From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtpout-03.galae.net (smtpout-03.galae.net [185.246.85.4]) (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 E5CED4317D for ; Tue, 28 Apr 2026 12:44:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.246.85.4 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777380279; cv=none; b=InRyzjE2ckQ9AMX5ey8kYqk26Fjagr9eBzA9Rg9b5GCEXugdpWTPAk6i2RRMoC+NKPDfJ7vAoS+Itvvdzq1LKIRrjImJw9ffyDKZaiDDCJ91gfOuEC3xSCZJedL34pCUuAuTEgMjrKJb7PqVIm8PNAPrnA2eQAEGcdlFvGmAeek= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777380279; c=relaxed/simple; bh=sz0zbVibYD3ws766mYrKtBGdJgj3I/pYhnlAXRz8F84=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=TPS45pPruQBjj87jP4/V0Hh99a1zZ1LXZUcZTAPtqmGCd7jDo4rxfdcRdsQE8wAwu0STUOiR4U93lQlni8TJQdb0MmGPfey6EDoz/HmawaKqwRa7NDSIuQ/5k2WAxcyky1zuVW0Kbu9zukb0vpL1lzdiJt68QfmVTFZguHV+bzA= 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=q8UPeq/P; arc=none smtp.client-ip=185.246.85.4 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="q8UPeq/P" Received: from smtpout-01.galae.net (smtpout-01.galae.net [212.83.139.233]) by smtpout-03.galae.net (Postfix) with ESMTPS id D99644E42B54; Tue, 28 Apr 2026 12:44:34 +0000 (UTC) Received: from mail.galae.net (mail.galae.net [212.83.136.155]) by smtpout-01.galae.net (Postfix) with ESMTPS id A7804601D0; Tue, 28 Apr 2026 12:44:34 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id 7056210728B2D; Tue, 28 Apr 2026 14:44:31 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=dkim; t=1777380273; h=from:subject:date:message-id:to:cc:mime-version:content-type: in-reply-to:references; bh=sz0zbVibYD3ws766mYrKtBGdJgj3I/pYhnlAXRz8F84=; b=q8UPeq/PDsYwFot0SvyZRpslhROcaSLOmfgDwKPM9fMDqPvX6zFXnZXtm4p1jiwRuhASnv HruUr3EJBZA51npI3/aq4ibQoZzcS5YaWyz/4MkBd0ipYuYj1ef+G1s8lbrJCrP8dI8n8y uNM1Ca2SD1VJp7q0FWSn4OoeFrZ+wF2ri2hiqd7TIFfmarFFjcmJ82wjt8/LnWoalnicI2 UVjDwVNAcnSVaglr7wmc1sztJYUPhS9g+oZv2Ay0xeM0YnuT2Q6C6smSWtd0+2k7FCkxof e7tINB0SofrQfyZMVgWqHarDKShk5qQ4114N+sScP8eo6Yc12ckDhvUrB3sFYA== From: Miquel Raynal To: Mark Brown Cc: Richard Weinberger , Vignesh Raghavendra , Thomas Petazzoni , linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org, Michael Walle , Takahiro Kuwano , Pratyush Yadav , Steam Lin , Santhosh Kumar K Subject: Re: [PATCH 0/4] spi: spi-mem/mtd: spinand: Prevent SPI NAND continuous reads on am65/am62 In-Reply-To: <20260326-winbond-v7-0-rc1-cadence-cont-read-v1-0-0d626e1dfb2b@bootlin.com> (Miquel Raynal's message of "Thu, 26 Mar 2026 17:47:14 +0100") References: <20260326-winbond-v7-0-rc1-cadence-cont-read-v1-0-0d626e1dfb2b@bootlin.com> User-Agent: mu4e 1.12.7; emacs 30.2 Date: Tue, 28 Apr 2026 14:44:33 +0200 Message-ID: <878qa7dzke.fsf@bootlin.com> Precedence: bulk X-Mailing-List: linux-spi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain X-Last-TLS-Session-Version: TLSv1.3 On 26/03/2026 at 17:47:14 +01, Miquel Raynal wrote: > TI errata i2351 explains there is a problem with CS handling, SPI NOR > are immune to the problem, but the CS being deasserted spuriously when > there is DMA arbitration on long accesses (every 1023 bytes), SPI NAND > continuous reads cannot be leveraged. > > Link: https://www.ti.com/lit/er/sprz544c/sprz544c.pdf > > I created a 2-page read setup for testing all variants available on a > W35N chip wired to this controller. I reliably observed all variants to > always (in my tests) report correct data, except the 8D-8D-8D > variant *when setting an extended number of dummy cycles* (>= 12, so 24 > dummy bytes). In this case, I got the first 6144 bytes correct (over > 8192), the rest being full of ones (0xFF), indicating the CS has likely > been deasserted there. This is not exactly 6 x 1023 bytes (?), but > close. > > This series shall be applied on top of the SPI NAND continuous read > series that I am also carrying, but ideally not too far in the future > because there are Winbond (continuous read capable) NAND chips mounted > on TI platforms AM62 based which could make use of that new feature and > expose the issue described above. Applied to nand/next (except the spi patch).