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
|
// SPDX-License-Identifier: GPL-2.0
/*
* DMA operations that map to virtual addresses without flushing memory.
*/
#include <linux/export.h>
#include <linux/mm.h>
#include <linux/dma-mapping.h>
#include <linux/scatterlist.h>
static void *dma_virt_alloc(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp,
unsigned long attrs)
{
void *ret;
ret = (void *)__get_free_pages(gfp | __GFP_ZERO, get_order(size));
if (ret)
*dma_handle = (uintptr_t)ret;
return ret;
}
static void dma_virt_free(struct device *dev, size_t size,
void *cpu_addr, dma_addr_t dma_addr,
unsigned long attrs)
{
free_pages((unsigned long)cpu_addr, get_order(size));
}
static dma_addr_t dma_virt_map_page(struct device *dev, struct page *page,
unsigned long offset, size_t size,
enum dma_data_direction dir,
unsigned long attrs)
{
return (uintptr_t)(page_address(page) + offset);
}
static int dma_virt_map_sg(struct device *dev, struct scatterlist *sgl,
int nents, enum dma_data_direction dir,
unsigned long attrs)
{
int i;
struct scatterlist *sg;
for_each_sg(sgl, sg, nents, i) {
BUG_ON(!sg_page(sg));
sg_dma_address(sg) = (uintptr_t)sg_virt(sg);
sg_dma_len(sg) = sg->length;
}
return nents;
}
const struct dma_map_ops dma_virt_ops = {
.alloc = dma_virt_alloc,
.free = dma_virt_free,
.map_page = dma_virt_map_page,
.map_sg = dma_virt_map_sg,
};
EXPORT_SYMBOL(dma_virt_ops);
|
