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>
12 #include <linux/ioport.h>
13 #include <linux/sched.h>
14 #include <linux/slab.h>
15 #include <linux/vmalloc.h>
16 #include <asm/cacheflush.h>
18 #include <asm/tlbflush.h>
20 static inline void remap_area_pte(pte_t * pte, unsigned long address,
21 phys_addr_t size, phys_addr_t phys_addr, unsigned long flags)
25 pgprot_t pgprot = __pgprot(_PAGE_GLOBAL | _PAGE_PRESENT | __READABLE
26 | __WRITEABLE | flags);
32 BUG_ON(address >= end);
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_addr_t size, phys_addr_t phys_addr, unsigned long flags)
51 address &= ~PGDIR_MASK;
56 BUG_ON(address >= end);
58 pte_t * pte = pte_alloc_kernel(pmd, address);
61 remap_area_pte(pte, address, end - address, address + phys_addr, flags);
62 address = (address + PMD_SIZE) & PMD_MASK;
64 } while (address && (address < end));
68 static int remap_area_pages(unsigned long address, phys_addr_t phys_addr,
69 phys_addr_t size, unsigned long flags)
73 unsigned long end = address + size;
76 dir = pgd_offset(&init_mm, address);
78 BUG_ON(address >= end);
84 pud = pud_alloc(&init_mm, dir, address);
87 pmd = pmd_alloc(&init_mm, pud, address);
90 if (remap_area_pmd(pmd, address, end - address,
91 phys_addr + address, flags))
94 address = (address + PGDIR_SIZE) & PGDIR_MASK;
96 } while (address && (address < end));
101 static int __ioremap_check_ram(unsigned long start_pfn, unsigned long nr_pages,
106 for (i = 0; i < nr_pages; i++) {
107 if (pfn_valid(start_pfn + i) &&
108 !PageReserved(pfn_to_page(start_pfn + i)))
116 * Generic mapping function (not visible outside):
120 * Remap an arbitrary physical address space into the kernel virtual
121 * address space. Needed when the kernel wants to access high addresses
124 * NOTE! We need to allow non-page-aligned mappings too: we will obviously
125 * have to convert them into an offset in a page-aligned mapping, but the
126 * caller shouldn't need to know that small detail.
129 #define IS_LOW512(addr) (!((phys_addr_t)(addr) & (phys_addr_t) ~0x1fffffffULL))
131 void __iomem * __ioremap(phys_addr_t phys_addr, phys_addr_t size, unsigned long flags)
133 unsigned long offset, pfn, last_pfn;
134 struct vm_struct * area;
135 phys_addr_t last_addr;
138 phys_addr = fixup_bigphys_addr(phys_addr, size);
140 /* Don't allow wraparound or zero size */
141 last_addr = phys_addr + size - 1;
142 if (!size || last_addr < phys_addr)
146 * Map uncached objects in the low 512mb of address space using KSEG1,
147 * otherwise map using page tables.
149 if (IS_LOW512(phys_addr) && IS_LOW512(last_addr) &&
150 flags == _CACHE_UNCACHED)
151 return (void __iomem *) CKSEG1ADDR(phys_addr);
154 * Don't allow anybody to remap RAM that may be allocated by the page
155 * allocator, since that could lead to races & data clobbering.
157 pfn = PFN_DOWN(phys_addr);
158 last_pfn = PFN_DOWN(last_addr);
159 if (walk_system_ram_range(pfn, last_pfn - pfn + 1, NULL,
160 __ioremap_check_ram) == 1) {
161 WARN_ONCE(1, "ioremap on RAM at %pa - %pa\n",
162 &phys_addr, &last_addr);
167 * Mappings have to be page-aligned
169 offset = phys_addr & ~PAGE_MASK;
170 phys_addr &= PAGE_MASK;
171 size = PAGE_ALIGN(last_addr + 1) - phys_addr;
176 area = get_vm_area(size, VM_IOREMAP);
180 if (remap_area_pages((unsigned long) addr, phys_addr, size, flags)) {
185 return (void __iomem *) (offset + (char *)addr);
188 #define IS_KSEG1(addr) (((unsigned long)(addr) & ~0x1fffffffUL) == CKSEG1)
190 void __iounmap(const volatile void __iomem *addr)
197 p = remove_vm_area((void *) (PAGE_MASK & (unsigned long __force) addr));
199 printk(KERN_ERR "iounmap: bad address %p\n", addr);
204 EXPORT_SYMBOL(__ioremap);
205 EXPORT_SYMBOL(__iounmap);