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         if (!IS_ENABLED(CONFIG_PREEMPT_RT))
  73                 preempt_disable();
  74         else
  75                 migrate_disable();
  76         pagefault_disable();
  77         return __iomap_local_pfn_prot(PHYS_PFN(phys_addr), mapping->prot);
  78 }
  79
  80 static inline void
  81 io_mapping_unmap_atomic(void __iomem *vaddr)
  82 {
  83         kunmap_local_indexed((void __force *)vaddr);
  84         pagefault_enable();
  85         if (!IS_ENABLED(CONFIG_PREEMPT_RT))
  86                 preempt_enable();
  87         else
  88                 migrate_enable();
  89 }
  90
  91 static inline void __iomem *
  92 io_mapping_map_local_wc(struct io_mapping *mapping, unsigned long offset)
  93 {
  94         resource_size_t phys_addr;
  95
  96         BUG_ON(offset >= mapping->size);
  97         phys_addr = mapping->base + offset;
  98         return __iomap_local_pfn_prot(PHYS_PFN(phys_addr), mapping->prot);
  99 }
 100
 101 static inline void io_mapping_unmap_local(void __iomem *vaddr)
 102 {
 103         kunmap_local_indexed((void __force *)vaddr);
 104 }
 105
 106 static inline void __iomem *
 107 io_mapping_map_wc(struct io_mapping *mapping,
 108                   unsigned long offset,
 109                   unsigned long size)
 110 {
 111         resource_size_t phys_addr;
 112
 113         BUG_ON(offset >= mapping->size);
 114         phys_addr = mapping->base + offset;
 115
 116         return ioremap_wc(phys_addr, size);
 117 }
 118
 119 static inline void
 120 io_mapping_unmap(void __iomem *vaddr)
 121 {
 122         iounmap(vaddr);
 123 }
 124
 125 #else  /* HAVE_ATOMIC_IOMAP */
 126
 127 #include <linux/uaccess.h>
 128
 129 /* Create the io_mapping object*/
 130 static inline struct io_mapping *
 131 io_mapping_init_wc(struct io_mapping *iomap,
 132                    resource_size_t base,
 133                    unsigned long size)
 134 {
 135         iomap->iomem = ioremap_wc(base, size);
 136         if (!iomap->iomem)
 137                 return NULL;
 138
 139         iomap->base = base;
 140         iomap->size = size;
 141         iomap->prot = pgprot_writecombine(PAGE_KERNEL);
 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         if (!IS_ENABLED(CONFIG_PREEMPT_RT))
 172                 preempt_disable();
 173         else
 174                 migrate_disable();
 175         pagefault_disable();
 176         return io_mapping_map_wc(mapping, offset, PAGE_SIZE);
 177 }
 178
 179 static inline void
 180 io_mapping_unmap_atomic(void __iomem *vaddr)
 181 {
 182         io_mapping_unmap(vaddr);
 183         pagefault_enable();
 184         if (!IS_ENABLED(CONFIG_PREEMPT_RT))
 185                 preempt_enable();
 186         else
 187                 migrate_enable();
 188 }
 189
 190 static inline void __iomem *
 191 io_mapping_map_local_wc(struct io_mapping *mapping, unsigned long offset)
 192 {
 193         return io_mapping_map_wc(mapping, offset, PAGE_SIZE);
 194 }
 195
 196 static inline void io_mapping_unmap_local(void __iomem *vaddr)
 197 {
 198         io_mapping_unmap(vaddr);
 199 }
 200
 201 #endif /* !HAVE_ATOMIC_IOMAP */
 202
 203 static inline struct io_mapping *
 204 io_mapping_create_wc(resource_size_t base,
 205                      unsigned long size)
 206 {
 207         struct io_mapping *iomap;
 208
 209         iomap = kmalloc(sizeof(*iomap), GFP_KERNEL);
 210         if (!iomap)
 211                 return NULL;
 212
 213         if (!io_mapping_init_wc(iomap, base, size)) {
 214                 kfree(iomap);
 215                 return NULL;
 216         }
 217
 218         return iomap;
 219 }
 220
 221 static inline void
 222 io_mapping_free(struct io_mapping *iomap)
 223 {
 224         io_mapping_fini(iomap);
 225         kfree(iomap);
 226 }
 227
 228 int io_mapping_map_user(struct io_mapping *iomap, struct vm_area_struct *vma,
 229                 unsigned long addr, unsigned long pfn, unsigned long size);
 230
 231 #endif /* _LINUX_IO_MAPPING_H */