1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 /* 3 * Copyright © 2008 Keith Packard <[email protected]> 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 return iomap_atomic_prot_pfn(PHYS_PFN(phys_addr), mapping->prot); 73 } 74 75 static inline void 76 io_mapping_unmap_atomic(void __iomem *vaddr) 77 { 78 iounmap_atomic(vaddr); 79 } 80 81 static inline void __iomem * 82 io_mapping_map_wc(struct io_mapping *mapping, 83 unsigned long offset, 84 unsigned long size) 85 { 86 resource_size_t phys_addr; 87 88 BUG_ON(offset >= mapping->size); 89 phys_addr = mapping->base + offset; 90 91 return ioremap_wc(phys_addr, size); 92 } 93 94 static inline void 95 io_mapping_unmap(void __iomem *vaddr) 96 { 97 iounmap(vaddr); 98 } 99 100 #else 101 102 #include <linux/uaccess.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->iomem = ioremap_wc(base, size); 111 if (!iomap->iomem) 112 return NULL; 113 114 iomap->base = base; 115 iomap->size = size; 116 #if defined(pgprot_noncached_wc) /* archs can't agree on a name ... */ 117 iomap->prot = pgprot_noncached_wc(PAGE_KERNEL); 118 #elif defined(pgprot_writecombine) 119 iomap->prot = pgprot_writecombine(PAGE_KERNEL); 120 #else 121 iomap->prot = pgprot_noncached(PAGE_KERNEL); 122 #endif 123 124 return iomap; 125 } 126 127 static inline void 128 io_mapping_fini(struct io_mapping *mapping) 129 { 130 iounmap(mapping->iomem); 131 } 132 133 /* Non-atomic map/unmap */ 134 static inline void __iomem * 135 io_mapping_map_wc(struct io_mapping *mapping, 136 unsigned long offset, 137 unsigned long size) 138 { 139 return mapping->iomem + offset; 140 } 141 142 static inline void 143 io_mapping_unmap(void __iomem *vaddr) 144 { 145 } 146 147 /* Atomic map/unmap */ 148 static inline void __iomem * 149 io_mapping_map_atomic_wc(struct io_mapping *mapping, 150 unsigned long offset) 151 { 152 preempt_disable(); 153 pagefault_disable(); 154 return io_mapping_map_wc(mapping, offset, PAGE_SIZE); 155 } 156 157 static inline void 158 io_mapping_unmap_atomic(void __iomem *vaddr) 159 { 160 io_mapping_unmap(vaddr); 161 pagefault_enable(); 162 preempt_enable(); 163 } 164 165 #endif /* HAVE_ATOMIC_IOMAP */ 166 167 static inline struct io_mapping * 168 io_mapping_create_wc(resource_size_t base, 169 unsigned long size) 170 { 171 struct io_mapping *iomap; 172 173 iomap = kmalloc(sizeof(*iomap), GFP_KERNEL); 174 if (!iomap) 175 return NULL; 176 177 if (!io_mapping_init_wc(iomap, base, size)) { 178 kfree(iomap); 179 return NULL; 180 } 181 182 return iomap; 183 } 184 185 static inline void 186 io_mapping_free(struct io_mapping *iomap) 187 { 188 io_mapping_fini(iomap); 189 kfree(iomap); 190 } 191 192 #endif /* _LINUX_IO_MAPPING_H */ 193