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
  32 static 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
  76 void __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 }
  81 EXPORT_SYMBOL(__ioremap);
  82
  83 void __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 (VMALLOC_START <= addr && addr < VMALLOC_END)
  92                 vunmap((void *)addr);
  93 }
  94 EXPORT_SYMBOL(__iounmap);
  95
  96 void __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 }
 105 EXPORT_SYMBOL(ioremap_cache);
 106
 107 /*
 108  * Must be called after early_fixmap_init
 109  */
 110 void __init early_ioremap_init(void)
 111 {
 112         early_ioremap_setup();
 113 }