Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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/* this struct isn't actually defined anywhere */
34struct io_mapping;
35
36#ifdef CONFIG_HAVE_ATOMIC_IOMAP
37
38/*
39 * For small address space machines, mapping large objects
40 * into the kernel virtual space isn't practical. Where
41 * available, use fixmap support to dynamically map pages
42 * of the object at run time.
43 */
44
45static inline struct io_mapping *
46io_mapping_create_wc(unsigned long base, unsigned long size)
47{
48 return (struct io_mapping *) base;
49}
50
51static inline void
52io_mapping_free(struct io_mapping *mapping)
53{
54}
55
56/* Atomic map/unmap */
57static inline void *
58io_mapping_map_atomic_wc(struct io_mapping *mapping, unsigned long offset)
59{
60 offset += (unsigned long) mapping;
61 return iomap_atomic_prot_pfn(offset >> PAGE_SHIFT, KM_USER0,
62 __pgprot(__PAGE_KERNEL_WC));
63}
64
65static inline void
66io_mapping_unmap_atomic(void *vaddr)
67{
68 iounmap_atomic(vaddr, KM_USER0);
69}
70
71static inline void *
72io_mapping_map_wc(struct io_mapping *mapping, unsigned long offset)
73{
74 offset += (unsigned long) mapping;
75 return ioremap_wc(offset, PAGE_SIZE);
76}
77
78static inline void
79io_mapping_unmap(void *vaddr)
80{
81 iounmap(vaddr);
82}
83
84#else
85
86/* Create the io_mapping object*/
87static inline struct io_mapping *
88io_mapping_create_wc(unsigned long base, unsigned long size)
89{
90 return (struct io_mapping *) ioremap_wc(base, size);
91}
92
93static inline void
94io_mapping_free(struct io_mapping *mapping)
95{
96 iounmap(mapping);
97}
98
99/* Atomic map/unmap */
100static inline void *
101io_mapping_map_atomic_wc(struct io_mapping *mapping, unsigned long offset)
102{
103 return ((char *) mapping) + offset;
104}
105
106static inline void
107io_mapping_unmap_atomic(void *vaddr)
108{
109}
110
111/* Non-atomic map/unmap */
112static inline void *
113io_mapping_map_wc(struct io_mapping *mapping, unsigned long offset)
114{
115 return ((char *) mapping) + offset;
116}
117
118static inline void
119io_mapping_unmap(void *vaddr)
120{
121}
122
123#endif /* HAVE_ATOMIC_IOMAP */
124
125#endif /* _LINUX_IO_MAPPING_H */