From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1423739AbcBQPFy (ORCPT ); Wed, 17 Feb 2016 10:05:54 -0500 Received: from mail-wm0-f48.google.com ([74.125.82.48]:33624 "EHLO mail-wm0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1423724AbcBQPFt (ORCPT ); Wed, 17 Feb 2016 10:05:49 -0500 Subject: Re: [PATCH V5 07/15] pci, acpi: Provide generic way to assign bus domain number. To: Jayachandran Chandrashekaran Nair References: <1455630825-27253-1-git-send-email-tn@semihalf.com> <1455630825-27253-8-git-send-email-tn@semihalf.com> <56C47E9A.5010901@semihalf.com> Cc: Bjorn Helgaas , Arnd Bergmann , will.deacon@arm.com, catalin.marinas@arm.com, rafael@kernel.org, hanjun.guo@linaro.org, Lorenzo Pieralisi , okaya@codeaurora.org, jiang.liu@linux.intel.com, Jayachandran Chandrashekaran Nair , Stefano.Stabellini@eu.citrix.com, robert.richter@caviumnetworks.com, mw@semihalf.com, Liviu.Dudau@arm.com, ddaney@caviumnetworks.com, wangyijing@huawei.com, Suravee.Suthikulpanit@amd.com, msalter@redhat.com, linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, linaro-acpi@lists.linaro.org, jcm@redhat.com From: Tomasz Nowicki Message-ID: <56C48C45.7050203@semihalf.com> Date: Wed, 17 Feb 2016 16:05:41 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Firefox/38.0 Thunderbird/38.5.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 17.02.2016 15:21, Jayachandran Chandrashekaran Nair wrote: > On Wed, Feb 17, 2016 at 7:37 PM, Tomasz Nowicki wrote: >> On 17.02.2016 14:44, Jayachandran Chandrashekaran Nair wrote: >>> >>> Tomasz, Lorenzo, >>> >>> On Tue, Feb 16, 2016 at 7:23 PM, Tomasz Nowicki wrote: >>>> >>>>> As we now have valid PCI host bridge device reference we can >>>>> introduce code that is going to find its bus domain number using >>>>> ACPI _SEG method. >>>>> >>>>> Note that _SEG method is optional, therefore _SEG absence means >>>>> that all PCI buses belong to domain 0. >>>>> >>>>> While at it, for the sake of code clarity we put ACPI and DT domain >>>>> assign methods into the corresponding helpers. >>> >>> In my patchset, I had a slightly different and I think better approach for >>> this without calling the _SEG method again. Please see >>> http://www.spinics.net/lists/arm-kernel/msg478167.html >>> at the last part ofhttp://www.spinics.net/lists/arm-kernel/msg478169.html >> >> Relying on NULL parent device to make decision on boot method is really ugly >> way. This may hit us again once we want to obtain another firmware specific >> info e.g. numa node. IMO we need to fix it this way. > > I am not relying on NULL there, in the current code parent is NULL > in case of ACPI, and the check is needed not to crash (unless that > has changed). This series passes down valid parent, see [PATCH V5 06/15]. > > The main part was the macro acpi_pci_get_segment() and the use > of acpi_pci_root_info from sysdata to do this. Since we can obtain related firmware specific data from valid parent device (without defining another accessors), I do not see the point to use sysdata. Let me know your opinion. Tomasz