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 <asm/page.h> 14 15 /* 16 * The io_mapping mechanism provides an abstraction for mapping 17 * individual pages from an io device to the CPU in an efficient fashion. 18 * 19 * See Documentation/io-mapping.txt 20 */ 21 22 struct io_mapping { 23 resource_size_t base; 24 unsigned long size; 25 pgprot_t prot; 26 void __iomem *iomem; 27 }; 28 29 #ifdef CONFIG_HAVE_ATOMIC_IOMAP 30 31 #include <linux/pfn.h> 32 #include <asm/iomap.h> 33 /* 34 * For small address space machines, mapping large objects 35 * into the kernel virtual space isn't practical. Where 36 * available, use fixmap support to dynamically map pages 37 * of the object at run time. 38 */ 39 40 static inline struct io_mapping * 41 io_mapping_init_wc(struct io_mapping *iomap, 42 resource_size_t base, 43 unsigned long size) 44 { 45 pgprot_t prot; 46 47 if (iomap_create_wc(base, size, &prot)) 48 return NULL; 49 50 iomap->base = base; 51 iomap->size = size; 52 iomap->prot = prot; 53 return iomap; 54 } 55 56 static inline void 57 io_mapping_fini(struct io_mapping *mapping) 58 { 59 iomap_free(mapping->base, mapping->size); 60 } 61 62 /* Atomic map/unmap */ 63 static inline void __iomem * 64 io_mapping_map_atomic_wc(struct io_mapping *mapping, 65 unsigned long offset) 66 { 67 resource_size_t phys_addr; 68 69 BUG_ON(offset >= mapping->size); 70 phys_addr = mapping->base + offset; 71 return iomap_atomic_prot_pfn(PHYS_PFN(phys_addr), mapping->prot); 72 } 73 74 static inline void 75 io_mapping_unmap_atomic(void __iomem *vaddr) 76 { 77 iounmap_atomic(vaddr); 78 } 79 80 static inline void __iomem * 81 io_mapping_map_wc(struct io_mapping *mapping, 82 unsigned long offset, 83 unsigned long size) 84 { 85 resource_size_t phys_addr; 86 87 BUG_ON(offset >= mapping->size); 88 phys_addr = mapping->base + offset; 89 90 return ioremap_wc(phys_addr, size); 91 } 92 93 static inline void 94 io_mapping_unmap(void __iomem *vaddr) 95 { 96 iounmap(vaddr); 97 } 98 99 #else 100 101 #include <linux/uaccess.h> 102 #include <asm/pgtable.h> 103 104 /* Create the io_mapping object*/ 105 static inline struct io_mapping * 106 io_mapping_init_wc(struct io_mapping *iomap, 107 resource_size_t base, 108 unsigned long size) 109 { 110 iomap->base = base; 111 iomap->size = size; 112 iomap->iomem = ioremap_wc(base, size); 113 #if defined(pgprot_noncached_wc) /* archs can't agree on a name ... */ 114 iomap->prot = pgprot_noncached_wc(PAGE_KERNEL); 115 #elif defined(pgprot_writecombine) 116 iomap->prot = pgprot_writecombine(PAGE_KERNEL); 117 #else 118 iomap->prot = pgprot_noncached(PAGE_KERNEL); 119 #endif 120 121 return iomap; 122 } 123 124 static inline void 125 io_mapping_fini(struct io_mapping *mapping) 126 { 127 iounmap(mapping->iomem); 128 } 129 130 /* Non-atomic map/unmap */ 131 static inline void __iomem * 132 io_mapping_map_wc(struct io_mapping *mapping, 133 unsigned long offset, 134 unsigned long size) 135 { 136 return mapping->iomem + offset; 137 } 138 139 static inline void 140 io_mapping_unmap(void __iomem *vaddr) 141 { 142 } 143 144 /* Atomic map/unmap */ 145 static inline void __iomem * 146 io_mapping_map_atomic_wc(struct io_mapping *mapping, 147 unsigned long offset) 148 { 149 preempt_disable(); 150 pagefault_disable(); 151 return io_mapping_map_wc(mapping, offset, PAGE_SIZE); 152 } 153 154 static inline void 155 io_mapping_unmap_atomic(void __iomem *vaddr) 156 { 157 io_mapping_unmap(vaddr); 158 pagefault_enable(); 159 preempt_enable(); 160 } 161 162 #endif /* HAVE_ATOMIC_IOMAP */ 163 164 static inline struct io_mapping * 165 io_mapping_create_wc(resource_size_t base, 166 unsigned long size) 167 { 168 struct io_mapping *iomap; 169 170 iomap = kmalloc(sizeof(*iomap), GFP_KERNEL); 171 if (!iomap) 172 return NULL; 173 174 if (!io_mapping_init_wc(iomap, base, size)) { 175 kfree(iomap); 176 return NULL; 177 } 178 179 return iomap; 180 } 181 182 static inline void 183 io_mapping_free(struct io_mapping *iomap) 184 { 185 io_mapping_fini(iomap); 186 kfree(iomap); 187 } 188 189 #endif /* _LINUX_IO_MAPPING_H */ 190