1/*
 2 *	lib/dma-noop.c
 3 *
 4 * Simple DMA noop-ops that map 1:1 with memory
 5 */
 6#include <linux/export.h>
 7#include <linux/mm.h>
 8#include <linux/dma-mapping.h>
 9#include <linux/scatterlist.h>
10
11static void *dma_noop_alloc(struct device *dev, size_t size,
12			    dma_addr_t *dma_handle, gfp_t gfp,
13			    unsigned long attrs)
14{
15	void *ret;
16
17	ret = (void *)__get_free_pages(gfp, get_order(size));
18	if (ret)
19		*dma_handle = virt_to_phys(ret);
20	return ret;
21}
22
23static void dma_noop_free(struct device *dev, size_t size,
24			  void *cpu_addr, dma_addr_t dma_addr,
25			  unsigned long attrs)
26{
27	free_pages((unsigned long)cpu_addr, get_order(size));
28}
29
30static dma_addr_t dma_noop_map_page(struct device *dev, struct page *page,
31				      unsigned long offset, size_t size,
32				      enum dma_data_direction dir,
33				      unsigned long attrs)
34{
35	return page_to_phys(page) + offset;
36}
37
38static int dma_noop_map_sg(struct device *dev, struct scatterlist *sgl, int nents,
39			     enum dma_data_direction dir,
40			     unsigned long attrs)
41{
42	int i;
43	struct scatterlist *sg;
44
45	for_each_sg(sgl, sg, nents, i) {
46		void *va;
47
48		BUG_ON(!sg_page(sg));
49		va = sg_virt(sg);
50		sg_dma_address(sg) = (dma_addr_t)virt_to_phys(va);
51		sg_dma_len(sg) = sg->length;
52	}
53
54	return nents;
55}
56
57static int dma_noop_mapping_error(struct device *dev, dma_addr_t dma_addr)
58{
59	return 0;
60}
61
62static int dma_noop_supported(struct device *dev, u64 mask)
63{
64	return 1;
65}
66
67struct dma_map_ops dma_noop_ops = {
68	.alloc			= dma_noop_alloc,
69	.free			= dma_noop_free,
70	.map_page		= dma_noop_map_page,
71	.map_sg			= dma_noop_map_sg,
72	.mapping_error		= dma_noop_mapping_error,
73	.dma_supported		= dma_noop_supported,
74};
75
76EXPORT_SYMBOL(dma_noop_ops);