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review.evervolv.com / android_kernel_htc_msm8960 / 538c29d43ebdac2edcef96ac07982d2296a63077 / . / kernel / dma-coherent.c
blob: 56dff5cb0f2901a186c8b3ba59a57cdcd9135f23 [file] [log] [blame]
Dmitry Baryshkovee7e5512008-06-29 14:18:46 +0400[diff] [blame]1/*
2 * Coherent per-device memory handling.
3 * Borrowed from i386
4 */
5#include <linux/kernel.h>
6#include <linux/dma-mapping.h>
7
8struct dma_coherent_mem {
9 void *virt_base;
10 u32 device_base;
11 int size;
12 int flags;
13 unsigned long *bitmap;
14};
15
16int 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}
60EXPORT_SYMBOL(dma_declare_coherent_memory);
61
62void 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}
73EXPORT_SYMBOL(dma_release_declared_memory);
74
75void *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}
93EXPORT_SYMBOL(dma_mark_declared_memory_occupied);
94
95int 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);
Dmitry Baryshkov538c29d2008-07-18 13:29:57 +0400[diff] [blame^]108 } else if (mem->flags & DMA_MEMORY_EXCLUSIVE)
Dmitry Baryshkovee7e5512008-06-29 14:18:46 +0400[diff] [blame]109 *ret = NULL;
110 }
111 return (mem != NULL);
112}
113
114int dma_release_from_coherent(struct device *dev, int order, void *vaddr)
115{
116 struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;
117
118 if (mem && vaddr >= mem->virt_base && vaddr <
119 (mem->virt_base + (mem->size << PAGE_SHIFT))) {
120 int page = (vaddr - mem->virt_base) >> PAGE_SHIFT;
121
122 bitmap_release_region(mem->bitmap, page, order);
123 return 1;
124 }
125 return 0;
126}