1 /*
2 * Re-map IO memory to kernel address space so that we can access it.
3 * Needed for memory-mapped I/O devices mapped outside our normal DRAM
4 * window (that is, all memory-mapped I/O devices).
5 *
6 * Copyright (C) 1995,1996 Linus Torvalds
7 *
8 * Meta port based on CRIS-port by Axis Communications AB
9 */
10
11 #include <linux/vmalloc.h>
12 #include <linux/io.h>
13 #include <linux/export.h>
14 #include <linux/slab.h>
15 #include <linux/mm.h>
16
17 #include <asm/pgtable.h>
18
19 /*
20 * Remap an arbitrary physical address space into the kernel virtual
21 * address space. Needed when the kernel wants to access high addresses
22 * directly.
23 *
24 * NOTE! We need to allow non-page-aligned mappings too: we will obviously
25 * have to convert them into an offset in a page-aligned mapping, but the
26 * caller shouldn't need to know that small detail.
27 */
__ioremap(unsigned long phys_addr,size_t size,unsigned long flags)28 void __iomem *__ioremap(unsigned long phys_addr, size_t size,
29 unsigned long flags)
30 {
31 unsigned long addr;
32 struct vm_struct *area;
33 unsigned long offset, last_addr;
34 pgprot_t prot;
35
36 /* Don't allow wraparound or zero size */
37 last_addr = phys_addr + size - 1;
38 if (!size || last_addr < phys_addr)
39 return NULL;
40
41 /* Custom region addresses are accessible and uncached by default. */
42 if (phys_addr >= LINSYSCUSTOM_BASE &&
43 phys_addr < (LINSYSCUSTOM_BASE + LINSYSCUSTOM_LIMIT))
44 return (__force void __iomem *) phys_addr;
45
46 /*
47 * Mappings have to be page-aligned
48 */
49 offset = phys_addr & ~PAGE_MASK;
50 phys_addr &= PAGE_MASK;
51 size = PAGE_ALIGN(last_addr+1) - phys_addr;
52 prot = __pgprot(_PAGE_PRESENT | _PAGE_WRITE | _PAGE_DIRTY |
53 _PAGE_ACCESSED | _PAGE_KERNEL | _PAGE_CACHE_WIN0 |
54 flags);
55
56 /*
57 * Ok, go for it..
58 */
59 area = get_vm_area(size, VM_IOREMAP);
60 if (!area)
61 return NULL;
62 area->phys_addr = phys_addr;
63 addr = (unsigned long) area->addr;
64 if (ioremap_page_range(addr, addr + size, phys_addr, prot)) {
65 vunmap((void *) addr);
66 return NULL;
67 }
68 return (__force void __iomem *) (offset + (char *)addr);
69 }
70 EXPORT_SYMBOL(__ioremap);
71
__iounmap(void __iomem * addr)72 void __iounmap(void __iomem *addr)
73 {
74 struct vm_struct *p;
75
76 if ((__force unsigned long)addr >= LINSYSCUSTOM_BASE &&
77 (__force unsigned long)addr < (LINSYSCUSTOM_BASE +
78 LINSYSCUSTOM_LIMIT))
79 return;
80
81 p = remove_vm_area((void *)(PAGE_MASK & (unsigned long __force)addr));
82 if (unlikely(!p)) {
83 pr_err("iounmap: bad address %p\n", addr);
84 return;
85 }
86
87 kfree(p);
88 }
89 EXPORT_SYMBOL(__iounmap);
90