Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * arch/i386/mm/ioremap.c |
| 3 | * |
| 4 | * Re-map IO memory to kernel address space so that we can access it. |
| 5 | * This is needed for high PCI addresses that aren't mapped in the |
| 6 | * 640k-1MB IO memory area on PC's |
| 7 | * |
| 8 | * (C) Copyright 1995 1996 Linus Torvalds |
| 9 | */ |
| 10 | |
| 11 | #include <linux/vmalloc.h> |
| 12 | #include <linux/init.h> |
| 13 | #include <linux/slab.h> |
| 14 | #include <asm/io.h> |
| 15 | #include <asm/fixmap.h> |
| 16 | #include <asm/cacheflush.h> |
| 17 | #include <asm/tlbflush.h> |
| 18 | #include <asm/pgtable.h> |
| 19 | |
| 20 | #define ISA_START_ADDRESS 0xa0000 |
| 21 | #define ISA_END_ADDRESS 0x100000 |
| 22 | |
| 23 | static int ioremap_pte_range(pmd_t *pmd, unsigned long addr, |
| 24 | unsigned long end, unsigned long phys_addr, unsigned long flags) |
| 25 | { |
| 26 | pte_t *pte; |
| 27 | unsigned long pfn; |
| 28 | |
| 29 | pfn = phys_addr >> PAGE_SHIFT; |
| 30 | pte = pte_alloc_kernel(&init_mm, pmd, addr); |
| 31 | if (!pte) |
| 32 | return -ENOMEM; |
| 33 | do { |
| 34 | BUG_ON(!pte_none(*pte)); |
| 35 | set_pte(pte, pfn_pte(pfn, __pgprot(_PAGE_PRESENT | _PAGE_RW | |
| 36 | _PAGE_DIRTY | _PAGE_ACCESSED | flags))); |
| 37 | pfn++; |
| 38 | } while (pte++, addr += PAGE_SIZE, addr != end); |
| 39 | return 0; |
| 40 | } |
| 41 | |
| 42 | static inline int ioremap_pmd_range(pud_t *pud, unsigned long addr, |
| 43 | unsigned long end, unsigned long phys_addr, unsigned long flags) |
| 44 | { |
| 45 | pmd_t *pmd; |
| 46 | unsigned long next; |
| 47 | |
| 48 | phys_addr -= addr; |
| 49 | pmd = pmd_alloc(&init_mm, pud, addr); |
| 50 | if (!pmd) |
| 51 | return -ENOMEM; |
| 52 | do { |
| 53 | next = pmd_addr_end(addr, end); |
| 54 | if (ioremap_pte_range(pmd, addr, next, phys_addr + addr, flags)) |
| 55 | return -ENOMEM; |
| 56 | } while (pmd++, addr = next, addr != end); |
| 57 | return 0; |
| 58 | } |
| 59 | |
| 60 | static inline int ioremap_pud_range(pgd_t *pgd, unsigned long addr, |
| 61 | unsigned long end, unsigned long phys_addr, unsigned long flags) |
| 62 | { |
| 63 | pud_t *pud; |
| 64 | unsigned long next; |
| 65 | |
| 66 | phys_addr -= addr; |
| 67 | pud = pud_alloc(&init_mm, pgd, addr); |
| 68 | if (!pud) |
| 69 | return -ENOMEM; |
| 70 | do { |
| 71 | next = pud_addr_end(addr, end); |
| 72 | if (ioremap_pmd_range(pud, addr, next, phys_addr + addr, flags)) |
| 73 | return -ENOMEM; |
| 74 | } while (pud++, addr = next, addr != end); |
| 75 | return 0; |
| 76 | } |
| 77 | |
| 78 | static int ioremap_page_range(unsigned long addr, |
| 79 | unsigned long end, unsigned long phys_addr, unsigned long flags) |
| 80 | { |
| 81 | pgd_t *pgd; |
| 82 | unsigned long next; |
| 83 | int err; |
| 84 | |
| 85 | BUG_ON(addr >= end); |
| 86 | flush_cache_all(); |
| 87 | phys_addr -= addr; |
| 88 | pgd = pgd_offset_k(addr); |
| 89 | spin_lock(&init_mm.page_table_lock); |
| 90 | do { |
| 91 | next = pgd_addr_end(addr, end); |
| 92 | err = ioremap_pud_range(pgd, addr, next, phys_addr+addr, flags); |
| 93 | if (err) |
| 94 | break; |
| 95 | } while (pgd++, addr = next, addr != end); |
| 96 | spin_unlock(&init_mm.page_table_lock); |
| 97 | flush_tlb_all(); |
| 98 | return err; |
| 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 | void __iomem * __ioremap(unsigned long phys_addr, unsigned long size, unsigned long flags) |
| 115 | { |
| 116 | void __iomem * addr; |
| 117 | struct vm_struct * area; |
| 118 | unsigned long offset, last_addr; |
| 119 | |
| 120 | /* Don't allow wraparound or zero size */ |
| 121 | last_addr = phys_addr + size - 1; |
| 122 | if (!size || last_addr < phys_addr) |
| 123 | return NULL; |
| 124 | |
| 125 | /* |
| 126 | * Don't remap the low PCI/ISA area, it's always mapped.. |
| 127 | */ |
| 128 | if (phys_addr >= ISA_START_ADDRESS && last_addr < ISA_END_ADDRESS) |
| 129 | return (void __iomem *) phys_to_virt(phys_addr); |
| 130 | |
| 131 | /* |
| 132 | * Don't allow anybody to remap normal RAM that we're using.. |
| 133 | */ |
| 134 | if (phys_addr <= virt_to_phys(high_memory - 1)) { |
| 135 | char *t_addr, *t_end; |
| 136 | struct page *page; |
| 137 | |
| 138 | t_addr = __va(phys_addr); |
| 139 | t_end = t_addr + (size - 1); |
| 140 | |
| 141 | for(page = virt_to_page(t_addr); page <= virt_to_page(t_end); page++) |
| 142 | if(!PageReserved(page)) |
| 143 | return NULL; |
| 144 | } |
| 145 | |
| 146 | /* |
| 147 | * Mappings have to be page-aligned |
| 148 | */ |
| 149 | offset = phys_addr & ~PAGE_MASK; |
| 150 | phys_addr &= PAGE_MASK; |
| 151 | size = PAGE_ALIGN(last_addr+1) - phys_addr; |
| 152 | |
| 153 | /* |
| 154 | * Ok, go for it.. |
| 155 | */ |
| 156 | area = get_vm_area(size, VM_IOREMAP | (flags << 20)); |
| 157 | if (!area) |
| 158 | return NULL; |
| 159 | area->phys_addr = phys_addr; |
| 160 | addr = (void __iomem *) area->addr; |
| 161 | if (ioremap_page_range((unsigned long) addr, |
| 162 | (unsigned long) addr + size, phys_addr, flags)) { |
| 163 | vunmap((void __force *) addr); |
| 164 | return NULL; |
| 165 | } |
| 166 | return (void __iomem *) (offset + (char __iomem *)addr); |
| 167 | } |
| 168 | |
| 169 | |
| 170 | /** |
| 171 | * ioremap_nocache - map bus memory into CPU space |
| 172 | * @offset: bus address of the memory |
| 173 | * @size: size of the resource to map |
| 174 | * |
| 175 | * ioremap_nocache performs a platform specific sequence of operations to |
| 176 | * make bus memory CPU accessible via the readb/readw/readl/writeb/ |
| 177 | * writew/writel functions and the other mmio helpers. The returned |
| 178 | * address is not guaranteed to be usable directly as a virtual |
| 179 | * address. |
| 180 | * |
| 181 | * This version of ioremap ensures that the memory is marked uncachable |
| 182 | * on the CPU as well as honouring existing caching rules from things like |
| 183 | * the PCI bus. Note that there are other caches and buffers on many |
| 184 | * busses. In particular driver authors should read up on PCI writes |
| 185 | * |
| 186 | * It's useful if some control registers are in such an area and |
| 187 | * write combining or read caching is not desirable: |
| 188 | * |
| 189 | * Must be freed with iounmap. |
| 190 | */ |
| 191 | |
| 192 | void __iomem *ioremap_nocache (unsigned long phys_addr, unsigned long size) |
| 193 | { |
| 194 | unsigned long last_addr; |
| 195 | void __iomem *p = __ioremap(phys_addr, size, _PAGE_PCD); |
| 196 | if (!p) |
| 197 | return p; |
| 198 | |
| 199 | /* Guaranteed to be > phys_addr, as per __ioremap() */ |
| 200 | last_addr = phys_addr + size - 1; |
| 201 | |
| 202 | if (last_addr < virt_to_phys(high_memory) - 1) { |
| 203 | struct page *ppage = virt_to_page(__va(phys_addr)); |
| 204 | unsigned long npages; |
| 205 | |
| 206 | phys_addr &= PAGE_MASK; |
| 207 | |
| 208 | /* This might overflow and become zero.. */ |
| 209 | last_addr = PAGE_ALIGN(last_addr); |
| 210 | |
| 211 | /* .. but that's ok, because modulo-2**n arithmetic will make |
| 212 | * the page-aligned "last - first" come out right. |
| 213 | */ |
| 214 | npages = (last_addr - phys_addr) >> PAGE_SHIFT; |
| 215 | |
| 216 | if (change_page_attr(ppage, npages, PAGE_KERNEL_NOCACHE) < 0) { |
| 217 | iounmap(p); |
| 218 | p = NULL; |
| 219 | } |
| 220 | global_flush_tlb(); |
| 221 | } |
| 222 | |
| 223 | return p; |
| 224 | } |
| 225 | |
| 226 | void iounmap(volatile void __iomem *addr) |
| 227 | { |
| 228 | struct vm_struct *p; |
| 229 | if ((void __force *) addr <= high_memory) |
| 230 | return; |
| 231 | |
| 232 | /* |
| 233 | * __ioremap special-cases the PCI/ISA range by not instantiating a |
| 234 | * vm_area and by simply returning an address into the kernel mapping |
| 235 | * of ISA space. So handle that here. |
| 236 | */ |
| 237 | if (addr >= phys_to_virt(ISA_START_ADDRESS) && |
| 238 | addr < phys_to_virt(ISA_END_ADDRESS)) |
| 239 | return; |
| 240 | |
| 241 | p = remove_vm_area((void *) (PAGE_MASK & (unsigned long __force) addr)); |
| 242 | if (!p) { |
| 243 | printk("__iounmap: bad address %p\n", addr); |
| 244 | return; |
| 245 | } |
| 246 | |
| 247 | if ((p->flags >> 20) && p->phys_addr < virt_to_phys(high_memory) - 1) { |
| 248 | /* p->size includes the guard page, but cpa doesn't like that */ |
| 249 | change_page_attr(virt_to_page(__va(p->phys_addr)), |
| 250 | p->size >> PAGE_SHIFT, |
| 251 | PAGE_KERNEL); |
| 252 | global_flush_tlb(); |
| 253 | } |
| 254 | kfree(p); |
| 255 | } |
| 256 | |
| 257 | void __init *bt_ioremap(unsigned long phys_addr, unsigned long size) |
| 258 | { |
| 259 | unsigned long offset, last_addr; |
| 260 | unsigned int nrpages; |
| 261 | enum fixed_addresses idx; |
| 262 | |
| 263 | /* Don't allow wraparound or zero size */ |
| 264 | last_addr = phys_addr + size - 1; |
| 265 | if (!size || last_addr < phys_addr) |
| 266 | return NULL; |
| 267 | |
| 268 | /* |
| 269 | * Don't remap the low PCI/ISA area, it's always mapped.. |
| 270 | */ |
| 271 | if (phys_addr >= ISA_START_ADDRESS && last_addr < ISA_END_ADDRESS) |
| 272 | return phys_to_virt(phys_addr); |
| 273 | |
| 274 | /* |
| 275 | * Mappings have to be page-aligned |
| 276 | */ |
| 277 | offset = phys_addr & ~PAGE_MASK; |
| 278 | phys_addr &= PAGE_MASK; |
| 279 | size = PAGE_ALIGN(last_addr) - phys_addr; |
| 280 | |
| 281 | /* |
| 282 | * Mappings have to fit in the FIX_BTMAP area. |
| 283 | */ |
| 284 | nrpages = size >> PAGE_SHIFT; |
| 285 | if (nrpages > NR_FIX_BTMAPS) |
| 286 | return NULL; |
| 287 | |
| 288 | /* |
| 289 | * Ok, go for it.. |
| 290 | */ |
| 291 | idx = FIX_BTMAP_BEGIN; |
| 292 | while (nrpages > 0) { |
| 293 | set_fixmap(idx, phys_addr); |
| 294 | phys_addr += PAGE_SIZE; |
| 295 | --idx; |
| 296 | --nrpages; |
| 297 | } |
| 298 | return (void*) (offset + fix_to_virt(FIX_BTMAP_BEGIN)); |
| 299 | } |
| 300 | |
| 301 | void __init bt_iounmap(void *addr, unsigned long size) |
| 302 | { |
| 303 | unsigned long virt_addr; |
| 304 | unsigned long offset; |
| 305 | unsigned int nrpages; |
| 306 | enum fixed_addresses idx; |
| 307 | |
| 308 | virt_addr = (unsigned long)addr; |
| 309 | if (virt_addr < fix_to_virt(FIX_BTMAP_BEGIN)) |
| 310 | return; |
| 311 | offset = virt_addr & ~PAGE_MASK; |
| 312 | nrpages = PAGE_ALIGN(offset + size - 1) >> PAGE_SHIFT; |
| 313 | |
| 314 | idx = FIX_BTMAP_BEGIN; |
| 315 | while (nrpages > 0) { |
| 316 | clear_fixmap(idx); |
| 317 | --idx; |
| 318 | --nrpages; |
| 319 | } |
| 320 | } |