linux/arch/arm64/mm/ioremap.c
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   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
  28static 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
  71void __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}
  76EXPORT_SYMBOL(__ioremap);
  77
  78void __iounmap(volatile void __iomem *io_addr)
  79{
  80        void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);
  81
  82        vunmap(addr);
  83}
  84EXPORT_SYMBOL(__iounmap);
  85