2 * Copyright © 2008 Keith Packard <keithp@keithp.com>
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.
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.
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.
18 #ifndef _LINUX_IO_MAPPING_H
19 #define _LINUX_IO_MAPPING_H
21 #include <linux/types.h>
24 #include <asm/iomap.h>
27 * The io_mapping mechanism provides an abstraction for mapping
28 * individual pages from an io device to the CPU in an efficient fashion.
30 * See Documentation/io_mapping.txt
33 /* this struct isn't actually defined anywhere */
36 #ifdef CONFIG_HAVE_ATOMIC_IOMAP
39 * For small address space machines, mapping large objects
40 * into the kernel virtual space isn't practical. Where
41 * available, use fixmap support to dynamically map pages
42 * of the object at run time.
45 static inline struct io_mapping
*
46 io_mapping_create_wc(unsigned long base
, unsigned long size
)
48 return (struct io_mapping
*) base
;
52 io_mapping_free(struct io_mapping
*mapping
)
56 /* Atomic map/unmap */
58 io_mapping_map_atomic_wc(struct io_mapping
*mapping
, unsigned long offset
)
60 offset
+= (unsigned long) mapping
;
61 return iomap_atomic_prot_pfn(offset
>> PAGE_SHIFT
, KM_USER0
,
62 __pgprot(__PAGE_KERNEL_WC
));
66 io_mapping_unmap_atomic(void *vaddr
)
68 iounmap_atomic(vaddr
, KM_USER0
);
72 io_mapping_map_wc(struct io_mapping
*mapping
, unsigned long offset
)
74 offset
+= (unsigned long) mapping
;
75 return ioremap_wc(offset
, PAGE_SIZE
);
79 io_mapping_unmap(void *vaddr
)
86 /* Create the io_mapping object*/
87 static inline struct io_mapping
*
88 io_mapping_create_wc(unsigned long base
, unsigned long size
)
90 return (struct io_mapping
*) ioremap_wc(base
, size
);
94 io_mapping_free(struct io_mapping
*mapping
)
99 /* Atomic map/unmap */
101 io_mapping_map_atomic_wc(struct io_mapping
*mapping
, unsigned long offset
)
103 return ((char *) mapping
) + offset
;
107 io_mapping_unmap_atomic(void *vaddr
)
111 /* Non-atomic map/unmap */
113 io_mapping_map_wc(struct io_mapping
*mapping
, unsigned long offset
)
115 return ((char *) mapping
) + offset
;
119 io_mapping_unmap(void *vaddr
)
123 #endif /* HAVE_ATOMIC_IOMAP */
125 #endif /* _LINUX_IO_MAPPING_H */