2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
6 * (C) Copyright 1995 1996 Linus Torvalds
7 * (C) Copyright 2001, 2002 Ralf Baechle
9 #include <linux/module.h>
10 #include <asm/addrspace.h>
11 #include <asm/byteorder.h>
13 #include <linux/vmalloc.h>
14 #include <asm/cacheflush.h>
16 #include <asm/pgalloc.h>
17 #include <asm/tlbflush.h>
19 static inline void remap_area_pte(pte_t * pte, unsigned long address,
20 phys_t size, phys_t phys_addr, unsigned long flags)
24 pgprot_t pgprot = __pgprot(_PAGE_GLOBAL | _PAGE_PRESENT | __READABLE
25 | __WRITEABLE | flags);
33 pfn = phys_addr >> PAGE_SHIFT;
35 if (!pte_none(*pte)) {
36 printk("remap_area_pte: page already exists\n");
39 set_pte(pte, pfn_pte(pfn, pgprot));
43 } while (address && (address < end));
46 static inline int remap_area_pmd(pmd_t * pmd, unsigned long address,
47 phys_t size, phys_t phys_addr, unsigned long flags)
51 address &= ~PGDIR_MASK;
59 pte_t * pte = pte_alloc_kernel(&init_mm, pmd, address);
62 remap_area_pte(pte, address, end - address, address + phys_addr, flags);
63 address = (address + PMD_SIZE) & PMD_MASK;
65 } while (address && (address < end));
69 static int remap_area_pages(unsigned long address, phys_t phys_addr,
70 phys_t size, unsigned long flags)
74 unsigned long end = address + size;
77 dir = pgd_offset(&init_mm, address);
81 spin_lock(&init_mm.page_table_lock);
84 pmd = pmd_alloc(&init_mm, dir, address);
88 if (remap_area_pmd(pmd, address, end - address,
89 phys_addr + address, flags))
92 address = (address + PGDIR_SIZE) & PGDIR_MASK;
94 } while (address && (address < end));
95 spin_unlock(&init_mm.page_table_lock);
101 * Generic mapping function (not visible outside):
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.
114 #define IS_LOW512(addr) (!((phys_t)(addr) & ~0x1fffffffUL))
116 void * __ioremap(phys_t phys_addr, phys_t size, unsigned long flags)
118 struct vm_struct * area;
119 unsigned long offset;
123 /* Don't allow wraparound or zero size */
124 last_addr = phys_addr + size - 1;
125 if (!size || last_addr < phys_addr)
129 * Map uncached objects in the low 512mb of address space using KSEG1,
130 * otherwise map using page tables.
132 if (IS_LOW512(phys_addr) && IS_LOW512(last_addr) &&
133 flags == _CACHE_UNCACHED)
134 return (void *) KSEG1ADDR(phys_addr);
137 * Don't allow anybody to remap normal RAM that we're using..
139 if (phys_addr < virt_to_phys(high_memory)) {
140 char *t_addr, *t_end;
143 t_addr = __va(phys_addr);
144 t_end = t_addr + (size - 1);
146 for(page = virt_to_page(t_addr); page <= virt_to_page(t_end); page++)
147 if(!PageReserved(page))
152 * Mappings have to be page-aligned
154 offset = phys_addr & ~PAGE_MASK;
155 phys_addr &= PAGE_MASK;
156 size = PAGE_ALIGN(last_addr) - phys_addr;
161 area = get_vm_area(size, VM_IOREMAP);
165 if (remap_area_pages(VMALLOC_VMADDR(addr), phys_addr, size, flags)) {
170 return (void *) (offset + (char *)addr);
173 #define IS_KSEG1(addr) (((unsigned long)(addr) & ~0x1fffffffUL) == KSEG1)
175 void __iounmap(void *addr)
182 vfree((void *) (PAGE_MASK & (unsigned long) addr));
183 p = remove_vm_area((void *) (PAGE_MASK & (unsigned long) addr));
185 printk(KERN_ERR "iounmap: bad address %p\n", addr);
192 EXPORT_SYMBOL(__ioremap);
193 EXPORT_SYMBOL(__iounmap);