1 /*
2 * Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation
3 *
4 * Provide default implementations of the DMA mapping callbacks for
5 * directly mapped busses.
6 */
7
8 #include <linux/device.h>
9 #include <linux/dma-mapping.h>
10 #include <asm/bug.h>
11 #include <asm/abs_addr.h>
12
13 /*
14 * Generic direct DMA implementation
15 *
16 * This implementation supports a per-device offset that can be applied if
17 * the address at which memory is visible to devices is not 0. Platform code
18 * can set archdata.dma_data to an unsigned long holding the offset. By
19 * default the offset is PCI_DRAM_OFFSET.
20 */
21
get_dma_direct_offset(struct device * dev)22 static unsigned long get_dma_direct_offset(struct device *dev)
23 {
24 if (dev)
25 return (unsigned long)dev->archdata.dma_data;
26
27 return PCI_DRAM_OFFSET;
28 }
29
dma_direct_alloc_coherent(struct device * dev,size_t size,dma_addr_t * dma_handle,gfp_t flag)30 void *dma_direct_alloc_coherent(struct device *dev, size_t size,
31 dma_addr_t *dma_handle, gfp_t flag)
32 {
33 void *ret;
34 #ifdef CONFIG_NOT_COHERENT_CACHE
35 ret = __dma_alloc_coherent(size, dma_handle, flag);
36 if (ret == NULL)
37 return NULL;
38 *dma_handle += get_dma_direct_offset(dev);
39 return ret;
40 #else
41 struct page *page;
42 int node = dev_to_node(dev);
43
44 /* ignore region specifiers */
45 flag &= ~(__GFP_HIGHMEM);
46
47 page = alloc_pages_node(node, flag, get_order(size));
48 if (page == NULL)
49 return NULL;
50 ret = page_address(page);
51 memset(ret, 0, size);
52 *dma_handle = virt_to_abs(ret) + get_dma_direct_offset(dev);
53
54 return ret;
55 #endif
56 }
57
dma_direct_free_coherent(struct device * dev,size_t size,void * vaddr,dma_addr_t dma_handle)58 void dma_direct_free_coherent(struct device *dev, size_t size,
59 void *vaddr, dma_addr_t dma_handle)
60 {
61 #ifdef CONFIG_NOT_COHERENT_CACHE
62 __dma_free_coherent(size, vaddr);
63 #else
64 free_pages((unsigned long)vaddr, get_order(size));
65 #endif
66 }
67
dma_direct_map_sg(struct device * dev,struct scatterlist * sgl,int nents,enum dma_data_direction direction,struct dma_attrs * attrs)68 static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl,
69 int nents, enum dma_data_direction direction,
70 struct dma_attrs *attrs)
71 {
72 struct scatterlist *sg;
73 int i;
74
75 for_each_sg(sgl, sg, nents, i) {
76 sg->dma_address = sg_phys(sg) + get_dma_direct_offset(dev);
77 sg->dma_length = sg->length;
78 __dma_sync_page(sg_page(sg), sg->offset, sg->length, direction);
79 }
80
81 return nents;
82 }
83
dma_direct_unmap_sg(struct device * dev,struct scatterlist * sg,int nents,enum dma_data_direction direction,struct dma_attrs * attrs)84 static void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sg,
85 int nents, enum dma_data_direction direction,
86 struct dma_attrs *attrs)
87 {
88 }
89
dma_direct_dma_supported(struct device * dev,u64 mask)90 static int dma_direct_dma_supported(struct device *dev, u64 mask)
91 {
92 #ifdef CONFIG_PPC64
93 /* Could be improved to check for memory though it better be
94 * done via some global so platforms can set the limit in case
95 * they have limited DMA windows
96 */
97 return mask >= DMA_32BIT_MASK;
98 #else
99 return 1;
100 #endif
101 }
102
dma_direct_map_page(struct device * dev,struct page * page,unsigned long offset,size_t size,enum dma_data_direction dir,struct dma_attrs * attrs)103 static inline dma_addr_t dma_direct_map_page(struct device *dev,
104 struct page *page,
105 unsigned long offset,
106 size_t size,
107 enum dma_data_direction dir,
108 struct dma_attrs *attrs)
109 {
110 BUG_ON(dir == DMA_NONE);
111 __dma_sync_page(page, offset, size, dir);
112 return page_to_phys(page) + offset + get_dma_direct_offset(dev);
113 }
114
dma_direct_unmap_page(struct device * dev,dma_addr_t dma_address,size_t size,enum dma_data_direction direction,struct dma_attrs * attrs)115 static inline void dma_direct_unmap_page(struct device *dev,
116 dma_addr_t dma_address,
117 size_t size,
118 enum dma_data_direction direction,
119 struct dma_attrs *attrs)
120 {
121 }
122
123 #ifdef CONFIG_NOT_COHERENT_CACHE
dma_direct_sync_sg(struct device * dev,struct scatterlist * sgl,int nents,enum dma_data_direction direction)124 static inline void dma_direct_sync_sg(struct device *dev,
125 struct scatterlist *sgl, int nents,
126 enum dma_data_direction direction)
127 {
128 struct scatterlist *sg;
129 int i;
130
131 for_each_sg(sgl, sg, nents, i)
132 __dma_sync_page(sg_page(sg), sg->offset, sg->length, direction);
133 }
134
dma_direct_sync_single_range(struct device * dev,dma_addr_t dma_handle,unsigned long offset,size_t size,enum dma_data_direction direction)135 static inline void dma_direct_sync_single_range(struct device *dev,
136 dma_addr_t dma_handle, unsigned long offset, size_t size,
137 enum dma_data_direction direction)
138 {
139 __dma_sync(bus_to_virt(dma_handle+offset), size, direction);
140 }
141 #endif
142
143 struct dma_mapping_ops dma_direct_ops = {
144 .alloc_coherent = dma_direct_alloc_coherent,
145 .free_coherent = dma_direct_free_coherent,
146 .map_sg = dma_direct_map_sg,
147 .unmap_sg = dma_direct_unmap_sg,
148 .dma_supported = dma_direct_dma_supported,
149 .map_page = dma_direct_map_page,
150 .unmap_page = dma_direct_unmap_page,
151 #ifdef CONFIG_NOT_COHERENT_CACHE
152 .sync_single_range_for_cpu = dma_direct_sync_single_range,
153 .sync_single_range_for_device = dma_direct_sync_single_range,
154 .sync_sg_for_cpu = dma_direct_sync_sg,
155 .sync_sg_for_device = dma_direct_sync_sg,
156 #endif
157 };
158 EXPORT_SYMBOL(dma_direct_ops);
159