// 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> /* * 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 = virt_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;} /* * 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;	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(virt_to_page(cpu_addr)) + vma->vm_pgoff,			user_count << PAGE_SHIFT, vma->vm_page_prot);#else	return -ENXIO;#endif /* CONFIG_MMU */} 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);}