1 /*
2 * Dynamic DMA mapping support.
3 *
4 * We never have any address translations to worry about, so this
5 * is just alloc/free.
6 */
7
8 #include <linux/types.h>
9 #include <linux/gfp.h>
10 #include <linux/mm.h>
11 #include <linux/device.h>
12 #include <linux/dma-mapping.h>
13 #include <linux/export.h>
14 #include <asm/cacheflush.h>
15
dma_alloc_coherent(struct device * dev,size_t size,dma_addr_t * dma_handle,gfp_t gfp)16 void *dma_alloc_coherent(struct device *dev, size_t size,
17 dma_addr_t *dma_handle, gfp_t gfp)
18 {
19 void *ret;
20 /* ignore region specifiers */
21 gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);
22
23 if (dev == NULL || (*dev->dma_mask < 0xffffffff))
24 gfp |= GFP_DMA;
25 ret = (void *)__get_free_pages(gfp, get_order(size));
26
27 if (ret != NULL) {
28 memset(ret, 0, size);
29 *dma_handle = virt_to_phys(ret);
30 }
31 return ret;
32 }
33
dma_free_coherent(struct device * dev,size_t size,void * vaddr,dma_addr_t dma_handle)34 void dma_free_coherent(struct device *dev, size_t size,
35 void *vaddr, dma_addr_t dma_handle)
36 {
37 free_pages((unsigned long)vaddr, get_order(size));
38 }
39
dma_sync_single_for_device(struct device * dev,dma_addr_t handle,size_t size,enum dma_data_direction dir)40 void dma_sync_single_for_device(struct device *dev, dma_addr_t handle,
41 size_t size, enum dma_data_direction dir)
42 {
43 switch (dir) {
44 case DMA_TO_DEVICE:
45 flush_dcache_range(handle, size);
46 break;
47 case DMA_FROM_DEVICE:
48 /* Should be clear already */
49 break;
50 default:
51 if (printk_ratelimit())
52 printk("dma_sync_single_for_device: unsupported dir %u\n", dir);
53 break;
54 }
55 }
56
57 EXPORT_SYMBOL(dma_sync_single_for_device);
dma_map_single(struct device * dev,void * addr,size_t size,enum dma_data_direction dir)58 dma_addr_t dma_map_single(struct device *dev, void *addr, size_t size,
59 enum dma_data_direction dir)
60 {
61 dma_addr_t handle = virt_to_phys(addr);
62 flush_dcache_range(handle, size);
63 return handle;
64 }
65 EXPORT_SYMBOL(dma_map_single);
66
dma_map_page(struct device * dev,struct page * page,unsigned long offset,size_t size,enum dma_data_direction dir)67 dma_addr_t dma_map_page(struct device *dev, struct page *page,
68 unsigned long offset, size_t size,
69 enum dma_data_direction dir)
70 {
71 dma_addr_t handle = page_to_phys(page) + offset;
72 dma_sync_single_for_device(dev, handle, size, dir);
73 return handle;
74 }
75 EXPORT_SYMBOL(dma_map_page);
76