1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 /* 3 * Copyright © 2008 Keith Packard <keithp@keithp.com> 4 */ 5 6 #ifndef _LINUX_IO_MAPPING_H 7 #define _LINUX_IO_MAPPING_H 8 9 #include <linux/types.h> 10 #include <linux/slab.h> 11 #include <linux/bug.h> 12 #include <linux/io.h> 13 #include <linux/pgtable.h> 14 #include <asm/page.h> 15 16 /* 17 * The io_mapping mechanism provides an abstraction for mapping 18 * individual pages from an io device to the CPU in an efficient fashion. 19 * 20 * See Documentation/driver-api/io-mapping.rst 21 */ 22 23 struct io_mapping { 24 resource_size_t base; 25 unsigned long size; 26 pgprot_t prot; 27 void __iomem *iomem; 28 }; 29 30 #ifdef CONFIG_HAVE_ATOMIC_IOMAP 31 32 #include <linux/pfn.h> 33 #include <asm/iomap.h> 34 /* 35 * For small address space machines, mapping large objects 36 * into the kernel virtual space isn't practical. Where 37 * available, use fixmap support to dynamically map pages 38 * of the object at run time. 39 */ 40 41 static inline struct io_mapping * 42 io_mapping_init_wc(struct io_mapping *iomap, 43 resource_size_t base, 44 unsigned long size) 45 { 46 pgprot_t prot; 47 48 if (iomap_create_wc(base, size, &prot)) 49 return NULL; 50 51 iomap->base = base; 52 iomap->size = size; 53 iomap->prot = prot; 54 return iomap; 55 } 56 57 static inline void 58 io_mapping_fini(struct io_mapping *mapping) 59 { 60 iomap_free(mapping->base, mapping->size); 61 } 62 63 /* Atomic map/unmap */ 64 static inline void __iomem * 65 io_mapping_map_atomic_wc(struct io_mapping *mapping, 66 unsigned long offset) 67 { 68 resource_size_t phys_addr; 69 70 BUG_ON(offset >= mapping->size); 71 phys_addr = mapping->base + offset; 72 preempt_disable(); 73 pagefault_disable(); 74 return __iomap_local_pfn_prot(PHYS_PFN(phys_addr), mapping->prot); 75 } 76 77 static inline void 78 io_mapping_unmap_atomic(void __iomem *vaddr) 79 { 80 kunmap_local_indexed((void __force *)vaddr); 81 pagefault_enable(); 82 preempt_enable(); 83 } 84 85 static inline void __iomem * 86 io_mapping_map_local_wc(struct io_mapping *mapping, unsigned long offset) 87 { 88 resource_size_t phys_addr; 89 90 BUG_ON(offset >= mapping->size); 91 phys_addr = mapping->base + offset; 92 return __iomap_local_pfn_prot(PHYS_PFN(phys_addr), mapping->prot); 93 } 94 95 static inline void io_mapping_unmap_local(void __iomem *vaddr) 96 { 97 kunmap_local_indexed((void __force *)vaddr); 98 } 99 100 static inline void __iomem * 101 io_mapping_map_wc(struct io_mapping *mapping, 102 unsigned long offset, 103 unsigned long size) 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, size); 111 } 112 113 static inline void 114 io_mapping_unmap(void __iomem *vaddr) 115 { 116 iounmap(vaddr); 117 } 118 119 #else /* HAVE_ATOMIC_IOMAP */ 120 121 #include <linux/uaccess.h> 122 123 /* Create the io_mapping object*/ 124 static inline struct io_mapping * 125 io_mapping_init_wc(struct io_mapping *iomap, 126 resource_size_t base, 127 unsigned long size) 128 { 129 iomap->iomem = ioremap_wc(base, size); 130 if (!iomap->iomem) 131 return NULL; 132 133 iomap->base = base; 134 iomap->size = size; 135 #if defined(pgprot_noncached_wc) /* archs can't agree on a name ... */ 136 iomap->prot = pgprot_noncached_wc(PAGE_KERNEL); 137 #elif defined(pgprot_writecombine) 138 iomap->prot = pgprot_writecombine(PAGE_KERNEL); 139 #else 140 iomap->prot = pgprot_noncached(PAGE_KERNEL); 141 #endif 142 143 return iomap; 144 } 145 146 static inline void 147 io_mapping_fini(struct io_mapping *mapping) 148 { 149 iounmap(mapping->iomem); 150 } 151 152 /* Non-atomic map/unmap */ 153 static inline void __iomem * 154 io_mapping_map_wc(struct io_mapping *mapping, 155 unsigned long offset, 156 unsigned long size) 157 { 158 return mapping->iomem + offset; 159 } 160 161 static inline void 162 io_mapping_unmap(void __iomem *vaddr) 163 { 164 } 165 166 /* Atomic map/unmap */ 167 static inline void __iomem * 168 io_mapping_map_atomic_wc(struct io_mapping *mapping, 169 unsigned long offset) 170 { 171 preempt_disable(); 172 pagefault_disable(); 173 return io_mapping_map_wc(mapping, offset, PAGE_SIZE); 174 } 175 176 static inline void 177 io_mapping_unmap_atomic(void __iomem *vaddr) 178 { 179 io_mapping_unmap(vaddr); 180 pagefault_enable(); 181 preempt_enable(); 182 } 183 184 static inline void __iomem * 185 io_mapping_map_local_wc(struct io_mapping *mapping, unsigned long offset) 186 { 187 return io_mapping_map_wc(mapping, offset, PAGE_SIZE); 188 } 189 190 static inline void io_mapping_unmap_local(void __iomem *vaddr) 191 { 192 io_mapping_unmap(vaddr); 193 } 194 195 #endif /* !HAVE_ATOMIC_IOMAP */ 196 197 static inline struct io_mapping * 198 io_mapping_create_wc(resource_size_t base, 199 unsigned long size) 200 { 201 struct io_mapping *iomap; 202 203 iomap = kmalloc(sizeof(*iomap), GFP_KERNEL); 204 if (!iomap) 205 return NULL; 206 207 if (!io_mapping_init_wc(iomap, base, size)) { 208 kfree(iomap); 209 return NULL; 210 } 211 212 return iomap; 213 } 214 215 static inline void 216 io_mapping_free(struct io_mapping *iomap) 217 { 218 io_mapping_fini(iomap); 219 kfree(iomap); 220 } 221 222 #endif /* _LINUX_IO_MAPPING_H */ 223