From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 61D65371D08 for ; Mon, 1 Jun 2026 12:57:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780318625; cv=none; b=hqUM+XtNVrsfWPiiCW7TI3BwHEajtWGQ3YG4I0yjpFV0fcsIU0PTx/sMgN7g3O/y3Zg1AdW/oLEn4jHkbPetE79j7gVLOieULhRuITIi+u+CQhmplxJZ4u3GUd3QH/pz7ri5DK38IEysSrpfYuwBXC64u71OXMXPOu70aL/uC74= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780318625; c=relaxed/simple; bh=X/csQuUwy+IWM9m7x2EvspM4DaVnOvkhnOPVe/lB1Cg=; h=Mime-Version:Content-Type:Date:Message-Id:Subject:Cc:From:To: References:In-Reply-To; b=RVjLTHJTFUpmH9FTCwXPouWpaTxu4KpemDlj4TvS29Br0A1I48sT8wmj4NmlziJcvjpupMV44+/Fv1hs54UgBAUVtSqCJ59wiqXI+OJVSywjehPibhyXKdO7bNWDkzlBcUp3LU74d5tOcBcbHBvx8LGfvwfJrHv9T6XvV9JPgxo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=RE6Qtf8S; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="RE6Qtf8S" Received: by smtp.kernel.org (Postfix) with UTF8SMTPSA id C33B81F00893; Mon, 1 Jun 2026 12:57:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780318624; bh=uOtGdQ10po6PYUzoNOVZJt/AVviEOzR047rRHV6QZ1Q=; h=Date:Subject:Cc:From:To:References:In-Reply-To; b=RE6Qtf8SZUxxnhNYYx/0QiTWuTcyboY6tatgNt6BXpBe84PZ8RuPXRihSr2jH+pxt vLhXajVBlbV0MTJk6e+Y4dNRquyg7ehSaMSzdUtv1Pk3lm4X8IFFeiv9Z4UwHPKFWd ZhCjAcU+RGe/f5X6trFXHi17ud6RZNIsRbJ9PhxN4ybIYheoRrtM1Yg4HosefXdXJO RMjej9CgY69a3Wv77S5+vUaL7F7tAF8O6NxIfbpkjJgUO8Je0sUK+gx8iFFgG4XLs4 OWYUVjZfX+/qarQ2WejxioQ7p7pdmKw4FN8+bggpl9tNkzP2snuVCxIIliozAPDlKJ do9LO1XDCeSRA== Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: multipart/signed; boundary=ed8d132310e85f4b2eec2d3d97e105344fc922fe0d44ac605c9c141fd8a6; micalg=pgp-sha384; protocol="application/pgp-signature" Date: Mon, 01 Jun 2026 14:57:00 +0200 Message-Id: Subject: Re: [PATCH] mtd: spi-nor: Add support for MX25L12833F and MX25L12845G Cc: "Miquel Raynal" , "Pratyush Yadav" , "Takahiro Kuwano" , "Richard Weinberger" , "Vignesh Raghavendra" , , , , "Cheng Ming Lin" From: "Michael Walle" To: "Cheng Ming Lin" X-Mailer: aerc 0.20.0 References: <20260528051751.1648246-1-linchengming884@gmail.com> <87eciwhtf8.fsf@bootlin.com> In-Reply-To: --ed8d132310e85f4b2eec2d3d97e105344fc922fe0d44ac605c9c141fd8a6 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 On Mon Jun 1, 2026 at 2:56 AM CEST, Cheng Ming Lin wrote: > Hi Michael, > > Michael Walle =E6=96=BC 2026=E5=B9=B45=E6=9C=8828=E6= =97=A5=E9=80=B1=E5=9B=9B =E4=B8=8B=E5=8D=883:52=E5=AF=AB=E9=81=93=EF=BC=9A >> >> Hi, >> >> On Thu May 28, 2026 at 9:42 AM CEST, Miquel Raynal wrote: >> > Hi Cheng Ming, >> > >> >>> It looks like you're getting bitten by the ID reuse. You can't just >> >>> unconditionally add the quad PP because as far as I can see the >> >>> MX25L12805D [1] is just a standard single bit i/o flash and doesn't >> >>> support the 4PP. >> >> >> >> You are absolutely right. Thanks for catching this. >> >> >> >> The MX25L12805D is indeed a much older product (released around 2009)= . >> >> Since the initial JESD216 SFDP standard wasn't published until 2011, >> >> I double-checked with our internal PM and confirmed that the MX25L128= 05D >> >> does not support SFDP at all. >> >> >> >> Since the newer flashes (MX25L12833F and MX25L12845G) do support SFDP= , >> >> we could use this as a differentiator to distinguish them from the le= gacy >> >> MX25L12805D. >> >> >> >> What if we try to read the SFDP signature (RDSFDP) in the fixup hook? >> >> If a valid SFDP signature is detected, we can safely identify it as t= he >> >> newer flash and apply the SNOR_HWCAPS_PP_1_4_4 capability. If there i= s >> >> no SFDP signature, we leave it as is for the legacy MX25L12805D. >> >> >> >> Do you think this approach is feasible and acceptable? If so, I will >> >> implement this logic and submit a v2 patch. >> > >> > The ->post_sfdp() fixup hook is documented as "not called for SPI NORs >> > that do not support SFDP". Alternatively, I believe an earlier hook, >> > like ->post_bfpt() could also work since it does not seem to run on >> > non SFDP compatible flashes. >> >> Moreover: >> >> * spi_nor_post_sfdp_fixups() is called after the SFDP tables are par= sed. >> * It is used to tweak various flash parameters when information prov= ided >> * by the SFDP tables are wrong. >> >> And it looks like that is the case for these flashes. Also, please >> provide a comment on the fixup describing that the flash misses that >> property. Basically, what you've written in the commit message. > > I am currently working on the flash part 0xc22018 and I am planning to > add its size back to the flash info table. However, I encountered an > issue regarding the fixup hooks. > > Since this specific flash does not support dual, quad, or octal reads, > the core logic in spi_nor_init_params_deprecated() determines that SFDP > parsing is not needed. Because the SFDP parsing is skipped, the post_bfpt > or post_sfdp hooks are never triggered, which prevents us from applying > the necessary fixups as we expected. > > I initially considered asking about the possibility of removing this > specific check in spi_nor_init_params_deprecated(), which would allow > all SPI-NOR flashes to go through SFDP parsing by default (unless > SPI_NOR_SKIP_SFDP is explicitly set). Oops, I've forgot to add you on CC. Sorry. I've just send a series to get rid of that legacy handling. Please give it a try on your flashes. [1] https://lore.kernel.org/linux-mtd/20260601125438.3481722-1-mwalle@kerne= l.org/ -michael > However, I am aware that forcing SFDP parsing globally on all legacy > 1-1-1 flashes might be risky. Flashes predating the JESD216 standard > might return garbage data when the SFDP opcode (0x5A) is issued, > potentially causing regressions if the garbage data accidentally matches > the SFDP signature. > > If dropping this global check is indeed considered too risky for older > hardware, would it be acceptable to use the late_init hook to handle > this flash individually? The idea would be to manually check and parse > the SFDP table exclusively for 0xc22018 within its own fixup, ensuring > that no other legacy 1-1-1 flashes are affected by this change. > > Any thoughts or guidance on whether this late_init approach is the right > way to go would be greatly appreciated. --ed8d132310e85f4b2eec2d3d97e105344fc922fe0d44ac605c9c141fd8a6 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iKgEABMJADAWIQTIVZIcOo5wfU/AngkSJzzuPgIf+AUCah2BnBIcbXdhbGxlQGtl cm5lbC5vcmcACgkQEic87j4CH/h3eQGA9opRdQ0dC72blLAiAtGF/+VPIGb0j1Y7 5BPFsh3pfCFFJeKsULeBO+14w0gNqf6nAX0fw+QONj2GS599XKdYCyo6NNyTDqUy M4LmdntTIEIxGzFkzeZh5RXOBJWhXkU+9xs= =8Rlz -----END PGP SIGNATURE----- --ed8d132310e85f4b2eec2d3d97e105344fc922fe0d44ac605c9c141fd8a6--