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
6 * (C) Copyright 1995 1996 Linus Torvalds
9 #include <linux/bootmem.h>
10 #include <linux/init.h>
12 #include <linux/module.h>
13 #include <linux/slab.h>
14 #include <linux/vmalloc.h>
16 #include <asm/cacheflush.h>
18 #include <asm/fixmap.h>
19 #include <asm/pgtable.h>
20 #include <asm/tlbflush.h>
24 unsigned long __phys_addr(unsigned long x)
26 if (x >= __START_KERNEL_map)
27 return x - __START_KERNEL_map + phys_base;
28 return x - PAGE_OFFSET;
30 EXPORT_SYMBOL(__phys_addr);
34 int page_is_ram(unsigned long pagenr)
36 unsigned long addr, end;
39 for (i = 0; i < e820.nr_map; i++) {
43 if (e820.map[i].type != E820_RAM)
46 * !!!FIXME!!! Some BIOSen report areas as RAM that
47 * are not. Notably the 640->1Mb area. We need a sanity
50 addr = (e820.map[i].addr + PAGE_SIZE-1) >> PAGE_SHIFT;
51 end = (e820.map[i].addr + e820.map[i].size) >> PAGE_SHIFT;
52 if ((pagenr >= addr) && (pagenr < end))
59 * Fix up the linear direct mapping of the kernel to avoid cache attribute
62 static int ioremap_change_attr(unsigned long phys_addr, unsigned long size,
65 unsigned long npages, vaddr, last_addr = phys_addr + size - 1;
68 /* No change for pages after the last mapping */
69 if (last_addr >= (max_pfn_mapped << PAGE_SHIFT))
72 npages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
73 vaddr = (unsigned long) __va(phys_addr);
76 * If there is no identity map for this address,
77 * change_page_attr_addr is unnecessary
79 if (!lookup_address(vaddr, &level))
83 * Must use an address here and not struct page because the
84 * phys addr can be a in hole between nodes and not have a
87 err = change_page_attr_addr(vaddr, npages, prot);
96 * Remap an arbitrary physical address space into the kernel virtual
97 * address space. Needed when the kernel wants to access high addresses
100 * NOTE! We need to allow non-page-aligned mappings too: we will obviously
101 * have to convert them into an offset in a page-aligned mapping, but the
102 * caller shouldn't need to know that small detail.
104 void __iomem *__ioremap(unsigned long phys_addr, unsigned long size,
108 struct vm_struct *area;
109 unsigned long offset, last_addr;
112 /* Don't allow wraparound or zero size */
113 last_addr = phys_addr + size - 1;
114 if (!size || last_addr < phys_addr)
118 * Don't remap the low PCI/ISA area, it's always mapped..
120 if (phys_addr >= ISA_START_ADDRESS && last_addr < ISA_END_ADDRESS)
121 return (__force void __iomem *)phys_to_virt(phys_addr);
125 * Don't allow anybody to remap normal RAM that we're using..
127 if (phys_addr <= virt_to_phys(high_memory - 1)) {
128 char *t_addr, *t_end;
131 t_addr = __va(phys_addr);
132 t_end = t_addr + (size - 1);
134 for (page = virt_to_page(t_addr);
135 page <= virt_to_page(t_end); page++)
136 if (!PageReserved(page))
141 pgprot = MAKE_GLOBAL(__PAGE_KERNEL | flags);
144 * Mappings have to be page-aligned
146 offset = phys_addr & ~PAGE_MASK;
147 phys_addr &= PAGE_MASK;
148 size = PAGE_ALIGN(last_addr+1) - phys_addr;
153 area = get_vm_area(size, VM_IOREMAP);
156 area->phys_addr = phys_addr;
157 addr = (void __iomem *) area->addr;
158 if (ioremap_page_range((unsigned long)addr, (unsigned long)addr + size,
159 phys_addr, pgprot)) {
160 remove_vm_area((void *)(PAGE_MASK & (unsigned long) addr));
164 if (ioremap_change_attr(phys_addr, size, pgprot) < 0) {
169 return (void __iomem *) (offset + (char __iomem *)addr);
171 EXPORT_SYMBOL(__ioremap);
174 * ioremap_nocache - map bus memory into CPU space
175 * @offset: bus address of the memory
176 * @size: size of the resource to map
178 * ioremap_nocache performs a platform specific sequence of operations to
179 * make bus memory CPU accessible via the readb/readw/readl/writeb/
180 * writew/writel functions and the other mmio helpers. The returned
181 * address is not guaranteed to be usable directly as a virtual
184 * This version of ioremap ensures that the memory is marked uncachable
185 * on the CPU as well as honouring existing caching rules from things like
186 * the PCI bus. Note that there are other caches and buffers on many
187 * busses. In particular driver authors should read up on PCI writes
189 * It's useful if some control registers are in such an area and
190 * write combining or read caching is not desirable:
192 * Must be freed with iounmap.
194 void __iomem *ioremap_nocache(unsigned long phys_addr, unsigned long size)
196 return __ioremap(phys_addr, size, _PAGE_PCD | _PAGE_PWT);
198 EXPORT_SYMBOL(ioremap_nocache);
201 * iounmap - Free a IO remapping
202 * @addr: virtual address from ioremap_*
204 * Caller must ensure there is only one unmapping for the same pointer.
206 void iounmap(volatile void __iomem *addr)
208 struct vm_struct *p, *o;
210 if ((void __force *)addr <= high_memory)
214 * __ioremap special-cases the PCI/ISA range by not instantiating a
215 * vm_area and by simply returning an address into the kernel mapping
216 * of ISA space. So handle that here.
218 if (addr >= phys_to_virt(ISA_START_ADDRESS) &&
219 addr < phys_to_virt(ISA_END_ADDRESS))
222 addr = (volatile void __iomem *)
223 (PAGE_MASK & (unsigned long __force)addr);
225 /* Use the vm area unlocked, assuming the caller
226 ensures there isn't another iounmap for the same address
227 in parallel. Reuse of the virtual address is prevented by
228 leaving it in the global lists until we're done with it.
229 cpa takes care of the direct mappings. */
230 read_lock(&vmlist_lock);
231 for (p = vmlist; p; p = p->next) {
235 read_unlock(&vmlist_lock);
238 printk(KERN_ERR "iounmap: bad address %p\n", addr);
243 /* Reset the direct mapping. Can block */
244 ioremap_change_attr(p->phys_addr, p->size, PAGE_KERNEL);
246 /* Finally remove it */
247 o = remove_vm_area((void *)addr);
248 BUG_ON(p != o || o == NULL);
251 EXPORT_SYMBOL(iounmap);
255 int __initdata early_ioremap_debug;
257 static int __init early_ioremap_debug_setup(char *str)
259 early_ioremap_debug = 1;
263 early_param("early_ioremap_debug", early_ioremap_debug_setup);
265 static __initdata int after_paging_init;
266 static __initdata unsigned long bm_pte[1024]
267 __attribute__((aligned(PAGE_SIZE)));
269 static inline unsigned long * __init early_ioremap_pgd(unsigned long addr)
271 return (unsigned long *)swapper_pg_dir + ((addr >> 22) & 1023);
274 static inline unsigned long * __init early_ioremap_pte(unsigned long addr)
276 return bm_pte + ((addr >> PAGE_SHIFT) & 1023);
279 void __init early_ioremap_init(void)
283 if (early_ioremap_debug)
284 printk(KERN_DEBUG "early_ioremap_init()\n");
286 pgd = early_ioremap_pgd(fix_to_virt(FIX_BTMAP_BEGIN));
287 *pgd = __pa(bm_pte) | _PAGE_TABLE;
288 memset(bm_pte, 0, sizeof(bm_pte));
290 * The boot-ioremap range spans multiple pgds, for which
291 * we are not prepared:
293 if (pgd != early_ioremap_pgd(fix_to_virt(FIX_BTMAP_END))) {
295 printk(KERN_WARNING "pgd %p != %p\n",
296 pgd, early_ioremap_pgd(fix_to_virt(FIX_BTMAP_END)));
297 printk(KERN_WARNING "fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
298 fix_to_virt(FIX_BTMAP_BEGIN));
299 printk(KERN_WARNING "fix_to_virt(FIX_BTMAP_END): %08lx\n",
300 fix_to_virt(FIX_BTMAP_END));
302 printk(KERN_WARNING "FIX_BTMAP_END: %d\n", FIX_BTMAP_END);
303 printk(KERN_WARNING "FIX_BTMAP_BEGIN: %d\n",
308 void __init early_ioremap_clear(void)
312 if (early_ioremap_debug)
313 printk(KERN_DEBUG "early_ioremap_clear()\n");
315 pgd = early_ioremap_pgd(fix_to_virt(FIX_BTMAP_BEGIN));
320 void __init early_ioremap_reset(void)
322 enum fixed_addresses idx;
323 unsigned long *pte, phys, addr;
325 after_paging_init = 1;
326 for (idx = FIX_BTMAP_BEGIN; idx >= FIX_BTMAP_END; idx--) {
327 addr = fix_to_virt(idx);
328 pte = early_ioremap_pte(addr);
329 if (!*pte & _PAGE_PRESENT) {
330 phys = *pte & PAGE_MASK;
331 set_fixmap(idx, phys);
336 static void __init __early_set_fixmap(enum fixed_addresses idx,
337 unsigned long phys, pgprot_t flags)
339 unsigned long *pte, addr = __fix_to_virt(idx);
341 if (idx >= __end_of_fixed_addresses) {
345 pte = early_ioremap_pte(addr);
346 if (pgprot_val(flags))
347 *pte = (phys & PAGE_MASK) | pgprot_val(flags);
350 __flush_tlb_one(addr);
353 static inline void __init early_set_fixmap(enum fixed_addresses idx,
356 if (after_paging_init)
357 set_fixmap(idx, phys);
359 __early_set_fixmap(idx, phys, PAGE_KERNEL);
362 static inline void __init early_clear_fixmap(enum fixed_addresses idx)
364 if (after_paging_init)
367 __early_set_fixmap(idx, 0, __pgprot(0));
371 int __initdata early_ioremap_nested;
373 static int __init check_early_ioremap_leak(void)
375 if (!early_ioremap_nested)
379 "Debug warning: early ioremap leak of %d areas detected.\n",
380 early_ioremap_nested);
382 "please boot with early_ioremap_debug and report the dmesg.\n");
387 late_initcall(check_early_ioremap_leak);
389 void __init *early_ioremap(unsigned long phys_addr, unsigned long size)
391 unsigned long offset, last_addr;
392 unsigned int nrpages, nesting;
393 enum fixed_addresses idx0, idx;
395 WARN_ON(system_state != SYSTEM_BOOTING);
397 nesting = early_ioremap_nested;
398 if (early_ioremap_debug) {
399 printk(KERN_DEBUG "early_ioremap(%08lx, %08lx) [%d] => ",
400 phys_addr, size, nesting);
404 /* Don't allow wraparound or zero size */
405 last_addr = phys_addr + size - 1;
406 if (!size || last_addr < phys_addr) {
411 if (nesting >= FIX_BTMAPS_NESTING) {
415 early_ioremap_nested++;
417 * Mappings have to be page-aligned
419 offset = phys_addr & ~PAGE_MASK;
420 phys_addr &= PAGE_MASK;
421 size = PAGE_ALIGN(last_addr) - phys_addr;
424 * Mappings have to fit in the FIX_BTMAP area.
426 nrpages = size >> PAGE_SHIFT;
427 if (nrpages > NR_FIX_BTMAPS) {
435 idx0 = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*nesting;
437 while (nrpages > 0) {
438 early_set_fixmap(idx, phys_addr);
439 phys_addr += PAGE_SIZE;
443 if (early_ioremap_debug)
444 printk(KERN_CONT "%08lx + %08lx\n", offset, fix_to_virt(idx0));
446 return (void *) (offset + fix_to_virt(idx0));
449 void __init early_iounmap(void *addr, unsigned long size)
451 unsigned long virt_addr;
452 unsigned long offset;
453 unsigned int nrpages;
454 enum fixed_addresses idx;
455 unsigned int nesting;
457 nesting = --early_ioremap_nested;
458 WARN_ON(nesting < 0);
460 if (early_ioremap_debug) {
461 printk(KERN_DEBUG "early_iounmap(%p, %08lx) [%d]\n", addr,
466 virt_addr = (unsigned long)addr;
467 if (virt_addr < fix_to_virt(FIX_BTMAP_BEGIN)) {
471 offset = virt_addr & ~PAGE_MASK;
472 nrpages = PAGE_ALIGN(offset + size - 1) >> PAGE_SHIFT;
474 idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*nesting;
475 while (nrpages > 0) {
476 early_clear_fixmap(idx);
482 void __this_fixmap_does_not_exist(void)
487 #endif /* CONFIG_X86_32 */