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 EA203E7718B for ; Mon, 23 Dec 2024 18:22:32 +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=aVhGuqggbjX8MX/TZ7H6A3fqvbqwvVs1VKW8iRtRR+4=; b=MSiH9VotzZHn2E wbThmC8ExlMC9NHRmhU8B/0S6r1eNxYZTSEJHaXWui6ZHbaIu/vNfZuCudh1Q9y1Wc67Lxe5vMfwt GxadtFVRRPvhgcPb4Jc8m3pCKe/Cw3ueOyfIN9uHsdoZZltF/PL0k/stYyexEVz2xgRch2/d8DGUt pZ2faE3TgeOsgH0tgKmSPHOScUQM1iT2sekutNQQOlZGYVolK4+AQRYeZISBFHMvUNCK2kS0u0lL5 cQnhzhb6K7Q7LOOf8VZzIQZJ1lANoty1XRT3WXj/Q0ksh8Nkwi1q7STEkzmdU5sEwRNTxCSn07FtU BeQ75TO0o1nE7rkU8HAQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tPn4S-0000000AXJQ-1jHr; Mon, 23 Dec 2024 18:22:24 +0000 Received: from relay9-d.mail.gandi.net ([2001:4b98:dc4:8::229]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tPn4P-0000000AXIu-1xFw for linux-mtd@lists.infradead.org; Mon, 23 Dec 2024 18:22:22 +0000 Received: by mail.gandi.net (Postfix) with ESMTPSA id 5A560FF803; Mon, 23 Dec 2024 18:22:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1734978135; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Tv6iJmtFz4jTMYOEld5KmoNhqIuilNzkh9WY1WJn4gY=; b=BprkTsBJ7qEtphtbRAxKat6cRkjsX/srJJKRA1XLh5YWmoOAyCAPaqPgNW2Qqj0LLQwnqS 9Ehjc1RPt1aXT9IyXvnCwO7qWEL5znOQG2uGXyfWlza6TT98LQMJEmwVQEg12UFq2o0026 nWSsoblBr8IKNCQgnWKnK3SgH0EWLxLtq8c3NbAskr3sLXOoYYEt9PSTrYBsoG3WUJ1Ho+ SWw+wNn+m2HX0WJCymjeEz9CGzeQMiy2+s6y/JwTJmlI5gNHhk1Kd95ez0CWTPpHe+WIm/ R4HtCk4+2gURT+7vgn9XrcTpRCwPMPhTpy9jgetF7UuAp9/6as98X/bbBfONUw== From: Miquel Raynal To: Tudor Ambarus Cc: Richard Weinberger , Vignesh Raghavendra , Pratyush Yadav , Michael Walle , linux-mtd@lists.infradead.org, Mark Brown , linux-spi@vger.kernel.org, Steam Lin , Thomas Petazzoni , Sanjay R Mehta , Han Xu , Conor Dooley , Daire McNamara , Matthias Brugger , AngeloGioacchino Del Regno , Haibo Chen , Yogesh Gaur , Heiko Stuebner , Michal Simek Subject: Re: [PATCH 24/24] mtd: spinand: winbond: Add support for DTR operations In-Reply-To: <6029a01f-dc4d-4a35-ad21-fd17e3fed9fc@linaro.org> (Tudor Ambarus's message of "Mon, 11 Nov 2024 14:40:59 +0000") References: <20241025161501.485684-1-miquel.raynal@bootlin.com> <20241025161501.485684-25-miquel.raynal@bootlin.com> <6029a01f-dc4d-4a35-ad21-fd17e3fed9fc@linaro.org> User-Agent: mu4e 1.12.7; emacs 29.4 Date: Mon, 23 Dec 2024 19:22:12 +0100 Message-ID: <87o712uunf.fsf@bootlin.com> MIME-Version: 1.0 X-GND-Sasl: miquel.raynal@bootlin.com X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241223_102221_666783_5DB8B2CE X-CRM114-Status: UNSURE ( 9.91 ) X-CRM114-Notice: Please train this message. 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arc=none smtp.client-ip=217.70.183.199 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="BprkTsBJ" Received: by mail.gandi.net (Postfix) with ESMTPSA id 5A560FF803; Mon, 23 Dec 2024 18:22:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1734978135; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Tv6iJmtFz4jTMYOEld5KmoNhqIuilNzkh9WY1WJn4gY=; b=BprkTsBJ7qEtphtbRAxKat6cRkjsX/srJJKRA1XLh5YWmoOAyCAPaqPgNW2Qqj0LLQwnqS 9Ehjc1RPt1aXT9IyXvnCwO7qWEL5znOQG2uGXyfWlza6TT98LQMJEmwVQEg12UFq2o0026 nWSsoblBr8IKNCQgnWKnK3SgH0EWLxLtq8c3NbAskr3sLXOoYYEt9PSTrYBsoG3WUJ1Ho+ SWw+wNn+m2HX0WJCymjeEz9CGzeQMiy2+s6y/JwTJmlI5gNHhk1Kd95ez0CWTPpHe+WIm/ R4HtCk4+2gURT+7vgn9XrcTpRCwPMPhTpy9jgetF7UuAp9/6as98X/bbBfONUw== From: Miquel Raynal To: Tudor Ambarus Cc: Richard Weinberger , Vignesh Raghavendra , Pratyush Yadav , Michael Walle , linux-mtd@lists.infradead.org, Mark Brown , linux-spi@vger.kernel.org, Steam Lin , Thomas Petazzoni , Sanjay R Mehta , Han Xu , Conor Dooley , Daire McNamara , Matthias Brugger , AngeloGioacchino Del Regno , Haibo Chen , Yogesh Gaur , Heiko Stuebner , Michal Simek Subject: Re: [PATCH 24/24] mtd: spinand: winbond: Add support for DTR operations In-Reply-To: <6029a01f-dc4d-4a35-ad21-fd17e3fed9fc@linaro.org> (Tudor Ambarus's message of "Mon, 11 Nov 2024 14:40:59 +0000") References: <20241025161501.485684-1-miquel.raynal@bootlin.com> <20241025161501.485684-25-miquel.raynal@bootlin.com> <6029a01f-dc4d-4a35-ad21-fd17e3fed9fc@linaro.org> User-Agent: mu4e 1.12.7; emacs 29.4 Date: Mon, 23 Dec 2024 19:22:12 +0100 Message-ID: <87o712uunf.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; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-GND-Sasl: miquel.raynal@bootlin.com Hello Tudor, On 11/11/2024 at 14:40:59 GMT, Tudor Ambarus wro= te: > On 10/25/24 5:15 PM, Miquel Raynal wrote: >> W25N01JW and W25N02JW support many DTR read modes in single, dual and >> quad configurations. >>=20 >> DTR modes however cannot be used at 166MHz, as the bus frequency in >> this case must be lowered to 80MHz. > > ha, what's the benefit then? Aren't we better of with non dtr modes > then? 80 MHz * 2 < 166 MHz? This is actually a good question, and you are right DDR in this case does not bring better throughputs, it can even make it a little bit slower. I think however we should expect some gains at the PCB design step, which may be way simpler as routing 8 166MHz lines might apparently be challenging. It is common to have PCB limitations on the frequency, so enabling DDR can be a great way to keep signal integrity while definitely improving the performances. However, you're right, I should probably move these definitions lower in the table to make sure we run at 166MHz if that's possible. Thanks, Miqu=C3=A8l