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 if (!IS_ENABLED(CONFIG_PREEMPT_RT))
73 preempt_disable();
74 else
75 migrate_disable();
76 pagefault_disable();
77 return __iomap_local_pfn_prot(PHYS_PFN(phys_addr), mapping->prot);
78}
79
80static inline void
81io_mapping_unmap_atomic(void __iomem *vaddr)
82{
83 kunmap_local_indexed((void __force *)vaddr);
84 pagefault_enable();
85 if (!IS_ENABLED(CONFIG_PREEMPT_RT))
86 preempt_enable();
87 else
88 migrate_enable();
89}
90
91static inline void __iomem *
92io_mapping_map_local_wc(struct io_mapping *mapping, unsigned long offset)
93{
94 resource_size_t phys_addr;
95
96 BUG_ON(offset >= mapping->size);
97 phys_addr = mapping->base + offset;
98 return __iomap_local_pfn_prot(PHYS_PFN(phys_addr), mapping->prot);
99}
100
101static inline void io_mapping_unmap_local(void __iomem *vaddr)
102{
103 kunmap_local_indexed((void __force *)vaddr);
104}
105
106static inline void __iomem *
107io_mapping_map_wc(struct io_mapping *mapping,
108 unsigned long offset,
109 unsigned long size)
110{
111 resource_size_t phys_addr;
112
113 BUG_ON(offset >= mapping->size);
114 phys_addr = mapping->base + offset;
115
116 return ioremap_wc(phys_addr, size);
117}
118
119static inline void
120io_mapping_unmap(void __iomem *vaddr)
121{
122 iounmap(vaddr);
123}
124
125#else /* HAVE_ATOMIC_IOMAP */
126
127#include <linux/uaccess.h>
128
129/* Create the io_mapping object*/
130static inline struct io_mapping *
131io_mapping_init_wc(struct io_mapping *iomap,
132 resource_size_t base,
133 unsigned long size)
134{
135 iomap->iomem = ioremap_wc(offset: base, size);
136 if (!iomap->iomem)
137 return NULL;
138
139 iomap->base = base;
140 iomap->size = size;
141 iomap->prot = pgprot_writecombine(PAGE_KERNEL);
142
143 return iomap;
144}
145
146static inline void
147io_mapping_fini(struct io_mapping *mapping)
148{
149 iounmap(addr: mapping->iomem);
150}
151
152/* Non-atomic map/unmap */
153static inline void __iomem *
154io_mapping_map_wc(struct io_mapping *mapping,
155 unsigned long offset,
156 unsigned long size)
157{
158 return mapping->iomem + offset;
159}
160
161static inline void
162io_mapping_unmap(void __iomem *vaddr)
163{
164}
165
166/* Atomic map/unmap */
167static inline void __iomem *
168io_mapping_map_atomic_wc(struct io_mapping *mapping,
169 unsigned long offset)
170{
171 if (!IS_ENABLED(CONFIG_PREEMPT_RT))
172 preempt_disable();
173 else
174 migrate_disable();
175 pagefault_disable();
176 return io_mapping_map_wc(mapping, offset, PAGE_SIZE);
177}
178
179static inline void
180io_mapping_unmap_atomic(void __iomem *vaddr)
181{
182 io_mapping_unmap(vaddr);
183 pagefault_enable();
184 if (!IS_ENABLED(CONFIG_PREEMPT_RT))
185 preempt_enable();
186 else
187 migrate_enable();
188}
189
190static inline void __iomem *
191io_mapping_map_local_wc(struct io_mapping *mapping, unsigned long offset)
192{
193 return io_mapping_map_wc(mapping, offset, PAGE_SIZE);
194}
195
196static inline void io_mapping_unmap_local(void __iomem *vaddr)
197{
198 io_mapping_unmap(vaddr);
199}
200
201#endif /* !HAVE_ATOMIC_IOMAP */
202
203static inline struct io_mapping *
204io_mapping_create_wc(resource_size_t base,
205 unsigned long size)
206{
207 struct io_mapping *iomap;
208
209 iomap = kmalloc(sizeof(*iomap), GFP_KERNEL);
210 if (!iomap)
211 return NULL;
212
213 if (!io_mapping_init_wc(iomap, base, size)) {
214 kfree(objp: iomap);
215 return NULL;
216 }
217
218 return iomap;
219}
220
221static inline void
222io_mapping_free(struct io_mapping *iomap)
223{
224 io_mapping_fini(mapping: iomap);
225 kfree(objp: iomap);
226}
227
228#endif /* _LINUX_IO_MAPPING_H */
229