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 79305C636CC for ; Tue, 7 Feb 2023 17:54:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232356AbjBGRyX (ORCPT ); Tue, 7 Feb 2023 12:54:23 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56400 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232288AbjBGRyI (ORCPT ); Tue, 7 Feb 2023 12:54:08 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7FC488699; Tue, 7 Feb 2023 09:54:07 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 1C73960F71; Tue, 7 Feb 2023 17:54:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 85A6CC4339E; Tue, 7 Feb 2023 17:54:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1675792446; bh=QRBQnyyHAR4nNDWnh2/Xyc0CKoOqb7mHoQfl7kZ5vpk=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=lgi/S5+a1/ZukFGv53T3arvczqE+I9asjszo6+cA1299DkGCPnySgcfj9zTFFlUTf T2Jt7Zd9IWFxaYQvUptoNjBfr4XCGQrn1RjxaQ0HKubVTj66/up/qYDwgsBsw4sXE3 aj4ZIUDZTZedaeuvuXTfAsVQiZmc9izSzFq3LPMI5P8GAVV9VDncsDBRw407iXjcdE axwkA0AEIbSF33cuR2fSOVRf4019mEArjfaK4wQmOCxOzEhL61zRU6SZCwDZvGgs73 S1GdrGJEjnD6VMs35rufyWWVn5CsQoYvYZLfQpjq6TUwFqzC8rhjk05pUupGHLwy6k oTyFWfNDu0Pkw== Received: by mail-vs1-f41.google.com with SMTP id t20so2851782vsa.12; Tue, 07 Feb 2023 09:54:06 -0800 (PST) X-Gm-Message-State: AO0yUKUQ8cQAagWOY/CcwOwg7LEvzCMwcMHMtdP0RpqIyt51AuIV4Ydr zeXHmFW0c89LAcHiJgBB6P0VGlS/51F5Klp5Cg== X-Google-Smtp-Source: AK7set+aGI6c3afb0NAGVijCIp/ouYbW3+D03JuQO2RqNg4GVnToaFDDhXrPsBKRZa22R6HxxHE3Q1Ywvlh75hzvsMs= X-Received: by 2002:a67:7206:0:b0:3ea:c8c:48a5 with SMTP id n6-20020a677206000000b003ea0c8c48a5mr825382vsc.53.1675792445449; Tue, 07 Feb 2023 09:54:05 -0800 (PST) MIME-Version: 1.0 References: <1675188609-20913-1-git-send-email-ssengar@linux.microsoft.com> <20230201020449.GC20379@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net> <20230201145146.GA3352796-robh@kernel.org> <20230201163455.GA21409@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net> In-Reply-To: <20230201163455.GA21409@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net> From: Rob Herring Date: Tue, 7 Feb 2023 11:53:54 -0600 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v2 0/6] Device tree support for Hyper-V VMBus driver To: Saurabh Singh Sengar Cc: krzysztof.kozlowski+dt@linaro.org, kys@microsoft.com, haiyangz@microsoft.com, wei.liu@kernel.org, decui@microsoft.com, daniel.lezcano@linaro.org, tglx@linutronix.de, virtualization@lists.linux-foundation.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org, mikelley@microsoft.com, ssengar@microsoft.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 1, 2023 at 10:34 AM Saurabh Singh Sengar wrote: > > On Wed, Feb 01, 2023 at 08:51:46AM -0600, Rob Herring wrote: > > On Tue, Jan 31, 2023 at 06:04:49PM -0800, Saurabh Singh Sengar wrote: > > > On Tue, Jan 31, 2023 at 02:27:51PM -0600, Rob Herring wrote: > > > > On Tue, Jan 31, 2023 at 12:10 PM Saurabh Sengar > > > > wrote: > > > > > > > > > > This set of patches expands the VMBus driver to include device tree > > > > > support. > > > > > > > > > > The first two patches enable compilation of Hyper-V APIs in a non-ACPI > > > > > build. > > > > > > > > > > The third patch converts the VMBus driver from acpi to more generic > > > > > platform driver. > > > > > > > > > > Further to add device tree documentation for VMBus, it needs to club with > > > > > other virtualization driver's documentation. For this rename the virtio > > > > > folder to more generic hypervisor, so that all the hypervisor based > > > > > devices can co-exist in a single place in device tree documentation. The > > > > > fourth patch does this renaming. > > > > > > > > > > The fifth patch introduces the device tree documentation for VMBus. > > > > > > > > > > The sixth patch adds device tree support to the VMBus driver. Currently > > > > > this is tested only for x86 and it may not work for other archs. > > > > > > > > I can read all the patches and see *what* they do. You don't really > > > > need to list that here. I'm still wondering *why*. That is what the > > > > cover letter and commit messages should answer. Why do you need DT > > > > support? How does this even work on x86? FDT is only enabled for > > > > CE4100 platform. > > > > > > HI Rob, > > > > > > Thanks for your comments. > > > We are working on a solution where kernel is booted without ACPI tables to keep > > > the overall system's memory footprints slim and possibly faster boot time. > > > We have tested this by enabling CONFIG_OF for x86. > > > > It's CONFIG_OF_EARLY_FLATTREE which you would need and that's not user > > selectable. At a minimum, you need some kconfig changes. Where are > > those? > > You are right we have define a new config flag in Kconfig, and selected CONFIG_OF > and CONFIG_OF_EARLY_FLATTREE. We are working on upstreaming that patch as well > however that will be a separate patch series. Fair enough, but that should come first IMO. Really I just want to see a complete picture. That can be a reference to a git branch(es) or other patch series. But again, what I want to see in particular is the actual DT and validation run on it. > > Also see my comment on v1 about running DT validation on your dtb. I'm > > sure running it would point out other issues. Such as the root level > > comaptible string(s) need to be documented. You need cpu nodes, > > interrupt controller, timers, etc. Those all have to be documented. > > I will be changing the parent node to soc node as suggested by Krzysztof > in other thread. Another issue yes, but orthogonal to my comments. > > soc { > #address-cells = <2>; > #size-cells = <2>; You are missing 'ranges' here. Without it, addresses aren't translatable. You are also missing 'compatible = "simple-bus";'. This happens to work on x86 because of legacy reasons, but we don't want new cases added. > > vmbus@ff0000000 { > #address-cells = <2>; > #size-cells = <1>; > compatible = "Microsoft,vmbus"; 'Microsoft' is not a vendor prefix. > ranges = <0x00 0x00 0x0f 0xf0000000 0x10000000>; > }; > }; > > This will be sufficient. All these comments are unnecessary because the tools will now check these things and we shouldn't have to. Rob