From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936214AbdGTNtD (ORCPT ); Thu, 20 Jul 2017 09:49:03 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:54306 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750860AbdGTNtC (ORCPT ); Thu, 20 Jul 2017 09:49:02 -0400 Subject: Re: [PATCH 2/2] ARM: NOMMU: Wire-up default DMA interface To: Vladimir Murzin , linux-kernel@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org, linux@armlinux.org.uk, sza@esh.hu, arnd@arndb.de, gregkh@linuxfoundation.org, akpm@linux-foundation.org, alexandre.torgue@st.com, kbuild-all@01.org, benjamin.gaignard@linaro.org, hch@lst.de, m.szyprowski@samsung.com, vitaly_kuzmichev@mentor.com, george_davis@mentor.com References: <1500545999-17177-1-git-send-email-vladimir.murzin@arm.com> <1500545999-17177-3-git-send-email-vladimir.murzin@arm.com> From: Robin Murphy Message-ID: <3872d014-7782-eac1-29ce-098d7e70ae07@arm.com> Date: Thu, 20 Jul 2017 14:48:58 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 MIME-Version: 1.0 In-Reply-To: <1500545999-17177-3-git-send-email-vladimir.murzin@arm.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 20/07/17 11:19, Vladimir Murzin wrote: > The way how default DMA pool is exposed has changed and now we need to > use dedicated interface to work with it. This patch makes alloc/release > operations to use such interface. Since, default DMA pool is not > handled by generic code anymore we have to implement our own mmap > operation. > > Tested-by: Andras Szemzo > Signed-off-by: Vladimir Murzin Looks like the right thing to do :) Reviewed-by: Robin Murphy > --- > arch/arm/mm/dma-mapping-nommu.c | 45 ++++++++++++++++++++++++++++++++--------- > 1 file changed, 36 insertions(+), 9 deletions(-) > > diff --git a/arch/arm/mm/dma-mapping-nommu.c b/arch/arm/mm/dma-mapping-nommu.c > index 90ee354..6db5fc2 100644 > --- a/arch/arm/mm/dma-mapping-nommu.c > +++ b/arch/arm/mm/dma-mapping-nommu.c > @@ -40,9 +40,21 @@ static void *arm_nommu_dma_alloc(struct device *dev, size_t size, > > { > const struct dma_map_ops *ops = &dma_noop_ops; > + void *ret; > > /* > - * We are here because: > + * Try generic allocator first if we are advertised that > + * consistency is not required. > + */ > + > + if (attrs & DMA_ATTR_NON_CONSISTENT) > + return ops->alloc(dev, size, dma_handle, gfp, attrs); > + > + ret = dma_alloc_from_global_coherent(size, dma_handle); > + > + /* > + * dma_alloc_from_global_coherent() may fail because: > + * > * - no consistent DMA region has been defined, so we can't > * continue. > * - there is no space left in consistent DMA region, so we > @@ -50,11 +62,8 @@ static void *arm_nommu_dma_alloc(struct device *dev, size_t size, > * advertised that consistency is not required. > */ > > - if (attrs & DMA_ATTR_NON_CONSISTENT) > - return ops->alloc(dev, size, dma_handle, gfp, attrs); > - > - WARN_ON_ONCE(1); > - return NULL; > + WARN_ON_ONCE(ret == NULL); > + return ret; > } > > static void arm_nommu_dma_free(struct device *dev, size_t size, > @@ -63,14 +72,31 @@ static void arm_nommu_dma_free(struct device *dev, size_t size, > { > const struct dma_map_ops *ops = &dma_noop_ops; > > - if (attrs & DMA_ATTR_NON_CONSISTENT) > + if (attrs & DMA_ATTR_NON_CONSISTENT) { > ops->free(dev, size, cpu_addr, dma_addr, attrs); > - else > - WARN_ON_ONCE(1); > + } else { > + int ret = dma_release_from_global_coherent(get_order(size), > + cpu_addr); > + > + WARN_ON_ONCE(ret == 0); > + } > > return; > } > > +static int arm_nommu_dma_mmap(struct device *dev, struct vm_area_struct *vma, > + void *cpu_addr, dma_addr_t dma_addr, size_t size, > + unsigned long attrs) > +{ > + int ret; > + > + if (dma_mmap_from_global_coherent(vma, cpu_addr, size, &ret)) > + return ret; > + > + return dma_common_mmap(dev, vma, cpu_addr, dma_addr, size); > +} > + > + > static void __dma_page_cpu_to_dev(phys_addr_t paddr, size_t size, > enum dma_data_direction dir) > { > @@ -173,6 +199,7 @@ static void arm_nommu_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist > const struct dma_map_ops arm_nommu_dma_ops = { > .alloc = arm_nommu_dma_alloc, > .free = arm_nommu_dma_free, > + .mmap = arm_nommu_dma_mmap, > .map_page = arm_nommu_dma_map_page, > .unmap_page = arm_nommu_dma_unmap_page, > .map_sg = arm_nommu_dma_map_sg, >