Re: [PATCH v2 0/5] mtd: spi-nor: Add support for Octal 8D-8D-8D mode

masonccyang
2020-05-15T02:27:38Z

Hi Pratyush,

> > > > I can't apply your patches to enable xSPI Octal mode for
> > > > mx25uw51245g because your patches set up Octal protocol first and
> > > > then using Octal protocol to write Configuration Register 2(CFG
> > > > Reg2). I think driver
> > > > should write CFG Reg2 in SPI 1-1-1 mode (power on state) and make
sure
> > > > write CFG Reg 2 is success and then setup Octa protocol in the
last.
> > >
> > > Register writes should work in 1S mode, because nor->reg_proto is
only
> > > set _after_ 8D mode is enabled (see spi_nor_octal_dtr_enable()). In
> > > fact, both patch 15 and 16 in my series use register writes in 1S
mode.
> >
> > but I didn't see driver roll back "nor->read/write_proto = 1"
> > if xxx->octal_dtr_enable() return failed!
>
> I copied what spi_nor_quad_enable() did, and made failure fatal. So if
> xxx->octal_dtr_enable() fails, the probe would fail and the flash would
> be unusable. You can try your hand at a fallback system where you try

IMHO, it's not a good for system booting from SPI-NOR,
driver should still keep system alive in SPI 1-1-1 mode in case of
enable Octal/Quad failed.

Therefore, my patches is to setup nor->read/write_proto = 8 in case
driver enable Octal mode is success. And to enable Octal mode in
spi_nor_late_init_params()rather than as spi_nor_quad_enable()did.

> all possible protocols available, but I think that should be a different

> patchset.
>
> --
> Regards,
> Pratyush Yadav

thanks & best regards,
Mason

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