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 #ifdef CONFIG_HAVE_ATOMIC_IOMAP 34 35 struct io_mapping { 36 resource_size_t base; 37 unsigned long size; 38 pgprot_t prot; 39 }; 40 41 /* 42 * For small address space machines, mapping large objects 43 * into the kernel virtual space isn't practical. Where 44 * available, use fixmap support to dynamically map pages 45 * of the object at run time. 46 */ 47 48 static inline struct io_mapping * 49 io_mapping_create_wc(resource_size_t base, unsigned long size) 50 { 51 struct io_mapping *iomap; 52 53 if (!is_io_mapping_possible(base, size)) 54 return NULL; 55 56 iomap = kmalloc(sizeof(*iomap), GFP_KERNEL); 57 if (!iomap) 58 return NULL; 59 60 iomap->base = base; 61 iomap->size = size; 62 iomap->prot = pgprot_writecombine(__pgprot(__PAGE_KERNEL)); 63 return iomap; 64 } 65 66 static inline void 67 io_mapping_free(struct io_mapping *mapping) 68 { 69 kfree(mapping); 70 } 71 72 /* Atomic map/unmap */ 73 static inline void * 74 io_mapping_map_atomic_wc(struct io_mapping *mapping, unsigned long offset) 75 { 76 resource_size_t phys_addr; 77 unsigned long pfn; 78 79 BUG_ON(offset >= mapping->size); 80 phys_addr = mapping->base + offset; 81 pfn = (unsigned long) (phys_addr >> PAGE_SHIFT); 82 return iomap_atomic_prot_pfn(pfn, KM_USER0, mapping->prot); 83 } 84 85 static inline void 86 io_mapping_unmap_atomic(void *vaddr) 87 { 88 iounmap_atomic(vaddr, KM_USER0); 89 } 90 91 static inline void * 92 io_mapping_map_wc(struct io_mapping *mapping, unsigned long offset) 93 { 94 resource_size_t phys_addr; 95 96 BUG_ON(offset >= mapping->size); 97 phys_addr = mapping->base + offset; 98 99 return ioremap_wc(phys_addr, PAGE_SIZE); 100 } 101 102 static inline void 103 io_mapping_unmap(void *vaddr) 104 { 105 iounmap(vaddr); 106 } 107 108 #else 109 110 /* this struct isn't actually defined anywhere */ 111 struct io_mapping; 112 113 /* Create the io_mapping object*/ 114 static inline struct io_mapping * 115 io_mapping_create_wc(resource_size_t base, unsigned long size) 116 { 117 return (struct io_mapping *) ioremap_wc(base, size); 118 } 119 120 static inline void 121 io_mapping_free(struct io_mapping *mapping) 122 { 123 iounmap(mapping); 124 } 125 126 /* Atomic map/unmap */ 127 static inline void * 128 io_mapping_map_atomic_wc(struct io_mapping *mapping, unsigned long offset) 129 { 130 return ((char *) mapping) + offset; 131 } 132 133 static inline void 134 io_mapping_unmap_atomic(void *vaddr) 135 { 136 } 137 138 /* Non-atomic map/unmap */ 139 static inline void * 140 io_mapping_map_wc(struct io_mapping *mapping, unsigned long offset) 141 { 142 return ((char *) mapping) + offset; 143 } 144 145 static inline void 146 io_mapping_unmap(void *vaddr) 147 { 148 } 149 150 #endif /* HAVE_ATOMIC_IOMAP */ 151 152 #endif /* _LINUX_IO_MAPPING_H */ 153