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817820b022
This patch adds the ability to the DMA direct ops to fallback to the IOMMU ops for coherent alloc/free if the coherent mask of the device isn't suitable for accessing the direct DMA space and the device also happens to have an active IOMMU table. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
120 lines
3.5 KiB
C
120 lines
3.5 KiB
C
/*
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* Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation
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*
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* Provide default implementations of the DMA mapping callbacks for
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* busses using the iommu infrastructure
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*/
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#include <linux/export.h>
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#include <asm/iommu.h>
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/*
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* Generic iommu implementation
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*/
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/* Allocates a contiguous real buffer and creates mappings over it.
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* Returns the virtual address of the buffer and sets dma_handle
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* to the dma address (mapping) of the first page.
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*/
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static void *dma_iommu_alloc_coherent(struct device *dev, size_t size,
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dma_addr_t *dma_handle, gfp_t flag,
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struct dma_attrs *attrs)
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{
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return iommu_alloc_coherent(dev, get_iommu_table_base(dev), size,
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dma_handle, dev->coherent_dma_mask, flag,
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dev_to_node(dev));
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}
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static void dma_iommu_free_coherent(struct device *dev, size_t size,
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void *vaddr, dma_addr_t dma_handle,
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struct dma_attrs *attrs)
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{
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iommu_free_coherent(get_iommu_table_base(dev), size, vaddr, dma_handle);
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}
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/* Creates TCEs for a user provided buffer. The user buffer must be
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* contiguous real kernel storage (not vmalloc). The address passed here
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* comprises a page address and offset into that page. The dma_addr_t
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* returned will point to the same byte within the page as was passed in.
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*/
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static dma_addr_t dma_iommu_map_page(struct device *dev, struct page *page,
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unsigned long offset, size_t size,
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enum dma_data_direction direction,
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struct dma_attrs *attrs)
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{
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return iommu_map_page(dev, get_iommu_table_base(dev), page, offset,
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size, device_to_mask(dev), direction, attrs);
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}
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static void dma_iommu_unmap_page(struct device *dev, dma_addr_t dma_handle,
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size_t size, enum dma_data_direction direction,
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struct dma_attrs *attrs)
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{
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iommu_unmap_page(get_iommu_table_base(dev), dma_handle, size, direction,
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attrs);
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}
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static int dma_iommu_map_sg(struct device *dev, struct scatterlist *sglist,
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int nelems, enum dma_data_direction direction,
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struct dma_attrs *attrs)
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{
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return ppc_iommu_map_sg(dev, get_iommu_table_base(dev), sglist, nelems,
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device_to_mask(dev), direction, attrs);
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}
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static void dma_iommu_unmap_sg(struct device *dev, struct scatterlist *sglist,
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int nelems, enum dma_data_direction direction,
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struct dma_attrs *attrs)
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{
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ppc_iommu_unmap_sg(get_iommu_table_base(dev), sglist, nelems,
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direction, attrs);
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}
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/* We support DMA to/from any memory page via the iommu */
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int dma_iommu_dma_supported(struct device *dev, u64 mask)
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{
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struct iommu_table *tbl = get_iommu_table_base(dev);
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if (!tbl) {
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dev_info(dev, "Warning: IOMMU dma not supported: mask 0x%08llx"
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", table unavailable\n", mask);
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return 0;
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}
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if (tbl->it_offset > (mask >> tbl->it_page_shift)) {
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dev_info(dev, "Warning: IOMMU offset too big for device mask\n");
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dev_info(dev, "mask: 0x%08llx, table offset: 0x%08lx\n",
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mask, tbl->it_offset << tbl->it_page_shift);
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return 0;
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} else
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return 1;
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}
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static u64 dma_iommu_get_required_mask(struct device *dev)
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{
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struct iommu_table *tbl = get_iommu_table_base(dev);
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u64 mask;
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if (!tbl)
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return 0;
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mask = 1ULL < (fls_long(tbl->it_offset + tbl->it_size) - 1);
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mask += mask - 1;
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return mask;
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}
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struct dma_map_ops dma_iommu_ops = {
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.alloc = dma_iommu_alloc_coherent,
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.free = dma_iommu_free_coherent,
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.mmap = dma_direct_mmap_coherent,
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.map_sg = dma_iommu_map_sg,
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.unmap_sg = dma_iommu_unmap_sg,
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.dma_supported = dma_iommu_dma_supported,
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.map_page = dma_iommu_map_page,
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.unmap_page = dma_iommu_unmap_page,
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.get_required_mask = dma_iommu_get_required_mask,
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};
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EXPORT_SYMBOL(dma_iommu_ops);
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