From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx164.postini.com [74.125.245.164]) by kanga.kvack.org (Postfix) with SMTP id 29CA66B0092 for ; Fri, 23 Mar 2012 08:26:12 -0400 (EDT) MIME-version: 1.0 Content-transfer-encoding: 7BIT Content-type: TEXT/PLAIN Received: from euspt1 ([210.118.77.14]) by mailout4.w1.samsung.com (Sun Java(tm) System Messaging Server 6.3-8.04 (built Jul 29 2009; 32bit)) with ESMTP id <0M1C00D127VOV050@mailout4.w1.samsung.com> for linux-mm@kvack.org; Fri, 23 Mar 2012 12:26:12 +0000 (GMT) Received: from linux.samsung.com ([106.116.38.10]) by spt1.w1.samsung.com (iPlanet Messaging Server 5.2 Patch 2 (built Jul 14 2004)) with ESMTPA id <0M1C00MBR7VLND@spt1.w1.samsung.com> for linux-mm@kvack.org; Fri, 23 Mar 2012 12:26:10 +0000 (GMT) Date: Fri, 23 Mar 2012 13:26:02 +0100 From: Marek Szyprowski Subject: [PATCH 1/2] common: add dma_mmap_from_coherent() function In-reply-to: <1332505563-17646-1-git-send-email-m.szyprowski@samsung.com> Message-id: <1332505563-17646-2-git-send-email-m.szyprowski@samsung.com> References: <08af01cd08ee$2fd04770$8f70d650$%szyprowski@samsung.com> <1332505563-17646-1-git-send-email-m.szyprowski@samsung.com> Sender: owner-linux-mm@kvack.org List-ID: To: linux-arm-kernel@lists.infradead.org, linaro-mm-sig@lists.linaro.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-samsung-soc@vger.kernel.org, iommu@lists.linux-foundation.org Cc: Marek Szyprowski , Kyungmin Park , Arnd Bergmann , Joerg Roedel , Russell King - ARM Linux , Chunsang Jeong , Krishna Reddy , KyongHo Cho , Andrzej Pietrasiewicz , Benjamin Herrenschmidt , Konrad Rzeszutek Wilk , Hiroshi Doyu , Subash Patel Add a common helper for dma-mapping core for mapping a coherent buffer to userspace. Signed-off-by: Marek Szyprowski --- drivers/base/dma-coherent.c | 42 ++++++++++++++++++++++++++++++++++++ include/asm-generic/dma-coherent.h | 4 ++- 2 files changed, 45 insertions(+), 1 deletions(-) diff --git a/drivers/base/dma-coherent.c b/drivers/base/dma-coherent.c index bb0025c..ef5ae05 100644 --- a/drivers/base/dma-coherent.c +++ b/drivers/base/dma-coherent.c @@ -10,6 +10,7 @@ struct dma_coherent_mem { void *virt_base; dma_addr_t device_base; + phys_addr_t pfn_base; int size; int flags; unsigned long *bitmap; @@ -44,6 +45,7 @@ int dma_declare_coherent_memory(struct device *dev, dma_addr_t bus_addr, dev->dma_mem->virt_base = mem_base; dev->dma_mem->device_base = device_addr; + dev->dma_mem->pfn_base = PFN_DOWN(bus_addr); dev->dma_mem->size = pages; dev->dma_mem->flags = flags; @@ -176,3 +178,43 @@ int dma_release_from_coherent(struct device *dev, int order, void *vaddr) return 0; } EXPORT_SYMBOL(dma_release_from_coherent); + +/** + * dma_mmap_from_coherent() - try to mmap the memory allocated from + * per-device coherent memory pool to userspace + * @dev: device from which the memory was allocated + * @vma: vm_area for the userspace memory + * @vaddr: cpu address returned by dma_alloc_from_coherent + * @size: size of the memory buffer allocated by dma_alloc_from_coherent + * + * This checks whether the memory was allocated from the per-device + * coherent memory pool and if so, maps that memory to the provided vma. + * + * Returns 1 if we correctly mapped the memory, or 0 if + * dma_release_coherent() should proceed with mapping memory from + * generic pools. + */ +int dma_mmap_from_coherent(struct device *dev, struct vm_area_struct *vma, + void *vaddr, size_t size, int *ret) +{ + struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL; + + if (mem && vaddr >= mem->virt_base && vaddr + size <= + (mem->virt_base + (mem->size << PAGE_SHIFT))) { + unsigned long off = vma->vm_pgoff; + int start = (vaddr - mem->virt_base) >> PAGE_SHIFT; + int user_count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; + int count = size >> PAGE_SHIFT; + + *ret = -ENXIO; + if (off < count && user_count <= count - off) { + unsigned pfn = mem->pfn_base + start + off; + *ret = remap_pfn_range(vma, vma->vm_start, pfn, + user_count << PAGE_SHIFT, + vma->vm_page_prot); + } + return 1; + } + return 0; +} +EXPORT_SYMBOL(dma_mmap_from_coherent); diff --git a/include/asm-generic/dma-coherent.h b/include/asm-generic/dma-coherent.h index 85a3ffa..b82051d 100644 --- a/include/asm-generic/dma-coherent.h +++ b/include/asm-generic/dma-coherent.h @@ -3,13 +3,15 @@ #ifdef CONFIG_HAVE_GENERIC_DMA_COHERENT /* - * These two functions are only for dma allocator. + * These three functions are only for dma allocator. * Don't use them in device drivers. */ int dma_alloc_from_coherent(struct device *dev, ssize_t size, dma_addr_t *dma_handle, void **ret); int dma_release_from_coherent(struct device *dev, int order, void *vaddr); +int dma_mmap_from_coherent(struct device *dev, struct vm_area_struct *vma, + void *cpu_addr, size_t size, int *ret); /* * Standard interface */ -- 1.7.1.569.g6f426 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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