summaryrefslogtreecommitdiffstats
path: root/arch/avr32/mm/dma-coherent.c
blob: 44ab8a7bdae2705b32f316be2dd7b9947487cd63 (plain)
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
/*
 *  Copyright (C) 2004-2006 Atmel Corporation
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/dma-mapping.h>

#include <asm/addrspace.h>
#include <asm/cacheflush.h>

void dma_cache_sync(void *vaddr, size_t size, int direction)
{
	/*
	 * No need to sync an uncached area
	 */
	if (PXSEG(vaddr) == P2SEG)
		return;

	switch (direction) {
	case DMA_FROM_DEVICE:		/* invalidate only */
		dma_cache_inv(vaddr, size);
		break;
	case DMA_TO_DEVICE:		/* writeback only */
		dma_cache_wback(vaddr, size);
		break;
	case DMA_BIDIRECTIONAL:		/* writeback and invalidate */
		dma_cache_wback_inv(vaddr, size);
		break;
	default:
		BUG();
	}
}
EXPORT_SYMBOL(dma_cache_sync);

static struct page *__dma_alloc(struct device *dev, size_t size,
				dma_addr_t *handle, gfp_t gfp)
{
	struct page *page, *free, *end;
	int order;

	size = PAGE_ALIGN(size);
	order = get_order(size);

	page = alloc_pages(gfp, order);
	if (!page)
		return NULL;
	split_page(page, order);

	/*
	 * When accessing physical memory with valid cache data, we
	 * get a cache hit even if the virtual memory region is marked
	 * as uncached.
	 *
	 * Since the memory is newly allocated, there is no point in
	 * doing a writeback. If the previous owner cares, he should
	 * have flushed the cache before releasing the memory.
	 */
	invalidate_dcache_region(phys_to_virt(page_to_phys(page)), size);

	*handle = page_to_bus(page);
	free = page + (size >> PAGE_SHIFT);
	end = page + (1 << order);

	/*
	 * Free any unused pages
	 */
	while (free < end) {
		__free_page(free);
		free++;
	}

	return page;
}

static void __dma_free(struct device *dev, size_t size,
		       struct page *page, dma_addr_t handle)
{
	struct page *end = page + (PAGE_ALIGN(size) >> PAGE_SHIFT);

	while (page < end)
		__free_page(page++);
}

void *dma_alloc_coherent(struct device *dev, size_t size,
			 dma_addr_t *handle, gfp_t gfp)
{
	struct page *page;
	void *ret = NULL;

	page = __dma_alloc(dev, size, handle, gfp);
	if (page)
		ret = phys_to_uncached(page_to_phys(page));

	return ret;
}
EXPORT_SYMBOL(dma_alloc_coherent);

void dma_free_coherent(struct device *dev, size_t size,
		       void *cpu_addr, dma_addr_t handle)
{
	void *addr = phys_to_cached(uncached_to_phys(cpu_addr));
	struct page *page;

	pr_debug("dma_free_coherent addr %p (phys %08lx) size %u\n",
		 cpu_addr, (unsigned long)handle, (unsigned)size);
	BUG_ON(!virt_addr_valid(addr));
	page = virt_to_page(addr);
	__dma_free(dev, size, page, handle);
}
EXPORT_SYMBOL(dma_free_coherent);

#if 0
void *dma_alloc_writecombine(struct device *dev, size_t size,
			     dma_addr_t *handle, gfp_t gfp)
{
	struct page *page;

	page = __dma_alloc(dev, size, handle, gfp);

	/* Now, map the page into P3 with write-combining turned on */
	return __ioremap(page_to_phys(page), size, _PAGE_BUFFER);
}
EXPORT_SYMBOL(dma_alloc_writecombine);

void dma_free_writecombine(struct device *dev, size_t size,
			   void *cpu_addr, dma_addr_t handle)
{
	struct page *page;

	iounmap(cpu_addr);

	page = bus_to_page(handle);
	__dma_free(dev, size, page, handle);
}
EXPORT_SYMBOL(dma_free_writecombine);
#endif