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Date: Wed, 24 Jan 2024 18:08:48 +0100
From: Miquel Raynal <miquel.raynal@bootlin.com>
To: Ezra Buehler <ezra@easyb.ch>
Cc: Chuanhong Guo <gch981213@gmail.com>, linux-mtd@lists.infradead.org,
 Richard Weinberger <richard@nod.at>, Vignesh Raghavendra <vigneshr@ti.com>,
 Patrice Chotard <patrice.chotard@foss.st.com>, Boris Brezillon
 <boris.brezillon@collabora.com>, Christophe Kerello
 <christophe.kerello@foss.st.com>, Mark Brown <broonie@kernel.org>, Daniel
 Palmer <daniel@0x0f.com>, open list <linux-kernel@vger.kernel.org>,
 quic_sridsn@quicinc.com, quic_mdalam@quicinc.com
Subject: Re: [PATCH v2] mtd: spinand: add support for ESMT F50x1G41LB
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Hi Ezra,

ezra@easyb.ch wrote on Tue, 23 Jan 2024 19:54:06 +0200:

> Hi Chuanhong Guo,
>=20
> On Wed, 13 Apr 2022 22:50:43 +0800 Chuanhong Guo <gch981213@gmail.com> wr=
ote:
> > Their device ID aren't conflicting yet, so nothing will happen
> > at the moment. =20
>=20
> Since commit aa08bf187f32 ("mtd: spinand: esmt: add support for
> F50D2G41KA") we have a conflict with the GigaDevice GD5F1GQ5UExxG
> (manufacturer ID 0xC8, device ID 0x51), preventing our board from
> booting.
>=20
> > There is a solution for future conflict: Recent SPI-NAND chips
> > contain a parameter page which has the exact chip vendor
> > and model. We can do one more detection with the parameter
> > page content.
> > Winbond W25N01KV is a 2k+96 SPI-NAND with 4-bit ECC.
> > It uses the exact same chip id as the current W25N01GV
> > (2k+64 1-bit ECC). We need to support detection using
> > parameter page for this crazy decision by Winbond anyway.
> > I'll try to code something for this with my free time.
> >
> > My current idea is: We first do a detection based on chip id.
> > If that failed, try to read the parameter page. If we got a
> > valid one, match the chip vendor and model string. =20
>=20
> According to the datasheets, the ESMT chips actually have a 5 byte ID,
> the last 3 bytes being 0x7F (JEDEC Maker Code Continuation Code). Why
> can't we simply extend the ID in esmt.c (as you had it in your original
> patch) and increase SPINAND_MAX_ID_LEN to 5? Or, alternatively, only
> extend the ID to 4 bytes?
>=20
> If that is the way to go, I would be happy to provide the patches.

Please send the patches. Chuanhong can you test them?

Thanks,
Miqu=C3=A8l