[PATCH] Revert "mtd: spi-nor: micron-st: use SFDP of mt35xu512aba"

[Bough Chen]

> -----Original Message-----
> From: Michael Walle <mwalle at kernel.org>
> Sent: 2025年12月12日 17:26
> To: Bough Chen <haibo.chen at nxp.com>; Tudor Ambarus
> <tudor.ambarus at linaro.org>; Pratyush Yadav <pratyush at kernel.org>; Miquel
> Raynal <miquel.raynal at bootlin.com>; Richard Weinberger <richard at nod.at>;
> Vignesh Raghavendra <vigneshr at ti.com>
> Cc: linux-mtd at lists.infradead.org; linux-kernel at vger.kernel.org; Han Xu
> <han.xu at nxp.com>; open list:NXP i.MX 7D/6SX/6UL/93 AND VF610 ADC
> DRIVER <imx at lists.linux.dev>
> Subject: Re: [PATCH] Revert "mtd: spi-nor: micron-st: use SFDP of
> mt35xu512aba"
> 
> Hi,
> 
> >> > Find two batches mt35xu512aba has different SFDP but with same
> >> > jedec ID. To make all batches of mt35xu512aba work well and support
> >> > OCT DTR mode, back to hardcode the flags.
> >>
> >> What are "batches" in this case? A new revision of the same flash
> >> chip? Why would they use a different ID then.
> >
> > Hi Michael,
> >
> > Yes, seems a new revision of the same flash chip. Anyone from Micron can
> confirm this?
> >
> > What's the normal way for vendors to update the SFDP? Seems also need to
> update/change the ID.
> 
> No why would they? It's the same flash, but with new/fixed SFDP.

Oh, I’m stuck in a fixed mindset. For this case, default use new SFDP, and can use fixup for the old SFDP.
(0DA15 RW303 is old one)

> 
> >> What's wrong with the parsed flags? Both support SFDP, so if you
> >> really need to fixup any flags, please use a fixup callback to
> >> actually fix them. But first, what will go wrong?
> >
> > Yes, sorry to lack this information.
> >
> > For mt35xu512aba chip with label 0DA15 RW303, the SFDP do not support
> > OCT DTR read/write operation, but still has one .fixups =
> > &mt35xu512aba_fixups, in this fix up, it config the OCT DTR read
> > operation, so finally read_proto == SNOR_PROTO_8_8_8_DTR, but
> > nor->write_proto == SNOR_PROTO_1_1_1, then has no chance to call
> micron_st_nor_octal_dtr_en(), when there is read operation, use OCT DTR read
> command meet issue.
> >
> > With this revert patch, I test mt35xu512aba chip with label 0DA15 RW303,
> OCT DTR mode can work well.
> > Also test mt35xu512aba chip with label 4KA17 RW303, OCT DTR mode work
> find too.
> 
> So both support actual octal mode. Then please fix mt35xu512aba_fixups. IIUC,
> you can just use
> spi_nor_set_pp_settings() there, to fixup the supported PP mode. But please
> add it with a comment describe *why* we need that fixup.

Yes, really good suggestion, I will have a try.

Regards
Haibo Chen
> 
> -michael