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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