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authorKeith Packard <keithp@keithp.com>2008-10-30 22:38:18 -0400
committerIngo Molnar <mingo@elte.hu>2008-10-31 05:12:39 -0400
commit9663f2e6a6cf3f82b06d8fb699b11b80f92553ba (patch)
tree108ce4d443e87c8ddc00c028c995b83a6d01e420 /include
parentfd9409343521eac22b6ed51686128a643c7c976b (diff)
resources: add io-mapping functions to dynamically map large device apertures
Impact: add new generic io_map_*() APIs Graphics devices have large PCI apertures which would consume a significant fraction of a 32-bit address space if mapped during driver initialization. Using ioremap at runtime is impractical as it is too slow. This new set of interfaces uses atomic mappings on 32-bit processors and a large static mapping on 64-bit processors to provide reasonable 32-bit performance and optimal 64-bit performance. The current implementation sits atop the io_map_atomic fixmap-based mechanism for 32-bit processors. This includes some editorial suggestions from Randy Dunlap for Documentation/io-mapping.txt Signed-off-by: Keith Packard <keithp@keithp.com> Signed-off-by: Eric Anholt <eric@anholt.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include')
-rw-r--r--include/linux/io-mapping.h118
1 files changed, 118 insertions, 0 deletions
diff --git a/include/linux/io-mapping.h b/include/linux/io-mapping.h
new file mode 100644
index 000000000000..1b566993db6e
--- /dev/null
+++ b/include/linux/io-mapping.h
@@ -0,0 +1,118 @@
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_X86_64
37
38/* Create the io_mapping object*/
39static inline struct io_mapping *
40io_mapping_create_wc(unsigned long base, unsigned long size)
41{
42 return (struct io_mapping *) ioremap_wc(base, size);
43}
44
45static inline void
46io_mapping_free(struct io_mapping *mapping)
47{
48 iounmap(mapping);
49}
50
51/* Atomic map/unmap */
52static inline void *
53io_mapping_map_atomic_wc(struct io_mapping *mapping, unsigned long offset)
54{
55 return ((char *) mapping) + offset;
56}
57
58static inline void
59io_mapping_unmap_atomic(void *vaddr)
60{
61}
62
63/* Non-atomic map/unmap */
64static inline void *
65io_mapping_map_wc(struct io_mapping *mapping, unsigned long offset)
66{
67 return ((char *) mapping) + offset;
68}
69
70static inline void
71io_mapping_unmap(void *vaddr)
72{
73}
74
75#endif /* CONFIG_X86_64 */
76
77#ifdef CONFIG_X86_32
78static inline struct io_mapping *
79io_mapping_create_wc(unsigned long base, unsigned long size)
80{
81 return (struct io_mapping *) base;
82}
83
84static inline void
85io_mapping_free(struct io_mapping *mapping)
86{
87}
88
89/* Atomic map/unmap */
90static inline void *
91io_mapping_map_atomic_wc(struct io_mapping *mapping, unsigned long offset)
92{
93 offset += (unsigned long) mapping;
94 return iomap_atomic_prot_pfn(offset >> PAGE_SHIFT, KM_USER0,
95 __pgprot(__PAGE_KERNEL_WC));
96}
97
98static inline void
99io_mapping_unmap_atomic(void *vaddr)
100{
101 iounmap_atomic(vaddr, KM_USER0);
102}
103
104static inline void *
105io_mapping_map_wc(struct io_mapping *mapping, unsigned long offset)
106{
107 offset += (unsigned long) mapping;
108 return ioremap_wc(offset, PAGE_SIZE);
109}
110
111static inline void
112io_mapping_unmap(void *vaddr)
113{
114 iounmap(vaddr);
115}
116#endif /* CONFIG_X86_32 */
117
118#endif /* _LINUX_IO_MAPPING_H */