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93 lines
2.5 KiB
93 lines
2.5 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Helpers for DMA ops implementations. These generally rely on the fact that |
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* the allocated memory contains normal pages in the direct kernel mapping. |
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*/ |
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#include <linux/dma-map-ops.h> |
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static struct page *dma_common_vaddr_to_page(void *cpu_addr) |
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{ |
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if (is_vmalloc_addr(cpu_addr)) |
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return vmalloc_to_page(cpu_addr); |
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return virt_to_page(cpu_addr); |
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} |
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/* |
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* Create scatter-list for the already allocated DMA buffer. |
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*/ |
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int dma_common_get_sgtable(struct device *dev, struct sg_table *sgt, |
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void *cpu_addr, dma_addr_t dma_addr, size_t size, |
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unsigned long attrs) |
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{ |
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struct page *page = dma_common_vaddr_to_page(cpu_addr); |
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int ret; |
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ret = sg_alloc_table(sgt, 1, GFP_KERNEL); |
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if (!ret) |
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sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0); |
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return ret; |
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} |
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/* |
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* Create userspace mapping for the DMA-coherent memory. |
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*/ |
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int dma_common_mmap(struct device *dev, struct vm_area_struct *vma, |
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void *cpu_addr, dma_addr_t dma_addr, size_t size, |
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unsigned long attrs) |
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{ |
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#ifdef CONFIG_MMU |
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unsigned long user_count = vma_pages(vma); |
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unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT; |
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unsigned long off = vma->vm_pgoff; |
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struct page *page = dma_common_vaddr_to_page(cpu_addr); |
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int ret = -ENXIO; |
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vma->vm_page_prot = dma_pgprot(dev, vma->vm_page_prot, attrs); |
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if (dma_mmap_from_dev_coherent(dev, vma, cpu_addr, size, &ret)) |
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return ret; |
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if (off >= count || user_count > count - off) |
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return -ENXIO; |
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return remap_pfn_range(vma, vma->vm_start, |
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page_to_pfn(page) + vma->vm_pgoff, |
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user_count << PAGE_SHIFT, vma->vm_page_prot); |
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#else |
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return -ENXIO; |
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#endif /* CONFIG_MMU */ |
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} |
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struct page *dma_common_alloc_pages(struct device *dev, size_t size, |
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dma_addr_t *dma_handle, enum dma_data_direction dir, gfp_t gfp) |
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{ |
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const struct dma_map_ops *ops = get_dma_ops(dev); |
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struct page *page; |
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page = dma_alloc_contiguous(dev, size, gfp); |
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if (!page) |
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page = alloc_pages_node(dev_to_node(dev), gfp, get_order(size)); |
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if (!page) |
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return NULL; |
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*dma_handle = ops->map_page(dev, page, 0, size, dir, |
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DMA_ATTR_SKIP_CPU_SYNC); |
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if (*dma_handle == DMA_MAPPING_ERROR) { |
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dma_free_contiguous(dev, page, size); |
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return NULL; |
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} |
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memset(page_address(page), 0, size); |
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return page; |
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} |
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void dma_common_free_pages(struct device *dev, size_t size, struct page *page, |
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dma_addr_t dma_handle, enum dma_data_direction dir) |
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{ |
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const struct dma_map_ops *ops = get_dma_ops(dev); |
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if (ops->unmap_page) |
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ops->unmap_page(dev, dma_handle, size, dir, |
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DMA_ATTR_SKIP_CPU_SYNC); |
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dma_free_contiguous(dev, page, size); |
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}
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