From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753780AbcDUWpl (ORCPT ); Thu, 21 Apr 2016 18:45:41 -0400 Received: from mail-oi0-f42.google.com ([209.85.218.42]:34327 "EHLO mail-oi0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751871AbcDUWpj (ORCPT ); Thu, 21 Apr 2016 18:45:39 -0400 MIME-Version: 1.0 In-Reply-To: <1460654743-7896-10-git-send-email-lorenzo.pieralisi@arm.com> References: <1460654743-7896-1-git-send-email-lorenzo.pieralisi@arm.com> <1460654743-7896-10-git-send-email-lorenzo.pieralisi@arm.com> Date: Fri, 22 Apr 2016 01:45:38 +0300 Message-ID: Subject: Re: [RFC PATCH 09/11] drivers: acpi: implement acpi_dma_configure From: Andy Shevchenko To: Lorenzo Pieralisi Cc: iommu@lists.linux-foundation.org, Bjorn Helgaas , Robin Murphy , Tomasz Nowicki , Joerg Roedel , "Rafael J. Wysocki" , Will Deacon , Marc Zyngier , Hanjun Guo , Jon Masters , Sinan Kaya , "linux-acpi@vger.kernel.org" , "linux-pci@vger.kernel.org" , "linux-kernel@vger.kernel.org" , linux-arm Mailing List Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 14, 2016 at 8:25 PM, 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. > Nitpicks below. > --- a/drivers/acpi/iort.c > +++ b/drivers/acpi/iort.c > @@ -72,6 +72,31 @@ int iort_iommu_set_node(struct iommu_ops *ops, struct acpi_iort_node *node, > return 0; > } > > +/** > + * iort_iommu_get_node - Retrieve iort_iommu_node associated with an IORT node. > + * > + * @node: IORT table node to be looked-up > + * > + * Returns: iort_iommu_node pointer on success > + * NULL on failure > + */ > +static struct iort_iommu_node *iort_iommu_get_node(struct acpi_iort_node *node) > +{ > + struct iort_iommu_node *iommu_node; > + > + spin_lock(&iort_iommu_lock); > + list_for_each_entry(iommu_node, &iort_iommu_list, list) { > + if (iommu_node->node == node) > + goto found; > + } > + > + iommu_node = NULL; > +found: > + spin_unlock(&iort_iommu_lock); > + > + return iommu_node; Ouch, and why not to strut iommu_node = NULL; lock list for each() { if () break; } unlock return iommu_node; ? > +} > +/** > + * 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); > + > + node = iort_scan_node(ACPI_IORT_NODE_PCI_ROOT_COMPLEX, > + iort_find_dev_callback, &bus->dev); > + } else checkpatch.pl ? > + 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); > + Redundant. > + 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; > +} > + -- With Best Regards, Andy Shevchenko