1 /* 2 * This file is subject to the terms and conditions of the GNU General Public 3 * License. See the file "COPYING" in the main directory of this archive 4 * for more details. 5 * 6 * (C) Copyright 1995 1996 Linus Torvalds 7 * (C) Copyright 2001, 2002 Ralf Baechle 8 */ 9 #include <linux/export.h> 10 #include <asm/addrspace.h> 11 #include <asm/byteorder.h> 12 #include <linux/ioport.h> 13 #include <linux/sched.h> 14 #include <linux/slab.h> 15 #include <linux/vmalloc.h> 16 #include <linux/mm_types.h> 17 #include <asm/cacheflush.h> 18 #include <asm/io.h> 19 #include <asm/tlbflush.h> 20 21 static inline void remap_area_pte(pte_t * pte, unsigned long address, 22 phys_addr_t size, phys_addr_t phys_addr, unsigned long flags) 23 { 24 phys_addr_t end; 25 unsigned long pfn; 26 pgprot_t pgprot = __pgprot(_PAGE_GLOBAL | _PAGE_PRESENT | __READABLE 27 | __WRITEABLE | flags); 28 29 address &= ~PMD_MASK; 30 end = address + size; 31 if (end > PMD_SIZE) 32 end = PMD_SIZE; 33 BUG_ON(address >= end); 34 pfn = phys_addr >> PAGE_SHIFT; 35 do { 36 if (!pte_none(*pte)) { 37 printk("remap_area_pte: page already exists\n"); 38 BUG(); 39 } 40 set_pte(pte, pfn_pte(pfn, pgprot)); 41 address += PAGE_SIZE; 42 pfn++; 43 pte++; 44 } while (address && (address < end)); 45 } 46 47 static inline int remap_area_pmd(pmd_t * pmd, unsigned long address, 48 phys_addr_t size, phys_addr_t phys_addr, unsigned long flags) 49 { 50 phys_addr_t end; 51 52 address &= ~PGDIR_MASK; 53 end = address + size; 54 if (end > PGDIR_SIZE) 55 end = PGDIR_SIZE; 56 phys_addr -= address; 57 BUG_ON(address >= end); 58 do { 59 pte_t * pte = pte_alloc_kernel(pmd, address); 60 if (!pte) 61 return -ENOMEM; 62 remap_area_pte(pte, address, end - address, address + phys_addr, flags); 63 address = (address + PMD_SIZE) & PMD_MASK; 64 pmd++; 65 } while (address && (address < end)); 66 return 0; 67 } 68 69 static int remap_area_pages(unsigned long address, phys_addr_t phys_addr, 70 phys_addr_t size, unsigned long flags) 71 { 72 int error; 73 pgd_t * dir; 74 unsigned long end = address + size; 75 76 phys_addr -= address; 77 dir = pgd_offset(&init_mm, address); 78 flush_cache_all(); 79 BUG_ON(address >= end); 80 do { 81 pud_t *pud; 82 pmd_t *pmd; 83 84 error = -ENOMEM; 85 pud = pud_alloc(&init_mm, dir, address); 86 if (!pud) 87 break; 88 pmd = pmd_alloc(&init_mm, pud, address); 89 if (!pmd) 90 break; 91 if (remap_area_pmd(pmd, address, end - address, 92 phys_addr + address, flags)) 93 break; 94 error = 0; 95 address = (address + PGDIR_SIZE) & PGDIR_MASK; 96 dir++; 97 } while (address && (address < end)); 98 flush_tlb_all(); 99 return error; 100 } 101 102 static int __ioremap_check_ram(unsigned long start_pfn, unsigned long nr_pages, 103 void *arg) 104 { 105 unsigned long i; 106 107 for (i = 0; i < nr_pages; i++) { 108 if (pfn_valid(start_pfn + i) && 109 !PageReserved(pfn_to_page(start_pfn + i))) 110 return 1; 111 } 112 113 return 0; 114 } 115 116 /* 117 * Generic mapping function (not visible outside): 118 */ 119 120 /* 121 * Remap an arbitrary physical address space into the kernel virtual 122 * address space. Needed when the kernel wants to access high addresses 123 * directly. 124 * 125 * NOTE! We need to allow non-page-aligned mappings too: we will obviously 126 * have to convert them into an offset in a page-aligned mapping, but the 127 * caller shouldn't need to know that small detail. 128 */ 129 130 #define IS_LOW512(addr) (!((phys_addr_t)(addr) & (phys_addr_t) ~0x1fffffffULL)) 131 132 void __iomem * __ioremap(phys_addr_t phys_addr, phys_addr_t size, unsigned long flags) 133 { 134 unsigned long offset, pfn, last_pfn; 135 struct vm_struct * area; 136 phys_addr_t last_addr; 137 void * addr; 138 139 phys_addr = fixup_bigphys_addr(phys_addr, size); 140 141 /* Don't allow wraparound or zero size */ 142 last_addr = phys_addr + size - 1; 143 if (!size || last_addr < phys_addr) 144 return NULL; 145 146 /* 147 * Map uncached objects in the low 512mb of address space using KSEG1, 148 * otherwise map using page tables. 149 */ 150 if (IS_LOW512(phys_addr) && IS_LOW512(last_addr) && 151 flags == _CACHE_UNCACHED) 152 return (void __iomem *) CKSEG1ADDR(phys_addr); 153 154 /* 155 * Don't allow anybody to remap RAM that may be allocated by the page 156 * allocator, since that could lead to races & data clobbering. 157 */ 158 pfn = PFN_DOWN(phys_addr); 159 last_pfn = PFN_DOWN(last_addr); 160 if (walk_system_ram_range(pfn, last_pfn - pfn + 1, NULL, 161 __ioremap_check_ram) == 1) { 162 WARN_ONCE(1, "ioremap on RAM at %pa - %pa\n", 163 &phys_addr, &last_addr); 164 return NULL; 165 } 166 167 /* 168 * Mappings have to be page-aligned 169 */ 170 offset = phys_addr & ~PAGE_MASK; 171 phys_addr &= PAGE_MASK; 172 size = PAGE_ALIGN(last_addr + 1) - phys_addr; 173 174 /* 175 * Ok, go for it.. 176 */ 177 area = get_vm_area(size, VM_IOREMAP); 178 if (!area) 179 return NULL; 180 addr = area->addr; 181 if (remap_area_pages((unsigned long) addr, phys_addr, size, flags)) { 182 vunmap(addr); 183 return NULL; 184 } 185 186 return (void __iomem *) (offset + (char *)addr); 187 } 188 189 #define IS_KSEG1(addr) (((unsigned long)(addr) & ~0x1fffffffUL) == CKSEG1) 190 191 void __iounmap(const volatile void __iomem *addr) 192 { 193 struct vm_struct *p; 194 195 if (IS_KSEG1(addr)) 196 return; 197 198 p = remove_vm_area((void *) (PAGE_MASK & (unsigned long __force) addr)); 199 if (!p) 200 printk(KERN_ERR "iounmap: bad address %p\n", addr); 201 202 kfree(p); 203 } 204 205 EXPORT_SYMBOL(__ioremap); 206 EXPORT_SYMBOL(__iounmap); 207