Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756683AbaLIMNH (ORCPT ); Tue, 9 Dec 2014 07:13:07 -0500 Received: from foss-mx-na.foss.arm.com ([217.140.108.86]:46912 "EHLO foss-mx-na.foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755999AbaLIMND (ORCPT ); Tue, 9 Dec 2014 07:13:03 -0500 Message-ID: <5486E747.4010804@arm.com> Date: Tue, 09 Dec 2014 12:12:55 +0000 From: Marc Zyngier User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Icedove/31.2.0 MIME-Version: 1.0 To: Yijing Wang , 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> In-Reply-To: <5486E3BF.70703@huawei.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Yijing, On 09/12/14 11:57, Yijing Wang wrote: >>>> +void __weak pcibios_set_phb_msi_domain(struct pci_bus *bus) >>>> +{ >>>> +} >>>> + >>>> +static void pci_set_bus_msi_domain(struct pci_bus *bus) >>>> +{ >>>> + struct pci_dev *bridge = bus->self; >>>> + >>>> + if (!bridge) >>>> + pcibios_set_phb_msi_domain(bus); >>>> + else >>>> + dev_set_msi_domain(&bus->dev, dev_get_msi_domain(&bridge->dev)); >>>> +} >>> >>> >>> Hi Marc, we can not assume pci devices under same phb share the same msi irq domain, >>> now in x86, pci devices under the same phb may associate different msi irq domain. > > Hi Marc, > >> >> 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? > 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. >> - 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? Thanks, M. -- Jazz is not dead. It just smells funny... -- 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/