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 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 #include <asm/iomap.h> 36 37 struct io_mapping { 38 resource_size_t base; 39 unsigned long size; 40 pgprot_t prot; 41 }; 42 43 /* 44 * For small address space machines, mapping large objects 45 * into the kernel virtual space isn't practical. Where 46 * available, use fixmap support to dynamically map pages 47 * of the object at run time. 48 */ 49 50 static inline struct io_mapping * 51 io_mapping_create_wc(resource_size_t base, unsigned long size) 52 { 53 struct io_mapping *iomap; 54 pgprot_t prot; 55 56 iomap = kmalloc(sizeof(*iomap), GFP_KERNEL); 57 if (!iomap) 58 goto out_err; 59 60 if (iomap_create_wc(base, size, &prot)) 61 goto out_free; 62 63 iomap->base = base; 64 iomap->size = size; 65 iomap->prot = prot; 66 return iomap; 67 68 out_free: 69 kfree(iomap); 70 out_err: 71 return NULL; 72 } 73 74 static inline void 75 io_mapping_free(struct io_mapping *mapping) 76 { 77 iomap_free(mapping->base, mapping->size); 78 kfree(mapping); 79 } 80 81 /* Atomic map/unmap */ 82 static inline void __iomem * 83 io_mapping_map_atomic_wc(struct io_mapping *mapping, 84 unsigned long offset) 85 { 86 resource_size_t phys_addr; 87 unsigned long pfn; 88 89 BUG_ON(offset >= mapping->size); 90 phys_addr = mapping->base + offset; 91 pfn = (unsigned long) (phys_addr >> PAGE_SHIFT); 92 return iomap_atomic_prot_pfn(pfn, mapping->prot); 93 } 94 95 static inline void 96 io_mapping_unmap_atomic(void __iomem *vaddr) 97 { 98 iounmap_atomic(vaddr); 99 } 100 101 static inline void __iomem * 102 io_mapping_map_wc(struct io_mapping *mapping, unsigned long offset) 103 { 104 resource_size_t phys_addr; 105 106 BUG_ON(offset >= mapping->size); 107 phys_addr = mapping->base + offset; 108 109 return ioremap_wc(phys_addr, PAGE_SIZE); 110 } 111 112 static inline void 113 io_mapping_unmap(void __iomem *vaddr) 114 { 115 iounmap(vaddr); 116 } 117 118 #else 119 120 #include <linux/uaccess.h> 121 122 /* this struct isn't actually defined anywhere */ 123 struct io_mapping; 124 125 /* Create the io_mapping object*/ 126 static inline struct io_mapping * 127 io_mapping_create_wc(resource_size_t base, unsigned long size) 128 { 129 return (struct io_mapping __force *) ioremap_wc(base, size); 130 } 131 132 static inline void 133 io_mapping_free(struct io_mapping *mapping) 134 { 135 iounmap((void __force __iomem *) mapping); 136 } 137 138 /* Atomic map/unmap */ 139 static inline void __iomem * 140 io_mapping_map_atomic_wc(struct io_mapping *mapping, 141 unsigned long offset) 142 { 143 pagefault_disable(); 144 return ((char __force __iomem *) mapping) + offset; 145 } 146 147 static inline void 148 io_mapping_unmap_atomic(void __iomem *vaddr) 149 { 150 pagefault_enable(); 151 } 152 153 /* Non-atomic map/unmap */ 154 static inline void __iomem * 155 io_mapping_map_wc(struct io_mapping *mapping, unsigned long offset) 156 { 157 return ((char __force __iomem *) mapping) + offset; 158 } 159 160 static inline void 161 io_mapping_unmap(void __iomem *vaddr) 162 { 163 } 164 165 #endif /* HAVE_ATOMIC_IOMAP */ 166 167 #endif /* _LINUX_IO_MAPPING_H */ 168