1 /* 2 * Copyright © 2008 Keith Packard <[email protected]> 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 <asm/io.h> 23 #include <asm/page.h> 24 #include <asm/iomap.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 /* this struct isn't actually defined anywhere */ 34 struct io_mapping; 35 36 #ifdef CONFIG_HAVE_ATOMIC_IOMAP 37 38 /* 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. 43 */ 44 45 static inline struct io_mapping * 46 io_mapping_create_wc(unsigned long base, unsigned long size) 47 { 48 return (struct io_mapping *) base; 49 } 50 51 static inline void 52 io_mapping_free(struct io_mapping *mapping) 53 { 54 } 55 56 /* Atomic map/unmap */ 57 static inline void * 58 io_mapping_map_atomic_wc(struct io_mapping *mapping, unsigned long offset) 59 { 60 offset += (unsigned long) mapping; 61 return iomap_atomic_prot_pfn(offset >> PAGE_SHIFT, KM_USER0, 62 __pgprot(__PAGE_KERNEL_WC)); 63 } 64 65 static inline void 66 io_mapping_unmap_atomic(void *vaddr) 67 { 68 iounmap_atomic(vaddr, KM_USER0); 69 } 70 71 static inline void * 72 io_mapping_map_wc(struct io_mapping *mapping, unsigned long offset) 73 { 74 offset += (unsigned long) mapping; 75 return ioremap_wc(offset, PAGE_SIZE); 76 } 77 78 static inline void 79 io_mapping_unmap(void *vaddr) 80 { 81 iounmap(vaddr); 82 } 83 84 #else 85 86 /* Create the io_mapping object*/ 87 static inline struct io_mapping * 88 io_mapping_create_wc(unsigned long base, unsigned long size) 89 { 90 return (struct io_mapping *) ioremap_wc(base, size); 91 } 92 93 static inline void 94 io_mapping_free(struct io_mapping *mapping) 95 { 96 iounmap(mapping); 97 } 98 99 /* Atomic map/unmap */ 100 static inline void * 101 io_mapping_map_atomic_wc(struct io_mapping *mapping, unsigned long offset) 102 { 103 return ((char *) mapping) + offset; 104 } 105 106 static inline void 107 io_mapping_unmap_atomic(void *vaddr) 108 { 109 } 110 111 /* Non-atomic map/unmap */ 112 static inline void * 113 io_mapping_map_wc(struct io_mapping *mapping, unsigned long offset) 114 { 115 return ((char *) mapping) + offset; 116 } 117 118 static inline void 119 io_mapping_unmap(void *vaddr) 120 { 121 } 122 123 #endif /* HAVE_ATOMIC_IOMAP */ 124 125 #endif /* _LINUX_IO_MAPPING_H */ 126