1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Dynamic DMA mapping support.
4 *
5 * On cris there is no hardware dynamic DMA address translation,
6 * so consistent alloc/free are merely page allocation/freeing.
7 * The rest of the dynamic DMA mapping interface is implemented
8 * in asm/pci.h.
9 *
10 * Borrowed from i386.
11 */
12
13 #include <linux/types.h>
14 #include <linux/mm.h>
15 #include <linux/string.h>
16 #include <linux/pci.h>
17 #include <linux/gfp.h>
18 #include <asm/io.h>
19
v32_dma_alloc(struct device * dev,size_t size,dma_addr_t * dma_handle,gfp_t gfp,unsigned long attrs)20 static void *v32_dma_alloc(struct device *dev, size_t size,
21 dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
22 {
23 void *ret;
24
25 /* ignore region specifiers */
26 gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);
27
28 if (dev == NULL || (dev->coherent_dma_mask < 0xffffffff))
29 gfp |= GFP_DMA;
30
31 ret = (void *)__get_free_pages(gfp, get_order(size));
32
33 if (ret != NULL) {
34 memset(ret, 0, size);
35 *dma_handle = virt_to_phys(ret);
36 }
37 return ret;
38 }
39
v32_dma_free(struct device * dev,size_t size,void * vaddr,dma_addr_t dma_handle,unsigned long attrs)40 static void v32_dma_free(struct device *dev, size_t size, void *vaddr,
41 dma_addr_t dma_handle, unsigned long attrs)
42 {
43 free_pages((unsigned long)vaddr, get_order(size));
44 }
45
v32_dma_map_page(struct device * dev,struct page * page,unsigned long offset,size_t size,enum dma_data_direction direction,unsigned long attrs)46 static inline dma_addr_t v32_dma_map_page(struct device *dev,
47 struct page *page, unsigned long offset, size_t size,
48 enum dma_data_direction direction, unsigned long attrs)
49 {
50 return page_to_phys(page) + offset;
51 }
52
v32_dma_map_sg(struct device * dev,struct scatterlist * sg,int nents,enum dma_data_direction direction,unsigned long attrs)53 static inline int v32_dma_map_sg(struct device *dev, struct scatterlist *sg,
54 int nents, enum dma_data_direction direction,
55 unsigned long attrs)
56 {
57 printk("Map sg\n");
58 return nents;
59 }
60
v32_dma_supported(struct device * dev,u64 mask)61 static inline int v32_dma_supported(struct device *dev, u64 mask)
62 {
63 /*
64 * we fall back to GFP_DMA when the mask isn't all 1s,
65 * so we can't guarantee allocations that must be
66 * within a tighter range than GFP_DMA..
67 */
68 if (mask < 0x00ffffff)
69 return 0;
70 return 1;
71 }
72
73 const struct dma_map_ops v32_dma_ops = {
74 .alloc = v32_dma_alloc,
75 .free = v32_dma_free,
76 .map_page = v32_dma_map_page,
77 .map_sg = v32_dma_map_sg,
78 .dma_supported = v32_dma_supported,
79 };
80 EXPORT_SYMBOL(v32_dma_ops);
81