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
37 struct 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
50 static inline struct io_mapping *
io_mapping_create_wc(resource_size_t base,unsigned long size)51 io_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
68 out_free:
69 kfree(iomap);
70 out_err:
71 return NULL;
72 }
73
74 static inline void
io_mapping_free(struct io_mapping * mapping)75 io_mapping_free(struct io_mapping *mapping)
76 {
77 iomap_free(mapping->base, mapping->size);
78 kfree(mapping);
79 }
80
81 /* Atomic map/unmap */
82 static inline void __iomem *
io_mapping_map_atomic_wc(struct io_mapping * mapping,unsigned long offset)83 io_mapping_map_atomic_wc(struct io_mapping *mapping,
84 unsigned long offset)
85 {
86 resource_size_t phys_addr;
87 unsigned long pfn;
88
89 BUG_ON(offset >= mapping->size);
90 phys_addr = mapping->base + offset;
91 pfn = (unsigned long) (phys_addr >> PAGE_SHIFT);
92 return iomap_atomic_prot_pfn(pfn, mapping->prot);
93 }
94
95 static inline void
io_mapping_unmap_atomic(void __iomem * vaddr)96 io_mapping_unmap_atomic(void __iomem *vaddr)
97 {
98 iounmap_atomic(vaddr);
99 }
100
101 static inline void __iomem *
io_mapping_map_wc(struct io_mapping * mapping,unsigned long offset)102 io_mapping_map_wc(struct io_mapping *mapping, unsigned long offset)
103 {
104 resource_size_t phys_addr;
105
106 BUG_ON(offset >= mapping->size);
107 phys_addr = mapping->base + offset;
108
109 return ioremap_wc(phys_addr, PAGE_SIZE);
110 }
111
112 static inline void
io_mapping_unmap(void __iomem * vaddr)113 io_mapping_unmap(void __iomem *vaddr)
114 {
115 iounmap(vaddr);
116 }
117
118 #else
119
120 #include <linux/uaccess.h>
121
122 /* this struct isn't actually defined anywhere */
123 struct io_mapping;
124
125 /* Create the io_mapping object*/
126 static inline struct io_mapping *
io_mapping_create_wc(resource_size_t base,unsigned long size)127 io_mapping_create_wc(resource_size_t base, unsigned long size)
128 {
129 return (struct io_mapping __force *) ioremap_wc(base, size);
130 }
131
132 static inline void
io_mapping_free(struct io_mapping * mapping)133 io_mapping_free(struct io_mapping *mapping)
134 {
135 iounmap((void __force __iomem *) mapping);
136 }
137
138 /* Atomic map/unmap */
139 static inline void __iomem *
io_mapping_map_atomic_wc(struct io_mapping * mapping,unsigned long offset)140 io_mapping_map_atomic_wc(struct io_mapping *mapping,
141 unsigned long offset)
142 {
143 pagefault_disable();
144 return ((char __force __iomem *) mapping) + offset;
145 }
146
147 static inline void
io_mapping_unmap_atomic(void __iomem * vaddr)148 io_mapping_unmap_atomic(void __iomem *vaddr)
149 {
150 pagefault_enable();
151 }
152
153 /* Non-atomic map/unmap */
154 static inline void __iomem *
io_mapping_map_wc(struct io_mapping * mapping,unsigned long offset)155 io_mapping_map_wc(struct io_mapping *mapping, unsigned long offset)
156 {
157 return ((char __force __iomem *) mapping) + offset;
158 }
159
160 static inline void
io_mapping_unmap(void __iomem * vaddr)161 io_mapping_unmap(void __iomem *vaddr)
162 {
163 }
164
165 #endif /* HAVE_ATOMIC_IOMAP */
166
167 #endif /* _LINUX_IO_MAPPING_H */
168