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/export.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 <linux/mm_types.h>
17 #include <asm/cacheflush.h>
19 #include <asm/tlbflush.h>
21 static inline void remap_area_pte(pte_t * pte, unsigned long address,
22 phys_addr_t size, phys_addr_t phys_addr, unsigned long flags)
26 pgprot_t pgprot = __pgprot(_PAGE_GLOBAL | _PAGE_PRESENT | __READABLE
27 | __WRITEABLE | flags);
33 BUG_ON(address >= end);
34 pfn = phys_addr >> PAGE_SHIFT;
36 if (!pte_none(*pte)) {
37 printk("remap_area_pte: page already exists\n");
40 set_pte(pte, pfn_pte(pfn, pgprot));
44 } while (address && (address < end));
47 static inline int remap_area_pmd(pmd_t * pmd, unsigned long address,
48 phys_addr_t size, phys_addr_t phys_addr, unsigned long flags)
52 address &= ~PGDIR_MASK;
57 BUG_ON(address >= end);
59 pte_t * pte = pte_alloc_kernel(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_addr_t phys_addr,
70 phys_addr_t size, unsigned long flags)
74 unsigned long end = address + size;
77 dir = pgd_offset(&init_mm, address);
79 BUG_ON(address >= end);
86 p4d = p4d_alloc(&init_mm, dir, address);
89 pud = pud_alloc(&init_mm, p4d, address);
92 pmd = pmd_alloc(&init_mm, pud, address);
95 if (remap_area_pmd(pmd, address, end - address,
96 phys_addr + address, flags))
99 address = (address + PGDIR_SIZE) & PGDIR_MASK;
101 } while (address && (address < end));
106 static int __ioremap_check_ram(unsigned long start_pfn, unsigned long nr_pages,
111 for (i = 0; i < nr_pages; i++) {
112 if (pfn_valid(start_pfn + i) &&
113 !PageReserved(pfn_to_page(start_pfn + i)))
121 * Generic mapping function (not visible outside):
125 * Remap an arbitrary physical address space into the kernel virtual
126 * address space. Needed when the kernel wants to access high addresses
129 * NOTE! We need to allow non-page-aligned mappings too: we will obviously
130 * have to convert them into an offset in a page-aligned mapping, but the
131 * caller shouldn't need to know that small detail.
134 #define IS_LOW512(addr) (!((phys_addr_t)(addr) & (phys_addr_t) ~0x1fffffffULL))
136 void __iomem * __ioremap(phys_addr_t phys_addr, phys_addr_t size, unsigned long flags)
138 unsigned long offset, pfn, last_pfn;
139 struct vm_struct * area;
140 phys_addr_t last_addr;
143 phys_addr = fixup_bigphys_addr(phys_addr, size);
145 /* Don't allow wraparound or zero size */
146 last_addr = phys_addr + size - 1;
147 if (!size || last_addr < phys_addr)
151 * Map uncached objects in the low 512mb of address space using KSEG1,
152 * otherwise map using page tables.
154 if (IS_LOW512(phys_addr) && IS_LOW512(last_addr) &&
155 flags == _CACHE_UNCACHED)
156 return (void __iomem *) CKSEG1ADDR(phys_addr);
159 * Don't allow anybody to remap RAM that may be allocated by the page
160 * allocator, since that could lead to races & data clobbering.
162 pfn = PFN_DOWN(phys_addr);
163 last_pfn = PFN_DOWN(last_addr);
164 if (walk_system_ram_range(pfn, last_pfn - pfn + 1, NULL,
165 __ioremap_check_ram) == 1) {
166 WARN_ONCE(1, "ioremap on RAM at %pa - %pa\n",
167 &phys_addr, &last_addr);
172 * Mappings have to be page-aligned
174 offset = phys_addr & ~PAGE_MASK;
175 phys_addr &= PAGE_MASK;
176 size = PAGE_ALIGN(last_addr + 1) - phys_addr;
181 area = get_vm_area(size, VM_IOREMAP);
185 if (remap_area_pages((unsigned long) addr, phys_addr, size, flags)) {
190 return (void __iomem *) (offset + (char *)addr);
193 #define IS_KSEG1(addr) (((unsigned long)(addr) & ~0x1fffffffUL) == CKSEG1)
195 void __iounmap(const volatile void __iomem *addr)
202 p = remove_vm_area((void *) (PAGE_MASK & (unsigned long __force) addr));
204 printk(KERN_ERR "iounmap: bad address %p\n", addr);
209 EXPORT_SYMBOL(__ioremap);
210 EXPORT_SYMBOL(__iounmap);