Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
[linux-2.6] / arch / powerpc / kernel / dma.c
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
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
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
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
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
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
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
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
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
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
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);