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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B9F6AC433EF for ; Fri, 11 Mar 2022 10:13:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347775AbiCKKOM (ORCPT ); Fri, 11 Mar 2022 05:14:12 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42338 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347751AbiCKKOH (ORCPT ); Fri, 11 Mar 2022 05:14:07 -0500 Received: from smtp2.axis.com (smtp2.axis.com [195.60.68.18]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2CC0B1BF933; Fri, 11 Mar 2022 02:13:02 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=axis.com; q=dns/txt; s=axis-central1; t=1646993583; x=1678529583; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=StZfRVd0d1zSRSJuYQP+XpRtxzfPsHSLjEbIXgq6bj4=; b=XoO1H0HufINNN9YnOJMmd+Tzr+w+Rx8/AKHqTxW0QxH+aPZqtsy2+tST b/Ko95zd1yvw6KPWz/q+BdIdC1Btq/4AOCCvK5qfZbtds0BLKe85rwMH1 CzFirUkf/pTo7bwlO23Td4oO68Wt0u34cLhgo1fAh1P+XwZ2xX343otAR XihwqSd5bcVOf1RmbIiaOocfVVzHKgmF1v95Sg5E6xf6eQUQWR+HKp95L aad3awvKbTJLK5rOsgLxXYVvkVy5G/w9Wf9VmzLWF8e71Iei9q2NtbA6g U9cSff4oSz1W9w+fqXHlYP5uEKH9ZVCynx1jlao8HZjCn0lm5B9LuXfOD Q==; Date: Fri, 11 Mar 2022 11:13:00 +0100 From: Vincent Whitchurch To: Rob Herring CC: "vigneshr@ti.com" , "richard@nod.at" , "miquel.raynal@bootlin.com" , "joern@lazybastard.org" , kernel , "linux-kernel@vger.kernel.org" , "linux-mtd@lists.infradead.org" , "devicetree@vger.kernel.org" , "frowand.list@gmail.com" , "krzysztof.kozlowski@canonical.com" Subject: Re: [PATCH 2/4] dt-bindings: reserved-memory: Add phram Message-ID: <20220311101300.GA32274@axis.com> References: <20220307141549.2732179-1-vincent.whitchurch@axis.com> <20220307141549.2732179-3-vincent.whitchurch@axis.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 10, 2022 at 09:58:58PM +0100, Rob Herring wrote: > On Mon, Mar 07, 2022 at 03:15:47PM +0100, Vincent Whitchurch wrote: > > Add bindings to allow MTD/block devices to be created in reserved-memory > > regions using the "phram" driver. > > What does 'ph' mean? Please define somewhere for the binding. Judging from the Kconfig description it means "physical", as in "physical memory" (as opposed to virtual memory I guess). I will added a note in the next version. [...] > > +examples: > > + - | > > + reserved-memory { > > + #address-cells = <1>; > > + #size-cells = <1>; > > + > > + phram: flash@12340000 { > > + compatible = "phram"; > > + label = "rootfs"; > > That's an odd example... If it's the "flash" name which is odd for RAM, that's mandated by the mtd schema. If it's the "rootfs" label which is odd, I'm not sure I understand why. I use this feature to pass the rootfs to the kernel when booting from RAM. It is much faster and requires less memory than initrd (which is on top of that being deprecated), and it allows the same disk images to be used when booting from RAM, unlike initramfs.