LXR linux/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 <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
  22struct 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 <asm/iomap.h>
  32/*
  33 * For small address space machines, mapping large objects
  34 * into the kernel virtual space isn't practical. Where
  35 * available, use fixmap support to dynamically map pages
  36 * of the object at run time.
  37 */
  38
  39static inline struct io_mapping *
  40io_mapping_init_wc(struct io_mapping *iomap,
  41                   resource_size_t base,
  42                   unsigned long size)
  43{
  44        pgprot_t prot;
  45
  46        if (iomap_create_wc(base, size, &prot))
  47                return NULL;
  48
  49        iomap->base = base;
  50        iomap->size = size;
  51        iomap->prot = prot;
  52        return iomap;
  53}
  54
  55static inline void
  56io_mapping_fini(struct io_mapping *mapping)
  57{
  58        iomap_free(mapping->base, mapping->size);
  59}
  60
  61/* Atomic map/unmap */
  62static inline void __iomem *
  63io_mapping_map_atomic_wc(struct io_mapping *mapping,
  64                         unsigned long offset)
  65{
  66        resource_size_t phys_addr;
  67        unsigned long pfn;
  68
  69        BUG_ON(offset >= mapping->size);
  70        phys_addr = mapping->base + offset;
  71        pfn = (unsigned long) (phys_addr >> PAGE_SHIFT);
  72        return iomap_atomic_prot_pfn(pfn, mapping->prot);
  73}
  74
  75static inline void
  76io_mapping_unmap_atomic(void __iomem *vaddr)
  77{
  78        iounmap_atomic(vaddr);
  79}
  80
  81static inline void __iomem *
  82io_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
  94static inline void
  95io_mapping_unmap(void __iomem *vaddr)
  96{
  97        iounmap(vaddr);
  98}
  99
 100#else
 101
 102#include <linux/uaccess.h>
 103#include <asm/pgtable.h>
 104
 105/* Create the io_mapping object*/
 106static inline struct io_mapping *
 107io_mapping_init_wc(struct io_mapping *iomap,
 108                   resource_size_t base,
 109                   unsigned long size)
 110{
 111        iomap->base = base;
 112        iomap->size = size;
 113        iomap->iomem = ioremap_wc(base, size);
 114#if defined(pgprot_noncached_wc) /* archs can't agree on a name ... */
 115        iomap->prot = pgprot_noncached_wc(PAGE_KERNEL);
 116#elif defined(pgprot_writecombine)
 117        iomap->prot = pgprot_writecombine(PAGE_KERNEL);
 118#else
 119        iomap->prot = pgprot_noncached(PAGE_KERNEL);
 120#endif
 121
 122        return iomap;
 123}
 124
 125static inline void
 126io_mapping_fini(struct io_mapping *mapping)
 127{
 128        iounmap(mapping->iomem);
 129}
 130
 131/* Non-atomic map/unmap */
 132static inline void __iomem *
 133io_mapping_map_wc(struct io_mapping *mapping,
 134                  unsigned long offset,
 135                  unsigned long size)
 136{
 137        return mapping->iomem + offset;
 138}
 139
 140static inline void
 141io_mapping_unmap(void __iomem *vaddr)
 142{
 143}
 144
 145/* Atomic map/unmap */
 146static inline void __iomem *
 147io_mapping_map_atomic_wc(struct io_mapping *mapping,
 148                         unsigned long offset)
 149{
 150        preempt_disable();
 151        pagefault_disable();
 152        return io_mapping_map_wc(mapping, offset, PAGE_SIZE);
 153}
 154
 155static inline void
 156io_mapping_unmap_atomic(void __iomem *vaddr)
 157{
 158        io_mapping_unmap(vaddr);
 159        pagefault_enable();
 160        preempt_enable();
 161}
 162
 163#endif /* HAVE_ATOMIC_IOMAP */
 164
 165static inline struct io_mapping *
 166io_mapping_create_wc(resource_size_t base,
 167                     unsigned long size)
 168{
 169        struct io_mapping *iomap;
 170
 171        iomap = kmalloc(sizeof(*iomap), GFP_KERNEL);
 172        if (!iomap)
 173                return NULL;
 174
 175        if (!io_mapping_init_wc(iomap, base, size)) {
 176                kfree(iomap);
 177                return NULL;
 178        }
 179
 180        return iomap;
 181}
 182
 183static inline void
 184io_mapping_free(struct io_mapping *iomap)
 185{
 186        io_mapping_fini(iomap);
 187        kfree(iomap);
 188}
 189
 190#endif /* _LINUX_IO_MAPPING_H */
 191