Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756711AbaLIL6M (ORCPT ); Tue, 9 Dec 2014 06:58:12 -0500 Received: from szxga01-in.huawei.com ([119.145.14.64]:50766 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755617AbaLIL6K (ORCPT ); Tue, 9 Dec 2014 06:58:10 -0500 Message-ID: <5486E3BF.70703@huawei.com> Date: Tue, 9 Dec 2014 19:57:51 +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> In-Reply-To: <5486C8BA.8030608@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 >>> +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. 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. > - What in-tree platform already has this requirements? As mentioned above, x86 does. 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/