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1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Copyright © 2008 Keith Packard <keithp@keithp.com>
4 */
5
6#ifndef _LINUX_IO_MAPPING_H
7#define _LINUX_IO_MAPPING_H
8
9#include <linux/types.h>
10#include <linux/slab.h>
11#include <linux/bug.h>
12#include <linux/io.h>
13#include <asm/page.h>
14
15/*
16 * The io_mapping mechanism provides an abstraction for mapping
17 * individual pages from an io device to the CPU in an efficient fashion.
18 *
19 * See Documentation/driver-api/io-mapping.rst
20 */
21
22struct io_mapping {
23 resource_size_t base;
24 unsigned long size;
25 pgprot_t prot;
26 void __iomem *iomem;
27};
28
29#ifdef CONFIG_HAVE_ATOMIC_IOMAP
30
31#include <linux/pfn.h>
32#include <asm/iomap.h>
33/*
34 * For small address space machines, mapping large objects
35 * into the kernel virtual space isn't practical. Where
36 * available, use fixmap support to dynamically map pages
37 * of the object at run time.
38 */
39
40static inline struct io_mapping *
41io_mapping_init_wc(struct io_mapping *iomap,
42 resource_size_t base,
43 unsigned long size)
44{
45 pgprot_t prot;
46
47 if (iomap_create_wc(base, size, &prot))
48 return NULL;
49
50 iomap->base = base;
51 iomap->size = size;
52 iomap->prot = prot;
53 return iomap;
54}
55
56static inline void
57io_mapping_fini(struct io_mapping *mapping)
58{
59 iomap_free(mapping->base, mapping->size);
60}
61
62/* Atomic map/unmap */
63static inline void __iomem *
64io_mapping_map_atomic_wc(struct io_mapping *mapping,
65 unsigned long offset)
66{
67 resource_size_t phys_addr;
68
69 BUG_ON(offset >= mapping->size);
70 phys_addr = mapping->base + offset;
71 return iomap_atomic_prot_pfn(PHYS_PFN(phys_addr), mapping->prot);
72}
73
74static inline void
75io_mapping_unmap_atomic(void __iomem *vaddr)
76{
77 iounmap_atomic(vaddr);
78}
79
80static inline void __iomem *
81io_mapping_map_wc(struct io_mapping *mapping,
82 unsigned long offset,
83 unsigned long size)
84{
85 resource_size_t phys_addr;
86
87 BUG_ON(offset >= mapping->size);
88 phys_addr = mapping->base + offset;
89
90 return ioremap_wc(phys_addr, size);
91}
92
93static inline void
94io_mapping_unmap(void __iomem *vaddr)
95{
96 iounmap(vaddr);
97}
98
99#else
100
101#include <linux/uaccess.h>
102#include <asm/pgtable.h>
103
104/* Create the io_mapping object*/
105static inline struct io_mapping *
106io_mapping_init_wc(struct io_mapping *iomap,
107 resource_size_t base,
108 unsigned long size)
109{
110 iomap->base = base;
111 iomap->size = size;
112 iomap->iomem = ioremap_wc(base, size);
113#if defined(pgprot_noncached_wc) /* archs can't agree on a name ... */
114 iomap->prot = pgprot_noncached_wc(PAGE_KERNEL);
115#elif defined(pgprot_writecombine)
116 iomap->prot = pgprot_writecombine(PAGE_KERNEL);
117#else
118 iomap->prot = pgprot_noncached(PAGE_KERNEL);
119#endif
120
121 return iomap;
122}
123
124static inline void
125io_mapping_fini(struct io_mapping *mapping)
126{
127 iounmap(mapping->iomem);
128}
129
130/* Non-atomic map/unmap */
131static inline void __iomem *
132io_mapping_map_wc(struct io_mapping *mapping,
133 unsigned long offset,
134 unsigned long size)
135{
136 return mapping->iomem + offset;
137}
138
139static inline void
140io_mapping_unmap(void __iomem *vaddr)
141{
142}
143
144/* Atomic map/unmap */
145static inline void __iomem *
146io_mapping_map_atomic_wc(struct io_mapping *mapping,
147 unsigned long offset)
148{
149 preempt_disable();
150 pagefault_disable();
151 return io_mapping_map_wc(mapping, offset, PAGE_SIZE);
152}
153
154static inline void
155io_mapping_unmap_atomic(void __iomem *vaddr)
156{
157 io_mapping_unmap(vaddr);
158 pagefault_enable();
159 preempt_enable();
160}
161
162#endif /* HAVE_ATOMIC_IOMAP */
163
164static inline struct io_mapping *
165io_mapping_create_wc(resource_size_t base,
166 unsigned long size)
167{
168 struct io_mapping *iomap;
169
170 iomap = kmalloc(sizeof(*iomap), GFP_KERNEL);
171 if (!iomap)
172 return NULL;
173
174 if (!io_mapping_init_wc(iomap, base, size)) {
175 kfree(iomap);
176 return NULL;
177 }
178
179 return iomap;
180}
181
182static inline void
183io_mapping_free(struct io_mapping *iomap)
184{
185 io_mapping_fini(iomap);
186 kfree(iomap);
187}
188
189#endif /* _LINUX_IO_MAPPING_H */