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authorMarek Szyprowski <m.szyprowski@samsung.com>2012-05-16 15:48:21 +0200
committerMarek Szyprowski <m.szyprowski@samsung.com>2012-05-21 15:06:23 +0200
commit4ce63fcd919c32d22528e54dcd89506962933719 (patch)
tree648f7681a5c89209b627e8c3e899d953ed38685d /arch/arm/include/asm
parentf99d60341238fe73fc514129cd9ae4e44e1b2c47 (diff)
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 <vdumpa@nvidia.com>, - Andrzej Pietrasiewicz <andrzej.p@samsung.com>, - Hiroshi DOYU <hdoyu@nvidia.com> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Acked-by: Kyungmin Park <kyungmin.park@samsung.com> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Tested-By: Subash Patel <subash.ramaswamy@linaro.org>
Diffstat (limited to 'arch/arm/include/asm')
-rw-r--r--arch/arm/include/asm/device.h3
-rw-r--r--arch/arm/include/asm/dma-iommu.h34
2 files changed, 37 insertions, 0 deletions
diff --git a/arch/arm/include/asm/device.h b/arch/arm/include/asm/device.h
index 6e2cb0ee770..b69c0d3285f 100644
--- a/arch/arm/include/asm/device.h
+++ b/arch/arm/include/asm/device.h
@@ -14,6 +14,9 @@ struct dev_archdata {
#ifdef CONFIG_IOMMU_API
void *iommu; /* private IOMMU data */
#endif
+#ifdef CONFIG_ARM_DMA_USE_IOMMU
+ struct dma_iommu_mapping *mapping;
+#endif
};
struct omap_device;
diff --git a/arch/arm/include/asm/dma-iommu.h b/arch/arm/include/asm/dma-iommu.h
new file mode 100644
index 00000000000..799b09409fa
--- /dev/null
+++ b/arch/arm/include/asm/dma-iommu.h
@@ -0,0 +1,34 @@
+#ifndef ASMARM_DMA_IOMMU_H
+#define ASMARM_DMA_IOMMU_H
+
+#ifdef __KERNEL__
+
+#include <linux/mm_types.h>
+#include <linux/scatterlist.h>
+#include <linux/dma-debug.h>
+#include <linux/kmemcheck.h>
+
+struct dma_iommu_mapping {
+ /* iommu specific data */
+ struct iommu_domain *domain;
+
+ void *bitmap;
+ size_t bits;
+ unsigned int order;
+ dma_addr_t base;
+
+ spinlock_t lock;
+ struct kref kref;
+};
+
+struct dma_iommu_mapping *
+arm_iommu_create_mapping(struct bus_type *bus, dma_addr_t base, size_t size,
+ int order);
+
+void arm_iommu_release_mapping(struct dma_iommu_mapping *mapping);
+
+int arm_iommu_attach_device(struct device *dev,
+ struct dma_iommu_mapping *mapping);
+
+#endif /* __KERNEL__ */
+#endif