/* * lib/dma-noop.c * * DMA operations that map to physical addresses without flushing memory. */ #include <linux/export.h> #include <linux/mm.h> #include <linux/dma-mapping.h> #include <linux/scatterlist.h> static void *dma_noop_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 = virt_to_phys(ret); return ret; } static void dma_noop_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_noop_map_page(struct device *dev, struct page *page, unsigned long offset, size_t size, enum dma_data_direction dir, unsigned long attrs) { return page_to_phys(page) + offset; } static int dma_noop_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) { void *va; BUG_ON(!sg_page(sg)); va = sg_virt(sg); sg_dma_address(sg) = (dma_addr_t)virt_to_phys(va); sg_dma_len(sg) = sg->length; } return nents; } static int dma_noop_mapping_error(struct device *dev, dma_addr_t dma_addr) { return 0; } static int dma_noop_supported(struct device *dev, u64 mask) { return 1; } const struct dma_map_ops dma_noop_ops = { .alloc = dma_noop_alloc, .free = dma_noop_free, .map_page = dma_noop_map_page, .map_sg = dma_noop_map_sg, .mapping_error = dma_noop_mapping_error, .dma_supported = dma_noop_supported, }; EXPORT_SYMBOL(dma_noop_ops);