From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751563AbaLRAJa (ORCPT ); Wed, 17 Dec 2014 19:09:30 -0500 Received: from mout.kundenserver.de ([212.227.126.187]:53007 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751030AbaLRAJ2 (ORCPT ); Wed, 17 Dec 2014 19:09:28 -0500 From: Arnd Bergmann To: linux-arm-kernel@lists.infradead.org Cc: Murali Karicheri , vinod.koul@intel.com, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org, linux-pci@vger.kernel.org, bhelgaas@google.com, will.deacon@arm.com, Catalin Marinas Subject: Re: [RFC PATCH 1/2] common: dma-mapping: introduce dma_get_parent_cfg() helper Date: Thu, 18 Dec 2014 01:09:17 +0100 Message-ID: <2935351.ba8Au9y4fE@wuerfel> User-Agent: KMail/4.11.5 (Linux/3.16.0-10-generic; KDE/4.11.5; x86_64; ; ) In-Reply-To: <549210BB.9080603@ti.com> References: <1418839344-14393-1-git-send-email-m-karicheri2@ti.com> <1949667.gMcOLHe7Sk@wuerfel> <549210BB.9080603@ti.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Provags-ID: V03:K0:Yk2CkOKOuzWM0WfH6zyO3l80UYWbjMBm4iuvKP46q5Ft2lSivL1 PLkm3MlDTn9FdG6ThwY6D/6ctGky+mQGqNF8+D0B17EcBbDnK9QXcMiSFze59aHQfsheaSX 60Gl37k/REzeo1ptVYwUeSwjQeKVzJPzqoW0aOjg92cv8hOwtKQIlLfLIdDsCOSHOpMZ/WC +ohdiBZ6OUW4SVRt2kOBw== X-UI-Out-Filterresults: notjunk:1; Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wednesday 17 December 2014 18:24:43 Murali Karicheri wrote: > On 12/17/2014 04:56 PM, Arnd Bergmann wrote: > > On Wednesday 17 December 2014 13:02:23 Murali Karicheri wrote: > > > > What's wrong with using arch_setup_dma_ops() from PCI as suggested > > previously? > > +Will Deacon > I had originally written a code based on that line as below. But > dma-ranges property is also used by ppc and other architectures in the > pci device DT node. So I wasn't sure how this code impact PCI driver > functionality on those platforms. Hence used a simpler change as all > that is needed for keystone is to get the dma_pfn_offset rightly set in > the pci slave device. But in your patch, you don't call arch_setup_dma_ops() at all. > Initially I had a function implemented as below for this in of_pci.c. > > + * of_pci_dma_configure - Setup DMA configuration for a pci device > + * @dev: pci device to apply DMA configuration > + * > + * Try to get devices's DMA configuration from DT and update it > + * accordingly. This is a similar to of_dma_configure() for platform > + * devices. > + * > + */ > +void of_pci_dma_configure(struct pci_dev *dev) > +{ > + struct device *host_bridge, *parent; > + struct pci_bus *bus = dev->bus; > + u64 dma_addr, paddr, size; > + int ret; > + > + while (!pci_is_root_bus(bus)) > + bus = bus->parent; > + host_bridge = bus->bridge; > + > + parent = host_bridge->parent; > + if (parent->of_node) { so far it looks good, although we may want to introduce a helper function to get the of_node. > + /* > + * if dma-coherent property exist, call arch hook to setup > + * dma coherent operations. > + */ > + if (of_dma_is_coherent(parent->of_node)) { > + set_arch_dma_coherent_ops(&dev->dev); > + dev_info(&dev->dev, "device is dma coherent\n"); > + } set_arch_dma_coherent_ops no longer exists. Just keep the flag in a local variable > + /* > + * if dma-ranges property doesn't exist - just return else > + * setup the dma offset > + */ > + ret = of_dma_get_range(parent->of_node, &dma_addr, > &paddr, &size); > + if (ret < 0) { > + dev_info(&dev->dev, "no dma range information to > setup\n"); > + printk("no dma range information to setup\n"); > + return; > + } > + > + /* DMA ranges found. Calculate and set dma_pfn_offset */ > + dev->dev.dma_pfn_offset = PFN_DOWN(paddr - dma_addr); > + dev_info(&dev->dev, "dma_pfn_offset(%#08lx)\n", > dev->dev.dma_pfn_offset); Same for the offset and size here, then pass all of the above into arch_setup_dma_ops. This is also where we need to hook up the iommu support once we decide how to make that work with the ARM SMMU. Will, I think we may have a problem on ARM64 now, since we only replaced set_arch_dma_coherent_ops on ARM32 but not ARM64. Can you send a fix for this? Without that, we don't have any coherent operations on ARM64 any more, unless I'm missing something. Arnd