Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752728AbbFCKDy (ORCPT ); Wed, 3 Jun 2015 06:03:54 -0400 Received: from foss.arm.com ([217.140.101.70]:39237 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751572AbbFCKDl (ORCPT ); Wed, 3 Jun 2015 06:03:41 -0400 Date: Wed, 3 Jun 2015 11:03:43 +0100 From: Lorenzo Pieralisi To: Jiang Liu Cc: "hanjun.guo@linaro.org" , "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 Message-ID: <20150603100343.GA27917@red-moon> 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> <556ECA93.7040800@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <556ECA93.7040800@linux.intel.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3753 Lines: 93 On Wed, Jun 03, 2015 at 10:36:19AM +0100, Jiang Liu wrote: > On 2015/6/3 16:44, Hanjun Guo wrote: > > On 2015???06???02??? 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. I guess you can't move that struct pci_controller to generic code since it is present on other archs too (with completely different members). What you can do is creating a new struct (ie same purpose of pci_controller with a different name) common to all archs that contains the common bits + a void* data that contains arch specific data, and convert x86 and ia64 to using it. It is weird to be forced to declare a pci_controller structure in arm64 code with 0 arch specific data in it. Lorenzo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/