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;
81 /* No change for pages after the last mapping */
82 if ((paddr + size - 1) >= (max_pfn_mapped << PAGE_SHIFT))
86 * If there is no identity map for this address,
87 * change_page_attr_addr is unnecessary
89 if (!lookup_address(vaddr, &level))
93 case IOR_MODE_UNCACHED:
95 err = set_memory_uc(vaddr, nrpages);
98 err = set_memory_wb(vaddr, nrpages);
106 * Remap an arbitrary physical address space into the kernel virtual
107 * address space. Needed when the kernel wants to access high addresses
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.
114 static void __iomem *__ioremap(unsigned long phys_addr, unsigned long size,
115 enum ioremap_mode mode)
118 struct vm_struct *area;
119 unsigned long offset, last_addr;
122 /* Don't allow wraparound or zero size */
123 last_addr = phys_addr + size - 1;
124 if (!size || last_addr < phys_addr)
128 * Don't remap the low PCI/ISA area, it's always mapped..
130 if (phys_addr >= ISA_START_ADDRESS && last_addr < ISA_END_ADDRESS)
131 return (__force void __iomem *)phys_to_virt(phys_addr);
134 * Don't allow anybody to remap normal RAM that we're using..
136 for (offset = phys_addr >> PAGE_SHIFT; offset < max_pfn_mapped &&
137 (offset << PAGE_SHIFT) < last_addr; offset++) {
138 if (page_is_ram(offset))
143 case IOR_MODE_UNCACHED:
145 prot = PAGE_KERNEL_NOCACHE;
147 case IOR_MODE_CACHED:
153 * Mappings have to be page-aligned
155 offset = phys_addr & ~PAGE_MASK;
156 phys_addr &= PAGE_MASK;
157 size = PAGE_ALIGN(last_addr+1) - phys_addr;
162 area = get_vm_area(size, VM_IOREMAP);
165 area->phys_addr = phys_addr;
166 addr = (void __iomem *) area->addr;
167 if (ioremap_page_range((unsigned long)addr, (unsigned long)addr + size,
169 remove_vm_area((void *)(PAGE_MASK & (unsigned long) addr));
173 if (ioremap_change_attr(phys_addr, size, mode) < 0) {
178 return (void __iomem *) (offset + (char __iomem *)addr);
182 * ioremap_nocache - map bus memory into CPU space
183 * @offset: bus address of the memory
184 * @size: size of the resource to map
186 * ioremap_nocache performs a platform specific sequence of operations to
187 * make bus memory CPU accessible via the readb/readw/readl/writeb/
188 * writew/writel functions and the other mmio helpers. The returned
189 * address is not guaranteed to be usable directly as a virtual
192 * This version of ioremap ensures that the memory is marked uncachable
193 * on the CPU as well as honouring existing caching rules from things like
194 * the PCI bus. Note that there are other caches and buffers on many
195 * busses. In particular driver authors should read up on PCI writes
197 * It's useful if some control registers are in such an area and
198 * write combining or read caching is not desirable:
200 * Must be freed with iounmap.
202 void __iomem *ioremap_nocache(unsigned long phys_addr, unsigned long size)
204 return __ioremap(phys_addr, size, IOR_MODE_UNCACHED);
206 EXPORT_SYMBOL(ioremap_nocache);
208 void __iomem *ioremap_cache(unsigned long phys_addr, unsigned long size)
210 return __ioremap(phys_addr, size, IOR_MODE_CACHED);
212 EXPORT_SYMBOL(ioremap_cache);
215 * iounmap - Free a IO remapping
216 * @addr: virtual address from ioremap_*
218 * Caller must ensure there is only one unmapping for the same pointer.
220 void iounmap(volatile void __iomem *addr)
222 struct vm_struct *p, *o;
224 if ((void __force *)addr <= high_memory)
228 * __ioremap special-cases the PCI/ISA range by not instantiating a
229 * vm_area and by simply returning an address into the kernel mapping
230 * of ISA space. So handle that here.
232 if (addr >= phys_to_virt(ISA_START_ADDRESS) &&
233 addr < phys_to_virt(ISA_END_ADDRESS))
236 addr = (volatile void __iomem *)
237 (PAGE_MASK & (unsigned long __force)addr);
239 /* Use the vm area unlocked, assuming the caller
240 ensures there isn't another iounmap for the same address
241 in parallel. Reuse of the virtual address is prevented by
242 leaving it in the global lists until we're done with it.
243 cpa takes care of the direct mappings. */
244 read_lock(&vmlist_lock);
245 for (p = vmlist; p; p = p->next) {
249 read_unlock(&vmlist_lock);
252 printk(KERN_ERR "iounmap: bad address %p\n", addr);
257 /* Reset the direct mapping. Can block */
258 ioremap_change_attr(p->phys_addr, p->size, IOR_MODE_CACHED);
260 /* Finally remove it */
261 o = remove_vm_area((void *)addr);
262 BUG_ON(p != o || o == NULL);
265 EXPORT_SYMBOL(iounmap);
269 int __initdata early_ioremap_debug;
271 static int __init early_ioremap_debug_setup(char *str)
273 early_ioremap_debug = 1;
277 early_param("early_ioremap_debug", early_ioremap_debug_setup);
279 static __initdata int after_paging_init;
280 static __initdata unsigned long bm_pte[1024]
281 __attribute__((aligned(PAGE_SIZE)));
283 static inline unsigned long * __init early_ioremap_pgd(unsigned long addr)
285 return (unsigned long *)swapper_pg_dir + ((addr >> 22) & 1023);
288 static inline unsigned long * __init early_ioremap_pte(unsigned long addr)
290 return bm_pte + ((addr >> PAGE_SHIFT) & 1023);
293 void __init early_ioremap_init(void)
297 if (early_ioremap_debug)
298 printk(KERN_INFO "early_ioremap_init()\n");
300 pgd = early_ioremap_pgd(fix_to_virt(FIX_BTMAP_BEGIN));
301 *pgd = __pa(bm_pte) | _PAGE_TABLE;
302 memset(bm_pte, 0, sizeof(bm_pte));
304 * The boot-ioremap range spans multiple pgds, for which
305 * we are not prepared:
307 if (pgd != early_ioremap_pgd(fix_to_virt(FIX_BTMAP_END))) {
309 printk(KERN_WARNING "pgd %p != %p\n",
310 pgd, early_ioremap_pgd(fix_to_virt(FIX_BTMAP_END)));
311 printk(KERN_WARNING "fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
312 fix_to_virt(FIX_BTMAP_BEGIN));
313 printk(KERN_WARNING "fix_to_virt(FIX_BTMAP_END): %08lx\n",
314 fix_to_virt(FIX_BTMAP_END));
316 printk(KERN_WARNING "FIX_BTMAP_END: %d\n", FIX_BTMAP_END);
317 printk(KERN_WARNING "FIX_BTMAP_BEGIN: %d\n",
322 void __init early_ioremap_clear(void)
326 if (early_ioremap_debug)
327 printk(KERN_INFO "early_ioremap_clear()\n");
329 pgd = early_ioremap_pgd(fix_to_virt(FIX_BTMAP_BEGIN));
331 paravirt_release_pt(__pa(pgd) >> PAGE_SHIFT);
335 void __init early_ioremap_reset(void)
337 enum fixed_addresses idx;
338 unsigned long *pte, phys, addr;
340 after_paging_init = 1;
341 for (idx = FIX_BTMAP_BEGIN; idx >= FIX_BTMAP_END; idx--) {
342 addr = fix_to_virt(idx);
343 pte = early_ioremap_pte(addr);
344 if (*pte & _PAGE_PRESENT) {
345 phys = *pte & PAGE_MASK;
346 set_fixmap(idx, phys);
351 static void __init __early_set_fixmap(enum fixed_addresses idx,
352 unsigned long phys, pgprot_t flags)
354 unsigned long *pte, addr = __fix_to_virt(idx);
356 if (idx >= __end_of_fixed_addresses) {
360 pte = early_ioremap_pte(addr);
361 if (pgprot_val(flags))
362 *pte = (phys & PAGE_MASK) | pgprot_val(flags);
365 __flush_tlb_one(addr);
368 static inline void __init early_set_fixmap(enum fixed_addresses idx,
371 if (after_paging_init)
372 set_fixmap(idx, phys);
374 __early_set_fixmap(idx, phys, PAGE_KERNEL);
377 static inline void __init early_clear_fixmap(enum fixed_addresses idx)
379 if (after_paging_init)
382 __early_set_fixmap(idx, 0, __pgprot(0));
386 int __initdata early_ioremap_nested;
388 static int __init check_early_ioremap_leak(void)
390 if (!early_ioremap_nested)
394 "Debug warning: early ioremap leak of %d areas detected.\n",
395 early_ioremap_nested);
397 "please boot with early_ioremap_debug and report the dmesg.\n");
402 late_initcall(check_early_ioremap_leak);
404 void __init *early_ioremap(unsigned long phys_addr, unsigned long size)
406 unsigned long offset, last_addr;
407 unsigned int nrpages, nesting;
408 enum fixed_addresses idx0, idx;
410 WARN_ON(system_state != SYSTEM_BOOTING);
412 nesting = early_ioremap_nested;
413 if (early_ioremap_debug) {
414 printk(KERN_INFO "early_ioremap(%08lx, %08lx) [%d] => ",
415 phys_addr, size, nesting);
419 /* Don't allow wraparound or zero size */
420 last_addr = phys_addr + size - 1;
421 if (!size || last_addr < phys_addr) {
426 if (nesting >= FIX_BTMAPS_NESTING) {
430 early_ioremap_nested++;
432 * Mappings have to be page-aligned
434 offset = phys_addr & ~PAGE_MASK;
435 phys_addr &= PAGE_MASK;
436 size = PAGE_ALIGN(last_addr) - phys_addr;
439 * Mappings have to fit in the FIX_BTMAP area.
441 nrpages = size >> PAGE_SHIFT;
442 if (nrpages > NR_FIX_BTMAPS) {
450 idx0 = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*nesting;
452 while (nrpages > 0) {
453 early_set_fixmap(idx, phys_addr);
454 phys_addr += PAGE_SIZE;
458 if (early_ioremap_debug)
459 printk(KERN_CONT "%08lx + %08lx\n", offset, fix_to_virt(idx0));
461 return (void *) (offset + fix_to_virt(idx0));
464 void __init early_iounmap(void *addr, unsigned long size)
466 unsigned long virt_addr;
467 unsigned long offset;
468 unsigned int nrpages;
469 enum fixed_addresses idx;
470 unsigned int nesting;
472 nesting = --early_ioremap_nested;
473 WARN_ON(nesting < 0);
475 if (early_ioremap_debug) {
476 printk(KERN_INFO "early_iounmap(%p, %08lx) [%d]\n", addr,
481 virt_addr = (unsigned long)addr;
482 if (virt_addr < fix_to_virt(FIX_BTMAP_BEGIN)) {
486 offset = virt_addr & ~PAGE_MASK;
487 nrpages = PAGE_ALIGN(offset + size - 1) >> PAGE_SHIFT;
489 idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*nesting;
490 while (nrpages > 0) {
491 early_clear_fixmap(idx);
497 void __this_fixmap_does_not_exist(void)
502 #endif /* CONFIG_X86_32 */