Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes...
[linux-2.6] / arch / blackfin / kernel / dma-mapping.c
1 /*
2  * File:         arch/blackfin/kernel/dma-mapping.c
3  * Based on:
4  * Author:
5  *
6  * Created:
7  * Description:  Dynamic DMA mapping support.
8  *
9  * Modified:
10  *               Copyright 2004-2006 Analog Devices Inc.
11  *
12  * Bugs:         Enter bugs at http://blackfin.uclinux.org/
13  *
14  * This program is free software; you can redistribute it and/or modify
15  * it under the terms of the GNU General Public License as published by
16  * the Free Software Foundation; either version 2 of the License, or
17  * (at your option) any later version.
18  *
19  * This program is distributed in the hope that it will be useful,
20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
22  * GNU General Public License for more details.
23  *
24  * You should have received a copy of the GNU General Public License
25  * along with this program; if not, see the file COPYING, or write
26  * to the Free Software Foundation, Inc.,
27  * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
28  */
29
30 #include <linux/types.h>
31 #include <linux/mm.h>
32 #include <linux/string.h>
33 #include <linux/bootmem.h>
34 #include <linux/spinlock.h>
35 #include <linux/device.h>
36 #include <linux/dma-mapping.h>
37 #include <linux/io.h>
38 #include <linux/scatterlist.h>
39 #include <asm/cacheflush.h>
40 #include <asm/bfin-global.h>
41
42 static spinlock_t dma_page_lock;
43 static unsigned int *dma_page;
44 static unsigned int dma_pages;
45 static unsigned long dma_base;
46 static unsigned long dma_size;
47 static unsigned int dma_initialized;
48
49 void dma_alloc_init(unsigned long start, unsigned long end)
50 {
51         spin_lock_init(&dma_page_lock);
52         dma_initialized = 0;
53
54         dma_page = (unsigned int *)__get_free_page(GFP_KERNEL);
55         memset(dma_page, 0, PAGE_SIZE);
56         dma_base = PAGE_ALIGN(start);
57         dma_size = PAGE_ALIGN(end) - PAGE_ALIGN(start);
58         dma_pages = dma_size >> PAGE_SHIFT;
59         memset((void *)dma_base, 0, DMA_UNCACHED_REGION);
60         dma_initialized = 1;
61
62         printk(KERN_INFO "%s: dma_page @ 0x%p - %d pages at 0x%08lx\n", __func__,
63                dma_page, dma_pages, dma_base);
64 }
65
66 static inline unsigned int get_pages(size_t size)
67 {
68         return ((size - 1) >> PAGE_SHIFT) + 1;
69 }
70
71 static unsigned long __alloc_dma_pages(unsigned int pages)
72 {
73         unsigned long ret = 0, flags;
74         int i, count = 0;
75
76         if (dma_initialized == 0)
77                 dma_alloc_init(_ramend - DMA_UNCACHED_REGION, _ramend);
78
79         spin_lock_irqsave(&dma_page_lock, flags);
80
81         for (i = 0; i < dma_pages;) {
82                 if (dma_page[i++] == 0) {
83                         if (++count == pages) {
84                                 while (count--)
85                                         dma_page[--i] = 1;
86                                 ret = dma_base + (i << PAGE_SHIFT);
87                                 break;
88                         }
89                 } else
90                         count = 0;
91         }
92         spin_unlock_irqrestore(&dma_page_lock, flags);
93         return ret;
94 }
95
96 static void __free_dma_pages(unsigned long addr, unsigned int pages)
97 {
98         unsigned long page = (addr - dma_base) >> PAGE_SHIFT;
99         unsigned long flags;
100         int i;
101
102         if ((page + pages) > dma_pages) {
103                 printk(KERN_ERR "%s: freeing outside range.\n", __func__);
104                 BUG();
105         }
106
107         spin_lock_irqsave(&dma_page_lock, flags);
108         for (i = page; i < page + pages; i++) {
109                 dma_page[i] = 0;
110         }
111         spin_unlock_irqrestore(&dma_page_lock, flags);
112 }
113
114 void *dma_alloc_coherent(struct device *dev, size_t size,
115                          dma_addr_t * dma_handle, gfp_t gfp)
116 {
117         void *ret;
118
119         ret = (void *)__alloc_dma_pages(get_pages(size));
120
121         if (ret) {
122                 memset(ret, 0, size);
123                 *dma_handle = virt_to_phys(ret);
124         }
125
126         return ret;
127 }
128 EXPORT_SYMBOL(dma_alloc_coherent);
129
130 void
131 dma_free_coherent(struct device *dev, size_t size, void *vaddr,
132                   dma_addr_t dma_handle)
133 {
134         __free_dma_pages((unsigned long)vaddr, get_pages(size));
135 }
136 EXPORT_SYMBOL(dma_free_coherent);
137
138 /*
139  * Dummy functions defined for some existing drivers
140  */
141
142 dma_addr_t
143 dma_map_single(struct device *dev, void *ptr, size_t size,
144                enum dma_data_direction direction)
145 {
146         BUG_ON(direction == DMA_NONE);
147
148         invalidate_dcache_range((unsigned long)ptr,
149                         (unsigned long)ptr + size);
150
151         return (dma_addr_t) ptr;
152 }
153 EXPORT_SYMBOL(dma_map_single);
154
155 int
156 dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
157            enum dma_data_direction direction)
158 {
159         int i;
160
161         BUG_ON(direction == DMA_NONE);
162
163         for (i = 0; i < nents; i++, sg++) {
164                 sg->dma_address = (dma_addr_t) sg_virt(sg);
165
166                 invalidate_dcache_range(sg_dma_address(sg),
167                                         sg_dma_address(sg) +
168                                         sg_dma_len(sg));
169         }
170
171         return nents;
172 }
173 EXPORT_SYMBOL(dma_map_sg);
174
175 void dma_unmap_single(struct device *dev, dma_addr_t dma_addr, size_t size,
176                 enum dma_data_direction direction)
177 {
178         BUG_ON(direction == DMA_NONE);
179 }
180 EXPORT_SYMBOL(dma_unmap_single);
181
182 void dma_unmap_sg(struct device *dev, struct scatterlist *sg,
183                 int nhwentries, enum dma_data_direction direction)
184 {
185         BUG_ON(direction == DMA_NONE);
186 }
187 EXPORT_SYMBOL(dma_unmap_sg);