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