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 pgprot_t prot; 53 54 iomap = kmalloc(sizeof(*iomap), GFP_KERNEL); 55 if (!iomap) 56 goto out_err; 57 58 if (iomap_create_wc(base, size, &prot)) 59 goto out_free; 60 61 iomap->base = base; 62 iomap->size = size; 63 iomap->prot = prot; 64 return iomap; 65 66 out_free: 67 kfree(iomap); 68 out_err: 69 return NULL; 70 } 71 72 static inline void 73 io_mapping_free(struct io_mapping *mapping) 74 { 75 iomap_free(mapping->base, mapping->size); 76 kfree(mapping); 77 } 78 79 /* Atomic map/unmap */ 80 static inline void * 81 io_mapping_map_atomic_wc(struct io_mapping *mapping, unsigned long offset) 82 { 83 resource_size_t phys_addr; 84 unsigned long pfn; 85 86 BUG_ON(offset >= mapping->size); 87 phys_addr = mapping->base + offset; 88 pfn = (unsigned long) (phys_addr >> PAGE_SHIFT); 89 return iomap_atomic_prot_pfn(pfn, KM_USER0, mapping->prot); 90 } 91 92 static inline void 93 io_mapping_unmap_atomic(void *vaddr) 94 { 95 iounmap_atomic(vaddr, KM_USER0); 96 } 97 98 static inline void * 99 io_mapping_map_wc(struct io_mapping *mapping, unsigned long offset) 100 { 101 resource_size_t phys_addr; 102 103 BUG_ON(offset >= mapping->size); 104 phys_addr = mapping->base + offset; 105 106 return ioremap_wc(phys_addr, PAGE_SIZE); 107 } 108 109 static inline void 110 io_mapping_unmap(void *vaddr) 111 { 112 iounmap(vaddr); 113 } 114 115 #else 116 117 /* this struct isn't actually defined anywhere */ 118 struct io_mapping; 119 120 /* Create the io_mapping object*/ 121 static inline struct io_mapping * 122 io_mapping_create_wc(resource_size_t base, unsigned long size) 123 { 124 return (struct io_mapping *) ioremap_wc(base, size); 125 } 126 127 static inline void 128 io_mapping_free(struct io_mapping *mapping) 129 { 130 iounmap(mapping); 131 } 132 133 /* Atomic map/unmap */ 134 static inline void * 135 io_mapping_map_atomic_wc(struct io_mapping *mapping, unsigned long offset) 136 { 137 return ((char *) mapping) + offset; 138 } 139 140 static inline void 141 io_mapping_unmap_atomic(void *vaddr) 142 { 143 } 144 145 /* Non-atomic map/unmap */ 146 static inline void * 147 io_mapping_map_wc(struct io_mapping *mapping, unsigned long offset) 148 { 149 return ((char *) mapping) + offset; 150 } 151 152 static inline void 153 io_mapping_unmap(void *vaddr) 154 { 155 } 156 157 #endif /* HAVE_ATOMIC_IOMAP */ 158 159 #endif /* _LINUX_IO_MAPPING_H */ 160