1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
|
/*
* Dynamic DMA mapping support
*
* Copyright 2005-2009 Analog Devices Inc.
*
* Licensed under the GPL-2 or later
*/
#include <linux/types.h>
#include <linux/gfp.h>
#include <linux/string.h>
#include <linux/spinlock.h>
#include <linux/dma-mapping.h>
#include <linux/scatterlist.h>
static spinlock_t dma_page_lock;
static unsigned long *dma_page;
static unsigned int dma_pages;
static unsigned long dma_base;
static unsigned long dma_size;
static unsigned int dma_initialized;
static void dma_alloc_init(unsigned long start, unsigned long end)
{
spin_lock_init(&dma_page_lock);
dma_initialized = 0;
dma_page = (unsigned long *)__get_free_page(GFP_KERNEL);
memset(dma_page, 0, PAGE_SIZE);
dma_base = PAGE_ALIGN(start);
dma_size = PAGE_ALIGN(end) - PAGE_ALIGN(start);
dma_pages = dma_size >> PAGE_SHIFT;
memset((void *)dma_base, 0, DMA_UNCACHED_REGION);
dma_initialized = 1;
printk(KERN_INFO "%s: dma_page @ 0x%p - %d pages at 0x%08lx\n", __func__,
dma_page, dma_pages, dma_base);
}
static inline unsigned int get_pages(size_t size)
{
return ((size - 1) >> PAGE_SHIFT) + 1;
}
static unsigned long __alloc_dma_pages(unsigned int pages)
{
unsigned long ret = 0, flags;
int i, count = 0;
if (dma_initialized == 0)
dma_alloc_init(_ramend - DMA_UNCACHED_REGION, _ramend);
spin_lock_irqsave(&dma_page_lock, flags);
for (i = 0; i < dma_pages;) {
if (test_bit(i++, dma_page) == 0) {
if (++count == pages) {
while (count--)
__set_bit(--i, dma_page);
ret = dma_base + (i << PAGE_SHIFT);
break;
}
} else
count = 0;
}
spin_unlock_irqrestore(&dma_page_lock, flags);
return ret;
}
static void __free_dma_pages(unsigned long addr, unsigned int pages)
{
unsigned long page = (addr - dma_base) >> PAGE_SHIFT;
unsigned long flags;
int i;
if ((page + pages) > dma_pages) {
printk(KERN_ERR "%s: freeing outside range.\n", __func__);
BUG();
}
spin_lock_irqsave(&dma_page_lock, flags);
for (i = page; i < page + pages; i++)
__clear_bit(i, dma_page);
spin_unlock_irqrestore(&dma_page_lock, flags);
}
void *dma_alloc_coherent(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp)
{
void *ret;
ret = (void *)__alloc_dma_pages(get_pages(size));
if (ret) {
memset(ret, 0, size);
*dma_handle = virt_to_phys(ret);
}
return ret;
}
EXPORT_SYMBOL(dma_alloc_coherent);
void
dma_free_coherent(struct device *dev, size_t size, void *vaddr,
dma_addr_t dma_handle)
{
__free_dma_pages((unsigned long)vaddr, get_pages(size));
}
EXPORT_SYMBOL(dma_free_coherent);
/*
* Streaming DMA mappings
*/
void __dma_sync(dma_addr_t addr, size_t size,
enum dma_data_direction dir)
{
__dma_sync_inline(addr, size, dir);
}
EXPORT_SYMBOL(__dma_sync);
int
dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
enum dma_data_direction direction)
{
int i;
for (i = 0; i < nents; i++, sg++) {
sg->dma_address = (dma_addr_t) sg_virt(sg);
__dma_sync(sg_dma_address(sg), sg_dma_len(sg), direction);
}
return nents;
}
EXPORT_SYMBOL(dma_map_sg);
void dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
int nelems, enum dma_data_direction direction)
{
int i;
for (i = 0; i < nelems; i++, sg++) {
sg->dma_address = (dma_addr_t) sg_virt(sg);
__dma_sync(sg_dma_address(sg), sg_dma_len(sg), direction);
}
}
EXPORT_SYMBOL(dma_sync_sg_for_device);
|
