Linux Kernel  3.7.1
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ioremap.c
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1 /*
2  * arch/sh/mm/ioremap.c
3  *
4  * (C) Copyright 1995 1996 Linus Torvalds
5  * (C) Copyright 2005 - 2010 Paul Mundt
6  *
7  * Re-map IO memory to kernel address space so that we can access it.
8  * This is needed for high PCI addresses that aren't mapped in the
9  * 640k-1MB IO memory area on PC's
10  *
11  * This file is subject to the terms and conditions of the GNU General
12  * Public License. See the file "COPYING" in the main directory of this
13  * archive for more details.
14  */
15 #include <linux/vmalloc.h>
16 #include <linux/module.h>
17 #include <linux/slab.h>
18 #include <linux/mm.h>
19 #include <linux/pci.h>
20 #include <linux/io.h>
21 #include <asm/page.h>
22 #include <asm/pgalloc.h>
23 #include <asm/addrspace.h>
24 #include <asm/cacheflush.h>
25 #include <asm/tlbflush.h>
26 #include <asm/mmu.h>
27 
28 /*
29  * Remap an arbitrary physical address space into the kernel virtual
30  * address space. Needed when the kernel wants to access high addresses
31  * directly.
32  *
33  * NOTE! We need to allow non-page-aligned mappings too: we will obviously
34  * have to convert them into an offset in a page-aligned mapping, but the
35  * caller shouldn't need to know that small detail.
36  */
37 void __iomem * __init_refok
39  pgprot_t pgprot, void *caller)
40 {
41  struct vm_struct *area;
42  unsigned long offset, last_addr, addr, orig_addr;
43  void __iomem *mapped;
44 
45  /* Don't allow wraparound or zero size */
46  last_addr = phys_addr + size - 1;
47  if (!size || last_addr < phys_addr)
48  return NULL;
49 
50  /*
51  * If we can't yet use the regular approach, go the fixmap route.
52  */
53  if (!mem_init_done)
54  return ioremap_fixed(phys_addr, size, pgprot);
55 
56  /*
57  * First try to remap through the PMB.
58  * PMB entries are all pre-faulted.
59  */
60  mapped = pmb_remap_caller(phys_addr, size, pgprot, caller);
61  if (mapped && !IS_ERR(mapped))
62  return mapped;
63 
64  /*
65  * Mappings have to be page-aligned
66  */
67  offset = phys_addr & ~PAGE_MASK;
68  phys_addr &= PAGE_MASK;
69  size = PAGE_ALIGN(last_addr+1) - phys_addr;
70 
71  /*
72  * Ok, go for it..
73  */
74  area = get_vm_area_caller(size, VM_IOREMAP, caller);
75  if (!area)
76  return NULL;
77  area->phys_addr = phys_addr;
78  orig_addr = addr = (unsigned long)area->addr;
79 
80  if (ioremap_page_range(addr, addr + size, phys_addr, pgprot)) {
81  vunmap((void *)orig_addr);
82  return NULL;
83  }
84 
85  return (void __iomem *)(offset + (char *)orig_addr);
86 }
87 EXPORT_SYMBOL(__ioremap_caller);
88 
89 /*
90  * Simple checks for non-translatable mappings.
91  */
92 static inline int iomapping_nontranslatable(unsigned long offset)
93 {
94 #ifdef CONFIG_29BIT
95  /*
96  * In 29-bit mode this includes the fixed P1/P2 areas, as well as
97  * parts of P3.
98  */
99  if (PXSEG(offset) < P3SEG || offset >= P3_ADDR_MAX)
100  return 1;
101 #endif
102 
103  return 0;
104 }
105 
106 void __iounmap(void __iomem *addr)
107 {
108  unsigned long vaddr = (unsigned long __force)addr;
109  struct vm_struct *p;
110 
111  /*
112  * Nothing to do if there is no translatable mapping.
113  */
114  if (iomapping_nontranslatable(vaddr))
115  return;
116 
117  /*
118  * There's no VMA if it's from an early fixed mapping.
119  */
120  if (iounmap_fixed(addr) == 0)
121  return;
122 
123  /*
124  * If the PMB handled it, there's nothing else to do.
125  */
126  if (pmb_unmap(addr) == 0)
127  return;
128 
129  p = remove_vm_area((void *)(vaddr & PAGE_MASK));
130  if (!p) {
131  printk(KERN_ERR "%s: bad address %p\n", __func__, addr);
132  return;
133  }
134 
135  kfree(p);
136 }