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/module.h> 10 #include <asm/addrspace.h> 11 #include <asm/byteorder.h> 12 13 #include <linux/vmalloc.h> 14 #include <asm/cacheflush.h> 15 #include <asm/io.h> 16 #include <asm/tlbflush.h> 17 18 static inline void remap_area_pte(pte_t * pte, unsigned long address, 19 phys_t size, phys_t phys_addr, unsigned long flags) 20 { 21 phys_t end; 22 unsigned long pfn; 23 pgprot_t pgprot = __pgprot(_PAGE_GLOBAL | _PAGE_PRESENT | __READABLE 24 | __WRITEABLE | flags); 25 26 address &= ~PMD_MASK; 27 end = address + size; 28 if (end > PMD_SIZE) 29 end = PMD_SIZE; 30 if (address >= end) 31 BUG(); 32 pfn = phys_addr >> PAGE_SHIFT; 33 do { 34 if (!pte_none(*pte)) { 35 printk("remap_area_pte: page already exists\n"); 36 BUG(); 37 } 38 set_pte(pte, pfn_pte(pfn, pgprot)); 39 address += PAGE_SIZE; 40 pfn++; 41 pte++; 42 } while (address && (address < end)); 43 } 44 45 static inline int remap_area_pmd(pmd_t * pmd, unsigned long address, 46 phys_t size, phys_t phys_addr, unsigned long flags) 47 { 48 phys_t end; 49 50 address &= ~PGDIR_MASK; 51 end = address + size; 52 if (end > PGDIR_SIZE) 53 end = PGDIR_SIZE; 54 phys_addr -= address; 55 if (address >= end) 56 BUG(); 57 do { 58 pte_t * pte = pte_alloc_kernel(&init_mm, pmd, address); 59 if (!pte) 60 return -ENOMEM; 61 remap_area_pte(pte, address, end - address, address + phys_addr, flags); 62 address = (address + PMD_SIZE) & PMD_MASK; 63 pmd++; 64 } while (address && (address < end)); 65 return 0; 66 } 67 68 static int remap_area_pages(unsigned long address, phys_t phys_addr, 69 phys_t size, unsigned long flags) 70 { 71 int error; 72 pgd_t * dir; 73 unsigned long end = address + size; 74 75 phys_addr -= address; 76 dir = pgd_offset(&init_mm, address); 77 flush_cache_all(); 78 if (address >= end) 79 BUG(); 80 spin_lock(&init_mm.page_table_lock); 81 do { 82 pmd_t *pmd; 83 pmd = pmd_alloc(&init_mm, dir, address); 84 error = -ENOMEM; 85 if (!pmd) 86 break; 87 if (remap_area_pmd(pmd, address, end - address, 88 phys_addr + address, flags)) 89 break; 90 error = 0; 91 address = (address + PGDIR_SIZE) & PGDIR_MASK; 92 dir++; 93 } while (address && (address < end)); 94 spin_unlock(&init_mm.page_table_lock); 95 flush_tlb_all(); 96 return error; 97 } 98 99 /* 100 * Allow physical addresses to be fixed up to help 36 bit peripherals. 101 */ 102 phys_t __attribute__ ((weak)) 103 fixup_bigphys_addr(phys_t phys_addr, phys_t size) 104 { 105 return phys_addr; 106 } 107 108 /* 109 * Generic mapping function (not visible outside): 110 */ 111 112 /* 113 * Remap an arbitrary physical address space into the kernel virtual 114 * address space. Needed when the kernel wants to access high addresses 115 * directly. 116 * 117 * NOTE! We need to allow non-page-aligned mappings too: we will obviously 118 * have to convert them into an offset in a page-aligned mapping, but the 119 * caller shouldn't need to know that small detail. 120 */ 121 122 #define IS_LOW512(addr) (!((phys_t)(addr) & (phys_t) ~0x1fffffffULL)) 123 124 void * __ioremap(phys_t phys_addr, phys_t size, unsigned long flags) 125 { 126 struct vm_struct * area; 127 unsigned long offset; 128 phys_t last_addr; 129 void * addr; 130 131 phys_addr = fixup_bigphys_addr(phys_addr, size); 132 133 /* Don't allow wraparound or zero size */ 134 last_addr = phys_addr + size - 1; 135 if (!size || last_addr < phys_addr) 136 return NULL; 137 138 /* 139 * Map uncached objects in the low 512mb of address space using KSEG1, 140 * otherwise map using page tables. 141 */ 142 if (IS_LOW512(phys_addr) && IS_LOW512(last_addr) && 143 flags == _CACHE_UNCACHED) 144 return (void *) KSEG1ADDR(phys_addr); 145 146 /* 147 * Don't allow anybody to remap normal RAM that we're using.. 148 */ 149 if (phys_addr < virt_to_phys(high_memory)) { 150 char *t_addr, *t_end; 151 struct page *page; 152 153 t_addr = __va(phys_addr); 154 t_end = t_addr + (size - 1); 155 156 for(page = virt_to_page(t_addr); page <= virt_to_page(t_end); page++) 157 if(!PageReserved(page)) 158 return NULL; 159 } 160 161 /* 162 * Mappings have to be page-aligned 163 */ 164 offset = phys_addr & ~PAGE_MASK; 165 phys_addr &= PAGE_MASK; 166 size = PAGE_ALIGN(last_addr + 1) - phys_addr; 167 168 /* 169 * Ok, go for it.. 170 */ 171 area = get_vm_area(size, VM_IOREMAP); 172 if (!area) 173 return NULL; 174 addr = area->addr; 175 if (remap_area_pages((unsigned long) addr, phys_addr, size, flags)) { 176 vunmap(addr); 177 return NULL; 178 } 179 180 return (void *) (offset + (char *)addr); 181 } 182 183 #define IS_KSEG1(addr) (((unsigned long)(addr) & ~0x1fffffffUL) == KSEG1) 184 185 void __iounmap(volatile void __iomem *addr) 186 { 187 struct vm_struct *p; 188 189 if (IS_KSEG1(addr)) 190 return; 191 192 p = remove_vm_area((void *) (PAGE_MASK & (unsigned long __force) addr)); 193 if (!p) { 194 printk(KERN_ERR "iounmap: bad address %p\n", addr); 195 return; 196 } 197 198 kfree(p); 199 } 200 201 EXPORT_SYMBOL(__ioremap); 202 EXPORT_SYMBOL(__iounmap); 203