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 X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_2 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B1927C11D3D for ; Thu, 27 Feb 2020 16:59:05 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 833982469F for ; Thu, 27 Feb 2020 16:59:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="hMxP/b/Z" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 833982469F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=collabora.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=xuZn6gRZn4Wzzl28junRZDjCSnedmIGvriS931RoLzw=; b=hMxP/b/ZNPV9xg gDPCvIy9jhu24rgG+RiWHsHVlTd//FYkzv5WOaxx5cTs6nkeOM/rTbXG/aw6I2un2JoqIbAeOC599 rk0igi6+UKguI5LgeWjpR8k4TlOM65c7T+eaZq/wyQRfk+zC/Wb+gNXzpwR3m17+NebdfMl3HO3wo h/aT3tKwMTBm3HG05YFAAuYxt3Eir8FGgOVuXyTBqkhWElhUa8gK6RSZ27RIntqpf8vpID/9j4pqN 7PEGnIaRirO/Byg95cHvznj2K4hEXhwU0BmE6xWp8V2Uc7b7CKg+3YdFQg1gWt5JEZW2uvcoHbEkz gFc7fzS7Fz2huOoKQrOw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1j7MUs-0004eH-C6; Thu, 27 Feb 2020 16:58:50 +0000 Received: from bhuna.collabora.co.uk ([46.235.227.227]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1j7MUn-0004Yk-N2 for linux-mtd@lists.infradead.org; Thu, 27 Feb 2020 16:58:47 +0000 Received: from localhost (unknown [IPv6:2a01:e0a:2c:6930:5cf4:84a1:2763:fe0d]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: bbrezillon) by bhuna.collabora.co.uk (Postfix) with ESMTPSA id 01505296437; Thu, 27 Feb 2020 16:58:43 +0000 (GMT) Date: Thu, 27 Feb 2020 17:58:41 +0100 From: Boris Brezillon To: Pratyush Yadav Subject: Re: [PATCH v2 06/11] mtd: spi-nor: add support for DTR protocol Message-ID: <20200227175841.51435e3f@collabora.com> In-Reply-To: <20200226093703.19765-7-p.yadav@ti.com> References: <20200226093703.19765-1-p.yadav@ti.com> <20200226093703.19765-7-p.yadav@ti.com> Organization: Collabora X-Mailer: Claws Mail 3.17.4 (GTK+ 2.24.32; x86_64-redhat-linux-gnu) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200227_085845_944781_FAD34330 X-CRM114-Status: GOOD ( 12.17 ) X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , devicetree@vger.kernel.org, Vignesh Raghavendra , Tudor Ambarus , Richard Weinberger , Sekhar Nori , linux-kernel@vger.kernel.org, Rob Herring , linux-spi@vger.kernel.org, Mark Brown , linux-mtd@lists.infradead.org, Miquel Raynal 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 Wed, 26 Feb 2020 15:06:58 +0530 Pratyush Yadav wrote: > Double Transfer Rate (DTR) is SPI protocol in which data is transferred > on each clock edge as opposed to on each clock cycle. Make > framework-level changes to allow supporting flashes in DTR mode. > > Right now, mixed DTR modes are not supported. So, for example a mode > like 4S-4D-4D will not work. All phases need to be either DTR or STR. Didn't go deep into the patch but at first glance you don't seem to extend the framework to support stateful modes as I tried to do here [1]. That's really something we should address before considering supporting xD-xD-xD modes, unless the SPI-NOR only supports one stateful mode. If we don't do that first, we might face all sort of unpleasant issues: * kexec not working correctly because the previous kernel left the NOR in an unknown state * suspend/resume not working properly * linux not booting properly because the bootloader left the device in its non-default mode * ... [1]https://patchwork.kernel.org/cover/10638055/ ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/