Merge branch 'master' of /home/davem/src/GIT/linux-2.6/
[kernel.git] / arch / microblaze / kernel / dma.c
1 /*
2  * Copyright (C) 2009-2010 PetaLogix
3  * Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corporation
4  *
5  * Provide default implementations of the DMA mapping callbacks for
6  * directly mapped busses.
7  */
8
9 #include <linux/device.h>
10 #include <linux/dma-mapping.h>
11 #include <linux/dma-debug.h>
12 #include <asm/bug.h>
13 #include <asm/cacheflush.h>
14
15 /*
16  * Generic direct DMA implementation
17  *
18  * This implementation supports a per-device offset that can be applied if
19  * the address at which memory is visible to devices is not 0. Platform code
20  * can set archdata.dma_data to an unsigned long holding the offset. By
21  * default the offset is PCI_DRAM_OFFSET.
22  */
23 static inline void __dma_sync_page(unsigned long paddr, unsigned long offset,
24                                 size_t size, enum dma_data_direction direction)
25 {
26         switch (direction) {
27         case DMA_TO_DEVICE:
28                 flush_dcache_range(paddr + offset, paddr + offset + size);
29                 break;
30         case DMA_FROM_DEVICE:
31                 invalidate_dcache_range(paddr + offset, paddr + offset + size);
32                 break;
33         default:
34                 BUG();
35         }
36 }
37
38 static unsigned long get_dma_direct_offset(struct device *dev)
39 {
40         if (likely(dev))
41                 return (unsigned long)dev->archdata.dma_data;
42
43         return PCI_DRAM_OFFSET; /* FIXME Not sure if is correct */
44 }
45
46 #define NOT_COHERENT_CACHE
47
48 static void *dma_direct_alloc_coherent(struct device *dev, size_t size,
49                                 dma_addr_t *dma_handle, gfp_t flag)
50 {
51 #ifdef NOT_COHERENT_CACHE
52         return consistent_alloc(flag, size, dma_handle);
53 #else
54         void *ret;
55         struct page *page;
56         int node = dev_to_node(dev);
57
58         /* ignore region specifiers */
59         flag  &= ~(__GFP_HIGHMEM);
60
61         page = alloc_pages_node(node, flag, get_order(size));
62         if (page == NULL)
63                 return NULL;
64         ret = page_address(page);
65         memset(ret, 0, size);
66         *dma_handle = virt_to_phys(ret) + get_dma_direct_offset(dev);
67
68         return ret;
69 #endif
70 }
71
72 static void dma_direct_free_coherent(struct device *dev, size_t size,
73                               void *vaddr, dma_addr_t dma_handle)
74 {
75 #ifdef NOT_COHERENT_CACHE
76         consistent_free(vaddr);
77 #else
78         free_pages((unsigned long)vaddr, get_order(size));
79 #endif
80 }
81
82 static int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl,
83                              int nents, enum dma_data_direction direction,
84                              struct dma_attrs *attrs)
85 {
86         struct scatterlist *sg;
87         int i;
88
89         /* FIXME this part of code is untested */
90         for_each_sg(sgl, sg, nents, i) {
91                 sg->dma_address = sg_phys(sg) + get_dma_direct_offset(dev);
92                 sg->dma_length = sg->length;
93                 __dma_sync_page(page_to_phys(sg_page(sg)), sg->offset,
94                                                         sg->length, direction);
95         }
96
97         return nents;
98 }
99
100 static void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sg,
101                                 int nents, enum dma_data_direction direction,
102                                 struct dma_attrs *attrs)
103 {
104 }
105
106 static int dma_direct_dma_supported(struct device *dev, u64 mask)
107 {
108         return 1;
109 }
110
111 static inline dma_addr_t dma_direct_map_page(struct device *dev,
112                                              struct page *page,
113                                              unsigned long offset,
114                                              size_t size,
115                                              enum dma_data_direction direction,
116                                              struct dma_attrs *attrs)
117 {
118         __dma_sync_page(page_to_phys(page), offset, size, direction);
119         return page_to_phys(page) + offset + get_dma_direct_offset(dev);
120 }
121
122 static inline void dma_direct_unmap_page(struct device *dev,
123                                          dma_addr_t dma_address,
124                                          size_t size,
125                                          enum dma_data_direction direction,
126                                          struct dma_attrs *attrs)
127 {
128 /* There is not necessary to do cache cleanup
129  *
130  * phys_to_virt is here because in __dma_sync_page is __virt_to_phys and
131  * dma_address is physical address
132  */
133         __dma_sync_page(dma_address, 0 , size, direction);
134 }
135
136 struct dma_map_ops dma_direct_ops = {
137         .alloc_coherent = dma_direct_alloc_coherent,
138         .free_coherent  = dma_direct_free_coherent,
139         .map_sg         = dma_direct_map_sg,
140         .unmap_sg       = dma_direct_unmap_sg,
141         .dma_supported  = dma_direct_dma_supported,
142         .map_page       = dma_direct_map_page,
143         .unmap_page     = dma_direct_unmap_page,
144 };
145 EXPORT_SYMBOL(dma_direct_ops);
146
147 /* Number of entries preallocated for DMA-API debugging */
148 #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
149
150 static int __init dma_init(void)
151 {
152        dma_debug_init(PREALLOC_DMA_DEBUG_ENTRIES);
153
154        return 0;
155 }
156 fs_initcall(dma_init);