aboutsummaryrefslogtreecommitdiff
path: root/arch/arm/mm/ioremap.c
blob: de3ce1eec2ece4d222a2293bfa325fb585104433 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
/*
 *  linux/arch/arm/mm/ioremap.c
 *
 * Re-map IO memory to kernel address space so that we can access it.
 *
 * (C) Copyright 1995 1996 Linus Torvalds
 *
 * Hacked for ARM by Phil Blundell <philb@gnu.org>
 * Hacked to allow all architectures to build, and various cleanups
 * by Russell King
 *
 * This allows a driver to remap an arbitrary region of bus memory into
 * virtual space.  One should *only* use readl, writel, memcpy_toio and
 * so on with such remapped areas.
 *
 * Because the ARM only has a 32-bit address space we can't address the
 * whole of the (physical) PCI space at once.  PCI huge-mode addressing
 * allows us to circumvent this restriction by splitting PCI space into
 * two 2GB chunks and mapping only one at a time into processor memory.
 * We use MMU protection domains to trap any attempt to access the bank
 * that is not currently mapped.  (This isn't fully implemented yet.)
 */
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/vmalloc.h>

#include <asm/cacheflush.h>
#include <asm/hardware.h>
#include <asm/io.h>
#include <asm/tlbflush.h>

static inline void
remap_area_pte(pte_t * pte, unsigned long address, unsigned long size,
	       unsigned long phys_addr, pgprot_t pgprot)
{
	unsigned long end;

	address &= ~PMD_MASK;
	end = address + size;
	if (end > PMD_SIZE)
		end = PMD_SIZE;
	BUG_ON(address >= end);
	do {
		if (!pte_none(*pte))
			goto bad;

		set_pte(pte, pfn_pte(phys_addr >> PAGE_SHIFT, pgprot));
		address += PAGE_SIZE;
		phys_addr += PAGE_SIZE;
		pte++;
	} while (address && (address < end));
	return;

 bad:
	printk("remap_area_pte: page already exists\n");
	BUG();
}

static inline int
remap_area_pmd(pmd_t * pmd, unsigned long address, unsigned long size,
	       unsigned long phys_addr, unsigned long flags)
{
	unsigned long end;
	pgprot_t pgprot;

	address &= ~PGDIR_MASK;
	end = address + size;

	if (end > PGDIR_SIZE)
		end = PGDIR_SIZE;

	phys_addr -= address;
	BUG_ON(address >= end);

	pgprot = __pgprot(L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY | L_PTE_WRITE | flags);
	do {
		pte_t * pte = pte_alloc_kernel(pmd, address);
		if (!pte)
			return -ENOMEM;
		remap_area_pte(pte, address, end - address, address + phys_addr, pgprot);
		address = (address + PMD_SIZE) & PMD_MASK;
		pmd++;
	} while (address && (address < end));
	return 0;
}

static int
remap_area_pages(unsigned long start, unsigned long pfn,
		 unsigned long size, unsigned long flags)
{
	unsigned long address = start;
	unsigned long end = start + size;
	unsigned long phys_addr = __pfn_to_phys(pfn);
	int err = 0;
	pgd_t * dir;

	phys_addr -= address;
	dir = pgd_offset(&init_mm, address);
	BUG_ON(address >= end);
	do {
		pmd_t *pmd = pmd_alloc(&init_mm, dir, address);
		if (!pmd) {
			err = -ENOMEM;
			break;
		}
		if (remap_area_pmd(pmd, address, end - address,
					 phys_addr + address, flags)) {
			err = -ENOMEM;
			break;
		}

		address = (address + PGDIR_SIZE) & PGDIR_MASK;
		dir++;
	} while (address && (address < end));

	flush_cache_vmap(start, end);
	return err;
}

/*
 * Remap an arbitrary physical address space into the kernel virtual
 * address space. Needed when the kernel wants to access high addresses
 * directly.
 *
 * NOTE! We need to allow non-page-aligned mappings too: we will obviously
 * have to convert them into an offset in a page-aligned mapping, but the
 * caller shouldn't need to know that small detail.
 *
 * 'flags' are the extra L_PTE_ flags that you want to specify for this
 * mapping.  See include/asm-arm/proc-armv/pgtable.h for more information.
 */
void __iomem *
__ioremap_pfn(unsigned long pfn, unsigned long offset, size_t size,
	      unsigned long flags)
{
	unsigned long addr;
 	struct vm_struct * area;

 	area = get_vm_area(size, VM_IOREMAP);
 	if (!area)
 		return NULL;
 	addr = (unsigned long)area->addr;
 	if (remap_area_pages(addr, pfn, size, flags)) {
 		vfree(addr);
 		return NULL;
 	}
 	return (void __iomem *) (offset + (char *)addr);
}
EXPORT_SYMBOL(__ioremap_pfn);

void __iomem *
__ioremap(unsigned long phys_addr, size_t size, unsigned long flags)
{
	unsigned long last_addr;
 	unsigned long offset = phys_addr & ~PAGE_MASK;
 	unsigned long pfn = __phys_to_pfn(phys_addr);

 	/*
 	 * Don't allow wraparound or zero size
	 */
	last_addr = phys_addr + size - 1;
	if (!size || last_addr < phys_addr)
		return NULL;

	/*
 	 * Page align the mapping size
	 */
	size = PAGE_ALIGN(last_addr + 1) - phys_addr;

 	return __ioremap_pfn(pfn, offset, size, flags);
}
EXPORT_SYMBOL(__ioremap);

void __iounmap(void __iomem *addr)
{
	vfree((void *) (PAGE_MASK & (unsigned long) addr));
}
EXPORT_SYMBOL(__iounmap);

#ifdef __io
void __iomem *ioport_map(unsigned long port, unsigned int nr)
{
	return __io(port);
}
EXPORT_SYMBOL(ioport_map);

void ioport_unmap(void __iomem *addr)
{
}
EXPORT_SYMBOL(ioport_unmap);
#endif

#ifdef CONFIG_PCI
#include <linux/pci.h>
#include <linux/ioport.h>

void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long maxlen)
{
	unsigned long start = pci_resource_start(dev, bar);
	unsigned long len   = pci_resource_len(dev, bar);
	unsigned long flags = pci_resource_flags(dev, bar);

	if (!len || !start)
		return NULL;
	if (maxlen && len > maxlen)
		len = maxlen;
	if (flags & IORESOURCE_IO)
		return ioport_map(start, len);
	if (flags & IORESOURCE_MEM) {
		if (flags & IORESOURCE_CACHEABLE)
			return ioremap(start, len);
		return ioremap_nocache(start, len);
	}
	return NULL;
}
EXPORT_SYMBOL(pci_iomap);

void pci_iounmap(struct pci_dev *dev, void __iomem *addr)
{
	if ((unsigned long)addr >= VMALLOC_START &&
	    (unsigned long)addr < VMALLOC_END)
		iounmap(addr);
}
EXPORT_SYMBOL(pci_iounmap);
#endif