From mboxrd@z Thu Jan 1 00:00:00 1970 From: lauraa@codeaurora.org (Laura Abbott) Date: Tue, 11 Mar 2014 11:04:19 -0700 Subject: Query on patch to be upstream ? In-Reply-To: <20140311121500.GH31104@arm.com> Message-ID: <1394561059-29307-1-git-send-email-lauraa@codeaurora.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org With one caveat below, you can add Tested-by: Laura Abbott for "arm64: Implement coherent DMA API based on swiotlb" Thanks, Laura -- 8< -- From: Laura Abbott Date: Thu, 6 Mar 2014 21:05:41 -0800 Subject: [PATCH] arm64: Use custom mmap function for noncoherent dma ops The non-coherent dma ops remap memory with appropriate attributes. This remapped address cannot be used with virt_to_page which dma_common_mmap uses. Implement a custom (but very similar) function which correctly calculates the physical address and remaps to userspace. Signed-off-by: Laura Abbott --- arch/arm64/mm/dma-mapping.c | 27 +++++++++++++++++++++++++++ 1 files changed, 27 insertions(+), 0 deletions(-) diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c index e923a5b..5ac7a14 100644 --- a/arch/arm64/mm/dma-mapping.c +++ b/arch/arm64/mm/dma-mapping.c @@ -194,9 +194,36 @@ static void arm64_swiotlb_sync_sg_for_device(struct device *dev, sg->length, dir); } +int arm64_swiotlb_mmap(struct device *dev, struct vm_area_struct *vma, + void *cpu_addr, dma_addr_t dma_addr, size_t size, + struct dma_attrs *attrs) +{ + int ret = -ENXIO; + unsigned long nr_vma_pages = (vma->vm_end - vma->vm_start) >> + PAGE_SHIFT; + unsigned long nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT; + unsigned long pfn = dma_to_phys(dev, dma_addr) >> PAGE_SHIFT; + unsigned long off = vma->vm_pgoff; + + vma->vm_page_prot = pgprot_dmacoherent(vma->vm_page_prot); + + if (dma_mmap_from_coherent(dev, vma, cpu_addr, size, &ret)) + return ret; + + if (off < nr_pages && nr_vma_pages <= (nr_pages - off)) { + ret = remap_pfn_range(vma, vma->vm_start, + pfn + off, + vma->vm_end - vma->vm_start, + vma->vm_page_prot); + } + + return ret; +} + struct dma_map_ops noncoherent_swiotlb_dma_ops = { .alloc = arm64_swiotlb_alloc_noncoherent, .free = arm64_swiotlb_free_noncoherent, + .mmap = arm64_swiotlb_mmap, .map_page = arm64_swiotlb_map_page, .unmap_page = arm64_swiotlb_unmap_page, .map_sg = arm64_swiotlb_map_sg_attrs, -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by The Linux Foundation