Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752646AbcDOQcF (ORCPT ); Fri, 15 Apr 2016 12:32:05 -0400 Received: from foss.arm.com ([217.140.101.70]:50812 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751285AbcDOQcD (ORCPT ); Fri, 15 Apr 2016 12:32:03 -0400 Subject: Re: [RFC PATCH 09/11] drivers: acpi: implement acpi_dma_configure To: Bjorn Helgaas , Lorenzo Pieralisi References: <1460654743-7896-1-git-send-email-lorenzo.pieralisi@arm.com> <1460654743-7896-10-git-send-email-lorenzo.pieralisi@arm.com> <20160415161400.GC7973@localhost> Cc: Marc Zyngier , Tomasz Nowicki , "Rafael J. Wysocki" , linux-kernel@vger.kernel.org, Will Deacon , linux-pci@vger.kernel.org, Sinan Kaya , linux-acpi@vger.kernel.org, iommu@lists.linux-foundation.org, Hanjun Guo , Jon Masters , Bjorn Helgaas , linux-arm-kernel@lists.infradead.org From: Robin Murphy Message-ID: <5711177E.2000509@arm.com> Date: Fri, 15 Apr 2016 17:31:58 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: <20160415161400.GC7973@localhost> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4077 Lines: 114 Hi Bjorn, On 15/04/16 17:14, Bjorn Helgaas wrote: > On Thu, Apr 14, 2016 at 06:25:41PM +0100, Lorenzo Pieralisi wrote: >> On DT based systems, the of_dma_configure() API implements DMA configuration >> for a given device. On ACPI systems an API equivalent to of_dma_configure() >> is missing which implies that it is currently not possible to set-up DMA >> operations for devices through the ACPI generic kernel layer. >> >> This patch fills the gap by introducing acpi_dma_configure/deconfigure() >> calls, that carry out IOMMU configuration through IORT (on systems where >> it is present) and call arch_setup_dma_ops(...) with the retrieved >> parameters. >> >> The DMA range size passed to arch_setup_dma_ops() is sized according >> to the device coherent_dma_mask (starting at address 0x0), mirroring the >> DT probing path behaviour when a dma-ranges property is not provided >> for the device being probed; this changes the current arch_setup_dma_ops() >> call parameters in the ACPI probing case, but since arch_setup_dma_ops() >> is a NOP on all architectures but ARM/ARM64 this patch does not change >> the current kernel behaviour on them. >> >> This patch updates ACPI and PCI core code to use the newly introduced >> acpi_dma_configure function, providing the same functionality >> as of_dma_configure on ARM systems and leaving behaviour unchanged >> for all other arches. >> >> Signed-off-by: Lorenzo Pieralisi >> Cc: Bjorn Helgaas >> Cc: Robin Murphy >> Cc: Tomasz Nowicki >> Cc: Joerg Roedel >> Cc: "Rafael J. Wysocki" > > There's only a tiny PCI change in this series, so I assume somebody > else will merge all this. Here's my ack for the PCI part: > > Acked-by: Bjorn Helgaas # for drivers/pci/probe.c change > > One question on use of pci_for_each_dma_alias() below. > >> +static int __get_pci_rid(struct pci_dev *pdev, u16 alias, void *data) >> +{ >> + u32 *rid = data; >> + >> + *rid = alias; >> + return 0; >> +} >> + >> +/** >> + * iort_iommu_configure - Set-up IOMMU configuration for a device. >> + * >> + * @dev: device that requires IOMMU set-up >> + * >> + * Returns: iommu_ops pointer on configuration success >> + * NULL on configuration failure >> + */ >> +struct iommu_ops *iort_iommu_configure(struct device *dev) >> +{ >> + struct acpi_iort_node *node, *parent; >> + struct iommu_ops *ops = NULL; >> + struct iommu_fwspec fwspec; >> + struct iort_iommu_node *iommu_node; >> + u32 rid = 0, devid = 0; >> + >> + if (dev_is_pci(dev)) { >> + struct pci_bus *bus = to_pci_dev(dev)->bus; >> + >> + pci_for_each_dma_alias(to_pci_dev(dev), __get_pci_rid, >> + &rid); > > You end up with only the last DMA alias in "rid". Is it really true > that you only need to call iort_dev_map_rid() for one of the aliases? Indeed - all we care about is what things look like by the time they come out of the root complex on their way to the the IOMMU, so whatever intermediate aliasing _within_ the PCI bus might happen along the way doesn't actually matter. Robin. >> + node = iort_scan_node(ACPI_IORT_NODE_PCI_ROOT_COMPLEX, >> + iort_find_dev_callback, &bus->dev); >> + } else >> + node = iort_scan_node(ACPI_IORT_NODE_NAMED_COMPONENT, >> + iort_find_dev_callback, dev); >> + >> + if (!node) >> + return NULL; >> + >> + iort_dev_map_rid(node, rid, &devid, ACPI_IORT_NODE_SMMU); >> + >> + parent = iort_find_parent_node(node, ACPI_IORT_NODE_SMMU); >> + >> + if (!parent) >> + return NULL; >> + >> + iommu_node = iort_iommu_get_node(parent); >> + ops = iommu_node->ops; >> + >> + fwspec.fwnode = iommu_node->fwnode; >> + fwspec.param_count = 1; >> + fwspec.param[0] = devid; >> + >> + if (!ops || !ops->fw_xlate || ops->fw_xlate(dev, &fwspec)) >> + return NULL; >> + >> + return ops; >> +} > _______________________________________________ > iommu mailing list > iommu@lists.linux-foundation.org > https://lists.linuxfoundation.org/mailman/listinfo/iommu >