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>
21 #include <asm/pgalloc.h>
30 unsigned long __phys_addr(unsigned long x)
32 if (x >= __START_KERNEL_map)
33 return x - __START_KERNEL_map + phys_base;
34 return x - PAGE_OFFSET;
36 EXPORT_SYMBOL(__phys_addr);
40 int page_is_ram(unsigned long pagenr)
42 unsigned long addr, end;
45 for (i = 0; i < e820.nr_map; i++) {
49 if (e820.map[i].type != E820_RAM)
51 addr = (e820.map[i].addr + PAGE_SIZE-1) >> PAGE_SHIFT;
52 end = (e820.map[i].addr + e820.map[i].size) >> PAGE_SHIFT;
55 * Sanity check: Some BIOSen report areas as RAM that
56 * are not. Notably the 640->1Mb area, which is the
59 if (addr >= (BIOS_BEGIN >> PAGE_SHIFT) &&
60 end < (BIOS_END >> PAGE_SHIFT))
63 if ((pagenr >= addr) && (pagenr < end))
70 * Fix up the linear direct mapping of the kernel to avoid cache attribute
73 static int ioremap_change_attr(unsigned long paddr, unsigned long size,
74 enum ioremap_mode mode)
76 unsigned long vaddr = (unsigned long)__va(paddr);
77 unsigned long nrpages = size >> PAGE_SHIFT;
80 /* No change for pages after the last mapping */
81 if ((paddr + size - 1) >= (max_pfn_mapped << PAGE_SHIFT))
85 * If there is no identity map for this address,
86 * change_page_attr_addr is unnecessary
88 if (!lookup_address(vaddr, &level))
92 case IOR_MODE_UNCACHED:
94 err = set_memory_uc(vaddr, nrpages);
97 err = set_memory_wb(vaddr, nrpages);
105 * Remap an arbitrary physical address space into the kernel virtual
106 * address space. Needed when the kernel wants to access high addresses
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.
113 static void __iomem *__ioremap(unsigned long phys_addr, unsigned long size,
114 enum ioremap_mode mode)
117 struct vm_struct *area;
118 unsigned long offset, last_addr;
121 /* Don't allow wraparound or zero size */
122 last_addr = phys_addr + size - 1;
123 if (!size || last_addr < phys_addr)
127 * Don't remap the low PCI/ISA area, it's always mapped..
129 if (phys_addr >= ISA_START_ADDRESS && last_addr < ISA_END_ADDRESS)
130 return (__force void __iomem *)phys_to_virt(phys_addr);
133 * Don't allow anybody to remap normal RAM that we're using..
135 for (offset = phys_addr >> PAGE_SHIFT; offset < max_pfn_mapped &&
136 (offset << PAGE_SHIFT) < last_addr; offset++) {
137 if (page_is_ram(offset))
142 case IOR_MODE_UNCACHED:
144 prot = PAGE_KERNEL_NOCACHE;
146 case IOR_MODE_CACHED:
152 * Mappings have to be page-aligned
154 offset = phys_addr & ~PAGE_MASK;
155 phys_addr &= PAGE_MASK;
156 size = PAGE_ALIGN(last_addr+1) - phys_addr;
161 area = get_vm_area(size, VM_IOREMAP);
164 area->phys_addr = phys_addr;
165 addr = (void __iomem *) area->addr;
166 if (ioremap_page_range((unsigned long)addr, (unsigned long)addr + size,
168 remove_vm_area((void *)(PAGE_MASK & (unsigned long) addr));
172 if (ioremap_change_attr(phys_addr, size, mode) < 0) {
177 return (void __iomem *) (offset + (char __iomem *)addr);
181 * ioremap_nocache - map bus memory into CPU space
182 * @offset: bus address of the memory
183 * @size: size of the resource to map
185 * ioremap_nocache performs a platform specific sequence of operations to
186 * make bus memory CPU accessible via the readb/readw/readl/writeb/
187 * writew/writel functions and the other mmio helpers. The returned
188 * address is not guaranteed to be usable directly as a virtual
191 * This version of ioremap ensures that the memory is marked uncachable
192 * on the CPU as well as honouring existing caching rules from things like
193 * the PCI bus. Note that there are other caches and buffers on many
194 * busses. In particular driver authors should read up on PCI writes
196 * It's useful if some control registers are in such an area and
197 * write combining or read caching is not desirable:
199 * Must be freed with iounmap.
201 void __iomem *ioremap_nocache(unsigned long phys_addr, unsigned long size)
203 return __ioremap(phys_addr, size, IOR_MODE_UNCACHED);
205 EXPORT_SYMBOL(ioremap_nocache);
207 void __iomem *ioremap_cache(unsigned long phys_addr, unsigned long size)
209 return __ioremap(phys_addr, size, IOR_MODE_CACHED);
211 EXPORT_SYMBOL(ioremap_cache);
214 * iounmap - Free a IO remapping
215 * @addr: virtual address from ioremap_*
217 * Caller must ensure there is only one unmapping for the same pointer.
219 void iounmap(volatile void __iomem *addr)
221 struct vm_struct *p, *o;
223 if ((void __force *)addr <= high_memory)
227 * __ioremap special-cases the PCI/ISA range by not instantiating a
228 * vm_area and by simply returning an address into the kernel mapping
229 * of ISA space. So handle that here.
231 if (addr >= phys_to_virt(ISA_START_ADDRESS) &&
232 addr < phys_to_virt(ISA_END_ADDRESS))
235 addr = (volatile void __iomem *)
236 (PAGE_MASK & (unsigned long __force)addr);
238 /* Use the vm area unlocked, assuming the caller
239 ensures there isn't another iounmap for the same address
240 in parallel. Reuse of the virtual address is prevented by
241 leaving it in the global lists until we're done with it.
242 cpa takes care of the direct mappings. */
243 read_lock(&vmlist_lock);
244 for (p = vmlist; p; p = p->next) {
248 read_unlock(&vmlist_lock);
251 printk(KERN_ERR "iounmap: bad address %p\n", addr);
256 /* Reset the direct mapping. Can block */
257 ioremap_change_attr(p->phys_addr, p->size, IOR_MODE_CACHED);
259 /* Finally remove it */
260 o = remove_vm_area((void *)addr);
261 BUG_ON(p != o || o == NULL);
264 EXPORT_SYMBOL(iounmap);
268 int __initdata early_ioremap_debug;
270 static int __init early_ioremap_debug_setup(char *str)
272 early_ioremap_debug = 1;
276 early_param("early_ioremap_debug", early_ioremap_debug_setup);
278 static __initdata int after_paging_init;
279 static __initdata unsigned long bm_pte[1024]
280 __attribute__((aligned(PAGE_SIZE)));
282 static inline unsigned long * __init early_ioremap_pgd(unsigned long addr)
284 return (unsigned long *)swapper_pg_dir + ((addr >> 22) & 1023);
287 static inline unsigned long * __init early_ioremap_pte(unsigned long addr)
289 return bm_pte + ((addr >> PAGE_SHIFT) & 1023);
292 void __init early_ioremap_init(void)
296 if (early_ioremap_debug)
297 printk(KERN_INFO "early_ioremap_init()\n");
299 pgd = early_ioremap_pgd(fix_to_virt(FIX_BTMAP_BEGIN));
300 *pgd = __pa(bm_pte) | _PAGE_TABLE;
301 memset(bm_pte, 0, sizeof(bm_pte));
303 * The boot-ioremap range spans multiple pgds, for which
304 * we are not prepared:
306 if (pgd != early_ioremap_pgd(fix_to_virt(FIX_BTMAP_END))) {
308 printk(KERN_WARNING "pgd %p != %p\n",
309 pgd, early_ioremap_pgd(fix_to_virt(FIX_BTMAP_END)));
310 printk(KERN_WARNING "fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
311 fix_to_virt(FIX_BTMAP_BEGIN));
312 printk(KERN_WARNING "fix_to_virt(FIX_BTMAP_END): %08lx\n",
313 fix_to_virt(FIX_BTMAP_END));
315 printk(KERN_WARNING "FIX_BTMAP_END: %d\n", FIX_BTMAP_END);
316 printk(KERN_WARNING "FIX_BTMAP_BEGIN: %d\n",
321 void __init early_ioremap_clear(void)
325 if (early_ioremap_debug)
326 printk(KERN_INFO "early_ioremap_clear()\n");
328 pgd = early_ioremap_pgd(fix_to_virt(FIX_BTMAP_BEGIN));
330 paravirt_release_pt(__pa(pgd) >> PAGE_SHIFT);
334 void __init early_ioremap_reset(void)
336 enum fixed_addresses idx;
337 unsigned long *pte, phys, addr;
339 after_paging_init = 1;
340 for (idx = FIX_BTMAP_BEGIN; idx >= FIX_BTMAP_END; idx--) {
341 addr = fix_to_virt(idx);
342 pte = early_ioremap_pte(addr);
343 if (*pte & _PAGE_PRESENT) {
344 phys = *pte & PAGE_MASK;
345 set_fixmap(idx, phys);
350 static void __init __early_set_fixmap(enum fixed_addresses idx,
351 unsigned long phys, pgprot_t flags)
353 unsigned long *pte, addr = __fix_to_virt(idx);
355 if (idx >= __end_of_fixed_addresses) {
359 pte = early_ioremap_pte(addr);
360 if (pgprot_val(flags))
361 *pte = (phys & PAGE_MASK) | pgprot_val(flags);
364 __flush_tlb_one(addr);
367 static inline void __init early_set_fixmap(enum fixed_addresses idx,
370 if (after_paging_init)
371 set_fixmap(idx, phys);
373 __early_set_fixmap(idx, phys, PAGE_KERNEL);
376 static inline void __init early_clear_fixmap(enum fixed_addresses idx)
378 if (after_paging_init)
381 __early_set_fixmap(idx, 0, __pgprot(0));
385 int __initdata early_ioremap_nested;
387 static int __init check_early_ioremap_leak(void)
389 if (!early_ioremap_nested)
393 "Debug warning: early ioremap leak of %d areas detected.\n",
394 early_ioremap_nested);
396 "please boot with early_ioremap_debug and report the dmesg.\n");
401 late_initcall(check_early_ioremap_leak);
403 void __init *early_ioremap(unsigned long phys_addr, unsigned long size)
405 unsigned long offset, last_addr;
406 unsigned int nrpages, nesting;
407 enum fixed_addresses idx0, idx;
409 WARN_ON(system_state != SYSTEM_BOOTING);
411 nesting = early_ioremap_nested;
412 if (early_ioremap_debug) {
413 printk(KERN_INFO "early_ioremap(%08lx, %08lx) [%d] => ",
414 phys_addr, size, nesting);
418 /* Don't allow wraparound or zero size */
419 last_addr = phys_addr + size - 1;
420 if (!size || last_addr < phys_addr) {
425 if (nesting >= FIX_BTMAPS_NESTING) {
429 early_ioremap_nested++;
431 * Mappings have to be page-aligned
433 offset = phys_addr & ~PAGE_MASK;
434 phys_addr &= PAGE_MASK;
435 size = PAGE_ALIGN(last_addr) - phys_addr;
438 * Mappings have to fit in the FIX_BTMAP area.
440 nrpages = size >> PAGE_SHIFT;
441 if (nrpages > NR_FIX_BTMAPS) {
449 idx0 = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*nesting;
451 while (nrpages > 0) {
452 early_set_fixmap(idx, phys_addr);
453 phys_addr += PAGE_SIZE;
457 if (early_ioremap_debug)
458 printk(KERN_CONT "%08lx + %08lx\n", offset, fix_to_virt(idx0));
460 return (void *) (offset + fix_to_virt(idx0));
463 void __init early_iounmap(void *addr, unsigned long size)
465 unsigned long virt_addr;
466 unsigned long offset;
467 unsigned int nrpages;
468 enum fixed_addresses idx;
469 unsigned int nesting;
471 nesting = --early_ioremap_nested;
472 WARN_ON(nesting < 0);
474 if (early_ioremap_debug) {
475 printk(KERN_INFO "early_iounmap(%p, %08lx) [%d]\n", addr,
480 virt_addr = (unsigned long)addr;
481 if (virt_addr < fix_to_virt(FIX_BTMAP_BEGIN)) {
485 offset = virt_addr & ~PAGE_MASK;
486 nrpages = PAGE_ALIGN(offset + size - 1) >> PAGE_SHIFT;
488 idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*nesting;
489 while (nrpages > 0) {
490 early_clear_fixmap(idx);
496 void __this_fixmap_does_not_exist(void)
501 #endif /* CONFIG_X86_32 */