| From dhobsong@igel.co.jp Mon Oct 29 00:52:31 2012 |
| From: Damian Hobson-Garcia <dhobsong@igel.co.jp> |
| Date: Mon, 29 Oct 2012 16:50:35 +0900 |
| Subject: [PATCH v2 18/58] common: add dma_mmap_from_coherent() function |
| To: greg@kroah.com, laurent.pinchart@ideasonboard.com, horms@verge.net.au |
| Cc: ltsi-dev@lists.linuxfoundation.org, dhobsong@igel.co.jp |
| Message-ID: <1351497075-32717-19-git-send-email-dhobsong@igel.co.jp> |
| |
| |
| From: Marek Szyprowski <m.szyprowski@samsung.com> |
| |
| Add a common helper for dma-mapping core for mapping a coherent buffer |
| to userspace. |
| |
| Reported-by: Subash Patel <subashrp@gmail.com> |
| Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> |
| Acked-by: Kyungmin Park <kyungmin.park@samsung.com> |
| Tested-By: Subash Patel <subash.ramaswamy@linaro.org> |
| (cherry picked from commit bca0fa5f12a6744a2b2e53154af65a51402b3426) |
| |
| Signed-off-by: Damian Hobson-Garcia <dhobsong@igel.co.jp> |
| Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> |
| --- |
| 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..1b85949 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..abfb268 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 |
| */ |
| -- |
| 1.7.5.4 |
| |