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)
45 addr = (e820.map[i].addr + PAGE_SIZE-1) >> PAGE_SHIFT;
46 end = (e820.map[i].addr + e820.map[i].size) >> PAGE_SHIFT;
49 * Sanity check: Some BIOSen report areas as RAM that
50 * are not. Notably the 640->1Mb area, which is the
53 if (addr >= (BIOS_BEGIN >> PAGE_SHIFT) &&
54 end < (BIOS_END >> PAGE_SHIFT))
57 if ((pagenr >= addr) && (pagenr < end))
64 * Fix up the linear direct mapping of the kernel to avoid cache attribute
67 static int ioremap_change_attr(unsigned long phys_addr, unsigned long size,
70 unsigned long npages, vaddr, last_addr = phys_addr + size - 1;
73 /* No change for pages after the last mapping */
74 if (last_addr >= (max_pfn_mapped << PAGE_SHIFT))
77 npages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
78 vaddr = (unsigned long) __va(phys_addr);
81 * If there is no identity map for this address,
82 * change_page_attr_addr is unnecessary
84 if (!lookup_address(vaddr, &level))
88 * Must use an address here and not struct page because the
89 * phys addr can be a in hole between nodes and not have a
92 err = change_page_attr_addr(vaddr, npages, prot);
101 * Remap an arbitrary physical address space into the kernel virtual
102 * address space. Needed when the kernel wants to access high addresses
105 * NOTE! We need to allow non-page-aligned mappings too: we will obviously
106 * have to convert them into an offset in a page-aligned mapping, but the
107 * caller shouldn't need to know that small detail.
109 static void __iomem *__ioremap(unsigned long phys_addr, unsigned long size,
113 struct vm_struct *area;
114 unsigned long offset, last_addr;
117 /* Don't allow wraparound or zero size */
118 last_addr = phys_addr + size - 1;
119 if (!size || last_addr < phys_addr)
123 * Don't remap the low PCI/ISA area, it's always mapped..
125 if (phys_addr >= ISA_START_ADDRESS && last_addr < ISA_END_ADDRESS)
126 return (__force void __iomem *)phys_to_virt(phys_addr);
129 * Don't allow anybody to remap normal RAM that we're using..
131 for (offset = phys_addr >> PAGE_SHIFT; offset < max_pfn_mapped &&
132 (offset << PAGE_SHIFT) < last_addr; offset++) {
133 if (page_is_ram(offset))
137 pgprot = MAKE_GLOBAL(__PAGE_KERNEL | flags);
140 * Mappings have to be page-aligned
142 offset = phys_addr & ~PAGE_MASK;
143 phys_addr &= PAGE_MASK;
144 size = PAGE_ALIGN(last_addr+1) - phys_addr;
149 area = get_vm_area(size, VM_IOREMAP);
152 area->phys_addr = phys_addr;
153 addr = (void __iomem *) area->addr;
154 if (ioremap_page_range((unsigned long)addr, (unsigned long)addr + size,
155 phys_addr, pgprot)) {
156 remove_vm_area((void *)(PAGE_MASK & (unsigned long) addr));
160 if (ioremap_change_attr(phys_addr, size, pgprot) < 0) {
165 return (void __iomem *) (offset + (char __iomem *)addr);
169 * ioremap_nocache - map bus memory into CPU space
170 * @offset: bus address of the memory
171 * @size: size of the resource to map
173 * ioremap_nocache performs a platform specific sequence of operations to
174 * make bus memory CPU accessible via the readb/readw/readl/writeb/
175 * writew/writel functions and the other mmio helpers. The returned
176 * address is not guaranteed to be usable directly as a virtual
179 * This version of ioremap ensures that the memory is marked uncachable
180 * on the CPU as well as honouring existing caching rules from things like
181 * the PCI bus. Note that there are other caches and buffers on many
182 * busses. In particular driver authors should read up on PCI writes
184 * It's useful if some control registers are in such an area and
185 * write combining or read caching is not desirable:
187 * Must be freed with iounmap.
189 void __iomem *ioremap_nocache(unsigned long phys_addr, unsigned long size)
191 return __ioremap(phys_addr, size, _PAGE_PCD | _PAGE_PWT);
193 EXPORT_SYMBOL(ioremap_nocache);
195 void __iomem *ioremap_cache(unsigned long phys_addr, unsigned long size)
197 return __ioremap(phys_addr, size, 0);
199 EXPORT_SYMBOL(ioremap_cache);
202 * iounmap - Free a IO remapping
203 * @addr: virtual address from ioremap_*
205 * Caller must ensure there is only one unmapping for the same pointer.
207 void iounmap(volatile void __iomem *addr)
209 struct vm_struct *p, *o;
211 if ((void __force *)addr <= high_memory)
215 * __ioremap special-cases the PCI/ISA range by not instantiating a
216 * vm_area and by simply returning an address into the kernel mapping
217 * of ISA space. So handle that here.
219 if (addr >= phys_to_virt(ISA_START_ADDRESS) &&
220 addr < phys_to_virt(ISA_END_ADDRESS))
223 addr = (volatile void __iomem *)
224 (PAGE_MASK & (unsigned long __force)addr);
226 /* Use the vm area unlocked, assuming the caller
227 ensures there isn't another iounmap for the same address
228 in parallel. Reuse of the virtual address is prevented by
229 leaving it in the global lists until we're done with it.
230 cpa takes care of the direct mappings. */
231 read_lock(&vmlist_lock);
232 for (p = vmlist; p; p = p->next) {
236 read_unlock(&vmlist_lock);
239 printk(KERN_ERR "iounmap: bad address %p\n", addr);
244 /* Reset the direct mapping. Can block */
245 ioremap_change_attr(p->phys_addr, p->size, PAGE_KERNEL);
247 /* Finally remove it */
248 o = remove_vm_area((void *)addr);
249 BUG_ON(p != o || o == NULL);
252 EXPORT_SYMBOL(iounmap);
256 int __initdata early_ioremap_debug;
258 static int __init early_ioremap_debug_setup(char *str)
260 early_ioremap_debug = 1;
264 early_param("early_ioremap_debug", early_ioremap_debug_setup);
266 static __initdata int after_paging_init;
267 static __initdata unsigned long bm_pte[1024]
268 __attribute__((aligned(PAGE_SIZE)));
270 static inline unsigned long * __init early_ioremap_pgd(unsigned long addr)
272 return (unsigned long *)swapper_pg_dir + ((addr >> 22) & 1023);
275 static inline unsigned long * __init early_ioremap_pte(unsigned long addr)
277 return bm_pte + ((addr >> PAGE_SHIFT) & 1023);
280 void __init early_ioremap_init(void)
284 if (early_ioremap_debug)
285 printk(KERN_DEBUG "early_ioremap_init()\n");
287 pgd = early_ioremap_pgd(fix_to_virt(FIX_BTMAP_BEGIN));
288 *pgd = __pa(bm_pte) | _PAGE_TABLE;
289 memset(bm_pte, 0, sizeof(bm_pte));
291 * The boot-ioremap range spans multiple pgds, for which
292 * we are not prepared:
294 if (pgd != early_ioremap_pgd(fix_to_virt(FIX_BTMAP_END))) {
296 printk(KERN_WARNING "pgd %p != %p\n",
297 pgd, early_ioremap_pgd(fix_to_virt(FIX_BTMAP_END)));
298 printk(KERN_WARNING "fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
299 fix_to_virt(FIX_BTMAP_BEGIN));
300 printk(KERN_WARNING "fix_to_virt(FIX_BTMAP_END): %08lx\n",
301 fix_to_virt(FIX_BTMAP_END));
303 printk(KERN_WARNING "FIX_BTMAP_END: %d\n", FIX_BTMAP_END);
304 printk(KERN_WARNING "FIX_BTMAP_BEGIN: %d\n",
309 void __init early_ioremap_clear(void)
313 if (early_ioremap_debug)
314 printk(KERN_DEBUG "early_ioremap_clear()\n");
316 pgd = early_ioremap_pgd(fix_to_virt(FIX_BTMAP_BEGIN));
321 void __init early_ioremap_reset(void)
323 enum fixed_addresses idx;
324 unsigned long *pte, phys, addr;
326 after_paging_init = 1;
327 for (idx = FIX_BTMAP_BEGIN; idx >= FIX_BTMAP_END; idx--) {
328 addr = fix_to_virt(idx);
329 pte = early_ioremap_pte(addr);
330 if (!*pte & _PAGE_PRESENT) {
331 phys = *pte & PAGE_MASK;
332 set_fixmap(idx, phys);
337 static void __init __early_set_fixmap(enum fixed_addresses idx,
338 unsigned long phys, pgprot_t flags)
340 unsigned long *pte, addr = __fix_to_virt(idx);
342 if (idx >= __end_of_fixed_addresses) {
346 pte = early_ioremap_pte(addr);
347 if (pgprot_val(flags))
348 *pte = (phys & PAGE_MASK) | pgprot_val(flags);
351 __flush_tlb_one(addr);
354 static inline void __init early_set_fixmap(enum fixed_addresses idx,
357 if (after_paging_init)
358 set_fixmap(idx, phys);
360 __early_set_fixmap(idx, phys, PAGE_KERNEL);
363 static inline void __init early_clear_fixmap(enum fixed_addresses idx)
365 if (after_paging_init)
368 __early_set_fixmap(idx, 0, __pgprot(0));
372 int __initdata early_ioremap_nested;
374 static int __init check_early_ioremap_leak(void)
376 if (!early_ioremap_nested)
380 "Debug warning: early ioremap leak of %d areas detected.\n",
381 early_ioremap_nested);
383 "please boot with early_ioremap_debug and report the dmesg.\n");
388 late_initcall(check_early_ioremap_leak);
390 void __init *early_ioremap(unsigned long phys_addr, unsigned long size)
392 unsigned long offset, last_addr;
393 unsigned int nrpages, nesting;
394 enum fixed_addresses idx0, idx;
396 WARN_ON(system_state != SYSTEM_BOOTING);
398 nesting = early_ioremap_nested;
399 if (early_ioremap_debug) {
400 printk(KERN_DEBUG "early_ioremap(%08lx, %08lx) [%d] => ",
401 phys_addr, size, nesting);
405 /* Don't allow wraparound or zero size */
406 last_addr = phys_addr + size - 1;
407 if (!size || last_addr < phys_addr) {
412 if (nesting >= FIX_BTMAPS_NESTING) {
416 early_ioremap_nested++;
418 * Mappings have to be page-aligned
420 offset = phys_addr & ~PAGE_MASK;
421 phys_addr &= PAGE_MASK;
422 size = PAGE_ALIGN(last_addr) - phys_addr;
425 * Mappings have to fit in the FIX_BTMAP area.
427 nrpages = size >> PAGE_SHIFT;
428 if (nrpages > NR_FIX_BTMAPS) {
436 idx0 = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*nesting;
438 while (nrpages > 0) {
439 early_set_fixmap(idx, phys_addr);
440 phys_addr += PAGE_SIZE;
444 if (early_ioremap_debug)
445 printk(KERN_CONT "%08lx + %08lx\n", offset, fix_to_virt(idx0));
447 return (void *) (offset + fix_to_virt(idx0));
450 void __init early_iounmap(void *addr, unsigned long size)
452 unsigned long virt_addr;
453 unsigned long offset;
454 unsigned int nrpages;
455 enum fixed_addresses idx;
456 unsigned int nesting;
458 nesting = --early_ioremap_nested;
459 WARN_ON(nesting < 0);
461 if (early_ioremap_debug) {
462 printk(KERN_DEBUG "early_iounmap(%p, %08lx) [%d]\n", addr,
467 virt_addr = (unsigned long)addr;
468 if (virt_addr < fix_to_virt(FIX_BTMAP_BEGIN)) {
472 offset = virt_addr & ~PAGE_MASK;
473 nrpages = PAGE_ALIGN(offset + size - 1) >> PAGE_SHIFT;
475 idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*nesting;
476 while (nrpages > 0) {
477 early_clear_fixmap(idx);
483 void __this_fixmap_does_not_exist(void)
488 #endif /* CONFIG_X86_32 */