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 #include <linux/sched.h> 13 #include <linux/slab.h> 14 #include <linux/vmalloc.h> 15 #include <asm/cacheflush.h> 16 #include <asm/io.h> 17 #include <asm/tlbflush.h> 18 19 static inline void remap_area_pte(pte_t * pte, unsigned long address, 20 phys_addr_t size, phys_addr_t phys_addr, unsigned long flags) 21 { 22 phys_addr_t end; 23 unsigned long pfn; 24 pgprot_t pgprot = __pgprot(_PAGE_GLOBAL | _PAGE_PRESENT | __READABLE 25 | __WRITEABLE | flags); 26 27 address &= ~PMD_MASK; 28 end = address + size; 29 if (end > PMD_SIZE) 30 end = PMD_SIZE; 31 BUG_ON(address >= end); 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_addr_t size, phys_addr_t phys_addr, unsigned long flags) 47 { 48 phys_addr_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 BUG_ON(address >= end); 56 do { 57 pte_t * pte = pte_alloc_kernel(pmd, address); 58 if (!pte) 59 return -ENOMEM; 60 remap_area_pte(pte, address, end - address, address + phys_addr, flags); 61 address = (address + PMD_SIZE) & PMD_MASK; 62 pmd++; 63 } while (address && (address < end)); 64 return 0; 65 } 66 67 static int remap_area_pages(unsigned long address, phys_addr_t phys_addr, 68 phys_addr_t size, unsigned long flags) 69 { 70 int error; 71 pgd_t * dir; 72 unsigned long end = address + size; 73 74 phys_addr -= address; 75 dir = pgd_offset(&init_mm, address); 76 flush_cache_all(); 77 BUG_ON(address >= end); 78 do { 79 pud_t *pud; 80 pmd_t *pmd; 81 82 error = -ENOMEM; 83 pud = pud_alloc(&init_mm, dir, address); 84 if (!pud) 85 break; 86 pmd = pmd_alloc(&init_mm, pud, address); 87 if (!pmd) 88 break; 89 if (remap_area_pmd(pmd, address, end - address, 90 phys_addr + address, flags)) 91 break; 92 error = 0; 93 address = (address + PGDIR_SIZE) & PGDIR_MASK; 94 dir++; 95 } while (address && (address < end)); 96 flush_tlb_all(); 97 return error; 98 } 99 100 /* 101 * Generic mapping function (not visible outside): 102 */ 103 104 /* 105 * Remap an arbitrary physical address space into the kernel virtual 106 * address space. Needed when the kernel wants to access high addresses 107 * directly. 108 * 109 * NOTE! We need to allow non-page-aligned mappings too: we will obviously 110 * have to convert them into an offset in a page-aligned mapping, but the 111 * caller shouldn't need to know that small detail. 112 */ 113 114 #define IS_LOW512(addr) (!((phys_addr_t)(addr) & (phys_addr_t) ~0x1fffffffULL)) 115 116 void __iomem * __ioremap(phys_addr_t phys_addr, phys_addr_t size, unsigned long flags) 117 { 118 struct vm_struct * area; 119 unsigned long offset; 120 phys_addr_t last_addr; 121 void * addr; 122 123 phys_addr = fixup_bigphys_addr(phys_addr, size); 124 125 /* Don't allow wraparound or zero size */ 126 last_addr = phys_addr + size - 1; 127 if (!size || last_addr < phys_addr) 128 return NULL; 129 130 /* 131 * Map uncached objects in the low 512mb of address space using KSEG1, 132 * otherwise map using page tables. 133 */ 134 if (IS_LOW512(phys_addr) && IS_LOW512(last_addr) && 135 flags == _CACHE_UNCACHED) 136 return (void __iomem *) CKSEG1ADDR(phys_addr); 137 138 /* 139 * Don't allow anybody to remap normal RAM that we're using.. 140 */ 141 if (phys_addr < virt_to_phys(high_memory)) { 142 char *t_addr, *t_end; 143 struct page *page; 144 145 t_addr = __va(phys_addr); 146 t_end = t_addr + (size - 1); 147 148 for(page = virt_to_page(t_addr); page <= virt_to_page(t_end); page++) 149 if(!PageReserved(page)) 150 return NULL; 151 } 152 153 /* 154 * Mappings have to be page-aligned 155 */ 156 offset = phys_addr & ~PAGE_MASK; 157 phys_addr &= PAGE_MASK; 158 size = PAGE_ALIGN(last_addr + 1) - phys_addr; 159 160 /* 161 * Ok, go for it.. 162 */ 163 area = get_vm_area(size, VM_IOREMAP); 164 if (!area) 165 return NULL; 166 addr = area->addr; 167 if (remap_area_pages((unsigned long) addr, phys_addr, size, flags)) { 168 vunmap(addr); 169 return NULL; 170 } 171 172 return (void __iomem *) (offset + (char *)addr); 173 } 174 175 #define IS_KSEG1(addr) (((unsigned long)(addr) & ~0x1fffffffUL) == CKSEG1) 176 177 void __iounmap(const volatile void __iomem *addr) 178 { 179 struct vm_struct *p; 180 181 if (IS_KSEG1(addr)) 182 return; 183 184 p = remove_vm_area((void *) (PAGE_MASK & (unsigned long __force) addr)); 185 if (!p) 186 printk(KERN_ERR "iounmap: bad address %p\n", addr); 187 188 kfree(p); 189 } 190 191 EXPORT_SYMBOL(__ioremap); 192 EXPORT_SYMBOL(__iounmap); 193