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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
53 if (!is_io_mapping_possible(base, size))
54 return NULL;
55
56 iomap = kmalloc(sizeof(*iomap), GFP_KERNEL);
57 if (!iomap)
58 return NULL;
59
60 iomap->base = base;
61 iomap->size = size;
62 iomap->prot = pgprot_writecombine(__pgprot(__PAGE_KERNEL));
63 return iomap;
64}
65
66static inline void
67io_mapping_free(struct io_mapping *mapping)
68{
69 kfree(mapping);
70}
71
72/* Atomic map/unmap */
73static inline void *
74io_mapping_map_atomic_wc(struct io_mapping *mapping, unsigned long offset)
75{
76 resource_size_t phys_addr;
77 unsigned long pfn;
78
79 BUG_ON(offset >= mapping->size);
80 phys_addr = mapping->base + offset;
81 pfn = (unsigned long) (phys_addr >> PAGE_SHIFT);
82 return iomap_atomic_prot_pfn(pfn, KM_USER0, mapping->prot);
83}
84
85static inline void
86io_mapping_unmap_atomic(void *vaddr)
87{
88 iounmap_atomic(vaddr, KM_USER0);
89}
90
91static inline void *
92io_mapping_map_wc(struct io_mapping *mapping, unsigned long offset)
93{
94 resource_size_t phys_addr;
95
96 BUG_ON(offset >= mapping->size);
97 phys_addr = mapping->base + offset;
98
99 return ioremap_wc(phys_addr, PAGE_SIZE);
100}
101
102static inline void
103io_mapping_unmap(void *vaddr)
104{
105 iounmap(vaddr);
106}
107
108#else
109
110/* this struct isn't actually defined anywhere */
111struct io_mapping;
112
113/* Create the io_mapping object*/
114static inline struct io_mapping *
115io_mapping_create_wc(resource_size_t base, unsigned long size)
116{
117 return (struct io_mapping *) ioremap_wc(base, size);
118}
119
120static inline void
121io_mapping_free(struct io_mapping *mapping)
122{
123 iounmap(mapping);
124}
125
126/* Atomic map/unmap */
127static inline void *
128io_mapping_map_atomic_wc(struct io_mapping *mapping, unsigned long offset)
129{
130 return ((char *) mapping) + offset;
131}
132
133static inline void
134io_mapping_unmap_atomic(void *vaddr)
135{
136}
137
138/* Non-atomic map/unmap */
139static inline void *
140io_mapping_map_wc(struct io_mapping *mapping, unsigned long offset)
141{
142 return ((char *) mapping) + offset;
143}
144
145static inline void
146io_mapping_unmap(void *vaddr)
147{
148}
149
150#endif /* HAVE_ATOMIC_IOMAP */
151
152#endif /* _LINUX_IO_MAPPING_H */