Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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 <linux/pgtable.h>
14#include <asm/page.h>
15
16/*
17 * The io_mapping mechanism provides an abstraction for mapping
18 * individual pages from an io device to the CPU in an efficient fashion.
19 *
20 * See Documentation/driver-api/io-mapping.rst
21 */
22
23struct io_mapping {
24 resource_size_t base;
25 unsigned long size;
26 pgprot_t prot;
27 void __iomem *iomem;
28};
29
30#ifdef CONFIG_HAVE_ATOMIC_IOMAP
31
32#include <linux/pfn.h>
33#include <asm/iomap.h>
34/*
35 * For small address space machines, mapping large objects
36 * into the kernel virtual space isn't practical. Where
37 * available, use fixmap support to dynamically map pages
38 * of the object at run time.
39 */
40
41static inline struct io_mapping *
42io_mapping_init_wc(struct io_mapping *iomap,
43 resource_size_t base,
44 unsigned long size)
45{
46 pgprot_t prot;
47
48 if (iomap_create_wc(base, size, &prot))
49 return NULL;
50
51 iomap->base = base;
52 iomap->size = size;
53 iomap->prot = prot;
54 return iomap;
55}
56
57static inline void
58io_mapping_fini(struct io_mapping *mapping)
59{
60 iomap_free(mapping->base, mapping->size);
61}
62
63/* Atomic map/unmap */
64static inline void __iomem *
65io_mapping_map_atomic_wc(struct io_mapping *mapping,
66 unsigned long offset)
67{
68 resource_size_t phys_addr;
69
70 BUG_ON(offset >= mapping->size);
71 phys_addr = mapping->base + offset;
72 return iomap_atomic_prot_pfn(PHYS_PFN(phys_addr), mapping->prot);
73}
74
75static inline void
76io_mapping_unmap_atomic(void __iomem *vaddr)
77{
78 iounmap_atomic(vaddr);
79}
80
81static inline void __iomem *
82io_mapping_map_wc(struct io_mapping *mapping,
83 unsigned long offset,
84 unsigned long size)
85{
86 resource_size_t phys_addr;
87
88 BUG_ON(offset >= mapping->size);
89 phys_addr = mapping->base + offset;
90
91 return ioremap_wc(phys_addr, size);
92}
93
94static inline void
95io_mapping_unmap(void __iomem *vaddr)
96{
97 iounmap(vaddr);
98}
99
100#else
101
102#include <linux/uaccess.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 */