From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753299AbbFCJgl (ORCPT ); Wed, 3 Jun 2015 05:36:41 -0400 Received: from mga09.intel.com ([134.134.136.24]:8632 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752949AbbFCJg3 (ORCPT ); Wed, 3 Jun 2015 05:36:29 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.13,546,1427785200"; d="scan'208";a="581230274" Message-ID: <556ECA93.7040800@linux.intel.com> Date: Wed, 03 Jun 2015 17:36:19 +0800 From: Jiang Liu Organization: Intel User-Agent: Mozilla/5.0 (Windows NT 6.2; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.4.0 MIME-Version: 1.0 To: Hanjun Guo , Lorenzo Pieralisi CC: "Rafael J . Wysocki" , Bjorn Helgaas , Marc Zyngier , Liviu Dudau , Yijing Wang , Catalin Marinas , Will Deacon , Lv Zheng , "lenb @ kernel . org" , LKML , "linux-pci@vger.kernel.org" , "linux-acpi@vger.kernel.org" , "x86 @ kernel . org" , "linux-arm-kernel@lists.infradead.org" , Arnd Bergmann Subject: Re: [Patch v4 5/8] ARM64/PCI/ACPI: Introduce struct pci_controller for ACPI References: <1433225576-8215-1-git-send-email-jiang.liu@linux.intel.com> <1433225576-8215-6-git-send-email-jiang.liu@linux.intel.com> <20150602093525.GA23543@red-moon> <556EBE6D.90907@linaro.org> In-Reply-To: <556EBE6D.90907@linaro.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2015/6/3 16:44, Hanjun Guo wrote: > On 2015年06月02日 17:35, Lorenzo Pieralisi wrote: >> On Tue, Jun 02, 2015 at 07:12:53AM +0100, Jiang Liu wrote: >>> From: Hanjun Guo >>> >>> ARM64 ACPI based PCI host bridge init needs a arch dependent >>> struct pci_controller to accommodate common PCI host bridge >>> code which is introduced later, or it will lead to compile >>> errors on ARM64. >>> >>> Signed-off-by: Hanjun Guo >>> Tested-by: Suravee Suthikulpanit >>> CC: Arnd Bergmann >>> CC: Catalin Marinas >>> CC: Liviu Dudau >>> CC: Lorenzo Pieralisi >>> CC: Will Deacon >>> Signed-off-by: Jiang Liu >>> --- >>> arch/arm64/include/asm/pci.h | 10 ++++++++++ >>> 1 file changed, 10 insertions(+) >>> >>> diff --git a/arch/arm64/include/asm/pci.h b/arch/arm64/include/asm/pci.h >>> index b008a72f8bc0..70884957f253 100644 >>> --- a/arch/arm64/include/asm/pci.h >>> +++ b/arch/arm64/include/asm/pci.h >>> @@ -10,6 +10,16 @@ >>> #include >>> #include >>> >>> +struct acpi_device; >>> + >>> +struct pci_controller { >>> +#ifdef CONFIG_ACPI >>> + struct acpi_device *companion; /* ACPI companion device */ >>> +#endif >>> + int segment; /* PCI domain */ >>> + int node; /* NUMA node */ >>> +}; >> >> There is nothing ARM64 specific in this structure. The only >> reason I see you want to keep it arch specific is the iommu >> pointer on x86, > > And also plarform_data for IA64 too. > >> but I think we should find a way to make >> the common bits shared across archs (ie the struct above) and >> add (maybe a void*) to the generic struct to cater for arch >> specific data. >> >> Thoughts ? > > We discussed this already, it has limitations to make it > common to all archs, I think the limitation are: > > - struct pci_controller are also used for other archs > such as PowerPC and Tile, they will not use it for > ACPI purpose, so we can not used for all archs. > > - if we let struct pci_controller defined only for archs > using ACPI, such as introduce it in linux/acpi.h, we still > can not satisfy that the struct pci_controller is not > only used for ACPI case on x86, it will be used for > non-ACPI too. > > So it's pretty difficult to share it with across archs to me, > any more ideas? Hi Hanjun and Lorenzo, As mentioned by Hanjun, I have no idea yet about how to consolidating "struct pci_controller" further. One possible way is to move "struct pci_controller" related code into arch, but apparently that will reduce code reusing. Thanks! Gerry > > Thanks > Hanjun