arch/sh/mm/ioremap_fixed.c

   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
  27 struct ioremap_map {
  28         void __iomem *addr;
  29         unsigned long size;
  30         unsigned long fixmap_addr;
  31 };
  32
  33 static struct ioremap_map ioremap_maps[FIX_N_IOREMAPS];
  34
  35 void __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
  46 void __init __iomem *
  47 ioremap_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
  99 int 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 }