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
38 struct 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
51 static inline struct io_mapping *
io_mapping_create_wc(resource_size_t base,unsigned long size)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
io_mapping_free(struct io_mapping * mapping)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 *
io_mapping_map_atomic_wc(struct io_mapping * mapping,unsigned long offset)84 io_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
96 static inline void
io_mapping_unmap_atomic(void __iomem * vaddr)97 io_mapping_unmap_atomic(void __iomem *vaddr)
98 {
99 iounmap_atomic(vaddr);
100 }
101
102 static inline void __iomem *
io_mapping_map_wc(struct io_mapping * mapping,unsigned long offset)103 io_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
113 static inline void
io_mapping_unmap(void __iomem * vaddr)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 *
io_mapping_create_wc(resource_size_t base,unsigned long size)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
io_mapping_free(struct io_mapping * mapping)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 *
io_mapping_map_atomic_wc(struct io_mapping * mapping,unsigned long offset)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
io_mapping_unmap_atomic(void __iomem * vaddr)149 io_mapping_unmap_atomic(void __iomem *vaddr)
150 {
151 pagefault_enable();
152 }
153
154 /* Non-atomic map/unmap */
155 static inline void __iomem *
io_mapping_map_wc(struct io_mapping * mapping,unsigned long offset)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
io_mapping_unmap(void __iomem * vaddr)162 io_mapping_unmap(void __iomem *vaddr)
163 {
164 }
165
166 #endif /* HAVE_ATOMIC_IOMAP */
167
168 #endif /* _LINUX_IO_MAPPING_H */
169