blackfin: use bitmap library functions
[~shefty/rdma-dev.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 #include <linux/export.h>
16 #include <linux/bitmap.h>
17
18 static spinlock_t dma_page_lock;
19 static unsigned long *dma_page;
20 static unsigned int dma_pages;
21 static unsigned long dma_base;
22 static unsigned long dma_size;
23 static unsigned int dma_initialized;
24
25 static 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
42 static inline unsigned int get_pages(size_t size)
43 {
44         return ((size - 1) >> PAGE_SHIFT) + 1;
45 }
46
47 static 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
66 static 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
81 void *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 }
95 EXPORT_SYMBOL(dma_alloc_coherent);
96
97 void
98 dma_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 }
103 EXPORT_SYMBOL(dma_free_coherent);
104
105 /*
106  * Streaming DMA mappings
107  */
108 void __dma_sync(dma_addr_t addr, size_t size,
109                 enum dma_data_direction dir)
110 {
111         __dma_sync_inline(addr, size, dir);
112 }
113 EXPORT_SYMBOL(__dma_sync);
114
115 int
116 dma_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 }
129 EXPORT_SYMBOL(dma_map_sg);
130
131 void 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 }
142 EXPORT_SYMBOL(dma_sync_sg_for_device);