arch/arm64/mm/ioremap.c

   1 /*
   2  * Based on arch/arm/mm/ioremap.c
   3  *
   4  * (C) Copyright 1995 1996 Linus Torvalds
   5  * Hacked for ARM by Phil Blundell <philb@gnu.org>
   6  * Hacked to allow all architectures to build, and various cleanups
   7  * by Russell King
   8  * Copyright (C) 2012 ARM Ltd.
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License version 2 as
  12  * published by the Free Software Foundation.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  21  */
  22
  23 #include <linux/export.h>
  24 #include <linux/mm.h>
  25 #include <linux/vmalloc.h>
  26 #include <linux/io.h>
  27
  28 static void __iomem *__ioremap_caller(phys_addr_t phys_addr, size_t size,
  29                                       pgprot_t prot, void *caller)
  30 {
  31         unsigned long last_addr;
  32         unsigned long offset = phys_addr & ~PAGE_MASK;
  33         int err;
  34         unsigned long addr;
  35         struct vm_struct *area;
  36
  37         /*
  38          * Page align the mapping address and size, taking account of any
  39          * offset.
  40          */
  41         phys_addr &= PAGE_MASK;
  42         size = PAGE_ALIGN(size + offset);
  43
  44         /*
  45          * Don't allow wraparound, zero size or outside PHYS_MASK.
  46          */
  47         last_addr = phys_addr + size - 1;
  48         if (!size || last_addr < phys_addr || (last_addr & ~PHYS_MASK))
  49                 return NULL;
  50
  51         /*
  52          * Don't allow RAM to be mapped.
  53          */
  54         if (WARN_ON(pfn_valid(__phys_to_pfn(phys_addr))))
  55                 return NULL;
  56
  57         area = get_vm_area_caller(size, VM_IOREMAP, caller);
  58         if (!area)
  59                 return NULL;
  60         addr = (unsigned long)area->addr;
  61
  62         err = ioremap_page_range(addr, addr + size, phys_addr, prot);
  63         if (err) {
  64                 vunmap((void *)addr);
  65                 return NULL;
  66         }
  67
  68         return (void __iomem *)(offset + addr);
  69 }
  70
  71 void __iomem *__ioremap(phys_addr_t phys_addr, size_t size, pgprot_t prot)
  72 {
  73         return __ioremap_caller(phys_addr, size, prot,
  74                                 __builtin_return_address(0));
  75 }
  76 EXPORT_SYMBOL(__ioremap);
  77
  78 void __iounmap(volatile void __iomem *io_addr)
  79 {
  80         void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);
  81
  82         vunmap(addr);
  83 }
  84 EXPORT_SYMBOL(__iounmap);