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 <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
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, 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#include <linux/uaccess.h>
122
123/* this struct isn't actually defined anywhere */
124struct io_mapping;
125
126/* Create the io_mapping object*/
127static inline struct io_mapping *
128io_mapping_create_wc(resource_size_t base, unsigned long size)
129{
130	return (struct io_mapping __force *) ioremap_wc(base, size);
131}
132
133static inline void
134io_mapping_free(struct io_mapping *mapping)
135{
136	iounmap((void __force __iomem *) mapping);
137}
138
139/* Atomic map/unmap */
140static inline void __iomem *
141io_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
148static inline void
149io_mapping_unmap_atomic(void __iomem *vaddr)
150{
151	pagefault_enable();
152}
153
154/* Non-atomic map/unmap */
155static inline void __iomem *
156io_mapping_map_wc(struct io_mapping *mapping, unsigned long offset)
157{
158	return ((char __force __iomem *) mapping) + offset;
159}
160
161static inline void
162io_mapping_unmap(void __iomem *vaddr)
163{
164}
165
166#endif /* HAVE_ATOMIC_IOMAP */
167
168#endif /* _LINUX_IO_MAPPING_H */
169