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