1 /*
2 * Copyright (C) 2004-2006 Atmel Corporation
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 */
8
9 #include <linux/dma-mapping.h>
10
11 #include <asm/addrspace.h>
12 #include <asm/cacheflush.h>
13
dma_cache_sync(struct device * dev,void * vaddr,size_t size,int direction)14 void dma_cache_sync(struct device *dev, void *vaddr, size_t size, int direction)
15 {
16 /*
17 * No need to sync an uncached area
18 */
19 if (PXSEG(vaddr) == P2SEG)
20 return;
21
22 switch (direction) {
23 case DMA_FROM_DEVICE: /* invalidate only */
24 invalidate_dcache_region(vaddr, size);
25 break;
26 case DMA_TO_DEVICE: /* writeback only */
27 clean_dcache_region(vaddr, size);
28 break;
29 case DMA_BIDIRECTIONAL: /* writeback and invalidate */
30 flush_dcache_region(vaddr, size);
31 break;
32 default:
33 BUG();
34 }
35 }
36 EXPORT_SYMBOL(dma_cache_sync);
37
__dma_alloc(struct device * dev,size_t size,dma_addr_t * handle,gfp_t gfp)38 static struct page *__dma_alloc(struct device *dev, size_t size,
39 dma_addr_t *handle, gfp_t gfp)
40 {
41 struct page *page, *free, *end;
42 int order;
43
44 /* Following is a work-around (a.k.a. hack) to prevent pages
45 * with __GFP_COMP being passed to split_page() which cannot
46 * handle them. The real problem is that this flag probably
47 * should be 0 on AVR32 as it is not supported on this
48 * platform--see CONFIG_HUGETLB_PAGE. */
49 gfp &= ~(__GFP_COMP);
50
51 size = PAGE_ALIGN(size);
52 order = get_order(size);
53
54 page = alloc_pages(gfp, order);
55 if (!page)
56 return NULL;
57 split_page(page, order);
58
59 /*
60 * When accessing physical memory with valid cache data, we
61 * get a cache hit even if the virtual memory region is marked
62 * as uncached.
63 *
64 * Since the memory is newly allocated, there is no point in
65 * doing a writeback. If the previous owner cares, he should
66 * have flushed the cache before releasing the memory.
67 */
68 invalidate_dcache_region(phys_to_virt(page_to_phys(page)), size);
69
70 *handle = page_to_bus(page);
71 free = page + (size >> PAGE_SHIFT);
72 end = page + (1 << order);
73
74 /*
75 * Free any unused pages
76 */
77 while (free < end) {
78 __free_page(free);
79 free++;
80 }
81
82 return page;
83 }
84
__dma_free(struct device * dev,size_t size,struct page * page,dma_addr_t handle)85 static void __dma_free(struct device *dev, size_t size,
86 struct page *page, dma_addr_t handle)
87 {
88 struct page *end = page + (PAGE_ALIGN(size) >> PAGE_SHIFT);
89
90 while (page < end)
91 __free_page(page++);
92 }
93
dma_alloc_coherent(struct device * dev,size_t size,dma_addr_t * handle,gfp_t gfp)94 void *dma_alloc_coherent(struct device *dev, size_t size,
95 dma_addr_t *handle, gfp_t gfp)
96 {
97 struct page *page;
98 void *ret = NULL;
99
100 page = __dma_alloc(dev, size, handle, gfp);
101 if (page)
102 ret = phys_to_uncached(page_to_phys(page));
103
104 return ret;
105 }
106 EXPORT_SYMBOL(dma_alloc_coherent);
107
dma_free_coherent(struct device * dev,size_t size,void * cpu_addr,dma_addr_t handle)108 void dma_free_coherent(struct device *dev, size_t size,
109 void *cpu_addr, dma_addr_t handle)
110 {
111 void *addr = phys_to_cached(uncached_to_phys(cpu_addr));
112 struct page *page;
113
114 pr_debug("dma_free_coherent addr %p (phys %08lx) size %u\n",
115 cpu_addr, (unsigned long)handle, (unsigned)size);
116 BUG_ON(!virt_addr_valid(addr));
117 page = virt_to_page(addr);
118 __dma_free(dev, size, page, handle);
119 }
120 EXPORT_SYMBOL(dma_free_coherent);
121
dma_alloc_writecombine(struct device * dev,size_t size,dma_addr_t * handle,gfp_t gfp)122 void *dma_alloc_writecombine(struct device *dev, size_t size,
123 dma_addr_t *handle, gfp_t gfp)
124 {
125 struct page *page;
126 dma_addr_t phys;
127
128 page = __dma_alloc(dev, size, handle, gfp);
129 if (!page)
130 return NULL;
131
132 phys = page_to_phys(page);
133 *handle = phys;
134
135 /* Now, map the page into P3 with write-combining turned on */
136 return __ioremap(phys, size, _PAGE_BUFFER);
137 }
138 EXPORT_SYMBOL(dma_alloc_writecombine);
139
dma_free_writecombine(struct device * dev,size_t size,void * cpu_addr,dma_addr_t handle)140 void dma_free_writecombine(struct device *dev, size_t size,
141 void *cpu_addr, dma_addr_t handle)
142 {
143 struct page *page;
144
145 iounmap(cpu_addr);
146
147 page = phys_to_page(handle);
148 __dma_free(dev, size, page, handle);
149 }
150 EXPORT_SYMBOL(dma_free_writecombine);
151