include/linux/io-mapping.h

   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
 224 int io_mapping_map_user(struct io_mapping *iomap, struct vm_area_struct *vma,
 225                 unsigned long addr, unsigned long pfn, unsigned long size);