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 static pte_t bm_pte[PTRS_PER_PTE] __page_aligned_bss;
 102 #ifndef CONFIG_ARM64_64K_PAGES
 103 static pte_t bm_pmd[PTRS_PER_PMD] __page_aligned_bss;
 104 #endif
 105
 106 static inline pud_t * __init early_ioremap_pud(unsigned long addr)
 107 {
 108         pgd_t *pgd;
 109
 110         pgd = pgd_offset_k(addr);
 111         BUG_ON(pgd_none(*pgd) || pgd_bad(*pgd));
 112
 113         return pud_offset(pgd, addr);
 114 }
 115
 116 static inline pmd_t * __init early_ioremap_pmd(unsigned long addr)
 117 {
 118         pud_t *pud = early_ioremap_pud(addr);
 119
 120         BUG_ON(pud_none(*pud) || pud_bad(*pud));
 121
 122         return pmd_offset(pud, addr);
 123 }
 124
 125 static inline pte_t * __init early_ioremap_pte(unsigned long addr)
 126 {
 127         pmd_t *pmd = early_ioremap_pmd(addr);
 128
 129         BUG_ON(pmd_none(*pmd) || pmd_bad(*pmd));
 130
 131         return pte_offset_kernel(pmd, addr);
 132 }
 133
 134 void __init early_ioremap_init(void)
 135 {
 136         pgd_t *pgd;
 137         pud_t *pud;
 138         pmd_t *pmd;
 139         unsigned long addr = fix_to_virt(FIX_BTMAP_BEGIN);
 140
 141         pgd = pgd_offset_k(addr);
 142         pud = pud_offset(pgd, addr);
 143         pud_populate(&init_mm, pud, bm_pmd);
 144         pmd = pmd_offset(pud, addr);
 145         pmd_populate_kernel(&init_mm, pmd, bm_pte);
 146
 147         /*
 148          * The boot-ioremap range spans multiple pmds, for which
 149          * we are not prepared:
 150          */
 151         BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT)
 152                      != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT));
 153
 154         if (pmd != early_ioremap_pmd(fix_to_virt(FIX_BTMAP_END))) {
 155                 WARN_ON(1);
 156                 pr_warn("pmd %p != %p\n",
 157                         pmd, early_ioremap_pmd(fix_to_virt(FIX_BTMAP_END)));
 158                 pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
 159                         fix_to_virt(FIX_BTMAP_BEGIN));
 160                 pr_warn("fix_to_virt(FIX_BTMAP_END):   %08lx\n",
 161                         fix_to_virt(FIX_BTMAP_END));
 162
 163                 pr_warn("FIX_BTMAP_END:       %d\n", FIX_BTMAP_END);
 164                 pr_warn("FIX_BTMAP_BEGIN:     %d\n",
 165                         FIX_BTMAP_BEGIN);
 166         }
 167
 168         early_ioremap_setup();
 169 }
 170
 171 void __init __early_set_fixmap(enum fixed_addresses idx,
 172                                phys_addr_t phys, pgprot_t flags)
 173 {
 174         unsigned long addr = __fix_to_virt(idx);
 175         pte_t *pte;
 176
 177         if (idx >= __end_of_fixed_addresses) {
 178                 BUG();
 179                 return;
 180         }
 181
 182         pte = early_ioremap_pte(addr);
 183
 184         if (pgprot_val(flags))
 185                 set_pte(pte, pfn_pte(phys >> PAGE_SHIFT, flags));
 186         else {
 187                 pte_clear(&init_mm, addr, pte);
 188                 flush_tlb_kernel_range(addr, addr+PAGE_SIZE);
 189         }
 190 }