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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 <linux/slab.h>
23#include <asm/io.h>
24#include <asm/page.h>
25#include <asm/iomap.h>
26
27/*
28 * The io_mapping mechanism provides an abstraction for mapping
29 * individual pages from an io device to the CPU in an efficient fashion.
30 *
31 * See Documentation/io_mapping.txt
32 */
33
34#ifdef CONFIG_HAVE_ATOMIC_IOMAP
35
36struct io_mapping {
37 resource_size_t base;
38 unsigned long size;
39 pgprot_t prot;
40};
41
42/*
43 * For small address space machines, mapping large objects
44 * into the kernel virtual space isn't practical. Where
45 * available, use fixmap support to dynamically map pages
46 * of the object at run time.
47 */
48
49static inline struct io_mapping *
50io_mapping_create_wc(resource_size_t base, unsigned long size)
51{
52 struct io_mapping *iomap;
53 pgprot_t prot;
54
55 iomap = kmalloc(sizeof(*iomap), GFP_KERNEL);
56 if (!iomap)
57 goto out_err;
58
59 if (iomap_create_wc(base, size, &prot))
60 goto out_free;
61
62 iomap->base = base;
63 iomap->size = size;
64 iomap->prot = prot;
65 return iomap;
66
67out_free:
68 kfree(iomap);
69out_err:
70 return NULL;
71}
72
73static inline void
74io_mapping_free(struct io_mapping *mapping)
75{
76 iomap_free(mapping->base, mapping->size);
77 kfree(mapping);
78}
79
80/* Atomic map/unmap */
81static inline void *
82io_mapping_map_atomic_wc(struct io_mapping *mapping, unsigned long offset)
83{
84 resource_size_t phys_addr;
85 unsigned long pfn;
86
87 BUG_ON(offset >= mapping->size);
88 phys_addr = mapping->base + offset;
89 pfn = (unsigned long) (phys_addr >> PAGE_SHIFT);
90 return iomap_atomic_prot_pfn(pfn, KM_USER0, mapping->prot);
91}
92
93static inline void
94io_mapping_unmap_atomic(void *vaddr)
95{
96 iounmap_atomic(vaddr, KM_USER0);
97}
98
99static inline void *
100io_mapping_map_wc(struct io_mapping *mapping, unsigned long offset)
101{
102 resource_size_t phys_addr;
103
104 BUG_ON(offset >= mapping->size);
105 phys_addr = mapping->base + offset;
106
107 return ioremap_wc(phys_addr, PAGE_SIZE);
108}
109
110static inline void
111io_mapping_unmap(void *vaddr)
112{
113 iounmap(vaddr);
114}
115
116#else
117
118/* this struct isn't actually defined anywhere */
119struct io_mapping;
120
121/* Create the io_mapping object*/
122static inline struct io_mapping *
123io_mapping_create_wc(resource_size_t base, unsigned long size)
124{
125 return (struct io_mapping *) ioremap_wc(base, size);
126}
127
128static inline void
129io_mapping_free(struct io_mapping *mapping)
130{
131 iounmap(mapping);
132}
133
134/* Atomic map/unmap */
135static inline void *
136io_mapping_map_atomic_wc(struct io_mapping *mapping, unsigned long offset)
137{
138 return ((char *) mapping) + offset;
139}
140
141static inline void
142io_mapping_unmap_atomic(void *vaddr)
143{
144}
145
146/* Non-atomic map/unmap */
147static inline void *
148io_mapping_map_wc(struct io_mapping *mapping, unsigned long offset)
149{
150 return ((char *) mapping) + offset;
151}
152
153static inline void
154io_mapping_unmap(void *vaddr)
155{
156}
157
158#endif /* HAVE_ATOMIC_IOMAP */
159
160#endif /* _LINUX_IO_MAPPING_H */