1 /*
2 * Copyright (C) 2004-2006 Atmel Corporation
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 */
8 #include <linux/vmalloc.h>
9 #include <linux/mm.h>
10 #include <linux/module.h>
11 #include <linux/io.h>
12 #include <linux/slab.h>
13
14 #include <asm/pgtable.h>
15 #include <asm/addrspace.h>
16
17 /*
18 * Re-map an arbitrary physical address space into the kernel virtual
19 * address space. Needed when the kernel wants to access physical
20 * memory directly.
21 */
__ioremap(unsigned long phys_addr,size_t size,unsigned long flags)22 void __iomem *__ioremap(unsigned long phys_addr, size_t size,
23 unsigned long flags)
24 {
25 unsigned long addr;
26 struct vm_struct *area;
27 unsigned long offset, last_addr;
28 pgprot_t prot;
29
30 /*
31 * Check if we can simply use the P4 segment. This area is
32 * uncacheable, so if caching/buffering is requested, we can't
33 * use it.
34 */
35 if ((phys_addr >= P4SEG) && (flags == 0))
36 return (void __iomem *)phys_addr;
37
38 /* Don't allow wraparound or zero size */
39 last_addr = phys_addr + size - 1;
40 if (!size || last_addr < phys_addr)
41 return NULL;
42
43 /*
44 * XXX: When mapping regular RAM, we'd better make damn sure
45 * it's never used for anything else. But this is really the
46 * caller's responsibility...
47 */
48 if (PHYSADDR(P2SEGADDR(phys_addr)) == phys_addr)
49 return (void __iomem *)P2SEGADDR(phys_addr);
50
51 /* Mappings have to be page-aligned */
52 offset = phys_addr & ~PAGE_MASK;
53 phys_addr &= PAGE_MASK;
54 size = PAGE_ALIGN(last_addr + 1) - phys_addr;
55
56 prot = __pgprot(_PAGE_PRESENT | _PAGE_GLOBAL | _PAGE_RW | _PAGE_DIRTY
57 | _PAGE_ACCESSED | _PAGE_TYPE_SMALL | flags);
58
59 /*
60 * Ok, go for it..
61 */
62 area = get_vm_area(size, VM_IOREMAP);
63 if (!area)
64 return NULL;
65 area->phys_addr = phys_addr;
66 addr = (unsigned long )area->addr;
67 if (ioremap_page_range(addr, addr + size, phys_addr, prot)) {
68 vunmap((void *)addr);
69 return NULL;
70 }
71
72 return (void __iomem *)(offset + (char *)addr);
73 }
74 EXPORT_SYMBOL(__ioremap);
75
__iounmap(void __iomem * addr)76 void __iounmap(void __iomem *addr)
77 {
78 struct vm_struct *p;
79
80 if ((unsigned long)addr >= P4SEG)
81 return;
82 if (PXSEG(addr) == P2SEG)
83 return;
84
85 p = remove_vm_area((void *)(PAGE_MASK & (unsigned long __force)addr));
86 if (unlikely(!p)) {
87 printk (KERN_ERR "iounmap: bad address %p\n", addr);
88 return;
89 }
90
91 kfree (p);
92 }
93 EXPORT_SYMBOL(__iounmap);
94