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61 lines
1.5 KiB
61 lines
1.5 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* DMA operations that map to virtual addresses without flushing memory. |
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*/ |
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#include <linux/export.h> |
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#include <linux/mm.h> |
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#include <linux/dma-map-ops.h> |
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#include <linux/scatterlist.h> |
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static void *dma_virt_alloc(struct device *dev, size_t size, |
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dma_addr_t *dma_handle, gfp_t gfp, |
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unsigned long attrs) |
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{ |
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void *ret; |
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ret = (void *)__get_free_pages(gfp | __GFP_ZERO, get_order(size)); |
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if (ret) |
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*dma_handle = (uintptr_t)ret; |
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return ret; |
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} |
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static void dma_virt_free(struct device *dev, size_t size, |
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void *cpu_addr, dma_addr_t dma_addr, |
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unsigned long attrs) |
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{ |
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free_pages((unsigned long)cpu_addr, get_order(size)); |
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} |
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static dma_addr_t dma_virt_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 dir, |
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unsigned long attrs) |
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{ |
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return (uintptr_t)(page_address(page) + offset); |
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} |
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static int dma_virt_map_sg(struct device *dev, struct scatterlist *sgl, |
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int nents, enum dma_data_direction dir, |
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unsigned long attrs) |
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{ |
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int i; |
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struct scatterlist *sg; |
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for_each_sg(sgl, sg, nents, i) { |
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BUG_ON(!sg_page(sg)); |
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sg_dma_address(sg) = (uintptr_t)sg_virt(sg); |
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sg_dma_len(sg) = sg->length; |
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} |
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return nents; |
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} |
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const struct dma_map_ops dma_virt_ops = { |
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.alloc = dma_virt_alloc, |
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.free = dma_virt_free, |
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.map_page = dma_virt_map_page, |
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.map_sg = dma_virt_map_sg, |
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.alloc_pages = dma_common_alloc_pages, |
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.free_pages = dma_common_free_pages, |
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}; |
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EXPORT_SYMBOL(dma_virt_ops);
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