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/*
* Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation
*
* Provide default implementations of the DMA mapping callbacks for
* busses using the iommu infrastructure
*/
#include <linux/export.h>
#include <asm/iommu.h>
/*
* Generic iommu implementation
*/
/* Allocates a contiguous real buffer and creates mappings over it.
* Returns the virtual address of the buffer and sets dma_handle
* to the dma address (mapping) of the first page.
*/
static void *dma_iommu_alloc_coherent(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t flag,
struct dma_attrs *attrs)
{
return iommu_alloc_coherent(dev, get_iommu_table_base(dev), size,
dma_handle, dev->coherent_dma_mask, flag,
dev_to_node(dev));
}
static void dma_iommu_free_coherent(struct device *dev, size_t size,
void *vaddr, dma_addr_t dma_handle,
struct dma_attrs *attrs)
{
iommu_free_coherent(get_iommu_table_base(dev), size, vaddr, dma_handle);
}
/* Creates TCEs for a user provided buffer. The user buffer must be
* contiguous real kernel storage (not vmalloc). The address passed here
* comprises a page address and offset into that page. The dma_addr_t
* returned will point to the same byte within the page as was passed in.
*/
static dma_addr_t dma_iommu_map_page(struct device *dev, struct page *page,
unsigned long offset, size_t size,
enum dma_data_direction direction,
struct dma_attrs *attrs)
{
return iommu_map_page(dev, get_iommu_table_base(dev), page, offset,
size, device_to_mask(dev), direction, attrs);
}
static void dma_iommu_unmap_page(struct device *dev, dma_addr_t dma_handle,
size_t size, enum dma_data_direction direction,
struct dma_attrs *attrs)
{
iommu_unmap_page(get_iommu_table_base(dev), dma_handle, size, direction,
attrs);
}
static int dma_iommu_map_sg(struct device *dev, struct scatterlist *sglist,
int nelems, enum dma_data_direction direction,
struct dma_attrs *attrs)
{
return iommu_map_sg(dev, get_iommu_table_base(dev), sglist, nelems,
device_to_mask(dev), direction, attrs);
}
static void dma_iommu_unmap_sg(struct device *dev, struct scatterlist *sglist,
int nelems, enum dma_data_direction direction,
struct dma_attrs *attrs)
{
iommu_unmap_sg(get_iommu_table_base(dev), sglist, nelems, direction,
attrs);
}
/* We support DMA to/from any memory page via the iommu */
static int dma_iommu_dma_supported(struct device *dev, u64 mask)
{
struct iommu_table *tbl = get_iommu_table_base(dev);
if (!tbl) {
dev_info(dev, "Warning: IOMMU dma not supported: mask 0x%08llx"
", table unavailable\n", mask);
return 0;
}
if (tbl->it_offset > (mask >> IOMMU_PAGE_SHIFT)) {
dev_info(dev, "Warning: IOMMU offset too big for device mask\n");
dev_info(dev, "mask: 0x%08llx, table offset: 0x%08lx\n",
mask, tbl->it_offset << IOMMU_PAGE_SHIFT);
return 0;
} else
return 1;
}
static u64 dma_iommu_get_required_mask(struct device *dev)
{
struct iommu_table *tbl = get_iommu_table_base(dev);
u64 mask;
if (!tbl)
return 0;
mask = 1ULL < (fls_long(tbl->it_offset + tbl->it_size) - 1);
mask += mask - 1;
return mask;
}
struct dma_map_ops dma_iommu_ops = {
.alloc = dma_iommu_alloc_coherent,
.free = dma_iommu_free_coherent,
.mmap = dma_direct_mmap_coherent,
.map_sg = dma_iommu_map_sg,
.unmap_sg = dma_iommu_unmap_sg,
.dma_supported = dma_iommu_dma_supported,
.map_page = dma_iommu_map_page,
.unmap_page = dma_iommu_unmap_page,
.get_required_mask = dma_iommu_get_required_mask,
};
EXPORT_SYMBOL(dma_iommu_ops);
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