LXR linux/arch/sh/mm/ioremap

   1/*
   2 * Re-map IO memory to kernel address space so that we can access it.
   3 *
   4 * These functions should only be used when it is necessary to map a
   5 * physical address space into the kernel address space before ioremap()
   6 * can be used, e.g. early in boot before paging_init().
   7 *
   8 * Copyright (C) 2009  Matt Fleming
   9 */
  10
  11#include <linux/vmalloc.h>
  12#include <linux/ioport.h>
  13#include <linux/module.h>
  14#include <linux/mm.h>
  15#include <linux/io.h>
  16#include <linux/bootmem.h>
  17#include <linux/proc_fs.h>
  18#include <asm/fixmap.h>
  19#include <asm/page.h>
  20#include <asm/pgalloc.h>
  21#include <asm/addrspace.h>
  22#include <asm/cacheflush.h>
  23#include <asm/tlbflush.h>
  24#include <asm/mmu.h>
  25#include <asm/mmu_context.h>
  26
  27struct ioremap_map {
  28        void __iomem *addr;
  29        unsigned long size;
  30        unsigned long fixmap_addr;
  31};
  32
  33static struct ioremap_map ioremap_maps[FIX_N_IOREMAPS];
  34
  35void __init ioremap_fixed_init(void)
  36{
  37        struct ioremap_map *map;
  38        int i;
  39
  40        for (i = 0; i < FIX_N_IOREMAPS; i++) {
  41                map = &ioremap_maps[i];
  42                map->fixmap_addr = __fix_to_virt(FIX_IOREMAP_BEGIN + i);
  43        }
  44}
  45
  46void __init __iomem *
  47ioremap_fixed(phys_addr_t phys_addr, unsigned long size, pgprot_t prot)
  48{
  49        enum fixed_addresses idx0, idx;
  50        struct ioremap_map *map;
  51        unsigned int nrpages;
  52        unsigned long offset;
  53        int i, slot;
  54
  55        /*
  56         * Mappings have to be page-aligned
  57         */
  58        offset = phys_addr & ~PAGE_MASK;
  59        phys_addr &= PAGE_MASK;
  60        size = PAGE_ALIGN(phys_addr + size) - phys_addr;
  61
  62        slot = -1;
  63        for (i = 0; i < FIX_N_IOREMAPS; i++) {
  64                map = &ioremap_maps[i];
  65                if (!map->addr) {
  66                        map->size = size;
  67                        slot = i;
  68                        break;
  69                }
  70        }
  71
  72        if (slot < 0)
  73                return NULL;
  74
  75        /*
  76         * Mappings have to fit in the FIX_IOREMAP area.
  77         */
  78        nrpages = size >> PAGE_SHIFT;
  79        if (nrpages > FIX_N_IOREMAPS)
  80                return NULL;
  81
  82        /*
  83         * Ok, go for it..
  84         */
  85        idx0 = FIX_IOREMAP_BEGIN + slot;
  86        idx = idx0;
  87        while (nrpages > 0) {
  88                pgprot_val(prot) |= _PAGE_WIRED;
  89                __set_fixmap(idx, phys_addr, prot);
  90                phys_addr += PAGE_SIZE;
  91                idx++;
  92                --nrpages;
  93        }
  94
  95        map->addr = (void __iomem *)(offset + map->fixmap_addr);
  96        return map->addr;
  97}
  98
  99int iounmap_fixed(void __iomem *addr)
 100{
 101        enum fixed_addresses idx;
 102        struct ioremap_map *map;
 103        unsigned int nrpages;
 104        int i, slot;
 105
 106        slot = -1;
 107        for (i = 0; i < FIX_N_IOREMAPS; i++) {
 108                map = &ioremap_maps[i];
 109                if (map->addr == addr) {
 110                        slot = i;
 111                        break;
 112                }
 113        }
 114
 115        /*
 116         * If we don't match, it's not for us.
 117         */
 118        if (slot < 0)
 119                return -EINVAL;
 120
 121        nrpages = map->size >> PAGE_SHIFT;
 122
 123        idx = FIX_IOREMAP_BEGIN + slot + nrpages - 1;
 124        while (nrpages > 0) {
 125                __clear_fixmap(idx, __pgprot(_PAGE_WIRED));
 126                --idx;
 127                --nrpages;
 128        }
 129
 130        map->size = 0;
 131        map->addr = NULL;
 132
 133        return 0;
 134}
 135