1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Re-map IO memory to kernel address space so that we can access it.
4 *
5 * These functions should only be used when it is necessary to map a
6 * physical address space into the kernel address space before ioremap()
7 * can be used, e.g. early in boot before paging_init().
8 *
9 * Copyright (C) 2009  Matt Fleming
10 */
11
12#include <linux/vmalloc.h>
13#include <linux/ioport.h>
14#include <linux/module.h>
15#include <linux/mm.h>
16#include <linux/io.h>
17#include <linux/memblock.h>
18#include <linux/proc_fs.h>
19#include <asm/fixmap.h>
20#include <asm/page.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#include "ioremap.h"
27
28struct ioremap_map {
29	void __iomem *addr;
30	unsigned long size;
31	unsigned long fixmap_addr;
32};
33
34static struct ioremap_map ioremap_maps[FIX_N_IOREMAPS];
35
36void __init ioremap_fixed_init(void)
37{
38	struct ioremap_map *map;
39	int i;
40
41	for (i = 0; i < FIX_N_IOREMAPS; i++) {
42		map = &ioremap_maps[i];
43		map->fixmap_addr = __fix_to_virt(FIX_IOREMAP_BEGIN + i);
44	}
45}
46
47void __init __iomem *
48ioremap_fixed(phys_addr_t phys_addr, unsigned long size, pgprot_t prot)
49{
50	enum fixed_addresses idx0, idx;
51	struct ioremap_map *map;
52	unsigned int nrpages;
53	unsigned long offset;
54	int i, slot;
55
56	/*
57	 * Mappings have to be page-aligned
58	 */
59	offset = phys_addr & ~PAGE_MASK;
60	phys_addr &= PAGE_MASK;
61	size = PAGE_ALIGN(phys_addr + size) - phys_addr;
62
63	slot = -1;
64	for (i = 0; i < FIX_N_IOREMAPS; i++) {
65		map = &ioremap_maps[i];
66		if (!map->addr) {
67			map->size = size;
68			slot = i;
69			break;
70		}
71	}
72
73	if (slot < 0)
74		return NULL;
75
76	/*
77	 * Mappings have to fit in the FIX_IOREMAP area.
78	 */
79	nrpages = size >> PAGE_SHIFT;
80	if (nrpages > FIX_N_IOREMAPS)
81		return NULL;
82
83	/*
84	 * Ok, go for it..
85	 */
86	idx0 = FIX_IOREMAP_BEGIN + slot;
87	idx = idx0;
88	while (nrpages > 0) {
89		pgprot_val(prot) |= _PAGE_WIRED;
90		__set_fixmap(idx, phys_addr, prot);
91		phys_addr += PAGE_SIZE;
92		idx++;
93		--nrpages;
94	}
95
96	map->addr = (void __iomem *)(offset + map->fixmap_addr);
97	return map->addr;
98}
99
100int iounmap_fixed(void __iomem *addr)
101{
102	enum fixed_addresses idx;
103	struct ioremap_map *map;
104	unsigned int nrpages;
105	int i, slot;
106
107	slot = -1;
108	for (i = 0; i < FIX_N_IOREMAPS; i++) {
109		map = &ioremap_maps[i];
110		if (map->addr == addr) {
111			slot = i;
112			break;
113		}
114	}
115
116	/*
117	 * If we don't match, it's not for us.
118	 */
119	if (slot < 0)
120		return -EINVAL;
121
122	nrpages = map->size >> PAGE_SHIFT;
123
124	idx = FIX_IOREMAP_BEGIN + slot + nrpages - 1;
125	while (nrpages > 0) {
126		__clear_fixmap(idx, __pgprot(_PAGE_WIRED));
127		--idx;
128		--nrpages;
129	}
130
131	map->size = 0;
132	map->addr = NULL;
133
134	return 0;
135}
136