From patchwork Wed Nov 12 13:47:38 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 5289351 X-Patchwork-Delegate: bhelgaas@google.com Return-Path: X-Original-To: patchwork-linux-pci@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 5B9B2C11AC for ; Wed, 12 Nov 2014 13:47:51 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 56A2920165 for ; Wed, 12 Nov 2014 13:47:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 339792017E for ; Wed, 12 Nov 2014 13:47:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752676AbaKLNrq (ORCPT ); Wed, 12 Nov 2014 08:47:46 -0500 Received: from service87.mimecast.com ([91.220.42.44]:38234 "EHLO service87.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752551AbaKLNrp convert rfc822-to-8bit (ORCPT ); Wed, 12 Nov 2014 08:47:45 -0500 Received: from cam-owa1.Emea.Arm.com (fw-tnat.cambridge.arm.com [217.140.96.21]) by service87.mimecast.com; Wed, 12 Nov 2014 13:47:42 +0000 Received: from [10.1.209.143] ([10.1.255.212]) by cam-owa1.Emea.Arm.com with Microsoft SMTPSVC(6.0.3790.3959); Wed, 12 Nov 2014 13:47:39 +0000 Message-ID: <546364FA.7010806@arm.com> Date: Wed, 12 Nov 2014 13:47:38 +0000 From: Marc Zyngier User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130330 Thunderbird/17.0.5 MIME-Version: 1.0 To: Jiang Liu CC: Bjorn Helgaas , Benjamin Herrenschmidt , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , "Rafael J. Wysocki" , Randy Dunlap , Yinghai Lu , Borislav Petkov , "grant.likely@linaro.org" , Yingjoe Chen , Matthias Brugger , Konrad Rzeszutek Wilk , Andrew Morton , Tony Luck , Joerg Roedel , Greg Kroah-Hartman , "x86@kernel.org" , "linux-kernel@vger.kernel.org" , "linux-pci@vger.kernel.org" , "linux-acpi@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" Subject: Re: [RFC Part4 v1 00/17] Refine support of non-PCI-compliant Message References: <1415545839-28263-1-git-send-email-jiang.liu@linux.intel.com> In-Reply-To: <1415545839-28263-1-git-send-email-jiang.liu@linux.intel.com> X-Enigmail-Version: 1.4.6 X-OriginalArrivalTime: 12 Nov 2014 13:47:39.0630 (UTC) FILETIME=[398430E0:01CFFE7F] X-MC-Unique: 114111213474205601 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org X-Spam-Status: No, score=-7.5 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Hi Jiang, On 09/11/14 15:10, Jiang Liu wrote: > Some interrupt controllers, such as DMAR/HPET/HT_IRQ, work almost in > the same as PCI MSI interrupt controller. And there some devices make > use of PCI MSI mechanism for non-PCI devices on ARm/ARM64 platforms. > > So this patches tries to split PCI MSI code into PCI dependent part > and PCI independent part. The PCI independent part will be used to > support other PCI MSI like interrupt controllers. > > Patch 1-9 are clean ups for previous hierarchy irqdomain patchset > and preparation for coming PCI MSI code reorganization. > Patch 10-15 split PCI MSI code and implement common mechanism to support > other MSI alike interrupt contollers. > Patch 16-17 converts HT_IRQ to use the common MSI support mechanism. [...] I used this patch series (or rather the v2 in your git tree) to rework the GICv3 ITS patch series. So far, the API seems cleaner (fewer global functions, increased flexibility), at the expense of a bit more complexity. One thing is still missing though: the way the MSI stacked domain works at the moment prevents the use of the msi_chip infrastructure (you need to override arch_setup_msi_irqs, which in turn prevents the use of msi_chips using setup_irq/teardown_irq callbacks. On arm/arm64, most MSI controllers are using the latter, while it is likely that the newer ones will be using the stacked domains. My solution to this is to slightly extend the msi_chip framework so that we can hock into the MSI domain framework on a per-msi-chip basis (see patch below). With this in place, I can completely get rid of any arm64-specific code (the msi_chip framework becomes good enough for us): From 5e9157ee7879953f89652d6ad9f296fc0ce6cb87 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Wed, 12 Nov 2014 10:32:46 +0000 Subject: [PATCH v2 02/14] PCI/MSI: Allow an msi_chip to be associated to an irq domain The new MSI stacked domain has the interesting effect that it is quite hard to use if the architecture doesn't provide its own arch_setup_msi_irqs() function to override the default. This inhibates the msi_chip infrastructure introduced in 0cbdcfcf427b (PCI: Introduce new MSI chip infrastructure), as it is not possible to use it as an indirection between the core MSI code and the MSI driver (useful when having multiple MSI controllers that do not share the same requirements). The setup_irq and teardown_irq are rendered useless, as their role is now taken over by the alloc/free functions in the irq domain code. This patch introduces two optionnal fields to the msi_chip structure: - a pointer to an irq domain, describing the MSI domain associated with this msi_chip. To be populated with msi_create_irq_domain. - a domain_alloc_irqs() callback that has the same purpose as arch_setup_msi_irqs(), with the above domain as an additional parameter. If both of these fields are non-NULL, then domain_alloc_irqs() is called, bypassing the setup_irq callback. This allows the MSI driver to use the domain stacking feature without mandating core support in the architecture. Tested on arm64 with the GICv3 ITS. Signed-off-by: Marc Zyngier --- drivers/pci/msi.c | 9 ++++++++- include/linux/msi.h | 5 +++++ 2 files changed, 13 insertions(+), 1 deletion(-) diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c index 6c38306..baefc21 100644 --- a/drivers/pci/msi.c +++ b/drivers/pci/msi.c @@ -63,8 +63,15 @@ int __weak arch_setup_msi_irqs(struct pci_dev *dev, int nvec, int type) /* * If an architecture wants to support multiple MSI, it needs to - * override arch_setup_msi_irqs() + * override arch_setup_msi_irqs(), or provide a way out on a per + * domain basis. */ +#ifdef CONFIG_PCI_MSI_IRQ_DOMAIN + struct msi_chip *chip = dev->bus->msi; + + if (chip->domain && chip->domain_alloc_irqs) + return chip->domain_alloc_irqs(chip->domain, dev, nvec, type); +#endif if (type == PCI_CAP_ID_MSI && nvec > 1) return 1; diff --git a/include/linux/msi.h b/include/linux/msi.h index 0789a4d..7170eea 100644 --- a/include/linux/msi.h +++ b/include/linux/msi.h @@ -110,7 +110,12 @@ struct msi_chip { struct device *dev; struct device_node *of_node; struct list_head list; +#ifdef CONFIG_PCI_MSI_IRQ_DOMAIN + struct irq_domain *domain; + int (*domain_alloc_irqs)(struct irq_domain *domain, + struct pci_dev *pdev, int nvec, int type); +#endif int (*setup_irq)(struct msi_chip *chip, struct pci_dev *dev, struct msi_desc *desc); void (*teardown_irq)(struct msi_chip *chip, unsigned int irq);