1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Dummy DMA ops that always fail.
4 */
5 #include <linux/dma-map-ops.h>
6
dma_dummy_mmap(struct device * dev,struct vm_area_struct * vma,void * cpu_addr,dma_addr_t dma_addr,size_t size,unsigned long attrs)7 static int dma_dummy_mmap(struct device *dev, struct vm_area_struct *vma,
8 void *cpu_addr, dma_addr_t dma_addr, size_t size,
9 unsigned long attrs)
10 {
11 return -ENXIO;
12 }
13
dma_dummy_map_phys(struct device * dev,phys_addr_t phys,size_t size,enum dma_data_direction dir,unsigned long attrs)14 static dma_addr_t dma_dummy_map_phys(struct device *dev, phys_addr_t phys,
15 size_t size, enum dma_data_direction dir, unsigned long attrs)
16 {
17 return DMA_MAPPING_ERROR;
18 }
dma_dummy_unmap_phys(struct device * dev,dma_addr_t dma_handle,size_t size,enum dma_data_direction dir,unsigned long attrs)19 static void dma_dummy_unmap_phys(struct device *dev, dma_addr_t dma_handle,
20 size_t size, enum dma_data_direction dir, unsigned long attrs)
21 {
22 /*
23 * Dummy ops doesn't support map_phys, so unmap_page should never be
24 * called.
25 */
26 WARN_ON_ONCE(true);
27 }
28
dma_dummy_map_sg(struct device * dev,struct scatterlist * sgl,int nelems,enum dma_data_direction dir,unsigned long attrs)29 static int dma_dummy_map_sg(struct device *dev, struct scatterlist *sgl,
30 int nelems, enum dma_data_direction dir,
31 unsigned long attrs)
32 {
33 return -EINVAL;
34 }
35
dma_dummy_unmap_sg(struct device * dev,struct scatterlist * sgl,int nelems,enum dma_data_direction dir,unsigned long attrs)36 static void dma_dummy_unmap_sg(struct device *dev, struct scatterlist *sgl,
37 int nelems, enum dma_data_direction dir,
38 unsigned long attrs)
39 {
40 /*
41 * Dummy ops doesn't support map_sg, so unmap_sg should never be called.
42 */
43 WARN_ON_ONCE(true);
44 }
45
dma_dummy_supported(struct device * hwdev,u64 mask)46 static int dma_dummy_supported(struct device *hwdev, u64 mask)
47 {
48 return 0;
49 }
50
51 const struct dma_map_ops dma_dummy_ops = {
52 .mmap = dma_dummy_mmap,
53 .map_phys = dma_dummy_map_phys,
54 .unmap_phys = dma_dummy_unmap_phys,
55 .map_sg = dma_dummy_map_sg,
56 .unmap_sg = dma_dummy_unmap_sg,
57 .dma_supported = dma_dummy_supported,
58 };
59