Linux Kernel  3.7.1
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
io-mapping.h
Go to the documentation of this file.
1 /*
2  * Copyright © 2008 Keith Packard <[email protected]>
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 <linux/bug.h>
24 #include <asm/io.h>
25 #include <asm/page.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 
36 #include <asm/iomap.h>
37 
38 struct io_mapping {
40  unsigned long size;
41  pgprot_t prot;
42 };
43 
44 /*
45  * For small address space machines, mapping large objects
46  * into the kernel virtual space isn't practical. Where
47  * available, use fixmap support to dynamically map pages
48  * of the object at run time.
49  */
50 
51 static inline struct io_mapping *
52 io_mapping_create_wc(resource_size_t base, unsigned long size)
53 {
54  struct io_mapping *iomap;
55  pgprot_t prot;
56 
57  iomap = kmalloc(sizeof(*iomap), GFP_KERNEL);
58  if (!iomap)
59  goto out_err;
60 
61  if (iomap_create_wc(base, size, &prot))
62  goto out_free;
63 
64  iomap->base = base;
65  iomap->size = size;
66  iomap->prot = prot;
67  return iomap;
68 
69 out_free:
70  kfree(iomap);
71 out_err:
72  return NULL;
73 }
74 
75 static inline void
76 io_mapping_free(struct io_mapping *mapping)
77 {
78  iomap_free(mapping->base, mapping->size);
79  kfree(mapping);
80 }
81 
82 /* Atomic map/unmap */
83 static inline void __iomem *
84 io_mapping_map_atomic_wc(struct io_mapping *mapping,
85  unsigned long offset)
86 {
88  unsigned long pfn;
89 
90  BUG_ON(offset >= mapping->size);
91  phys_addr = mapping->base + offset;
92  pfn = (unsigned long) (phys_addr >> PAGE_SHIFT);
93  return iomap_atomic_prot_pfn(pfn, mapping->prot);
94 }
95 
96 static inline void
97 io_mapping_unmap_atomic(void __iomem *vaddr)
98 {
99  iounmap_atomic(vaddr);
100 }
101 
102 static inline void __iomem *
103 io_mapping_map_wc(struct io_mapping *mapping, unsigned long offset)
104 {
106 
107  BUG_ON(offset >= mapping->size);
108  phys_addr = mapping->base + offset;
109 
110  return ioremap_wc(phys_addr, PAGE_SIZE);
111 }
112 
113 static inline void
114 io_mapping_unmap(void __iomem *vaddr)
115 {
116  iounmap(vaddr);
117 }
118 
119 #else
120 
121 #include <linux/uaccess.h>
122 
123 /* this struct isn't actually defined anywhere */
124 struct io_mapping;
125 
126 /* Create the io_mapping object*/
127 static inline struct io_mapping *
128 io_mapping_create_wc(resource_size_t base, unsigned long size)
129 {
130  return (struct io_mapping __force *) ioremap_wc(base, size);
131 }
132 
133 static inline void
134 io_mapping_free(struct io_mapping *mapping)
135 {
136  iounmap((void __force __iomem *) mapping);
137 }
138 
139 /* Atomic map/unmap */
140 static inline void __iomem *
141 io_mapping_map_atomic_wc(struct io_mapping *mapping,
142  unsigned long offset)
143 {
144  pagefault_disable();
145  return ((char __force __iomem *) mapping) + offset;
146 }
147 
148 static inline void
149 io_mapping_unmap_atomic(void __iomem *vaddr)
150 {
151  pagefault_enable();
152 }
153 
154 /* Non-atomic map/unmap */
155 static inline void __iomem *
156 io_mapping_map_wc(struct io_mapping *mapping, unsigned long offset)
157 {
158  return ((char __force __iomem *) mapping) + offset;
159 }
160 
161 static inline void
162 io_mapping_unmap(void __iomem *vaddr)
163 {
164 }
165 
166 #endif /* HAVE_ATOMIC_IOMAP */
167 
168 #endif /* _LINUX_IO_MAPPING_H */