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
  66         err = ioremap_page_range(addr, addr + size, phys_addr, prot);
  67         if (err) {
  68                 vunmap((void *)addr);
  69                 return NULL;
  70         }
  71
  72         return (void __iomem *)(offset + addr);
  73 }
  74
  75 void __iomem *__ioremap(phys_addr_t phys_addr, size_t size, pgprot_t prot)
  76 {
  77         return __ioremap_caller(phys_addr, size, prot,
  78                                 __builtin_return_address(0));
  79 }
  80 EXPORT_SYMBOL(__ioremap);
  81
  82 void __iounmap(volatile void __iomem *io_addr)
  83 {
  84         void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);
  85
  86         vunmap(addr);
  87 }
  88 EXPORT_SYMBOL(__iounmap);
  89
  90 void __iomem *ioremap_cache(phys_addr_t phys_addr, size_t size)
  91 {
  92         /* For normal memory we already have a cacheable mapping. */
  93         if (pfn_valid(__phys_to_pfn(phys_addr)))
  94                 return (void __iomem *)__phys_to_virt(phys_addr);
  95
  96         return __ioremap_caller(phys_addr, size, __pgprot(PROT_NORMAL),
  97                                 __builtin_return_address(0));
  98 }
  99 EXPORT_SYMBOL(ioremap_cache);
 100
 101 #ifndef CONFIG_ARM64_64K_PAGES
 102 static pte_t bm_pte[PTRS_PER_PTE] __page_aligned_bss;
 103 #endif
 104
 105 static inline pmd_t * __init early_ioremap_pmd(unsigned long addr)
 106 {
 107         pgd_t *pgd;
 108         pud_t *pud;
 109
 110         pgd = pgd_offset_k(addr);
 111         BUG_ON(pgd_none(*pgd) || pgd_bad(*pgd));
 112
 113         pud = pud_offset(pgd, addr);
 114         BUG_ON(pud_none(*pud) || pud_bad(*pud));
 115
 116         return pmd_offset(pud, addr);
 117 }
 118
 119 static inline pte_t * __init early_ioremap_pte(unsigned long addr)
 120 {
 121         pmd_t *pmd = early_ioremap_pmd(addr);
 122
 123         BUG_ON(pmd_none(*pmd) || pmd_bad(*pmd));
 124
 125         return pte_offset_kernel(pmd, addr);
 126 }
 127
 128 void __init early_ioremap_init(void)
 129 {
 130         pmd_t *pmd;
 131
 132         pmd = early_ioremap_pmd(fix_to_virt(FIX_BTMAP_BEGIN));
 133 #ifndef CONFIG_ARM64_64K_PAGES
 134         /* need to populate pmd for 4k pagesize only */
 135         pmd_populate_kernel(&init_mm, pmd, bm_pte);
 136 #endif
 137         /*
 138          * The boot-ioremap range spans multiple pmds, for which
 139          * we are not prepared:
 140          */
 141         BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT)
 142                      != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT));
 143
 144         if (pmd != early_ioremap_pmd(fix_to_virt(FIX_BTMAP_END))) {
 145                 WARN_ON(1);
 146                 pr_warn("pmd %p != %p\n",
 147                         pmd, early_ioremap_pmd(fix_to_virt(FIX_BTMAP_END)));
 148                 pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
 149                         fix_to_virt(FIX_BTMAP_BEGIN));
 150                 pr_warn("fix_to_virt(FIX_BTMAP_END):   %08lx\n",
 151                         fix_to_virt(FIX_BTMAP_END));
 152
 153                 pr_warn("FIX_BTMAP_END:       %d\n", FIX_BTMAP_END);
 154                 pr_warn("FIX_BTMAP_BEGIN:     %d\n",
 155                         FIX_BTMAP_BEGIN);
 156         }
 157
 158         early_ioremap_setup();
 159 }
 160
 161 void __init __early_set_fixmap(enum fixed_addresses idx,
 162                                phys_addr_t phys, pgprot_t flags)
 163 {
 164         unsigned long addr = __fix_to_virt(idx);
 165         pte_t *pte;
 166
 167         if (idx >= __end_of_fixed_addresses) {
 168                 BUG();
 169                 return;
 170         }
 171
 172         pte = early_ioremap_pte(addr);
 173
 174         if (pgprot_val(flags))
 175                 set_pte(pte, pfn_pte(phys >> PAGE_SHIFT, flags));
 176         else {
 177                 pte_clear(&init_mm, addr, pte);
 178                 flush_tlb_kernel_range(addr, addr+PAGE_SIZE);
 179         }
 180 }