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 <asm/io.h> 24 #include <asm/page.h> 25 #include <asm/iomap.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 #ifdef CONFIG_HAVE_ATOMIC_IOMAP 35 36 struct io_mapping { 37 resource_size_t base; 38 unsigned long size; 39 pgprot_t prot; 40 }; 41 42 /* 43 * For small address space machines, mapping large objects 44 * into the kernel virtual space isn't practical. Where 45 * available, use fixmap support to dynamically map pages 46 * of the object at run time. 47 */ 48 49 static inline struct io_mapping * 50 io_mapping_create_wc(resource_size_t base, unsigned long size) 51 { 52 struct io_mapping *iomap; 53 pgprot_t prot; 54 55 iomap = kmalloc(sizeof(*iomap), GFP_KERNEL); 56 if (!iomap) 57 goto out_err; 58 59 if (iomap_create_wc(base, size, &prot)) 60 goto out_free; 61 62 iomap->base = base; 63 iomap->size = size; 64 iomap->prot = prot; 65 return iomap; 66 67 out_free: 68 kfree(iomap); 69 out_err: 70 return NULL; 71 } 72 73 static inline void 74 io_mapping_free(struct io_mapping *mapping) 75 { 76 iomap_free(mapping->base, mapping->size); 77 kfree(mapping); 78 } 79 80 /* Atomic map/unmap */ 81 static inline void * 82 io_mapping_map_atomic_wc(struct io_mapping *mapping, unsigned long offset) 83 { 84 resource_size_t phys_addr; 85 unsigned long pfn; 86 87 BUG_ON(offset >= mapping->size); 88 phys_addr = mapping->base + offset; 89 pfn = (unsigned long) (phys_addr >> PAGE_SHIFT); 90 return iomap_atomic_prot_pfn(pfn, KM_USER0, mapping->prot); 91 } 92 93 static inline void 94 io_mapping_unmap_atomic(void *vaddr) 95 { 96 iounmap_atomic(vaddr, KM_USER0); 97 } 98 99 static inline void * 100 io_mapping_map_wc(struct io_mapping *mapping, unsigned long offset) 101 { 102 resource_size_t phys_addr; 103 104 BUG_ON(offset >= mapping->size); 105 phys_addr = mapping->base + offset; 106 107 return ioremap_wc(phys_addr, PAGE_SIZE); 108 } 109 110 static inline void 111 io_mapping_unmap(void *vaddr) 112 { 113 iounmap(vaddr); 114 } 115 116 #else 117 118 /* this struct isn't actually defined anywhere */ 119 struct io_mapping; 120 121 /* Create the io_mapping object*/ 122 static inline struct io_mapping * 123 io_mapping_create_wc(resource_size_t base, unsigned long size) 124 { 125 return (struct io_mapping *) ioremap_wc(base, size); 126 } 127 128 static inline void 129 io_mapping_free(struct io_mapping *mapping) 130 { 131 iounmap(mapping); 132 } 133 134 /* Atomic map/unmap */ 135 static inline void * 136 io_mapping_map_atomic_wc(struct io_mapping *mapping, unsigned long offset) 137 { 138 return ((char *) mapping) + offset; 139 } 140 141 static inline void 142 io_mapping_unmap_atomic(void *vaddr) 143 { 144 } 145 146 /* Non-atomic map/unmap */ 147 static inline void * 148 io_mapping_map_wc(struct io_mapping *mapping, unsigned long offset) 149 { 150 return ((char *) mapping) + offset; 151 } 152 153 static inline void 154 io_mapping_unmap(void *vaddr) 155 { 156 } 157 158 #endif /* HAVE_ATOMIC_IOMAP */ 159 160 #endif /* _LINUX_IO_MAPPING_H */ 161