LXR linux/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#include <asm/fixmap.h>
  29#include <asm/tlbflush.h>
  30#include <asm/pgalloc.h>
  31
  32static void __iomem *__ioremap_caller(phys_addr_t phys_addr, size_t size,
  33                                      pgprot_t prot, void *caller)
  34{
  35        unsigned long last_addr;
  36        unsigned long offset = phys_addr & ~PAGE_MASK;
  37        int err;
  38        unsigned long addr;
  39        struct vm_struct *area;
  40
  41        /*
  42         * Page align the mapping address and size, taking account of any
  43         * offset.
  44         */
  45        phys_addr &= PAGE_MASK;
  46        size = PAGE_ALIGN(size + offset);
  47
  48        /*
  49         * Don't allow wraparound, zero size or outside PHYS_MASK.
  50         */
  51        last_addr = phys_addr + size - 1;
  52        if (!size || last_addr < phys_addr || (last_addr & ~PHYS_MASK))
  53                return NULL;
  54
  55        /*
  56         * Don't allow RAM to be mapped.
  57         */
  58        if (WARN_ON(pfn_valid(__phys_to_pfn(phys_addr))))
  59                return NULL;
  60
  61        area = get_vm_area_caller(size, VM_IOREMAP, caller);
  62        if (!area)
  63                return NULL;
  64        addr = (unsigned long)area->addr;
  65        area->phys_addr = phys_addr;
  66
  67        err = ioremap_page_range(addr, addr + size, phys_addr, prot);
  68        if (err) {
  69                vunmap((void *)addr);
  70                return NULL;
  71        }
  72
  73        return (void __iomem *)(offset + addr);
  74}
  75
  76void __iomem *__ioremap(phys_addr_t phys_addr, size_t size, pgprot_t prot)
  77{
  78        return __ioremap_caller(phys_addr, size, prot,
  79                                __builtin_return_address(0));
  80}
  81EXPORT_SYMBOL(__ioremap);
  82
  83void __iounmap(volatile void __iomem *io_addr)
  84{
  85        unsigned long addr = (unsigned long)io_addr & PAGE_MASK;
  86
  87        /*
  88         * We could get an address outside vmalloc range in case
  89         * of ioremap_cache() reusing a RAM mapping.
  90         */
  91        if (is_vmalloc_addr((void *)addr))
  92                vunmap((void *)addr);
  93}
  94EXPORT_SYMBOL(__iounmap);
  95
  96void __iomem *ioremap_cache(phys_addr_t phys_addr, size_t size)
  97{
  98        /* For normal memory we already have a cacheable mapping. */
  99        if (pfn_valid(__phys_to_pfn(phys_addr)))
 100                return (void __iomem *)__phys_to_virt(phys_addr);
 101
 102        return __ioremap_caller(phys_addr, size, __pgprot(PROT_NORMAL),
 103                                __builtin_return_address(0));
 104}
 105EXPORT_SYMBOL(ioremap_cache);
 106
 107/*
 108 * Must be called after early_fixmap_init
 109 */
 110void __init early_ioremap_init(void)
 111{
 112        early_ioremap_setup();
 113}
 114