Merge branch 'for-linus' of git://git.o-hand.com/linux-rpurdie-backlight
[linux-2.6] / arch / powerpc / kernel / dma_64.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 and busses using the iommu infrastructure
6  */
7
8 #include <linux/device.h>
9 #include <linux/dma-mapping.h>
10 #include <asm/bug.h>
11 #include <asm/iommu.h>
12 #include <asm/abs_addr.h>
13
14 /*
15  * Generic iommu implementation
16  */
17
18 static inline unsigned long device_to_mask(struct device *dev)
19 {
20         if (dev->dma_mask && *dev->dma_mask)
21                 return *dev->dma_mask;
22         /* Assume devices without mask can take 32 bit addresses */
23         return 0xfffffffful;
24 }
25
26
27 /* Allocates a contiguous real buffer and creates mappings over it.
28  * Returns the virtual address of the buffer and sets dma_handle
29  * to the dma address (mapping) of the first page.
30  */
31 static void *dma_iommu_alloc_coherent(struct device *dev, size_t size,
32                                       dma_addr_t *dma_handle, gfp_t flag)
33 {
34         return iommu_alloc_coherent(dev->archdata.dma_data, size, dma_handle,
35                                     device_to_mask(dev), flag,
36                                     dev->archdata.numa_node);
37 }
38
39 static void dma_iommu_free_coherent(struct device *dev, size_t size,
40                                     void *vaddr, dma_addr_t dma_handle)
41 {
42         iommu_free_coherent(dev->archdata.dma_data, size, vaddr, dma_handle);
43 }
44
45 /* Creates TCEs for a user provided buffer.  The user buffer must be
46  * contiguous real kernel storage (not vmalloc).  The address of the buffer
47  * passed here is the kernel (virtual) address of the buffer.  The buffer
48  * need not be page aligned, the dma_addr_t returned will point to the same
49  * byte within the page as vaddr.
50  */
51 static dma_addr_t dma_iommu_map_single(struct device *dev, void *vaddr,
52                                        size_t size,
53                                        enum dma_data_direction direction)
54 {
55         return iommu_map_single(dev->archdata.dma_data, vaddr, size,
56                                 device_to_mask(dev), direction);
57 }
58
59
60 static void dma_iommu_unmap_single(struct device *dev, dma_addr_t dma_handle,
61                                    size_t size,
62                                    enum dma_data_direction direction)
63 {
64         iommu_unmap_single(dev->archdata.dma_data, dma_handle, size, direction);
65 }
66
67
68 static int dma_iommu_map_sg(struct device *dev, struct scatterlist *sglist,
69                             int nelems, enum dma_data_direction direction)
70 {
71         return iommu_map_sg(dev->archdata.dma_data, sglist, nelems,
72                             device_to_mask(dev), direction);
73 }
74
75 static void dma_iommu_unmap_sg(struct device *dev, struct scatterlist *sglist,
76                 int nelems, enum dma_data_direction direction)
77 {
78         iommu_unmap_sg(dev->archdata.dma_data, sglist, nelems, direction);
79 }
80
81 /* We support DMA to/from any memory page via the iommu */
82 static int dma_iommu_dma_supported(struct device *dev, u64 mask)
83 {
84         struct iommu_table *tbl = dev->archdata.dma_data;
85
86         if (!tbl || tbl->it_offset > mask) {
87                 printk(KERN_INFO
88                        "Warning: IOMMU offset too big for device mask\n");
89                 if (tbl)
90                         printk(KERN_INFO
91                                "mask: 0x%08lx, table offset: 0x%08lx\n",
92                                 mask, tbl->it_offset);
93                 else
94                         printk(KERN_INFO "mask: 0x%08lx, table unavailable\n",
95                                 mask);
96                 return 0;
97         } else
98                 return 1;
99 }
100
101 struct dma_mapping_ops dma_iommu_ops = {
102         .alloc_coherent = dma_iommu_alloc_coherent,
103         .free_coherent  = dma_iommu_free_coherent,
104         .map_single     = dma_iommu_map_single,
105         .unmap_single   = dma_iommu_unmap_single,
106         .map_sg         = dma_iommu_map_sg,
107         .unmap_sg       = dma_iommu_unmap_sg,
108         .dma_supported  = dma_iommu_dma_supported,
109 };
110 EXPORT_SYMBOL(dma_iommu_ops);
111
112 /*
113  * Generic direct DMA implementation
114  *
115  * This implementation supports a global offset that can be applied if
116  * the address at which memory is visible to devices is not 0.
117  */
118 unsigned long dma_direct_offset;
119
120 static void *dma_direct_alloc_coherent(struct device *dev, size_t size,
121                                        dma_addr_t *dma_handle, gfp_t flag)
122 {
123         struct page *page;
124         void *ret;
125         int node = dev->archdata.numa_node;
126
127         /* TODO: Maybe use the numa node here too ? */
128         page = alloc_pages_node(node, flag, get_order(size));
129         if (page == NULL)
130                 return NULL;
131         ret = page_address(page);
132         memset(ret, 0, size);
133         *dma_handle = virt_to_abs(ret) | dma_direct_offset;
134
135         return ret;
136 }
137
138 static void dma_direct_free_coherent(struct device *dev, size_t size,
139                                      void *vaddr, dma_addr_t dma_handle)
140 {
141         free_pages((unsigned long)vaddr, get_order(size));
142 }
143
144 static dma_addr_t dma_direct_map_single(struct device *dev, void *ptr,
145                                         size_t size,
146                                         enum dma_data_direction direction)
147 {
148         return virt_to_abs(ptr) | dma_direct_offset;
149 }
150
151 static void dma_direct_unmap_single(struct device *dev, dma_addr_t dma_addr,
152                                     size_t size,
153                                     enum dma_data_direction direction)
154 {
155 }
156
157 static int dma_direct_map_sg(struct device *dev, struct scatterlist *sg,
158                              int nents, enum dma_data_direction direction)
159 {
160         int i;
161
162         for (i = 0; i < nents; i++, sg++) {
163                 sg->dma_address = (page_to_phys(sg->page) + sg->offset) |
164                         dma_direct_offset;
165                 sg->dma_length = sg->length;
166         }
167
168         return nents;
169 }
170
171 static void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sg,
172                                 int nents, enum dma_data_direction direction)
173 {
174 }
175
176 static int dma_direct_dma_supported(struct device *dev, u64 mask)
177 {
178         /* Could be improved to check for memory though it better be
179          * done via some global so platforms can set the limit in case
180          * they have limited DMA windows
181          */
182         return mask >= DMA_32BIT_MASK;
183 }
184
185 struct dma_mapping_ops dma_direct_ops = {
186         .alloc_coherent = dma_direct_alloc_coherent,
187         .free_coherent  = dma_direct_free_coherent,
188         .map_single     = dma_direct_map_single,
189         .unmap_single   = dma_direct_unmap_single,
190         .map_sg         = dma_direct_map_sg,
191         .unmap_sg       = dma_direct_unmap_sg,
192         .dma_supported  = dma_direct_dma_supported,
193 };
194 EXPORT_SYMBOL(dma_direct_ops);