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 <linux/slab.h> 23 #include <linux/bug.h> 24 #include <linux/io.h> 25 #include <asm/page.h> 26 27 /* 28 * The io_mapping mechanism provides an abstraction for mapping 29 * individual pages from an io device to the CPU in an efficient fashion. 30 * 31 * See Documentation/io-mapping.txt 32 */ 33 34 struct io_mapping { 35 resource_size_t base; 36 unsigned long size; 37 pgprot_t prot; 38 void __iomem *iomem; 39 }; 40 41 #ifdef CONFIG_HAVE_ATOMIC_IOMAP 42 43 #include <asm/iomap.h> 44 /* 45 * For small address space machines, mapping large objects 46 * into the kernel virtual space isn't practical. Where 47 * available, use fixmap support to dynamically map pages 48 * of the object at run time. 49 */ 50 51 static inline struct io_mapping * 52 io_mapping_init_wc(struct io_mapping *iomap, 53 resource_size_t base, 54 unsigned long size) 55 { 56 pgprot_t prot; 57 58 if (iomap_create_wc(base, size, &prot)) 59 return NULL; 60 61 iomap->base = base; 62 iomap->size = size; 63 iomap->prot = prot; 64 return iomap; 65 } 66 67 static inline void 68 io_mapping_fini(struct io_mapping *mapping) 69 { 70 iomap_free(mapping->base, mapping->size); 71 } 72 73 /* Atomic map/unmap */ 74 static inline void __iomem * 75 io_mapping_map_atomic_wc(struct io_mapping *mapping, 76 unsigned long offset) 77 { 78 resource_size_t phys_addr; 79 unsigned long pfn; 80 81 BUG_ON(offset >= mapping->size); 82 phys_addr = mapping->base + offset; 83 pfn = (unsigned long) (phys_addr >> PAGE_SHIFT); 84 return iomap_atomic_prot_pfn(pfn, mapping->prot); 85 } 86 87 static inline void 88 io_mapping_unmap_atomic(void __iomem *vaddr) 89 { 90 iounmap_atomic(vaddr); 91 } 92 93 static inline void __iomem * 94 io_mapping_map_wc(struct io_mapping *mapping, 95 unsigned long offset, 96 unsigned long size) 97 { 98 resource_size_t phys_addr; 99 100 BUG_ON(offset >= mapping->size); 101 phys_addr = mapping->base + offset; 102 103 return ioremap_wc(phys_addr, size); 104 } 105 106 static inline void 107 io_mapping_unmap(void __iomem *vaddr) 108 { 109 iounmap(vaddr); 110 } 111 112 #else 113 114 #include <linux/uaccess.h> 115 #include <asm/pgtable.h> 116 117 /* Create the io_mapping object*/ 118 static inline struct io_mapping * 119 io_mapping_init_wc(struct io_mapping *iomap, 120 resource_size_t base, 121 unsigned long size) 122 { 123 iomap->base = base; 124 iomap->size = size; 125 iomap->iomem = ioremap_wc(base, size); 126 iomap->prot = pgprot_writecombine(PAGE_KERNEL); 127 128 return iomap; 129 } 130 131 static inline void 132 io_mapping_fini(struct io_mapping *mapping) 133 { 134 iounmap(mapping->iomem); 135 } 136 137 /* Non-atomic map/unmap */ 138 static inline void __iomem * 139 io_mapping_map_wc(struct io_mapping *mapping, 140 unsigned long offset, 141 unsigned long size) 142 { 143 return mapping->iomem + offset; 144 } 145 146 static inline void 147 io_mapping_unmap(void __iomem *vaddr) 148 { 149 } 150 151 /* Atomic map/unmap */ 152 static inline void __iomem * 153 io_mapping_map_atomic_wc(struct io_mapping *mapping, 154 unsigned long offset) 155 { 156 preempt_disable(); 157 pagefault_disable(); 158 return io_mapping_map_wc(mapping, offset, PAGE_SIZE); 159 } 160 161 static inline void 162 io_mapping_unmap_atomic(void __iomem *vaddr) 163 { 164 io_mapping_unmap(vaddr); 165 pagefault_enable(); 166 preempt_enable(); 167 } 168 169 #endif /* HAVE_ATOMIC_IOMAP */ 170 171 static inline struct io_mapping * 172 io_mapping_create_wc(resource_size_t base, 173 unsigned long size) 174 { 175 struct io_mapping *iomap; 176 177 iomap = kmalloc(sizeof(*iomap), GFP_KERNEL); 178 if (!iomap) 179 return NULL; 180 181 if (!io_mapping_init_wc(iomap, base, size)) { 182 kfree(iomap); 183 return NULL; 184 } 185 186 return iomap; 187 } 188 189 static inline void 190 io_mapping_free(struct io_mapping *iomap) 191 { 192 io_mapping_fini(iomap); 193 kfree(iomap); 194 } 195 196 #endif /* _LINUX_IO_MAPPING_H */ 197