arch/sh/mm/ioremap_fixed.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Re-map IO memory to kernel address space so that we can access it.
   4  *
   5  * These functions should only be used when it is necessary to map a
   6  * physical address space into the kernel address space before ioremap()
   7  * can be used, e.g. early in boot before paging_init().
   8  *
   9  * Copyright (C) 2009  Matt Fleming
  10  */
  11
  12 #include <linux/vmalloc.h>
  13 #include <linux/ioport.h>
  14 #include <linux/module.h>
  15 #include <linux/mm.h>
  16 #include <linux/io.h>
  17 #include <linux/memblock.h>
  18 #include <linux/proc_fs.h>
  19 #include <asm/fixmap.h>
  20 #include <asm/page.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 #include "ioremap.h"
  27
  28 struct ioremap_map {
  29         void __iomem *addr;
  30         unsigned long size;
  31         unsigned long fixmap_addr;
  32 };
  33
  34 static struct ioremap_map ioremap_maps[FIX_N_IOREMAPS];
  35
  36 void __init ioremap_fixed_init(void)
  37 {
  38         struct ioremap_map *map;
  39         int i;
  40
  41         for (i = 0; i < FIX_N_IOREMAPS; i++) {
  42                 map = &ioremap_maps[i];
  43                 map->fixmap_addr = __fix_to_virt(FIX_IOREMAP_BEGIN + i);
  44         }
  45 }
  46
  47 void __init __iomem *
  48 ioremap_fixed(phys_addr_t phys_addr, unsigned long size, pgprot_t prot)
  49 {
  50         enum fixed_addresses idx0, idx;
  51         struct ioremap_map *map;
  52         unsigned int nrpages;
  53         unsigned long offset;
  54         int i, slot;
  55
  56         /*
  57          * Mappings have to be page-aligned
  58          */
  59         offset = phys_addr & ~PAGE_MASK;
  60         phys_addr &= PAGE_MASK;
  61         size = PAGE_ALIGN(phys_addr + size) - phys_addr;
  62
  63         slot = -1;
  64         for (i = 0; i < FIX_N_IOREMAPS; i++) {
  65                 map = &ioremap_maps[i];
  66                 if (!map->addr) {
  67                         map->size = size;
  68                         slot = i;
  69                         break;
  70                 }
  71         }
  72
  73         if (slot < 0)
  74                 return NULL;
  75
  76         /*
  77          * Mappings have to fit in the FIX_IOREMAP area.
  78          */
  79         nrpages = size >> PAGE_SHIFT;
  80         if (nrpages > FIX_N_IOREMAPS)
  81                 return NULL;
  82
  83         /*
  84          * Ok, go for it..
  85          */
  86         idx0 = FIX_IOREMAP_BEGIN + slot;
  87         idx = idx0;
  88         while (nrpages > 0) {
  89                 pgprot_val(prot) |= _PAGE_WIRED;
  90                 __set_fixmap(idx, phys_addr, prot);
  91                 phys_addr += PAGE_SIZE;
  92                 idx++;
  93                 --nrpages;
  94         }
  95
  96         map->addr = (void __iomem *)(offset + map->fixmap_addr);
  97         return map->addr;
  98 }
  99
 100 int iounmap_fixed(void __iomem *addr)
 101 {
 102         enum fixed_addresses idx;
 103         struct ioremap_map *map;
 104         unsigned int nrpages;
 105         int i, slot;
 106
 107         slot = -1;
 108         for (i = 0; i < FIX_N_IOREMAPS; i++) {
 109                 map = &ioremap_maps[i];
 110                 if (map->addr == addr) {
 111                         slot = i;
 112                         break;
 113                 }
 114         }
 115
 116         /*
 117          * If we don't match, it's not for us.
 118          */
 119         if (slot < 0)
 120                 return -EINVAL;
 121
 122         nrpages = map->size >> PAGE_SHIFT;
 123
 124         idx = FIX_IOREMAP_BEGIN + slot + nrpages - 1;
 125         while (nrpages > 0) {
 126                 __clear_fixmap(idx, __pgprot(_PAGE_WIRED));
 127                 --idx;
 128                 --nrpages;
 129         }
 130
 131         map->size = 0;
 132         map->addr = NULL;
 133
 134         return 0;
 135 }