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
81 size += device_addr & ~PAGE_MASK;
82
83 if (!mem)
84 return ERR_PTR(-EINVAL);
85
86 pos = (device_addr - mem->device_base) >> PAGE_SHIFT;
87 err = bitmap_allocate_region(mem->bitmap, pos, get_order(size));
88 if (err != 0)
89 return ERR_PTR(err);
90 return mem->virt_base + (pos << PAGE_SHIFT);
91 }
92 EXPORT_SYMBOL(dma_mark_declared_memory_occupied);
93
94 /**
95 * dma_alloc_from_coherent() - try to allocate memory from the per-device coherent area
96 *
97 * @dev: device from which we allocate memory
98 * @size: size of requested memory area
99 * @dma_handle: This will be filled with the correct dma handle
100 * @ret: This pointer will be filled with the virtual address
101 * to allocated area.
102 *
103 * This function should be only called from per-arch dma_alloc_coherent()
104 * to support allocation from per-device coherent memory pools.
105 *
106 * Returns 0 if dma_alloc_coherent should continue with allocating from
107 * generic memory areas, or !0 if dma_alloc_coherent should return @ret.
108 */
109 int dma_alloc_from_coherent(struct device *dev, ssize_t size,
110 dma_addr_t *dma_handle, void **ret)
111 {
112 struct dma_coherent_mem *mem;
113 int order = get_order(size);
114 int pageno;
115
116 if (!dev)
117 return 0;
118 mem = dev->dma_mem;
119 if (!mem)
120 return 0;
121
122 *ret = NULL;
123
124 if (unlikely(size > (mem->size << PAGE_SHIFT)))
125 goto err;
126
127 pageno = bitmap_find_free_region(mem->bitmap, mem->size, order);
128 if (unlikely(pageno < 0))
129 goto err;
130
131 /*
132 * Memory was found in the per-device area.
133 */
134 *dma_handle = mem->device_base + (pageno << PAGE_SHIFT);
135 *ret = mem->virt_base + (pageno << PAGE_SHIFT);
136 memset(*ret, 0, size);
137
138 return 1;
139
140 err:
141 /*
142 * In the case where the allocation can not be satisfied from the
143 * per-device area, try to fall back to generic memory if the
144 * constraints allow it.
145 */
146 return mem->flags & DMA_MEMORY_EXCLUSIVE;
147 }
148 EXPORT_SYMBOL(dma_alloc_from_coherent);
149
150 /**
151 * dma_release_from_coherent() - try to free the memory allocated from per-device coherent memory pool
152 * @dev: device from which the memory was allocated
153 * @order: the order of pages allocated
154 * @vaddr: virtual address of allocated pages
155 *
156 * This checks whether the memory was allocated from the per-device
157 * coherent memory pool and if so, releases that memory.
158 *
159 * Returns 1 if we correctly released the memory, or 0 if
160 * dma_release_coherent() should proceed with releasing memory from
161 * generic pools.
162 */
163 int dma_release_from_coherent(struct device *dev, int order, void *vaddr)
164 {
165 struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
166
167 if (mem && vaddr >= mem->virt_base && vaddr <
168 (mem->virt_base + (mem->size << PAGE_SHIFT))) {
169 int page = (vaddr - mem->virt_base) >> PAGE_SHIFT;
170
171 bitmap_release_region(mem->bitmap, page, order);
172 return 1;
173 }
174 return 0;
175 }
176 EXPORT_SYMBOL(dma_release_from_coherent);
177
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