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