From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 3BFB6D5D682 for ; Thu, 7 Nov 2024 18:16:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-ID:Date:References :In-Reply-To:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=HRhlDcS/ofHrTaZkXwPrgIFiOCfimpibwXMWyW0OUYI=; b=Iu5oi+qRiRJd/F YYbHlWAaramsYKHc60G5TvZdPvGaCJH/Uff5bXA17VAa1aTNSi5+w6khCFcbH+1rC3z08/M7CBGkm AjYuabd0L3GDXemqN7TYfHTyvxoU2CJ/abRv6jMPKakcoY8SDOK3+kvi/tWWICMJKvu3SJS8z3HqU 22tVo+B786abYCOUVNSH4yk8OjYo8/dmftPiWhf4qAX7yPl3KXHEoma3809ebSkao+WgUbatUdQNv 3gsl/Epn9fq1jtELbW/m148qQOEXhLb5TUK36d7HxAQuX64P0hjXYKfdPaNPeU0y7zCEy3CRiQCTb rl58d6AJXJjymBji26Nw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1t973h-00000007v2s-39pL; Thu, 07 Nov 2024 18:16:41 +0000 Received: from desiato.infradead.org ([2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1t95s0-00000007k2H-2Wvm for linux-mtd@bombadil.infradead.org; Thu, 07 Nov 2024 17:00:32 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Content-Type:MIME-Version:Message-ID: Date:References:In-Reply-To:Subject:Cc:To:From:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=7xJQ8PRClRx/G/uC6ZDPRhLZup1QBQXHZih8qzyEFAw=; b=E5MJQv9dQbEl3Aa11rJq9QnNYG w0d60M5XQocsajggVrNDdajtmfpYnsL4JL+0eM9FoipEcv1ckuDu/NWw+ROCOzOZjFkOXXbGlIWEe ewSiI4zwBkI+j9EYjKkSzhTwIf/ErAGazeVFPWcRKf9Pr3uBJpASwQmx2GdcDLpnXHwhIfR9vm2Va Ra0p7PjEvdHxq9hzawg/lJqNIrYkwSkEMnLYYFhrU5kCA6xPyzGfl511yUWfK2vTsvBsKBFXOigBV 5oYcfV93xmd/7ZacmEH9aSTPFOnd0JbA1F1ZcELgO5mZB6HR5oU1Vj3oQLTQX7kDvmbHEcgDzJWmP SbxuDxXg==; Received: from dfw.source.kernel.org ([139.178.84.217]) by desiato.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1t95rx-0000000CAMI-0QzP for linux-mtd@lists.infradead.org; Thu, 07 Nov 2024 17:00:30 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id 177D85C309C; Thu, 7 Nov 2024 16:59:41 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 204B8C4CECD; Thu, 7 Nov 2024 17:00:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1730998824; bh=fmEMZSN8aYDktJAftW6kTuaO7wJAwwzSFJuKFKEOrmI=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=bXaGhoDSo3pT7F+q6VnOjjxAJKmMyTf3z43Vw6z3BrqOuoGzRAup2kUvvObIE3bsx YmMIgnVEo7EwHtOKAmdylTlqn6vThURcB8YPWkE58fsaQqXgyaiqptHx/ERu0tZP0M /wxwRFenyvfTGxbp1M6NqafnaH6cKXWDL7gB1Cz8taM6FICIaKlJCsbR6GZ449xv4Z AFHHO0Q0j2D0JuSkw5muppQSdEz5lsitrJjEecaHNXR1Yx+bR4rJqtd36F+bbdAv4+ ZWO0a0kZQoFMBoAWQQNckpCCnRzXQOemPJB2EEu/UMgA7tt0LFchvRLD90gh1AleDo f0NyZ8bXMlHtw== From: Pratyush Yadav To: Cheng Ming Lin Cc: tudor.ambarus@linaro.org, pratyush@kernel.org, mwalle@kernel.org, miquel.raynal@bootlin.com, richard@nod.at, vigneshr@ti.com, linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org, alvinzhou@mxic.com.tw, leoyu@mxic.com.tw, Cheng Ming Lin Subject: Re: [PATCH] mtd: spi-nor: core: replace dummy buswidth from addr to data In-Reply-To: <20241107093016.151448-1-linchengming884@gmail.com> (Cheng Ming Lin's message of "Thu, 7 Nov 2024 17:30:16 +0800") References: <20241107093016.151448-1-linchengming884@gmail.com> Date: Thu, 07 Nov 2024 17:00:21 +0000 Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241107_170029_355331_07201B62 X-CRM114-Status: UNSURE ( 9.87 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-mtd" Errors-To: linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org On Thu, Nov 07 2024, Cheng Ming Lin wrote: > From: Cheng Ming Lin > > The default dummy cycle for Macronix SPI NOR flash in Octal Output > Read Mode(1-1-8) is 20. > > Currently, the dummy buswidth is set according to the address bus width. > In the 1-1-8 mode, this means the dummy buswidth is 1. When converting > dummy cycles to bytes, this results in 20 x 1 / 8 = 2 bytes, causing the > host to read data 4 cycles too early. > > Since the protocol data buswidth is always greater than or equal to the > address buswidth. Setting the dummy buswidth to match the data buswidth > increases the likelihood that the dummy cycle-to-byte conversion will be > divisible, preventing the host from reading data prematurely. Makes sense. Reviewed-by: Pratyush Yadav -- Regards, Pratyush Yadav ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/