generic: per-device coherent dma allocator
[linux-2.6.git] / kernel / dma-coherent.c
1 /*
2  * Coherent per-device memory handling.
3  * Borrowed from i386
4  */
5 #include <linux/kernel.h>
6 #include <linux/dma-mapping.h>
7
8 struct dma_coherent_mem {
9         void            *virt_base;
10         u32             device_base;
11         int             size;
12         int             flags;
13         unsigned long   *bitmap;
14 };
15
16 int dma_declare_coherent_memory(struct device *dev, dma_addr_t bus_addr,
17                                 dma_addr_t device_addr, size_t size, int flags)
18 {
19         void __iomem *mem_base = NULL;
20         int pages = size >> PAGE_SHIFT;
21         int bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
22
23         if ((flags & (DMA_MEMORY_MAP | DMA_MEMORY_IO)) == 0)
24                 goto out;
25         if (!size)
26                 goto out;
27         if (dev->dma_mem)
28                 goto out;
29
30         /* FIXME: this routine just ignores DMA_MEMORY_INCLUDES_CHILDREN */
31
32         mem_base = ioremap(bus_addr, size);
33         if (!mem_base)
34                 goto out;
35
36         dev->dma_mem = kzalloc(sizeof(struct dma_coherent_mem), GFP_KERNEL);
37         if (!dev->dma_mem)
38                 goto out;
39         dev->dma_mem->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
40         if (!dev->dma_mem->bitmap)
41                 goto free1_out;
42
43         dev->dma_mem->virt_base = mem_base;
44         dev->dma_mem->device_base = device_addr;
45         dev->dma_mem->size = pages;
46         dev->dma_mem->flags = flags;
47
48         if (flags & DMA_MEMORY_MAP)
49                 return DMA_MEMORY_MAP;
50
51         return DMA_MEMORY_IO;
52
53  free1_out:
54         kfree(dev->dma_mem);
55  out:
56         if (mem_base)
57                 iounmap(mem_base);
58         return 0;
59 }
60 EXPORT_SYMBOL(dma_declare_coherent_memory);
61
62 void dma_release_declared_memory(struct device *dev)
63 {
64         struct dma_coherent_mem *mem = dev->dma_mem;
65
66         if (!mem)
67                 return;
68         dev->dma_mem = NULL;
69         iounmap(mem->virt_base);
70         kfree(mem->bitmap);
71         kfree(mem);
72 }
73 EXPORT_SYMBOL(dma_release_declared_memory);
74
75 void *dma_mark_declared_memory_occupied(struct device *dev,
76                                         dma_addr_t device_addr, size_t size)
77 {
78         struct dma_coherent_mem *mem = dev->dma_mem;
79         int pos, err;
80         int pages = (size + (device_addr & ~PAGE_MASK) + PAGE_SIZE - 1);
81
82         pages >>= PAGE_SHIFT;
83
84         if (!mem)
85                 return ERR_PTR(-EINVAL);
86
87         pos = (device_addr - mem->device_base) >> PAGE_SHIFT;
88         err = bitmap_allocate_region(mem->bitmap, pos, get_order(pages));
89         if (err != 0)
90                 return ERR_PTR(err);
91         return mem->virt_base + (pos << PAGE_SHIFT);
92 }
93 EXPORT_SYMBOL(dma_mark_declared_memory_occupied);
94
95 int dma_alloc_from_coherent(struct device *dev, ssize_t size,
96                                        dma_addr_t *dma_handle, void **ret)
97 {
98         struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
99         int order = get_order(size);
100
101         if (mem) {
102                 int page = bitmap_find_free_region(mem->bitmap, mem->size,
103                                                      order);
104                 if (page >= 0) {
105                         *dma_handle = mem->device_base + (page << PAGE_SHIFT);
106                         *ret = mem->virt_base + (page << PAGE_SHIFT);
107                         memset(*ret, 0, size);
108                 }
109                 if (mem->flags & DMA_MEMORY_EXCLUSIVE)
110                         *ret = NULL;
111         }
112         return (mem != NULL);
113 }
114
115 int dma_release_from_coherent(struct device *dev, int order, void *vaddr)
116 {
117         struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
118
119         if (mem && vaddr >= mem->virt_base && vaddr <
120                    (mem->virt_base + (mem->size << PAGE_SHIFT))) {
121                 int page = (vaddr - mem->virt_base) >> PAGE_SHIFT;
122
123                 bitmap_release_region(mem->bitmap, page, order);
124                 return 1;
125         }
126         return 0;
127 }