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