Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...
[linux-2.6.git] / arch / blackfin / kernel / dma-mapping.c
1 /*
2  * Dynamic DMA mapping support
3  *
4  * Copyright 2005-2009 Analog Devices Inc.
5  *
6  * Licensed under the GPL-2 or later
7  */
8
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
16 static spinlock_t dma_page_lock;
17 static unsigned long *dma_page;
18 static unsigned int dma_pages;
19 static unsigned long dma_base;
20 static unsigned long dma_size;
21 static unsigned int dma_initialized;
22
23 static void dma_alloc_init(unsigned long start, unsigned long end)
24 {
25         spin_lock_init(&dma_page_lock);
26         dma_initialized = 0;
27
28         dma_page = (unsigned long *)__get_free_page(GFP_KERNEL);
29         memset(dma_page, 0, PAGE_SIZE);
30         dma_base = PAGE_ALIGN(start);
31         dma_size = PAGE_ALIGN(end) - PAGE_ALIGN(start);
32         dma_pages = dma_size >> PAGE_SHIFT;
33         memset((void *)dma_base, 0, DMA_UNCACHED_REGION);
34         dma_initialized = 1;
35
36         printk(KERN_INFO "%s: dma_page @ 0x%p - %d pages at 0x%08lx\n", __func__,
37                dma_page, dma_pages, dma_base);
38 }
39
40 static inline unsigned int get_pages(size_t size)
41 {
42         return ((size - 1) >> PAGE_SHIFT) + 1;
43 }
44
45 static unsigned long __alloc_dma_pages(unsigned int pages)
46 {
47         unsigned long ret = 0, flags;
48         int i, count = 0;
49
50         if (dma_initialized == 0)
51                 dma_alloc_init(_ramend - DMA_UNCACHED_REGION, _ramend);
52
53         spin_lock_irqsave(&dma_page_lock, flags);
54
55         for (i = 0; i < dma_pages;) {
56                 if (test_bit(i++, dma_page) == 0) {
57                         if (++count == pages) {
58                                 while (count--)
59                                         __set_bit(--i, dma_page);
60
61                                 ret = dma_base + (i << PAGE_SHIFT);
62                                 break;
63                         }
64                 } else
65                         count = 0;
66         }
67         spin_unlock_irqrestore(&dma_page_lock, flags);
68         return ret;
69 }
70
71 static void __free_dma_pages(unsigned long addr, unsigned int pages)
72 {
73         unsigned long page = (addr - dma_base) >> PAGE_SHIFT;
74         unsigned long flags;
75         int i;
76
77         if ((page + pages) > dma_pages) {
78                 printk(KERN_ERR "%s: freeing outside range.\n", __func__);
79                 BUG();
80         }
81
82         spin_lock_irqsave(&dma_page_lock, flags);
83         for (i = page; i < page + pages; i++)
84                 __clear_bit(i, dma_page);
85
86         spin_unlock_irqrestore(&dma_page_lock, flags);
87 }
88
89 void *dma_alloc_coherent(struct device *dev, size_t size,
90                          dma_addr_t *dma_handle, gfp_t gfp)
91 {
92         void *ret;
93
94         ret = (void *)__alloc_dma_pages(get_pages(size));
95
96         if (ret) {
97                 memset(ret, 0, size);
98                 *dma_handle = virt_to_phys(ret);
99         }
100
101         return ret;
102 }
103 EXPORT_SYMBOL(dma_alloc_coherent);
104
105 void
106 dma_free_coherent(struct device *dev, size_t size, void *vaddr,
107                   dma_addr_t dma_handle)
108 {
109         __free_dma_pages((unsigned long)vaddr, get_pages(size));
110 }
111 EXPORT_SYMBOL(dma_free_coherent);
112
113 /*
114  * Streaming DMA mappings
115  */
116 void __dma_sync(dma_addr_t addr, size_t size,
117                 enum dma_data_direction dir)
118 {
119         _dma_sync(addr, size, dir);
120 }
121 EXPORT_SYMBOL(__dma_sync);
122
123 int
124 dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
125            enum dma_data_direction direction)
126 {
127         int i;
128
129         for (i = 0; i < nents; i++, sg++) {
130                 sg->dma_address = (dma_addr_t) sg_virt(sg);
131                 __dma_sync(sg_dma_address(sg), sg_dma_len(sg), direction);
132         }
133
134         return nents;
135 }
136 EXPORT_SYMBOL(dma_map_sg);
137
138 void dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
139                             int nelems, enum dma_data_direction direction)
140 {
141         int i;
142
143         for (i = 0; i < nelems; i++, sg++) {
144                 sg->dma_address = (dma_addr_t) sg_virt(sg);
145                 __dma_sync(sg_dma_address(sg), sg_dma_len(sg), direction);
146         }
147 }
148 EXPORT_SYMBOL(dma_sync_sg_for_device);