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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 <linux/bug.h>
24#include <linux/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
38struct io_mapping {
39 resource_size_t base;
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
51static inline struct io_mapping *
52io_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
69out_free:
70 kfree(iomap);
71out_err:
72 return NULL;
73}
74
75static inline void
76io_mapping_free(struct io_mapping *mapping)
77{
78 iomap_free(mapping->base, mapping->size);
79 kfree(mapping);
80}
81
82/* Atomic map/unmap */
83static inline void __iomem *
84io_mapping_map_atomic_wc(struct io_mapping *mapping,
85 unsigned long offset)
86{
87 resource_size_t phys_addr;
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
96static inline void
97io_mapping_unmap_atomic(void __iomem *vaddr)
98{
99 iounmap_atomic(vaddr);
100}
101
102static inline void __iomem *
103io_mapping_map_wc(struct io_mapping *mapping,
104 unsigned long offset,
105 unsigned long size)
106{
107 resource_size_t phys_addr;
108
109 BUG_ON(offset >= mapping->size);
110 phys_addr = mapping->base + offset;
111
112 return ioremap_wc(phys_addr, size);
113}
114
115static inline void
116io_mapping_unmap(void __iomem *vaddr)
117{
118 iounmap(vaddr);
119}
120
121#else
122
123#include <linux/uaccess.h>
124
125/* this struct isn't actually defined anywhere */
126struct io_mapping;
127
128/* Create the io_mapping object*/
129static inline struct io_mapping *
130io_mapping_create_wc(resource_size_t base, unsigned long size)
131{
132 return (struct io_mapping __force *) ioremap_wc(base, size);
133}
134
135static inline void
136io_mapping_free(struct io_mapping *mapping)
137{
138 iounmap((void __force __iomem *) mapping);
139}
140
141/* Atomic map/unmap */
142static inline void __iomem *
143io_mapping_map_atomic_wc(struct io_mapping *mapping,
144 unsigned long offset)
145{
146 preempt_disable();
147 pagefault_disable();
148 return ((char __force __iomem *) mapping) + offset;
149}
150
151static inline void
152io_mapping_unmap_atomic(void __iomem *vaddr)
153{
154 pagefault_enable();
155 preempt_enable();
156}
157
158/* Non-atomic map/unmap */
159static inline void __iomem *
160io_mapping_map_wc(struct io_mapping *mapping,
161 unsigned long offset,
162 unsigned long size)
163{
164 return ((char __force __iomem *) mapping) + offset;
165}
166
167static inline void
168io_mapping_unmap(void __iomem *vaddr)
169{
170}
171
172#endif /* HAVE_ATOMIC_IOMAP */
173
174#endif /* _LINUX_IO_MAPPING_H */