2 * linux/arch/arm/mm/ioremap.c
4 * Re-map IO memory to kernel address space so that we can access it.
6 * (C) Copyright 1995 1996 Linus Torvalds
8 * Hacked for ARM by Phil Blundell <philb@gnu.org>
9 * Hacked to allow all architectures to build, and various cleanups
12 * This allows a driver to remap an arbitrary region of bus memory into
13 * virtual space. One should *only* use readl, writel, memcpy_toio and
14 * so on with such remapped areas.
16 * Because the ARM only has a 32-bit address space we can't address the
17 * whole of the (physical) PCI space at once. PCI huge-mode addressing
18 * allows us to circumvent this restriction by splitting PCI space into
19 * two 2GB chunks and mapping only one at a time into processor memory.
20 * We use MMU protection domains to trap any attempt to access the bank
21 * that is not currently mapped. (This isn't fully implemented yet.)
23 #include <linux/module.h>
24 #include <linux/errno.h>
26 #include <linux/vmalloc.h>
28 #include <asm/cacheflush.h>
30 #include <asm/tlbflush.h>
33 remap_area_pte(pte_t
* pte
, unsigned long address
, unsigned long size
,
34 unsigned long phys_addr
, pgprot_t pgprot
)
42 BUG_ON(address
>= end
);
47 set_pte(pte
, pfn_pte(phys_addr
>> PAGE_SHIFT
, pgprot
));
49 phys_addr
+= PAGE_SIZE
;
51 } while (address
&& (address
< end
));
55 printk("remap_area_pte: page already exists\n");
60 remap_area_pmd(pmd_t
* pmd
, unsigned long address
, unsigned long size
,
61 unsigned long phys_addr
, unsigned long flags
)
66 address
&= ~PGDIR_MASK
;
73 BUG_ON(address
>= end
);
75 pgprot
= __pgprot(L_PTE_PRESENT
| L_PTE_YOUNG
| L_PTE_DIRTY
| L_PTE_WRITE
| flags
);
77 pte_t
* pte
= pte_alloc_kernel(&init_mm
, pmd
, address
);
80 remap_area_pte(pte
, address
, end
- address
, address
+ phys_addr
, pgprot
);
81 address
= (address
+ PMD_SIZE
) & PMD_MASK
;
83 } while (address
&& (address
< end
));
88 remap_area_pages(unsigned long start
, unsigned long phys_addr
,
89 unsigned long size
, unsigned long flags
)
91 unsigned long address
= start
;
92 unsigned long end
= start
+ size
;
97 dir
= pgd_offset(&init_mm
, address
);
98 BUG_ON(address
>= end
);
99 spin_lock(&init_mm
.page_table_lock
);
101 pmd_t
*pmd
= pmd_alloc(&init_mm
, dir
, address
);
106 if (remap_area_pmd(pmd
, address
, end
- address
,
107 phys_addr
+ address
, flags
)) {
112 address
= (address
+ PGDIR_SIZE
) & PGDIR_MASK
;
114 } while (address
&& (address
< end
));
116 spin_unlock(&init_mm
.page_table_lock
);
117 flush_cache_vmap(start
, end
);
122 * Remap an arbitrary physical address space into the kernel virtual
123 * address space. Needed when the kernel wants to access high addresses
126 * NOTE! We need to allow non-page-aligned mappings too: we will obviously
127 * have to convert them into an offset in a page-aligned mapping, but the
128 * caller shouldn't need to know that small detail.
130 * 'flags' are the extra L_PTE_ flags that you want to specify for this
131 * mapping. See include/asm-arm/proc-armv/pgtable.h for more information.
134 __ioremap(unsigned long phys_addr
, size_t size
, unsigned long flags
,
138 struct vm_struct
* area
;
139 unsigned long offset
, last_addr
;
141 /* Don't allow wraparound or zero size */
142 last_addr
= phys_addr
+ size
- 1;
143 if (!size
|| last_addr
< phys_addr
)
147 * Mappings have to be page-aligned
149 offset
= phys_addr
& ~PAGE_MASK
;
150 phys_addr
&= PAGE_MASK
;
151 size
= PAGE_ALIGN(last_addr
) - phys_addr
;
156 area
= get_vm_area(size
, VM_IOREMAP
);
160 if (remap_area_pages((unsigned long) addr
, phys_addr
, size
, flags
)) {
164 return (void *) (offset
+ (char *)addr
);
166 EXPORT_SYMBOL(__ioremap
);
168 void __iounmap(void *addr
)
170 vfree((void *) (PAGE_MASK
& (unsigned long) addr
));
172 EXPORT_SYMBOL(__iounmap
);