From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andreas Herrmann Subject: [PATCH 3/9] ARM: dma-mapping: Always pass proper prot flags to iommu_map() Date: Fri, 27 Sep 2013 00:36:15 +0200 Message-ID: <1380234982-1677-4-git-send-email-andreas.herrmann@calxeda.com> References: <1380234982-1677-1-git-send-email-andreas.herrmann@calxeda.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1380234982-1677-1-git-send-email-andreas.herrmann-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Will Deacon Cc: Andreas Herrmann , iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, Rob Herring , linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: iommu@lists.linux-foundation.org ... otherwise it is impossible for the low level iommu driver to figure out which pte flags should be used. In __map_sg_chunk we can derive the flags from dma_data_direction. In __iommu_create_mapping we should treat the memory like DMA_BIDIRECTIONAL and pass both IOMMU_READ and IOMMU_WRITE to iommu_map. __iommu_create_mapping is used during dma_alloc_coherent (via arm_iommu_alloc_attrs). AFAIK dma_alloc_coherent is responsible for allocation _and_ mapping. I think this implies that access to the mapped pages should be allowed. Cc: Marek Szyprowski Signed-off-by: Andreas Herrmann --- arch/arm/mm/dma-mapping.c | 43 ++++++++++++++++++++++++++++--------------- 1 file changed, 28 insertions(+), 15 deletions(-) diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c index f5e1a84..1272ed2 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -1232,7 +1232,8 @@ __iommu_create_mapping(struct device *dev, struct page **pages, size_t size) break; len = (j - i) << PAGE_SHIFT; - ret = iommu_map(mapping->domain, iova, phys, len, 0); + ret = iommu_map(mapping->domain, iova, phys, len, + IOMMU_READ|IOMMU_WRITE); if (ret < 0) goto fail; iova += len; @@ -1431,6 +1432,27 @@ static int arm_iommu_get_sgtable(struct device *dev, struct sg_table *sgt, GFP_KERNEL); } +static int __dma_direction_to_prot(enum dma_data_direction dir) +{ + int prot; + + switch (dir) { + case DMA_BIDIRECTIONAL: + prot = IOMMU_READ | IOMMU_WRITE; + break; + case DMA_TO_DEVICE: + prot = IOMMU_READ; + break; + case DMA_FROM_DEVICE: + prot = IOMMU_WRITE; + break; + default: + prot = 0; + } + + return prot; +} + /* * Map a part of the scatter-gather list into contiguous io address space */ @@ -1444,6 +1466,7 @@ static int __map_sg_chunk(struct device *dev, struct scatterlist *sg, int ret = 0; unsigned int count; struct scatterlist *s; + int prot; size = PAGE_ALIGN(size); *handle = DMA_ERROR_CODE; @@ -1460,7 +1483,9 @@ static int __map_sg_chunk(struct device *dev, struct scatterlist *sg, !dma_get_attr(DMA_ATTR_SKIP_CPU_SYNC, attrs)) __dma_page_cpu_to_dev(sg_page(s), s->offset, s->length, dir); - ret = iommu_map(mapping->domain, iova, phys, len, 0); + prot = __dma_direction_to_prot(dir); + + ret = iommu_map(mapping->domain, iova, phys, len, prot); if (ret < 0) goto fail; count += len >> PAGE_SHIFT; @@ -1665,19 +1690,7 @@ static dma_addr_t arm_coherent_iommu_map_page(struct device *dev, struct page *p if (dma_addr == DMA_ERROR_CODE) return dma_addr; - switch (dir) { - case DMA_BIDIRECTIONAL: - prot = IOMMU_READ | IOMMU_WRITE; - break; - case DMA_TO_DEVICE: - prot = IOMMU_READ; - break; - case DMA_FROM_DEVICE: - prot = IOMMU_WRITE; - break; - default: - prot = 0; - } + prot = __dma_direction_to_prot(dir); ret = iommu_map(mapping->domain, dma_addr, page_to_phys(page), len, prot); if (ret < 0) -- 1.7.9.5