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 E5237C52D70 for ; Tue, 6 Aug 2024 15:39:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:Message-ID:References:In-Reply-To:Subject:Cc:To:From:Date: MIME-Version:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=2Chn8ymlqazavJ1DZmXPdLBrye9DBk3cugxlezlxhvc=; b=vs/K8L9+W3dSd8nudhMA7uAuiF X2z4VLFHdZk7RQuUzFxX5qZRmiaTTizZGXCdCmE+SCiqUpd6XnD2J9i6bspOV06O/N91loEqXW2fV MBVT7VYXEl9LBe7jYdC9KHzj31w5qJBqVlMa5uFueNJFYL5ZmCjPfCM1Eb7LLEvhVFwiJ+E2OR2fV aXYlDV7x08zfbP4iR36Sms7Lr8BRsJxQVLg1wnY3HJn3qNzOG344/XdKJzp8UbWxide1K1XuOuHYP gKhiY8YGhlGzVbI3I7NemmjpiHqjq5yiZ5XrG6t8Sa8NMXx4mGybgPRaQpNuG7XrNFC0E+NlOsqi9 i9+VdYLw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sbMHz-00000002CsU-2Omt; Tue, 06 Aug 2024 15:39:55 +0000 Received: from mail.manjaro.org ([2a01:4f8:c0c:51f3::1]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1sbMHi-00000002Cog-046m; Tue, 06 Aug 2024 15:39:40 +0000 MIME-Version: 1.0 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=manjaro.org; s=2021; t=1722958773; 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=2Chn8ymlqazavJ1DZmXPdLBrye9DBk3cugxlezlxhvc=; b=VfEMfp9veTf9vofJGHvARhjKJLQWxXoE6CZ4ZfPJBcyubeBt6RFYznvEmk0qhNLGaLcWIZ V4ZVilXZpCU9C/H3Fj/ysZ/XgET0TF1ZDcxMeq8V3CyxyQdsNk7NIj2fbogg2t01z7WsLv wvZqgRJCniv7XWLsHstRuSCgMls15R5RXpdkYXYEbuirc0/HNhXfXfbC+UTQp1+RTHuNyc HQCGgdhhrNGrjo/ZN4a8er9JdyzG+eHz0KiwhMuHq/wV0VtW6AozR7DoRbDrDnLY5G34gi SGgRl+hV/9eqi04hVkBzZk6CNzURj7hKvvnqvMopGb0w7ymNHesO9/LnmyrCtw== Date: Tue, 06 Aug 2024 17:39:32 +0200 From: Dragan Simic To: Christian Marangi Cc: Christoph Hellwig , Ulf Hansson , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Miquel Raynal , Richard Weinberger , Vignesh Raghavendra , Joern Engel , Keith Busch , Jens Axboe , Sagi Grimberg , Wolfram Sang , Florian Fainelli , Thomas Bogendoerfer , linux-mmc@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org, linux-nvme@lists.infradead.org Subject: Re: [PATCH v3 2/6] nvme: assign of_node to nvme device In-Reply-To: <66b21f20.5d0a0220.200175.4b9b@mx.google.com> References: <20240806114118.17198-1-ansuelsmth@gmail.com> <20240806114118.17198-3-ansuelsmth@gmail.com> <20240806124312.GB10156@lst.de> <66b21f20.5d0a0220.200175.4b9b@mx.google.com> Message-ID: X-Sender: dsimic@manjaro.org Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Authentication-Results: ORIGINATING; auth=pass smtp.auth=dsimic@manjaro.org smtp.mailfrom=dsimic@manjaro.org X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240806_083938_701293_45C5F903 X-CRM114-Status: GOOD ( 24.73 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org Hello all, On 2024-08-06 15:03, Christian Marangi wrote: > On Tue, Aug 06, 2024 at 02:43:12PM +0200, Christoph Hellwig wrote: >> On Tue, Aug 06, 2024 at 01:41:12PM +0200, Christian Marangi wrote: >> > Introduce support for a dedicated node for a nvme card. This will be a >> > subnode of the nvme controller node that will have the "nvme-card" >> > compatible. >> > >> > This follow a similar implementation done for mmc where the specific mmc >> > card have a dedicated of_node. >> > >> > This can be used for scenario where block2mtd module is used to declare >> > partition in DT and block2mtd is called on the root block of the nvme >> > card, permitting the usage of fixed-partition parser or alternative >> > ones. >> >> Err, hell no. Why would you wire up a purely PCIe device to OF? >> PCIe is self-discovering. >> > > Well on embedded pure PCIe card most of the time are not a thing... > Unless it's an enterprise product, everything is integrated in the pcb > and not detachable for cost saving measure or also if the thing use > PCIe > protocol but it tighlty coupled with the SoC. > > This implementation is already very common for all kind of pcie devices > like wireless card, gpio expander that are integrated in the PCB and > require property in DT like calibration data, quirks or GPIO pin > definitions, i2c... > > In modern SoC we are seeing an influx of using cheap flash storage > option instead of NAND or NOR as modern hw require more space and price > increase is not that high... Almost any high tier device is switching > to > using emmc and even attached NVME and simulating MTD with them for easy > usage. > > Please consider this well used scenario in emebedded where PCIe is just > a comunication way and the concept of detachable doesn't exist at all > and things can be described in DT as static. Also these storage are > used > for rootfs mount so userspace is not so viable. As a note, perhaps this is another good example of a "fixed layout" PCIe device found on an SBC: https://lore.kernel.org/linux-rockchip/20240805073425.3492078-1-jacobe.zang@wesion.com/T/#u