Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756792AbaLIMYp (ORCPT ); Tue, 9 Dec 2014 07:24:45 -0500 Received: from szxga02-in.huawei.com ([119.145.14.65]:53585 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756257AbaLIMYn (ORCPT ); Tue, 9 Dec 2014 07:24:43 -0500 Message-ID: <5486EA00.6080901@huawei.com> Date: Tue, 9 Dec 2014 20:24:32 +0800 From: Yijing Wang User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:24.0) Gecko/20100101 Thunderbird/24.0.1 MIME-Version: 1.0 To: Marc Zyngier , Bjorn Helgaas , Thomas Gleixner , Jiang Liu CC: "linux-arm-kernel@lists.infradead.org" , "linux-pci@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Will Deacon , "suravee.suthikulpanit@amd.com" Subject: Re: [PATCH 2/6] PCI/MSI: add hooks to populate the msi_domain field References: <1418069543-21969-1-git-send-email-marc.zyngier@arm.com> <1418069543-21969-3-git-send-email-marc.zyngier@arm.com> <5486585B.40000@huawei.com> <5486C8BA.8030608@arm.com> <5486E3BF.70703@huawei.com> <5486E747.4010804@arm.com> In-Reply-To: <5486E747.4010804@arm.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.27.212] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >>> Well, this is not supposed to be a perfect solution yet, but instead a >>> basis for discussion. What I'd like to find out is: >>> >>> - What is the minimum granularity for associating a device with its MSI >>> domain in existing platforms? >> >> PCI device, after Gerry's msi irq domain patchset which now in linux-next, >> in x86, we will find msi irq domain by pci_dev. > > Are you *really* associating the MSI domain on a per pci-device basis? > That is, you have devices on the same PCI bus talking to different MSI hw? Yes. > >> I generally agree your first patch which associate basic device with msi irq domain. >> >>> - What topology data structures do you use to find out what MSI >>> controller a device should be matched with? >> >> Now only arm and arm64 use msi controller to setup/teardown msi irqs, >> in arm, now msi controller saved in pci_sys_data, and for arm64, it seems >> to be saved in pci_bus. For a more common method to find msi controller/irq domain, >> I prefer pci_dev/device. > > Forget about msi_controller, the whole goal of this series is to make it > obsolete. On your x86 platform, what how do you identify which MSI > domain should be associated with a given PCI device? Surely you must > have a set of data structures or ACPI tables which give you that > information. Yes, by ACPI DMAR table. > >>> - What in-tree platform already has this requirements? >> >> As mentioned above, x86 does. > > Let me rephrase that in a non-ambiguous manner: can you point me to a > file implementing this in mainline? Please refer to arch/x86/kernel/apic/msi.c native_setup_msi_irqs() in linux-next tree. Thanks! Yijing. > > Thanks, > > M. > -- Thanks! Yijing -- 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/