arch/x86/mm/ioremap.c

   1 /*
   2  * Re-map IO memory to kernel address space so that we can access it.
   3  * This is needed for high PCI addresses that aren't mapped in the
   4  * 640k-1MB IO memory area on PC's
   5  *
   6  * (C) Copyright 1995 1996 Linus Torvalds
   7  */
   8
   9 #include <linux/bootmem.h>
  10 #include <linux/init.h>
  11 #include <linux/io.h>
  12 #include <linux/module.h>
  13 #include <linux/slab.h>
  14 #include <linux/vmalloc.h>
  15 #include <linux/mmiotrace.h>
  16
  17 #include <asm/cacheflush.h>
  18 #include <asm/e820.h>
  19 #include <asm/fixmap.h>
  20 #include <asm/pgtable.h>
  21 #include <asm/tlbflush.h>
  22 #include <asm/pgalloc.h>
  23 #include <asm/pat.h>
  24
  25 #ifdef CONFIG_X86_64
  26
  27 static inline int phys_addr_valid(unsigned long addr)
  28 {
  29         return addr < (1UL << boot_cpu_data.x86_phys_bits);
  30 }
  31
  32 unsigned long __phys_addr(unsigned long x)
  33 {
  34         if (x >= __START_KERNEL_map) {
  35                 x -= __START_KERNEL_map;
  36                 VIRTUAL_BUG_ON(x >= KERNEL_IMAGE_SIZE);
  37                 x += phys_base;
  38         } else {
  39                 VIRTUAL_BUG_ON(x < PAGE_OFFSET);
  40                 x -= PAGE_OFFSET;
  41                 VIRTUAL_BUG_ON(!phys_addr_valid(x));
  42         }
  43         return x;
  44 }
  45 EXPORT_SYMBOL(__phys_addr);
  46
  47 bool __virt_addr_valid(unsigned long x)
  48 {
  49         if (x >= __START_KERNEL_map) {
  50                 x -= __START_KERNEL_map;
  51                 if (x >= KERNEL_IMAGE_SIZE)
  52                         return false;
  53                 x += phys_base;
  54         } else {
  55                 if (x < PAGE_OFFSET)
  56                         return false;
  57                 x -= PAGE_OFFSET;
  58                 if (!phys_addr_valid(x))
  59                         return false;
  60         }
  61
  62         return pfn_valid(x >> PAGE_SHIFT);
  63 }
  64 EXPORT_SYMBOL(__virt_addr_valid);
  65
  66 #else
  67
  68 static inline int phys_addr_valid(unsigned long addr)
  69 {
  70         return 1;
  71 }
  72
  73 #ifdef CONFIG_DEBUG_VIRTUAL
  74 unsigned long __phys_addr(unsigned long x)
  75 {
  76         /* VMALLOC_* aren't constants  */
  77         VIRTUAL_BUG_ON(x < PAGE_OFFSET);
  78         VIRTUAL_BUG_ON(__vmalloc_start_set && is_vmalloc_addr((void *) x));
  79         return x - PAGE_OFFSET;
  80 }
  81 EXPORT_SYMBOL(__phys_addr);
  82 #endif
  83
  84 bool __virt_addr_valid(unsigned long x)
  85 {
  86         if (x < PAGE_OFFSET)
  87                 return false;
  88         if (__vmalloc_start_set && is_vmalloc_addr((void *) x))
  89                 return false;
  90         if (x >= FIXADDR_START)
  91                 return false;
  92         return pfn_valid((x - PAGE_OFFSET) >> PAGE_SHIFT);
  93 }
  94 EXPORT_SYMBOL(__virt_addr_valid);
  95
  96 #endif
  97
  98 int page_is_ram(unsigned long pagenr)
  99 {
 100         resource_size_t addr, end;
 101         int i;
 102
 103         /*
 104          * A special case is the first 4Kb of memory;
 105          * This is a BIOS owned area, not kernel ram, but generally
 106          * not listed as such in the E820 table.
 107          */
 108         if (pagenr == 0)
 109                 return 0;
 110
 111         /*
 112          * Second special case: Some BIOSen report the PC BIOS
 113          * area (640->1Mb) as ram even though it is not.
 114          */
 115         if (pagenr >= (BIOS_BEGIN >> PAGE_SHIFT) &&
 116                     pagenr < (BIOS_END >> PAGE_SHIFT))
 117                 return 0;
 118
 119         for (i = 0; i < e820.nr_map; i++) {
 120                 /*
 121                  * Not usable memory:
 122                  */
 123                 if (e820.map[i].type != E820_RAM)
 124                         continue;
 125                 addr = (e820.map[i].addr + PAGE_SIZE-1) >> PAGE_SHIFT;
 126                 end = (e820.map[i].addr + e820.map[i].size) >> PAGE_SHIFT;
 127
 128
 129                 if ((pagenr >= addr) && (pagenr < end))
 130                         return 1;
 131         }
 132         return 0;
 133 }
 134
 135 /*
 136  * Fix up the linear direct mapping of the kernel to avoid cache attribute
 137  * conflicts.
 138  */
 139 int ioremap_change_attr(unsigned long vaddr, unsigned long size,
 140                                unsigned long prot_val)
 141 {
 142         unsigned long nrpages = size >> PAGE_SHIFT;
 143         int err;
 144
 145         switch (prot_val) {
 146         case _PAGE_CACHE_UC:
 147         default:
 148                 err = _set_memory_uc(vaddr, nrpages);
 149                 break;
 150         case _PAGE_CACHE_WC:
 151                 err = _set_memory_wc(vaddr, nrpages);
 152                 break;
 153         case _PAGE_CACHE_WB:
 154                 err = _set_memory_wb(vaddr, nrpages);
 155                 break;
 156         }
 157
 158         return err;
 159 }
 160
 161 /*
 162  * Remap an arbitrary physical address space into the kernel virtual
 163  * address space. Needed when the kernel wants to access high addresses
 164  * directly.
 165  *
 166  * NOTE! We need to allow non-page-aligned mappings too: we will obviously
 167  * have to convert them into an offset in a page-aligned mapping, but the
 168  * caller shouldn't need to know that small detail.
 169  */
 170 static void __iomem *__ioremap_caller(resource_size_t phys_addr,
 171                 unsigned long size, unsigned long prot_val, void *caller)
 172 {
 173         unsigned long pfn, offset, vaddr;
 174         resource_size_t last_addr;
 175         const resource_size_t unaligned_phys_addr = phys_addr;
 176         const unsigned long unaligned_size = size;
 177         struct vm_struct *area;
 178         unsigned long new_prot_val;
 179         pgprot_t prot;
 180         int retval;
 181         void __iomem *ret_addr;
 182
 183         /* Don't allow wraparound or zero size */
 184         last_addr = phys_addr + size - 1;
 185         if (!size || last_addr < phys_addr)
 186                 return NULL;
 187
 188         if (!phys_addr_valid(phys_addr)) {
 189                 printk(KERN_WARNING "ioremap: invalid physical address %llx\n",
 190                        (unsigned long long)phys_addr);
 191                 WARN_ON_ONCE(1);
 192                 return NULL;
 193         }
 194
 195         /*
 196          * Don't remap the low PCI/ISA area, it's always mapped..
 197          */
 198         if (is_ISA_range(phys_addr, last_addr))
 199                 return (__force void __iomem *)phys_to_virt(phys_addr);
 200
 201         /*
 202          * Check if the request spans more than any BAR in the iomem resource
 203          * tree.
 204          */
 205         WARN_ONCE(iomem_map_sanity_check(phys_addr, size),
 206                   KERN_INFO "Info: mapping multiple BARs. Your kernel is fine.");
 207
 208         /*
 209          * Don't allow anybody to remap normal RAM that we're using..
 210          */
 211         for (pfn = phys_addr >> PAGE_SHIFT;
 212                                 (pfn << PAGE_SHIFT) < (last_addr & PAGE_MASK);
 213                                 pfn++) {
 214
 215                 int is_ram = page_is_ram(pfn);
 216
 217                 if (is_ram && pfn_valid(pfn) && !PageReserved(pfn_to_page(pfn)))
 218                         return NULL;
 219                 WARN_ON_ONCE(is_ram);
 220         }
 221
 222         /*
 223          * Mappings have to be page-aligned
 224          */
 225         offset = phys_addr & ~PAGE_MASK;
 226         phys_addr &= PAGE_MASK;
 227         size = PAGE_ALIGN(last_addr+1) - phys_addr;
 228
 229         retval = reserve_memtype(phys_addr, (u64)phys_addr + size,
 230                                                 prot_val, &new_prot_val);
 231         if (retval) {
 232                 pr_debug("Warning: reserve_memtype returned %d\n", retval);
 233                 return NULL;
 234         }
 235
 236         if (prot_val != new_prot_val) {
 237                 /*
 238                  * Do not fallback to certain memory types with certain
 239                  * requested type:
 240                  * - request is uc-, return cannot be write-back
 241                  * - request is uc-, return cannot be write-combine
 242                  * - request is write-combine, return cannot be write-back
 243                  */
 244                 if ((prot_val == _PAGE_CACHE_UC_MINUS &&
 245                      (new_prot_val == _PAGE_CACHE_WB ||
 246                       new_prot_val == _PAGE_CACHE_WC)) ||
 247                     (prot_val == _PAGE_CACHE_WC &&
 248                      new_prot_val == _PAGE_CACHE_WB)) {
 249                         pr_debug(
 250                 "ioremap error for 0x%llx-0x%llx, requested 0x%lx, got 0x%lx\n",
 251                                 (unsigned long long)phys_addr,
 252                                 (unsigned long long)(phys_addr + size),
 253                                 prot_val, new_prot_val);
 254                         free_memtype(phys_addr, phys_addr + size);
 255                         return NULL;
 256                 }
 257                 prot_val = new_prot_val;
 258         }
 259
 260         switch (prot_val) {
 261         case _PAGE_CACHE_UC:
 262         default:
 263                 prot = PAGE_KERNEL_IO_NOCACHE;
 264                 break;
 265         case _PAGE_CACHE_UC_MINUS:
 266                 prot = PAGE_KERNEL_IO_UC_MINUS;
 267                 break;
 268         case _PAGE_CACHE_WC:
 269                 prot = PAGE_KERNEL_IO_WC;
 270                 break;
 271         case _PAGE_CACHE_WB:
 272                 prot = PAGE_KERNEL_IO;
 273                 break;
 274         }
 275
 276         /*
 277          * Ok, go for it..
 278          */
 279         area = get_vm_area_caller(size, VM_IOREMAP, caller);
 280         if (!area)
 281                 return NULL;
 282         area->phys_addr = phys_addr;
 283         vaddr = (unsigned long) area->addr;
 284         if (ioremap_page_range(vaddr, vaddr + size, phys_addr, prot)) {
 285                 free_memtype(phys_addr, phys_addr + size);
 286                 free_vm_area(area);
 287                 return NULL;
 288         }
 289
 290         if (ioremap_change_attr(vaddr, size, prot_val) < 0) {
 291                 free_memtype(phys_addr, phys_addr + size);
 292                 vunmap(area->addr);
 293                 return NULL;
 294         }
 295
 296         ret_addr = (void __iomem *) (vaddr + offset);
 297         mmiotrace_ioremap(unaligned_phys_addr, unaligned_size, ret_addr);
 298
 299         return ret_addr;
 300 }
 301
 302 /**
 303  * ioremap_nocache     -   map bus memory into CPU space
 304  * @offset:    bus address of the memory
 305  * @size:      size of the resource to map
 306  *
 307  * ioremap_nocache performs a platform specific sequence of operations to
 308  * make bus memory CPU accessible via the readb/readw/readl/writeb/
 309  * writew/writel functions and the other mmio helpers. The returned
 310  * address is not guaranteed to be usable directly as a virtual
 311  * address.
 312  *
 313  * This version of ioremap ensures that the memory is marked uncachable
 314  * on the CPU as well as honouring existing caching rules from things like
 315  * the PCI bus. Note that there are other caches and buffers on many
 316  * busses. In particular driver authors should read up on PCI writes
 317  *
 318  * It's useful if some control registers are in such an area and
 319  * write combining or read caching is not desirable:
 320  *
 321  * Must be freed with iounmap.
 322  */
 323 void __iomem *ioremap_nocache(resource_size_t phys_addr, unsigned long size)
 324 {
 325         /*
 326          * Ideally, this should be:
 327          *      pat_enabled ? _PAGE_CACHE_UC : _PAGE_CACHE_UC_MINUS;
 328          *
 329          * Till we fix all X drivers to use ioremap_wc(), we will use
 330          * UC MINUS.
 331          */
 332         unsigned long val = _PAGE_CACHE_UC_MINUS;
 333
 334         return __ioremap_caller(phys_addr, size, val,
 335                                 __builtin_return_address(0));
 336 }
 337 EXPORT_SYMBOL(ioremap_nocache);
 338
 339 /**
 340  * ioremap_wc   -       map memory into CPU space write combined
 341  * @offset:     bus address of the memory
 342  * @size:       size of the resource to map
 343  *
 344  * This version of ioremap ensures that the memory is marked write combining.
 345  * Write combining allows faster writes to some hardware devices.
 346  *
 347  * Must be freed with iounmap.
 348  */
 349 void __iomem *ioremap_wc(resource_size_t phys_addr, unsigned long size)
 350 {
 351         if (pat_enabled)
 352                 return __ioremap_caller(phys_addr, size, _PAGE_CACHE_WC,
 353                                         __builtin_return_address(0));
 354         else
 355                 return ioremap_nocache(phys_addr, size);
 356 }
 357 EXPORT_SYMBOL(ioremap_wc);
 358
 359 void __iomem *ioremap_cache(resource_size_t phys_addr, unsigned long size)
 360 {
 361         return __ioremap_caller(phys_addr, size, _PAGE_CACHE_WB,
 362                                 __builtin_return_address(0));
 363 }
 364 EXPORT_SYMBOL(ioremap_cache);
 365
 366 static void __iomem *ioremap_default(resource_size_t phys_addr,
 367                                         unsigned long size)
 368 {
 369         unsigned long flags;
 370         void __iomem *ret;
 371         int err;
 372
 373         /*
 374          * - WB for WB-able memory and no other conflicting mappings
 375          * - UC_MINUS for non-WB-able memory with no other conflicting mappings
 376          * - Inherit from confliting mappings otherwise
 377          */
 378         err = reserve_memtype(phys_addr, phys_addr + size, -1, &flags);
 379         if (err < 0)
 380                 return NULL;
 381
 382         ret = __ioremap_caller(phys_addr, size, flags,
 383                                __builtin_return_address(0));
 384
 385         free_memtype(phys_addr, phys_addr + size);
 386         return ret;
 387 }
 388
 389 void __iomem *ioremap_prot(resource_size_t phys_addr, unsigned long size,
 390                                 unsigned long prot_val)
 391 {
 392         return __ioremap_caller(phys_addr, size, (prot_val & _PAGE_CACHE_MASK),
 393                                 __builtin_return_address(0));
 394 }
 395 EXPORT_SYMBOL(ioremap_prot);
 396
 397 /**
 398  * iounmap - Free a IO remapping
 399  * @addr: virtual address from ioremap_*
 400  *
 401  * Caller must ensure there is only one unmapping for the same pointer.
 402  */
 403 void iounmap(volatile void __iomem *addr)
 404 {
 405         struct vm_struct *p, *o;
 406
 407         if ((void __force *)addr <= high_memory)
 408                 return;
 409
 410         /*
 411          * __ioremap special-cases the PCI/ISA range by not instantiating a
 412          * vm_area and by simply returning an address into the kernel mapping
 413          * of ISA space.   So handle that here.
 414          */
 415         if ((void __force *)addr >= phys_to_virt(ISA_START_ADDRESS) &&
 416             (void __force *)addr < phys_to_virt(ISA_END_ADDRESS))
 417                 return;
 418
 419         addr = (volatile void __iomem *)
 420                 (PAGE_MASK & (unsigned long __force)addr);
 421
 422         mmiotrace_iounmap(addr);
 423
 424         /* Use the vm area unlocked, assuming the caller
 425            ensures there isn't another iounmap for the same address
 426            in parallel. Reuse of the virtual address is prevented by
 427            leaving it in the global lists until we're done with it.
 428            cpa takes care of the direct mappings. */
 429         read_lock(&vmlist_lock);
 430         for (p = vmlist; p; p = p->next) {
 431                 if (p->addr == (void __force *)addr)
 432                         break;
 433         }
 434         read_unlock(&vmlist_lock);
 435
 436         if (!p) {
 437                 printk(KERN_ERR "iounmap: bad address %p\n", addr);
 438                 dump_stack();
 439                 return;
 440         }
 441
 442         free_memtype(p->phys_addr, p->phys_addr + get_vm_area_size(p));
 443
 444         /* Finally remove it */
 445         o = remove_vm_area((void __force *)addr);
 446         BUG_ON(p != o || o == NULL);
 447         kfree(p);
 448 }
 449 EXPORT_SYMBOL(iounmap);
 450
 451 /*
 452  * Convert a physical pointer to a virtual kernel pointer for /dev/mem
 453  * access
 454  */
 455 void *xlate_dev_mem_ptr(unsigned long phys)
 456 {
 457         void *addr;
 458         unsigned long start = phys & PAGE_MASK;
 459
 460         /* If page is RAM, we can use __va. Otherwise ioremap and unmap. */
 461         if (page_is_ram(start >> PAGE_SHIFT))
 462                 return __va(phys);
 463
 464         addr = (void __force *)ioremap_default(start, PAGE_SIZE);
 465         if (addr)
 466                 addr = (void *)((unsigned long)addr | (phys & ~PAGE_MASK));
 467
 468         return addr;
 469 }
 470
 471 void unxlate_dev_mem_ptr(unsigned long phys, void *addr)
 472 {
 473         if (page_is_ram(phys >> PAGE_SHIFT))
 474                 return;
 475
 476         iounmap((void __iomem *)((unsigned long)addr & PAGE_MASK));
 477         return;
 478 }
 479
 480 static int __initdata early_ioremap_debug;
 481
 482 static int __init early_ioremap_debug_setup(char *str)
 483 {
 484         early_ioremap_debug = 1;
 485
 486         return 0;
 487 }
 488 early_param("early_ioremap_debug", early_ioremap_debug_setup);
 489
 490 static __initdata int after_paging_init;
 491 static pte_t bm_pte[PAGE_SIZE/sizeof(pte_t)] __page_aligned_bss;
 492
 493 static inline pmd_t * __init early_ioremap_pmd(unsigned long addr)
 494 {
 495         /* Don't assume we're using swapper_pg_dir at this point */
 496         pgd_t *base = __va(read_cr3());
 497         pgd_t *pgd = &base[pgd_index(addr)];
 498         pud_t *pud = pud_offset(pgd, addr);
 499         pmd_t *pmd = pmd_offset(pud, addr);
 500
 501         return pmd;
 502 }
 503
 504 static inline pte_t * __init early_ioremap_pte(unsigned long addr)
 505 {
 506         return &bm_pte[pte_index(addr)];
 507 }
 508
 509 void __init early_ioremap_init(void)
 510 {
 511         pmd_t *pmd;
 512
 513         if (early_ioremap_debug)
 514                 printk(KERN_INFO "early_ioremap_init()\n");
 515
 516         pmd = early_ioremap_pmd(fix_to_virt(FIX_BTMAP_BEGIN));
 517         memset(bm_pte, 0, sizeof(bm_pte));
 518         pmd_populate_kernel(&init_mm, pmd, bm_pte);
 519
 520         /*
 521          * The boot-ioremap range spans multiple pmds, for which
 522          * we are not prepared:
 523          */
 524         if (pmd != early_ioremap_pmd(fix_to_virt(FIX_BTMAP_END))) {
 525                 WARN_ON(1);
 526                 printk(KERN_WARNING "pmd %p != %p\n",
 527                        pmd, early_ioremap_pmd(fix_to_virt(FIX_BTMAP_END)));
 528                 printk(KERN_WARNING "fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
 529                         fix_to_virt(FIX_BTMAP_BEGIN));
 530                 printk(KERN_WARNING "fix_to_virt(FIX_BTMAP_END):   %08lx\n",
 531                         fix_to_virt(FIX_BTMAP_END));
 532
 533                 printk(KERN_WARNING "FIX_BTMAP_END:       %d\n", FIX_BTMAP_END);
 534                 printk(KERN_WARNING "FIX_BTMAP_BEGIN:     %d\n",
 535                        FIX_BTMAP_BEGIN);
 536         }
 537 }
 538
 539 void __init early_ioremap_reset(void)
 540 {
 541         after_paging_init = 1;
 542 }
 543
 544 static void __init __early_set_fixmap(enum fixed_addresses idx,
 545                                    unsigned long phys, pgprot_t flags)
 546 {
 547         unsigned long addr = __fix_to_virt(idx);
 548         pte_t *pte;
 549
 550         if (idx >= __end_of_fixed_addresses) {
 551                 BUG();
 552                 return;
 553         }
 554         pte = early_ioremap_pte(addr);
 555
 556         if (pgprot_val(flags))
 557                 set_pte(pte, pfn_pte(phys >> PAGE_SHIFT, flags));
 558         else
 559                 pte_clear(&init_mm, addr, pte);
 560         __flush_tlb_one(addr);
 561 }
 562
 563 static inline void __init early_set_fixmap(enum fixed_addresses idx,
 564                                            unsigned long phys, pgprot_t prot)
 565 {
 566         if (after_paging_init)
 567                 __set_fixmap(idx, phys, prot);
 568         else
 569                 __early_set_fixmap(idx, phys, prot);
 570 }
 571
 572 static inline void __init early_clear_fixmap(enum fixed_addresses idx)
 573 {
 574         if (after_paging_init)
 575                 clear_fixmap(idx);
 576         else
 577                 __early_set_fixmap(idx, 0, __pgprot(0));
 578 }
 579
 580 static void __iomem *prev_map[FIX_BTMAPS_SLOTS] __initdata;
 581 static unsigned long prev_size[FIX_BTMAPS_SLOTS] __initdata;
 582 static int __init check_early_ioremap_leak(void)
 583 {
 584         int count = 0;
 585         int i;
 586
 587         for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
 588                 if (prev_map[i])
 589                         count++;
 590
 591         if (!count)
 592                 return 0;
 593         WARN(1, KERN_WARNING
 594                "Debug warning: early ioremap leak of %d areas detected.\n",
 595                 count);
 596         printk(KERN_WARNING
 597                 "please boot with early_ioremap_debug and report the dmesg.\n");
 598
 599         return 1;
 600 }
 601 late_initcall(check_early_ioremap_leak);
 602
 603 static void __init __iomem *__early_ioremap(unsigned long phys_addr, unsigned long size, pgprot_t prot)
 604 {
 605         unsigned long offset, last_addr;
 606         unsigned int nrpages;
 607         enum fixed_addresses idx0, idx;
 608         int i, slot;
 609
 610         WARN_ON(system_state != SYSTEM_BOOTING);
 611
 612         slot = -1;
 613         for (i = 0; i < FIX_BTMAPS_SLOTS; i++) {
 614                 if (!prev_map[i]) {
 615                         slot = i;
 616                         break;
 617                 }
 618         }
 619
 620         if (slot < 0) {
 621                 printk(KERN_INFO "early_iomap(%08lx, %08lx) not found slot\n",
 622                          phys_addr, size);
 623                 WARN_ON(1);
 624                 return NULL;
 625         }
 626
 627         if (early_ioremap_debug) {
 628                 printk(KERN_INFO "early_ioremap(%08lx, %08lx) [%d] => ",
 629                        phys_addr, size, slot);
 630                 dump_stack();
 631         }
 632
 633         /* Don't allow wraparound or zero size */
 634         last_addr = phys_addr + size - 1;
 635         if (!size || last_addr < phys_addr) {
 636                 WARN_ON(1);
 637                 return NULL;
 638         }
 639
 640         prev_size[slot] = size;
 641         /*
 642          * Mappings have to be page-aligned
 643          */
 644         offset = phys_addr & ~PAGE_MASK;
 645         phys_addr &= PAGE_MASK;
 646         size = PAGE_ALIGN(last_addr + 1) - phys_addr;
 647
 648         /*
 649          * Mappings have to fit in the FIX_BTMAP area.
 650          */
 651         nrpages = size >> PAGE_SHIFT;
 652         if (nrpages > NR_FIX_BTMAPS) {
 653                 WARN_ON(1);
 654                 return NULL;
 655         }
 656
 657         /*
 658          * Ok, go for it..
 659          */
 660         idx0 = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*slot;
 661         idx = idx0;
 662         while (nrpages > 0) {
 663                 early_set_fixmap(idx, phys_addr, prot);
 664                 phys_addr += PAGE_SIZE;
 665                 --idx;
 666                 --nrpages;
 667         }
 668         if (early_ioremap_debug)
 669                 printk(KERN_CONT "%08lx + %08lx\n", offset, fix_to_virt(idx0));
 670
 671         prev_map[slot] = (void __iomem *)(offset + fix_to_virt(idx0));
 672         return prev_map[slot];
 673 }
 674
 675 /* Remap an IO device */
 676 void __init __iomem *early_ioremap(unsigned long phys_addr, unsigned long size)
 677 {
 678         return __early_ioremap(phys_addr, size, PAGE_KERNEL_IO);
 679 }
 680
 681 /* Remap memory */
 682 void __init __iomem *early_memremap(unsigned long phys_addr, unsigned long size)
 683 {
 684         return __early_ioremap(phys_addr, size, PAGE_KERNEL);
 685 }
 686
 687 void __init early_iounmap(void __iomem *addr, unsigned long size)
 688 {
 689         unsigned long virt_addr;
 690         unsigned long offset;
 691         unsigned int nrpages;
 692         enum fixed_addresses idx;
 693         int i, slot;
 694
 695         slot = -1;
 696         for (i = 0; i < FIX_BTMAPS_SLOTS; i++) {
 697                 if (prev_map[i] == addr) {
 698                         slot = i;
 699                         break;
 700                 }
 701         }
 702
 703         if (slot < 0) {
 704                 printk(KERN_INFO "early_iounmap(%p, %08lx) not found slot\n",
 705                          addr, size);
 706                 WARN_ON(1);
 707                 return;
 708         }
 709
 710         if (prev_size[slot] != size) {
 711                 printk(KERN_INFO "early_iounmap(%p, %08lx) [%d] size not consistent %08lx\n",
 712                          addr, size, slot, prev_size[slot]);
 713                 WARN_ON(1);
 714                 return;
 715         }
 716
 717         if (early_ioremap_debug) {
 718                 printk(KERN_INFO "early_iounmap(%p, %08lx) [%d]\n", addr,
 719                        size, slot);
 720                 dump_stack();
 721         }
 722
 723         virt_addr = (unsigned long)addr;
 724         if (virt_addr < fix_to_virt(FIX_BTMAP_BEGIN)) {
 725                 WARN_ON(1);
 726                 return;
 727         }
 728         offset = virt_addr & ~PAGE_MASK;
 729         nrpages = PAGE_ALIGN(offset + size - 1) >> PAGE_SHIFT;
 730
 731         idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*slot;
 732         while (nrpages > 0) {
 733                 early_clear_fixmap(idx);
 734                 --idx;
 735                 --nrpages;
 736         }
 737         prev_map[slot] = NULL;
 738 }
 739
 740 void __this_fixmap_does_not_exist(void)
 741 {
 742         WARN_ON(1);
 743 }