>
> I just added Cheng Ming from Macronix. Cheng Ming, can you confirm these
> chips support continuous read? Is there anything specific about them
> that might cause this breakage?

Yes, I’ve confirmed from the datasheets that these chips do support
continuous read. Additionally, I’ve validated this on the Zynq platform
when using ubiattach, the chip operates normally and continuous read
works as expected.

That’s why I followed up with him today to confirm the exact experiment
procedure. I’d like to understand how the test was conducted that led to
the observed issue.

>
> Thanks a lot,
> Miquèl

Thanks,
Cheng Ming Lin