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9#include <linux/types.h>
10#include <linux/gfp.h>
11#include <linux/string.h>
12#include <linux/spinlock.h>
13#include <linux/dma-mapping.h>
14#include <linux/scatterlist.h>
15#include <linux/export.h>
16#include <linux/bitmap.h>
17
18static spinlock_t dma_page_lock;
19static unsigned long *dma_page;
20static unsigned int dma_pages;
21static unsigned long dma_base;
22static unsigned long dma_size;
23static unsigned int dma_initialized;
24
25static void dma_alloc_init(unsigned long start, unsigned long end)
26{
27 spin_lock_init(&dma_page_lock);
28 dma_initialized = 0;
29
30 dma_page = (unsigned long *)__get_free_page(GFP_KERNEL);
31 memset(dma_page, 0, PAGE_SIZE);
32 dma_base = PAGE_ALIGN(start);
33 dma_size = PAGE_ALIGN(end) - PAGE_ALIGN(start);
34 dma_pages = dma_size >> PAGE_SHIFT;
35 memset((void *)dma_base, 0, DMA_UNCACHED_REGION);
36 dma_initialized = 1;
37
38 printk(KERN_INFO "%s: dma_page @ 0x%p - %d pages at 0x%08lx\n", __func__,
39 dma_page, dma_pages, dma_base);
40}
41
42static inline unsigned int get_pages(size_t size)
43{
44 return ((size - 1) >> PAGE_SHIFT) + 1;
45}
46
47static unsigned long __alloc_dma_pages(unsigned int pages)
48{
49 unsigned long ret = 0, flags;
50 unsigned long start;
51
52 if (dma_initialized == 0)
53 dma_alloc_init(_ramend - DMA_UNCACHED_REGION, _ramend);
54
55 spin_lock_irqsave(&dma_page_lock, flags);
56
57 start = bitmap_find_next_zero_area(dma_page, dma_pages, 0, pages, 0);
58 if (start < dma_pages) {
59 ret = dma_base + (start << PAGE_SHIFT);
60 bitmap_set(dma_page, start, pages);
61 }
62 spin_unlock_irqrestore(&dma_page_lock, flags);
63 return ret;
64}
65
66static void __free_dma_pages(unsigned long addr, unsigned int pages)
67{
68 unsigned long page = (addr - dma_base) >> PAGE_SHIFT;
69 unsigned long flags;
70
71 if ((page + pages) > dma_pages) {
72 printk(KERN_ERR "%s: freeing outside range.\n", __func__);
73 BUG();
74 }
75
76 spin_lock_irqsave(&dma_page_lock, flags);
77 bitmap_clear(dma_page, page, pages);
78 spin_unlock_irqrestore(&dma_page_lock, flags);
79}
80
81void *dma_alloc_coherent(struct device *dev, size_t size,
82 dma_addr_t *dma_handle, gfp_t gfp)
83{
84 void *ret;
85
86 ret = (void *)__alloc_dma_pages(get_pages(size));
87
88 if (ret) {
89 memset(ret, 0, size);
90 *dma_handle = virt_to_phys(ret);
91 }
92
93 return ret;
94}
95EXPORT_SYMBOL(dma_alloc_coherent);
96
97void
98dma_free_coherent(struct device *dev, size_t size, void *vaddr,
99 dma_addr_t dma_handle)
100{
101 __free_dma_pages((unsigned long)vaddr, get_pages(size));
102}
103EXPORT_SYMBOL(dma_free_coherent);
104
105
106
107
108void __dma_sync(dma_addr_t addr, size_t size,
109 enum dma_data_direction dir)
110{
111 __dma_sync_inline(addr, size, dir);
112}
113EXPORT_SYMBOL(__dma_sync);
114
115int
116dma_map_sg(struct device *dev, struct scatterlist *sg_list, int nents,
117 enum dma_data_direction direction)
118{
119 struct scatterlist *sg;
120 int i;
121
122 for_each_sg(sg_list, sg, nents, i) {
123 sg->dma_address = (dma_addr_t) sg_virt(sg);
124 __dma_sync(sg_dma_address(sg), sg_dma_len(sg), direction);
125 }
126
127 return nents;
128}
129EXPORT_SYMBOL(dma_map_sg);
130
131void dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg_list,
132 int nelems, enum dma_data_direction direction)
133{
134 struct scatterlist *sg;
135 int i;
136
137 for_each_sg(sg_list, sg, nelems, i) {
138 sg->dma_address = (dma_addr_t) sg_virt(sg);
139 __dma_sync(sg_dma_address(sg), sg_dma_len(sg), direction);
140 }
141}
142EXPORT_SYMBOL(dma_sync_sg_for_device);
143
