From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtpout-04.galae.net (smtpout-04.galae.net [185.171.202.116]) (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 502B031B83B for ; Tue, 3 Feb 2026 21:26:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.171.202.116 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770154008; cv=none; b=uDNlPgvlNAw6czg+VvgDg19vAVFQ31QQ+IzmKj/Ln04v2vRA0Cf0A+cnqM1JPXio//XHrZl3S7XDX6Mhc+i+YM+agNct1mu9rM+HRrczUvs4oEvW9o2c2Pb8oOs8OcJjzxaJt5Pnbik+aJSlaQDu1De6lRTzhtULdMFlLTuATME= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770154008; c=relaxed/simple; bh=/+q/af+ksPE7jzykWj7uXSqYHTn46N8s30ZmdgeaZUw=; h=Mime-Version:Content-Type:Date:Message-Id:Cc:To:From:Subject: References:In-Reply-To; b=AKCRcphgpaSqkH2JRJAhCz1/hvZ+46K2Yh+8NbLcMJyxoVHEg35igEPBYgpD0d5k0XEVPSVge/FgUEnsRf2x/DhYlScZZVccPHioxj5+Fi8Ixq6aH9U285zQaFgGnW4XAgXRvIk55yyhbH+3tT2Ddw5RTsc5JhPs7wtf1wUsAVg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com; spf=pass smtp.mailfrom=bootlin.com; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b=uOqf8q9g; arc=none smtp.client-ip=185.171.202.116 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bootlin.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b="uOqf8q9g" Received: from smtpout-01.galae.net (smtpout-01.galae.net [212.83.139.233]) by smtpout-04.galae.net (Postfix) with ESMTPS id EA165C24389; Tue, 3 Feb 2026 21:26:49 +0000 (UTC) Received: from mail.galae.net (mail.galae.net [212.83.136.155]) by smtpout-01.galae.net (Postfix) with ESMTPS id 805B760728; Tue, 3 Feb 2026 21:26:44 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id 86720119A8888; Tue, 3 Feb 2026 22:26:40 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=dkim; t=1770154003; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding:in-reply-to:references; bh=/+q/af+ksPE7jzykWj7uXSqYHTn46N8s30ZmdgeaZUw=; b=uOqf8q9gdfCzsbKOilwihAPJ5Fjpslxn5EEJlOaKrKxhFjn4XYA4frT6Ji5iawmkc8hQru nG6d0X2J9FqSlTbwDDfYES1OF9+s5sFyiQiHtuCwQM7FTCYP8+IhuDC33qT54l/BFllSFa SbSDQtHrbA1lKX6sfNp0EGR69Ll1b5fvDMiSBgmqbpgYmg2Y3MiROunVeQjnBGzOwkQ0fa 3o/g8RC6tUMSXE3k14cAFxZydStB9zftmUaCvfMp6EOhp7goFu9LMYD0CtPJKCldsh0Md4 etmkVCoG3NNiGaEmlXc1YJVdoqKbJOf2D+O+3UYGRXwBVzzO8ZW2UB+S0l4kgA== Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Tue, 03 Feb 2026 22:26:39 +0100 Message-Id: Cc: "Amit Kumar Mahapatra" , "Michal Simek" , "Bernhard Frauendienst" , "Thomas Petazzoni" , , , To: "Luca Ceresoli" , "Miquel Raynal" , "Richard Weinberger" , "Vignesh Raghavendra" , "Rob Herring" , "Krzysztof Kozlowski" , "Conor Dooley" , =?utf-8?q?Rafa=C5=82_Mi=C5=82ecki?= From: "Luca Ceresoli" Subject: Re: [PATCH v16 0/3] mtd: Add support for stacked memories X-Mailer: aerc 0.20.1 References: <20260203-mtd-virt-concat-v16-0-a112a979c813@bootlin.com> In-Reply-To: <20260203-mtd-virt-concat-v16-0-a112a979c813@bootlin.com> X-Last-TLS-Session-Version: TLSv1.3 Hello, On Tue Feb 3, 2026 at 9:39 PM CET, Luca Ceresoli wrote: > [TL;DR for v15: as agreed with Amit I'm sending a new iteration of his > patches to fix the build-time failure due to a module dependency > loop. Original cover follows.] > > This patch series adds stacked support by enhancing the existing mtd-conc= at > driver to be more generic. > > As background, a few years ago, Bernhard Frauendienst initiated an effort > [2] to achieve the same, which was later adapted by Miquel [1] to introdu= ce > stacked mode support. In this approach, partitions to be concatenated wer= e > specified using a DT property "part-concat" within the partitions > definition, allowing two MTD devices to function as a single larger one i= n > order to be able to define partitions across chip boundaries. However, th= e > bindings were not accepted. As a result, the mtd-concat approach was > dropped, and alternative DT bindings were introduced [3][4][5], describin= g > the two flash devices as one. Corresponding SPI core changes to support > these bindings were later added [6]. > > While integrating stacked mode support into SPI-NOR, Tudor provided > additional feedback, leading to discussions about updating the existing > DT bindings. To address this, I sent an RFC [7] to initiate discussions o= n > adapting the DT bindings as suggested by Miquel in [1]. Following that, > I am now submitting this patch series that updates the virtual concat DT > bindings and the driver referenced in [1], along with some minor mtdcore > changes. > Since I have taken ownership of this effort, I have included Bernhard and > Miquel under the "Suggested-by" tag. > > [1] https://lore.kernel.org/linux-mtd/20191127105522.31445-1-miquel.rayna= l@bootlin.com/ > [2] https://lwn.net/ml/linux-kernel/20180907173515.19990-1-kernel@nospam.= obeliks.de/ > [3] https://github.com/torvalds/linux/commit/f89504300e94524d5d5846ff8b72= 8592ac72cec4 > [4] https://github.com/torvalds/linux/commit/eba5368503b4291db7819512600f= a014ea17c5a8 > [5] https://github.com/torvalds/linux/commit/e2edd1b64f1c79e8abda365149ed= 62a2a9a494b4 > [6] https://github.com/torvalds/linux/commit/4d8ff6b0991d5e86b17b235fc46e= c62e9195cb9b > [7] https://lore.kernel.org/all/20241026075347.580858-1-amit.kumar-mahapa= tra@amd.com/ > > Signed-off-by: Luca Ceresoli Aargh, I forgot to add my SoB line! Please ignore this series, v17 incoming. Sorry about the mess! Luca -- Luca Ceresoli, Bootlin Embedded Linux and Kernel engineering https://bootlin.com