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 vaddr, unsigned long size,
74 enum ioremap_mode mode)
76 unsigned long nrpages = size >> PAGE_SHIFT;
80 case IOR_MODE_UNCACHED:
82 err = set_memory_uc(vaddr, nrpages);
85 err = set_memory_wb(vaddr, nrpages);
93 * Remap an arbitrary physical address space into the kernel virtual
94 * address space. Needed when the kernel wants to access high addresses
97 * NOTE! We need to allow non-page-aligned mappings too: we will obviously
98 * have to convert them into an offset in a page-aligned mapping, but the
99 * caller shouldn't need to know that small detail.
101 static void __iomem *__ioremap(unsigned long phys_addr, unsigned long size,
102 enum ioremap_mode mode)
104 unsigned long pfn, offset, last_addr, vaddr;
105 struct vm_struct *area;
108 /* Don't allow wraparound or zero size */
109 last_addr = phys_addr + size - 1;
110 if (!size || last_addr < phys_addr)
114 * Don't remap the low PCI/ISA area, it's always mapped..
116 if (phys_addr >= ISA_START_ADDRESS && last_addr < ISA_END_ADDRESS)
117 return (__force void __iomem *)phys_to_virt(phys_addr);
120 * Don't allow anybody to remap normal RAM that we're using..
122 for (pfn = phys_addr >> PAGE_SHIFT; pfn < max_pfn_mapped &&
123 (pfn << PAGE_SHIFT) < last_addr; pfn++) {
124 if (page_is_ram(pfn) && pfn_valid(pfn) &&
125 !PageReserved(pfn_to_page(pfn)))
129 WARN_ON_ONCE(page_is_ram(pfn));
132 case IOR_MODE_UNCACHED:
134 prot = PAGE_KERNEL_NOCACHE;
136 case IOR_MODE_CACHED:
142 * Mappings have to be page-aligned
144 offset = phys_addr & ~PAGE_MASK;
145 phys_addr &= PAGE_MASK;
146 size = PAGE_ALIGN(last_addr+1) - phys_addr;
151 area = get_vm_area(size, VM_IOREMAP);
154 area->phys_addr = phys_addr;
155 vaddr = (unsigned long) area->addr;
156 if (ioremap_page_range(vaddr, vaddr + size, phys_addr, prot)) {
157 remove_vm_area((void *)(vaddr & PAGE_MASK));
161 if (ioremap_change_attr(vaddr, size, mode) < 0) {
166 return (void __iomem *) (vaddr + offset);
170 * ioremap_nocache - map bus memory into CPU space
171 * @offset: bus address of the memory
172 * @size: size of the resource to map
174 * ioremap_nocache performs a platform specific sequence of operations to
175 * make bus memory CPU accessible via the readb/readw/readl/writeb/
176 * writew/writel functions and the other mmio helpers. The returned
177 * address is not guaranteed to be usable directly as a virtual
180 * This version of ioremap ensures that the memory is marked uncachable
181 * on the CPU as well as honouring existing caching rules from things like
182 * the PCI bus. Note that there are other caches and buffers on many
183 * busses. In particular driver authors should read up on PCI writes
185 * It's useful if some control registers are in such an area and
186 * write combining or read caching is not desirable:
188 * Must be freed with iounmap.
190 void __iomem *ioremap_nocache(unsigned long phys_addr, unsigned long size)
192 return __ioremap(phys_addr, size, IOR_MODE_UNCACHED);
194 EXPORT_SYMBOL(ioremap_nocache);
196 void __iomem *ioremap_cache(unsigned long phys_addr, unsigned long size)
198 return __ioremap(phys_addr, size, IOR_MODE_CACHED);
200 EXPORT_SYMBOL(ioremap_cache);
203 * iounmap - Free a IO remapping
204 * @addr: virtual address from ioremap_*
206 * Caller must ensure there is only one unmapping for the same pointer.
208 void iounmap(volatile void __iomem *addr)
210 struct vm_struct *p, *o;
212 if ((void __force *)addr <= high_memory)
216 * __ioremap special-cases the PCI/ISA range by not instantiating a
217 * vm_area and by simply returning an address into the kernel mapping
218 * of ISA space. So handle that here.
220 if (addr >= phys_to_virt(ISA_START_ADDRESS) &&
221 addr < phys_to_virt(ISA_END_ADDRESS))
224 addr = (volatile void __iomem *)
225 (PAGE_MASK & (unsigned long __force)addr);
227 /* Use the vm area unlocked, assuming the caller
228 ensures there isn't another iounmap for the same address
229 in parallel. Reuse of the virtual address is prevented by
230 leaving it in the global lists until we're done with it.
231 cpa takes care of the direct mappings. */
232 read_lock(&vmlist_lock);
233 for (p = vmlist; p; p = p->next) {
237 read_unlock(&vmlist_lock);
240 printk(KERN_ERR "iounmap: bad address %p\n", addr);
245 /* Finally remove it */
246 o = remove_vm_area((void *)addr);
247 BUG_ON(p != o || o == NULL);
250 EXPORT_SYMBOL(iounmap);
254 int __initdata early_ioremap_debug;
256 static int __init early_ioremap_debug_setup(char *str)
258 early_ioremap_debug = 1;
262 early_param("early_ioremap_debug", early_ioremap_debug_setup);
264 static __initdata int after_paging_init;
265 static __initdata pte_t bm_pte[PAGE_SIZE/sizeof(pte_t)]
266 __attribute__((aligned(PAGE_SIZE)));
268 static inline pmd_t * __init early_ioremap_pmd(unsigned long addr)
270 /* Don't assume we're using swapper_pg_dir at this point */
271 pgd_t *base = __va(read_cr3());
272 pgd_t *pgd = &base[pgd_index(addr)];
273 pud_t *pud = pud_offset(pgd, addr);
274 pmd_t *pmd = pmd_offset(pud, addr);
279 static inline pte_t * __init early_ioremap_pte(unsigned long addr)
281 return &bm_pte[pte_index(addr)];
284 void __init early_ioremap_init(void)
288 if (early_ioremap_debug)
289 printk(KERN_INFO "early_ioremap_init()\n");
291 pmd = early_ioremap_pmd(fix_to_virt(FIX_BTMAP_BEGIN));
292 memset(bm_pte, 0, sizeof(bm_pte));
293 pmd_populate_kernel(&init_mm, pmd, bm_pte);
296 * The boot-ioremap range spans multiple pmds, for which
297 * we are not prepared:
299 if (pmd != early_ioremap_pmd(fix_to_virt(FIX_BTMAP_END))) {
301 printk(KERN_WARNING "pmd %p != %p\n",
302 pmd, early_ioremap_pmd(fix_to_virt(FIX_BTMAP_END)));
303 printk(KERN_WARNING "fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
304 fix_to_virt(FIX_BTMAP_BEGIN));
305 printk(KERN_WARNING "fix_to_virt(FIX_BTMAP_END): %08lx\n",
306 fix_to_virt(FIX_BTMAP_END));
308 printk(KERN_WARNING "FIX_BTMAP_END: %d\n", FIX_BTMAP_END);
309 printk(KERN_WARNING "FIX_BTMAP_BEGIN: %d\n",
314 void __init early_ioremap_clear(void)
318 if (early_ioremap_debug)
319 printk(KERN_INFO "early_ioremap_clear()\n");
321 pmd = early_ioremap_pmd(fix_to_virt(FIX_BTMAP_BEGIN));
323 paravirt_release_pt(__pa(bm_pte) >> PAGE_SHIFT);
327 void __init early_ioremap_reset(void)
329 enum fixed_addresses idx;
330 unsigned long addr, phys;
333 after_paging_init = 1;
334 for (idx = FIX_BTMAP_BEGIN; idx >= FIX_BTMAP_END; idx--) {
335 addr = fix_to_virt(idx);
336 pte = early_ioremap_pte(addr);
337 if (pte_present(*pte)) {
338 phys = pte_val(*pte) & PAGE_MASK;
339 set_fixmap(idx, phys);
344 static void __init __early_set_fixmap(enum fixed_addresses idx,
345 unsigned long phys, pgprot_t flags)
347 unsigned long addr = __fix_to_virt(idx);
350 if (idx >= __end_of_fixed_addresses) {
354 pte = early_ioremap_pte(addr);
355 if (pgprot_val(flags))
356 set_pte(pte, pfn_pte(phys >> PAGE_SHIFT, flags));
358 pte_clear(NULL, addr, pte);
359 __flush_tlb_one(addr);
362 static inline void __init early_set_fixmap(enum fixed_addresses idx,
365 if (after_paging_init)
366 set_fixmap(idx, phys);
368 __early_set_fixmap(idx, phys, PAGE_KERNEL);
371 static inline void __init early_clear_fixmap(enum fixed_addresses idx)
373 if (after_paging_init)
376 __early_set_fixmap(idx, 0, __pgprot(0));
380 int __initdata early_ioremap_nested;
382 static int __init check_early_ioremap_leak(void)
384 if (!early_ioremap_nested)
388 "Debug warning: early ioremap leak of %d areas detected.\n",
389 early_ioremap_nested);
391 "please boot with early_ioremap_debug and report the dmesg.\n");
396 late_initcall(check_early_ioremap_leak);
398 void __init *early_ioremap(unsigned long phys_addr, unsigned long size)
400 unsigned long offset, last_addr;
401 unsigned int nrpages, nesting;
402 enum fixed_addresses idx0, idx;
404 WARN_ON(system_state != SYSTEM_BOOTING);
406 nesting = early_ioremap_nested;
407 if (early_ioremap_debug) {
408 printk(KERN_INFO "early_ioremap(%08lx, %08lx) [%d] => ",
409 phys_addr, size, nesting);
413 /* Don't allow wraparound or zero size */
414 last_addr = phys_addr + size - 1;
415 if (!size || last_addr < phys_addr) {
420 if (nesting >= FIX_BTMAPS_NESTING) {
424 early_ioremap_nested++;
426 * Mappings have to be page-aligned
428 offset = phys_addr & ~PAGE_MASK;
429 phys_addr &= PAGE_MASK;
430 size = PAGE_ALIGN(last_addr) - phys_addr;
433 * Mappings have to fit in the FIX_BTMAP area.
435 nrpages = size >> PAGE_SHIFT;
436 if (nrpages > NR_FIX_BTMAPS) {
444 idx0 = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*nesting;
446 while (nrpages > 0) {
447 early_set_fixmap(idx, phys_addr);
448 phys_addr += PAGE_SIZE;
452 if (early_ioremap_debug)
453 printk(KERN_CONT "%08lx + %08lx\n", offset, fix_to_virt(idx0));
455 return (void *) (offset + fix_to_virt(idx0));
458 void __init early_iounmap(void *addr, unsigned long size)
460 unsigned long virt_addr;
461 unsigned long offset;
462 unsigned int nrpages;
463 enum fixed_addresses idx;
464 unsigned int nesting;
466 nesting = --early_ioremap_nested;
467 WARN_ON(nesting < 0);
469 if (early_ioremap_debug) {
470 printk(KERN_INFO "early_iounmap(%p, %08lx) [%d]\n", addr,
475 virt_addr = (unsigned long)addr;
476 if (virt_addr < fix_to_virt(FIX_BTMAP_BEGIN)) {
480 offset = virt_addr & ~PAGE_MASK;
481 nrpages = PAGE_ALIGN(offset + size - 1) >> PAGE_SHIFT;
483 idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*nesting;
484 while (nrpages > 0) {
485 early_clear_fixmap(idx);
491 void __this_fixmap_does_not_exist(void)
496 #endif /* CONFIG_X86_32 */