From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756671AbbAPTKi (ORCPT ); Fri, 16 Jan 2015 14:10:38 -0500 Received: from foss-mx-na.foss.arm.com ([217.140.108.86]:36575 "EHLO foss-mx-na.foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753380AbbAPTKh (ORCPT ); Fri, 16 Jan 2015 14:10:37 -0500 Message-ID: <54B9621E.5080209@arm.com> Date: Fri, 16 Jan 2015 19:10:22 +0000 From: Marc Zyngier User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Icedove/31.3.0 MIME-Version: 1.0 To: Stuart Yoder CC: Bjorn Helgaas , Thomas Gleixner , Jiang Liu , "linux-arm-kernel@lists.infradead.org" , "linux-pci@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Yijing Wang , "suravee.suthikulpanit@amd.com" Subject: Re: [PATCH v2 1/8] device core: Introduce per-device MSI domain pointer References: <1420736772-11088-1-git-send-email-marc.zyngier@arm.com> <1420736772-11088-2-git-send-email-marc.zyngier@arm.com> In-Reply-To: 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 Hi Stuart, On 15/01/15 20:35, Stuart Yoder wrote: > On Thu, Jan 8, 2015 at 11:06 AM, Marc Zyngier wrote: >> As MSI-type features are creeping into non-PCI devices, it is >> starting to make sense to give our struct device some form of >> support for this, by allowing a pointer to an MSI irq domain to >> be set/retrieved. >> >> Signed-off-by: Marc Zyngier >> --- >> include/linux/device.h | 20 ++++++++++++++++++++ >> 1 file changed, 20 insertions(+) >> >> diff --git a/include/linux/device.h b/include/linux/device.h >> index fb50673..ec4cee5 100644 >> --- a/include/linux/device.h >> +++ b/include/linux/device.h >> @@ -690,6 +690,7 @@ struct acpi_dev_node { >> * along with subsystem-level and driver-level callbacks. >> * @pins: For device pin management. >> * See Documentation/pinctrl.txt for details. >> + * @msi_domain: The generic MSI domain this device is using. >> * @numa_node: NUMA node this device is close to. >> * @dma_mask: Dma mask (if dma'ble device). >> * @coherent_dma_mask: Like dma_mask, but for alloc_coherent mapping as not all >> @@ -750,6 +751,9 @@ struct device { >> struct dev_pm_info power; >> struct dev_pm_domain *pm_domain; >> >> +#ifdef CONFIG_GENERIC_MSI_IRQ_DOMAIN >> + struct irq_domain *msi_domain; /* MSI domain device uses */ >> +#endif > > This is not a comment on this patch specifically, but a question about other > MSI specific fields that might be needed in struct device. > > Currently the generic MSI domain handling has hardcoded assumptions > that devices are PCI-- see the for_each_msi_entry() iterator in msi.h: > > #define dev_to_msi_list(dev) (&to_pci_dev((dev))->msi_list) > > #define for_each_msi_entry(desc, dev) \ > list_for_each_entry((desc), dev_to_msi_list((dev)), list) > > One approach would be to move the msi_list out of pci_dev and put > it in struct device, so all devices can have an msi_list. > > The other approach would be to keep msi_list in a bus specific > device struct, and then dev_to_msi_list() would need to be > implemented as a bus specific callback of some kind. > > The above hardcoded PCI assumption isn't going to work. Wanted to > see if there is any advice in which direction to go. The question is: can we define a generic msi_desc? If yes, then your first proposal make sense. If not, then it is the second one. My hunch is that we'll have to move to a model that would look like this: struct mybus_msi_desc { struct msi_desc desc; struct mybus_stuff stuff; }; and move the PCI-specific stuff out of msi_desc. Thoughts? M. -- Jazz is not dead. It just smells funny...