1/*
2 * Re-map IO memory to kernel address space so that we can access it.
3 *
4 * These functions should only be used when it is necessary to map a
5 * physical address space into the kernel address space before ioremap()
6 * can be used, e.g. early in boot before paging_init().
7 *
8 * Copyright (C) 2009  Matt Fleming
9 */
10
11#include <linux/vmalloc.h>
12#include <linux/ioport.h>
13#include <linux/module.h>
14#include <linux/mm.h>
15#include <linux/io.h>
16#include <linux/bootmem.h>
17#include <linux/proc_fs.h>
18#include <asm/fixmap.h>
19#include <asm/page.h>
20#include <asm/pgalloc.h>
21#include <asm/addrspace.h>
22#include <asm/cacheflush.h>
23#include <asm/tlbflush.h>
24#include <asm/mmu.h>
25#include <asm/mmu_context.h>
26
27struct ioremap_map {
28	void __iomem *addr;
29	unsigned long size;
30	unsigned long fixmap_addr;
31};
32
33static struct ioremap_map ioremap_maps[FIX_N_IOREMAPS];
34
35void __init ioremap_fixed_init(void)
36{
37	struct ioremap_map *map;
38	int i;
39
40	for (i = 0; i < FIX_N_IOREMAPS; i++) {
41		map = &ioremap_maps[i];
42		map->fixmap_addr = __fix_to_virt(FIX_IOREMAP_BEGIN + i);
43	}
44}
45
46void __init __iomem *
47ioremap_fixed(phys_addr_t phys_addr, unsigned long size, pgprot_t prot)
48{
49	enum fixed_addresses idx0, idx;
50	struct ioremap_map *map;
51	unsigned int nrpages;
52	unsigned long offset;
53	int i, slot;
54
55	/*
56	 * Mappings have to be page-aligned
57	 */
58	offset = phys_addr & ~PAGE_MASK;
59	phys_addr &= PAGE_MASK;
60	size = PAGE_ALIGN(phys_addr + size) - phys_addr;
61
62	slot = -1;
63	for (i = 0; i < FIX_N_IOREMAPS; i++) {
64		map = &ioremap_maps[i];
65		if (!map->addr) {
66			map->size = size;
67			slot = i;
68			break;
69		}
70	}
71
72	if (slot < 0)
73		return NULL;
74
75	/*
76	 * Mappings have to fit in the FIX_IOREMAP area.
77	 */
78	nrpages = size >> PAGE_SHIFT;
79	if (nrpages > FIX_N_IOREMAPS)
80		return NULL;
81
82	/*
83	 * Ok, go for it..
84	 */
85	idx0 = FIX_IOREMAP_BEGIN + slot;
86	idx = idx0;
87	while (nrpages > 0) {
88		pgprot_val(prot) |= _PAGE_WIRED;
89		__set_fixmap(idx, phys_addr, prot);
90		phys_addr += PAGE_SIZE;
91		idx++;
92		--nrpages;
93	}
94
95	map->addr = (void __iomem *)(offset + map->fixmap_addr);
96	return map->addr;
97}
98
99int iounmap_fixed(void __iomem *addr)
100{
101	enum fixed_addresses idx;
102	struct ioremap_map *map;
103	unsigned int nrpages;
104	int i, slot;
105
106	slot = -1;
107	for (i = 0; i < FIX_N_IOREMAPS; i++) {
108		map = &ioremap_maps[i];
109		if (map->addr == addr) {
110			slot = i;
111			break;
112		}
113	}
114
115	/*
116	 * If we don't match, it's not for us.
117	 */
118	if (slot < 0)
119		return -EINVAL;
120
121	nrpages = map->size >> PAGE_SHIFT;
122
123	idx = FIX_IOREMAP_BEGIN + slot + nrpages - 1;
124	while (nrpages > 0) {
125		__clear_fixmap(idx, __pgprot(_PAGE_WIRED));
126		--idx;
127		--nrpages;
128	}
129
130	map->size = 0;
131	map->addr = NULL;
132
133	return 0;
134}
135