From 4ce63fcd919c32d22528e54dcd89506962933719 Mon Sep 17 00:00:00 2001 From: Marek Szyprowski Date: Wed, 16 May 2012 15:48:21 +0200 Subject: ARM: dma-mapping: add support for IOMMU mapper This patch add a complete implementation of DMA-mapping API for devices which have IOMMU support. This implementation tries to optimize dma address space usage by remapping all possible physical memory chunks into a single dma address space chunk. DMA address space is managed on top of the bitmap stored in the dma_iommu_mapping structure stored in device->archdata. Platform setup code has to initialize parameters of the dma address space (base address, size, allocation precision order) with arm_iommu_create_mapping() function. To reduce the size of the bitmap, all allocations are aligned to the specified order of base 4 KiB pages. dma_alloc_* functions allocate physical memory in chunks, each with alloc_pages() function to avoid failing if the physical memory gets fragmented. In worst case the allocated buffer is composed of 4 KiB page chunks. dma_map_sg() function minimizes the total number of dma address space chunks by merging of physical memory chunks into one larger dma address space chunk. If requested chunk (scatter list entry) boundaries match physical page boundaries, most calls to dma_map_sg() requests will result in creating only one chunk in dma address space. dma_map_page() simply creates a mapping for the given page(s) in the dma address space. All dma functions also perform required cache operation like their counterparts from the arm linear physical memory mapping version. This patch contains code and fixes kindly provided by: - Krishna Reddy , - Andrzej Pietrasiewicz , - Hiroshi DOYU Signed-off-by: Marek Szyprowski Acked-by: Kyungmin Park Reviewed-by: Konrad Rzeszutek Wilk Tested-By: Subash Patel --- arch/arm/Kconfig | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'arch/arm/Kconfig') diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index c8111c58a982..97478a5d316f 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -46,6 +46,14 @@ config ARM config ARM_HAS_SG_CHAIN bool +config NEED_SG_DMA_LENGTH + bool + +config ARM_DMA_USE_IOMMU + select NEED_SG_DMA_LENGTH + select ARM_HAS_SG_CHAIN + bool + config HAVE_PWM bool -- cgit v1.2.3