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 <asm/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 #ifdef CONFIG_HAVE_ATOMIC_IOMAP 35 36 #include <asm/iomap.h> 37 38 struct io_mapping { 39 resource_size_t base; 40 unsigned long size; 41 pgprot_t prot; 42 }; 43 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_create_wc(resource_size_t base, unsigned long size) 53 { 54 struct io_mapping *iomap; 55 pgprot_t prot; 56 57 iomap = kmalloc(sizeof(*iomap), GFP_KERNEL); 58 if (!iomap) 59 goto out_err; 60 61 if (iomap_create_wc(base, size, &prot)) 62 goto out_free; 63 64 iomap->base = base; 65 iomap->size = size; 66 iomap->prot = prot; 67 return iomap; 68 69 out_free: 70 kfree(iomap); 71 out_err: 72 return NULL; 73 } 74 75 static inline void 76 io_mapping_free(struct io_mapping *mapping) 77 { 78 iomap_free(mapping->base, mapping->size); 79 kfree(mapping); 80 } 81 82 /* Atomic map/unmap */ 83 static inline void __iomem * 84 io_mapping_map_atomic_wc(struct io_mapping *mapping, 85 unsigned long offset) 86 { 87 resource_size_t phys_addr; 88 unsigned long pfn; 89 90 BUG_ON(offset >= mapping->size); 91 phys_addr = mapping->base + offset; 92 pfn = (unsigned long) (phys_addr >> PAGE_SHIFT); 93 return iomap_atomic_prot_pfn(pfn, mapping->prot); 94 } 95 96 static inline void 97 io_mapping_unmap_atomic(void __iomem *vaddr) 98 { 99 iounmap_atomic(vaddr); 100 } 101 102 static inline void __iomem * 103 io_mapping_map_wc(struct io_mapping *mapping, unsigned long offset) 104 { 105 resource_size_t phys_addr; 106 107 BUG_ON(offset >= mapping->size); 108 phys_addr = mapping->base + offset; 109 110 return ioremap_wc(phys_addr, PAGE_SIZE); 111 } 112 113 static inline void 114 io_mapping_unmap(void __iomem *vaddr) 115 { 116 iounmap(vaddr); 117 } 118 119 #else 120 121 #include <linux/uaccess.h> 122 123 /* this struct isn't actually defined anywhere */ 124 struct io_mapping; 125 126 /* Create the io_mapping object*/ 127 static inline struct io_mapping * 128 io_mapping_create_wc(resource_size_t base, unsigned long size) 129 { 130 return (struct io_mapping __force *) ioremap_wc(base, size); 131 } 132 133 static inline void 134 io_mapping_free(struct io_mapping *mapping) 135 { 136 iounmap((void __force __iomem *) mapping); 137 } 138 139 /* Atomic map/unmap */ 140 static inline void __iomem * 141 io_mapping_map_atomic_wc(struct io_mapping *mapping, 142 unsigned long offset) 143 { 144 pagefault_disable(); 145 return ((char __force __iomem *) mapping) + offset; 146 } 147 148 static inline void 149 io_mapping_unmap_atomic(void __iomem *vaddr) 150 { 151 pagefault_enable(); 152 } 153 154 /* Non-atomic map/unmap */ 155 static inline void __iomem * 156 io_mapping_map_wc(struct io_mapping *mapping, unsigned long offset) 157 { 158 return ((char __force __iomem *) mapping) + offset; 159 } 160 161 static inline void 162 io_mapping_unmap(void __iomem *vaddr) 163 { 164 } 165 166 #endif /* HAVE_ATOMIC_IOMAP */ 167 168 #endif /* _LINUX_IO_MAPPING_H */ 169