Blackfin arch: as pointed out by Robert P. J. Day, update the CPU_FREQ name to match...
[linux-2.6.git] / 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 <asm/cacheflush.h>
39 #include <asm/bfin-global.h>
40
41 static spinlock_t dma_page_lock;
42 static unsigned int *dma_page;
43 static unsigned int dma_pages;
44 static unsigned long dma_base;
45 static unsigned long dma_size;
46 static unsigned int dma_initialized;
47
48 void dma_alloc_init(unsigned long start, unsigned long end)
49 {
50         spin_lock_init(&dma_page_lock);
51         dma_initialized = 0;
52
53         dma_page = (unsigned int *)__get_free_page(GFP_KERNEL);
54         memset(dma_page, 0, PAGE_SIZE);
55         dma_base = PAGE_ALIGN(start);
56         dma_size = PAGE_ALIGN(end) - PAGE_ALIGN(start);
57         dma_pages = dma_size >> PAGE_SHIFT;
58         memset((void *)dma_base, 0, DMA_UNCACHED_REGION);
59         dma_initialized = 1;
60
61         printk(KERN_INFO "%s: dma_page @ 0x%p - %d pages at 0x%08lx\n", __FUNCTION__,
62                dma_page, dma_pages, dma_base);
63 }
64
65 static inline unsigned int get_pages(size_t size)
66 {
67         return ((size - 1) >> PAGE_SHIFT) + 1;
68 }
69
70 static unsigned long __alloc_dma_pages(unsigned int pages)
71 {
72         unsigned long ret = 0, flags;
73         int i, count = 0;
74
75         if (dma_initialized == 0)
76                 dma_alloc_init(_ramend - DMA_UNCACHED_REGION, _ramend);
77
78         spin_lock_irqsave(&dma_page_lock, flags);
79
80         for (i = 0; i < dma_pages;) {
81                 if (dma_page[i++] == 0) {
82                         if (++count == pages) {
83                                 while (count--)
84                                         dma_page[--i] = 1;
85                                 ret = dma_base + (i << PAGE_SHIFT);
86                                 break;
87                         }
88                 } else
89                         count = 0;
90         }
91         spin_unlock_irqrestore(&dma_page_lock, flags);
92         return ret;
93 }
94
95 static void __free_dma_pages(unsigned long addr, unsigned int pages)
96 {
97         unsigned long page = (addr - dma_base) >> PAGE_SHIFT;
98         unsigned long flags;
99         int i;
100
101         if ((page + pages) > dma_pages) {
102                 printk(KERN_ERR "%s: freeing outside range.\n", __FUNCTION__);
103                 BUG();
104         }
105
106         spin_lock_irqsave(&dma_page_lock, flags);
107         for (i = page; i < page + pages; i++) {
108                 dma_page[i] = 0;
109         }
110         spin_unlock_irqrestore(&dma_page_lock, flags);
111 }
112
113 void *dma_alloc_coherent(struct device *dev, size_t size,
114                          dma_addr_t * dma_handle, gfp_t gfp)
115 {
116         void *ret;
117
118         ret = (void *)__alloc_dma_pages(get_pages(size));
119
120         if (ret) {
121                 memset(ret, 0, size);
122                 *dma_handle = virt_to_phys(ret);
123         }
124
125         return ret;
126 }
127 EXPORT_SYMBOL(dma_alloc_coherent);
128
129 void
130 dma_free_coherent(struct device *dev, size_t size, void *vaddr,
131                   dma_addr_t dma_handle)
132 {
133         __free_dma_pages((unsigned long)vaddr, get_pages(size));
134 }
135 EXPORT_SYMBOL(dma_free_coherent);
136
137 /*
138  * Dummy functions defined for some existing drivers
139  */
140
141 dma_addr_t
142 dma_map_single(struct device *dev, void *ptr, size_t size,
143                enum dma_data_direction direction)
144 {
145         BUG_ON(direction == DMA_NONE);
146
147         invalidate_dcache_range((unsigned long)ptr,
148                         (unsigned long)ptr + size);
149
150         return (dma_addr_t) ptr;
151 }
152 EXPORT_SYMBOL(dma_map_single);
153
154 int
155 dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
156            enum dma_data_direction direction)
157 {
158         int i;
159
160         BUG_ON(direction == DMA_NONE);
161
162         for (i = 0; i < nents; i++, sg++) {
163                 sg->dma_address = page_address(sg->page) + sg->offset;
164
165                 invalidate_dcache_range(sg_dma_address(sg),
166                                         sg_dma_address(sg) +
167                                         sg_dma_len(sg));
168         }
169
170         return nents;
171 }
172 EXPORT_SYMBOL(dma_map_sg);
173
174 void dma_unmap_single(struct device *dev, dma_addr_t dma_addr, size_t size,
175                 enum dma_data_direction direction)
176 {
177         BUG_ON(direction == DMA_NONE);
178 }
179 EXPORT_SYMBOL(dma_unmap_single);
180
181 void dma_unmap_sg(struct device *dev, struct scatterlist *sg,
182                 int nhwentries, enum dma_data_direction direction)
183 {
184         BUG_ON(direction == DMA_NONE);
185 }
186 EXPORT_SYMBOL(dma_unmap_sg);