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/sched.h> 13 #include <linux/slab.h> 14 #include <linux/vmalloc.h> 15 #include <linux/mm_types.h> 16 #include <asm/cacheflush.h> 17 #include <asm/io.h> 18 #include <asm/tlbflush.h> 19 20 static inline void remap_area_pte(pte_t * pte, unsigned long address, 21 phys_addr_t size, phys_addr_t phys_addr, unsigned long flags) 22 { 23 phys_addr_t end; 24 unsigned long pfn; 25 pgprot_t pgprot = __pgprot(_PAGE_GLOBAL | _PAGE_PRESENT | __READABLE 26 | __WRITEABLE | flags); 27 28 address &= ~PMD_MASK; 29 end = address + size; 30 if (end > PMD_SIZE) 31 end = PMD_SIZE; 32 BUG_ON(address >= end); 33 pfn = phys_addr >> PAGE_SHIFT; 34 do { 35 if (!pte_none(*pte)) { 36 printk("remap_area_pte: page already exists\n"); 37 BUG(); 38 } 39 set_pte(pte, pfn_pte(pfn, pgprot)); 40 address += PAGE_SIZE; 41 pfn++; 42 pte++; 43 } while (address && (address < end)); 44 } 45 46 static inline int remap_area_pmd(pmd_t * pmd, unsigned long address, 47 phys_addr_t size, phys_addr_t phys_addr, unsigned long flags) 48 { 49 phys_addr_t end; 50 51 address &= ~PGDIR_MASK; 52 end = address + size; 53 if (end > PGDIR_SIZE) 54 end = PGDIR_SIZE; 55 phys_addr -= address; 56 BUG_ON(address >= end); 57 do { 58 pte_t * pte = pte_alloc_kernel(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_addr_t phys_addr, 69 phys_addr_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 BUG_ON(address >= end); 79 do { 80 pud_t *pud; 81 pmd_t *pmd; 82 83 error = -ENOMEM; 84 pud = pud_alloc(&init_mm, dir, address); 85 if (!pud) 86 break; 87 pmd = pmd_alloc(&init_mm, pud, address); 88 if (!pmd) 89 break; 90 if (remap_area_pmd(pmd, address, end - address, 91 phys_addr + address, flags)) 92 break; 93 error = 0; 94 address = (address + PGDIR_SIZE) & PGDIR_MASK; 95 dir++; 96 } while (address && (address < end)); 97 flush_tlb_all(); 98 return error; 99 } 100 101 /* 102 * Generic mapping function (not visible outside): 103 */ 104 105 /* 106 * Remap an arbitrary physical address space into the kernel virtual 107 * address space. Needed when the kernel wants to access high addresses 108 * directly. 109 * 110 * NOTE! We need to allow non-page-aligned mappings too: we will obviously 111 * have to convert them into an offset in a page-aligned mapping, but the 112 * caller shouldn't need to know that small detail. 113 */ 114 115 #define IS_LOW512(addr) (!((phys_addr_t)(addr) & (phys_addr_t) ~0x1fffffffULL)) 116 117 void __iomem * __ioremap(phys_addr_t phys_addr, phys_addr_t size, unsigned long flags) 118 { 119 struct vm_struct * area; 120 unsigned long offset; 121 phys_addr_t last_addr; 122 void * addr; 123 124 phys_addr = fixup_bigphys_addr(phys_addr, size); 125 126 /* Don't allow wraparound or zero size */ 127 last_addr = phys_addr + size - 1; 128 if (!size || last_addr < phys_addr) 129 return NULL; 130 131 /* 132 * Map uncached objects in the low 512mb of address space using KSEG1, 133 * otherwise map using page tables. 134 */ 135 if (IS_LOW512(phys_addr) && IS_LOW512(last_addr) && 136 flags == _CACHE_UNCACHED) 137 return (void __iomem *) CKSEG1ADDR(phys_addr); 138 139 /* 140 * Don't allow anybody to remap normal RAM that we're using.. 141 */ 142 if (phys_addr < virt_to_phys(high_memory)) { 143 char *t_addr, *t_end; 144 struct page *page; 145 146 t_addr = __va(phys_addr); 147 t_end = t_addr + (size - 1); 148 149 for(page = virt_to_page(t_addr); page <= virt_to_page(t_end); page++) 150 if(!PageReserved(page)) 151 return NULL; 152 } 153 154 /* 155 * Mappings have to be page-aligned 156 */ 157 offset = phys_addr & ~PAGE_MASK; 158 phys_addr &= PAGE_MASK; 159 size = PAGE_ALIGN(last_addr + 1) - phys_addr; 160 161 /* 162 * Ok, go for it.. 163 */ 164 area = get_vm_area(size, VM_IOREMAP); 165 if (!area) 166 return NULL; 167 addr = area->addr; 168 if (remap_area_pages((unsigned long) addr, phys_addr, size, flags)) { 169 vunmap(addr); 170 return NULL; 171 } 172 173 return (void __iomem *) (offset + (char *)addr); 174 } 175 176 #define IS_KSEG1(addr) (((unsigned long)(addr) & ~0x1fffffffUL) == CKSEG1) 177 178 void __iounmap(const volatile void __iomem *addr) 179 { 180 struct vm_struct *p; 181 182 if (IS_KSEG1(addr)) 183 return; 184 185 p = remove_vm_area((void *) (PAGE_MASK & (unsigned long __force) addr)); 186 if (!p) 187 printk(KERN_ERR "iounmap: bad address %p\n", addr); 188 189 kfree(p); 190 } 191 192 EXPORT_SYMBOL(__ioremap); 193 EXPORT_SYMBOL(__iounmap); 194