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1/*
2 * Copyright © 2008 Keith Packard <keithp@keithp.com>
3 *
4 * This file is free software; you can redistribute it and/or modify
5 * it under the terms of version 2 of the GNU General Public License
6 * as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public License
14 * along with this program; if not, write to the Free Software Foundation,
15 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
16 */
17
18#ifndef _LINUX_IO_MAPPING_H
19#define _LINUX_IO_MAPPING_H
20
21#include <linux/types.h>
22#include <asm/io.h>
23#include <asm/page.h>
24#include <asm/iomap.h>
25
26/*
27 * The io_mapping mechanism provides an abstraction for mapping
28 * individual pages from an io device to the CPU in an efficient fashion.
29 *
30 * See Documentation/io_mapping.txt
31 */
32
33#ifdef CONFIG_HAVE_ATOMIC_IOMAP
34
35struct io_mapping {
36 resource_size_t base;
37 unsigned long size;
38 pgprot_t prot;
39};
40
41/*
42 * For small address space machines, mapping large objects
43 * into the kernel virtual space isn't practical. Where
44 * available, use fixmap support to dynamically map pages
45 * of the object at run time.
46 */
47
48static inline struct io_mapping *
49io_mapping_create_wc(resource_size_t base, unsigned long size)
50{
51 struct io_mapping *iomap;
52 pgprot_t prot;
53
54 iomap = kmalloc(sizeof(*iomap), GFP_KERNEL);
55 if (!iomap)
56 goto out_err;
57
58 if (iomap_create_wc(base, size, &prot))
59 goto out_free;
60
61 iomap->base = base;
62 iomap->size = size;
63 iomap->prot = prot;
64 return iomap;
65
66out_free:
67 kfree(iomap);
68out_err:
69 return NULL;
70}
71
72static inline void
73io_mapping_free(struct io_mapping *mapping)
74{
75 iomap_free(mapping->base, mapping->size);
76 kfree(mapping);
77}
78
79/* Atomic map/unmap */
80static inline void *
81io_mapping_map_atomic_wc(struct io_mapping *mapping, unsigned long offset)
82{
83 resource_size_t phys_addr;
84 unsigned long pfn;
85
86 BUG_ON(offset >= mapping->size);
87 phys_addr = mapping->base + offset;
88 pfn = (unsigned long) (phys_addr >> PAGE_SHIFT);
89 return iomap_atomic_prot_pfn(pfn, KM_USER0, mapping->prot);
90}
91
92static inline void
93io_mapping_unmap_atomic(void *vaddr)
94{
95 iounmap_atomic(vaddr, KM_USER0);
96}
97
98static inline void *
99io_mapping_map_wc(struct io_mapping *mapping, unsigned long offset)
100{
101 resource_size_t phys_addr;
102
103 BUG_ON(offset >= mapping->size);
104 phys_addr = mapping->base + offset;
105
106 return ioremap_wc(phys_addr, PAGE_SIZE);
107}
108
109static inline void
110io_mapping_unmap(void *vaddr)
111{
112 iounmap(vaddr);
113}
114
115#else
116
117/* this struct isn't actually defined anywhere */
118struct io_mapping;
119
120/* Create the io_mapping object*/
121static inline struct io_mapping *
122io_mapping_create_wc(resource_size_t base, unsigned long size)
123{
124 return (struct io_mapping *) ioremap_wc(base, size);
125}
126
127static inline void
128io_mapping_free(struct io_mapping *mapping)
129{
130 iounmap(mapping);
131}
132
133/* Atomic map/unmap */
134static inline void *
135io_mapping_map_atomic_wc(struct io_mapping *mapping, unsigned long offset)
136{
137 return ((char *) mapping) + offset;
138}
139
140static inline void
141io_mapping_unmap_atomic(void *vaddr)
142{
143}
144
145/* Non-atomic map/unmap */
146static inline void *
147io_mapping_map_wc(struct io_mapping *mapping, unsigned long offset)
148{
149 return ((char *) mapping) + offset;
150}
151
152static inline void
153io_mapping_unmap(void *vaddr)
154{
155}
156
157#endif /* HAVE_ATOMIC_IOMAP */
158
159#endif /* _LINUX_IO_MAPPING_H */