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
23 struct 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
41 static inline struct io_mapping *
io_mapping_init_wc(struct io_mapping * iomap,resource_size_t base,unsigned long size)42 io_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
57 static inline void
io_mapping_fini(struct io_mapping * mapping)58 io_mapping_fini(struct io_mapping *mapping)
59 {
60 iomap_free(mapping->base, mapping->size);
61 }
62
63 /* Atomic map/unmap */
64 static inline void __iomem *
io_mapping_map_atomic_wc(struct io_mapping * mapping,unsigned long offset)65 io_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
75 static inline void
io_mapping_unmap_atomic(void __iomem * vaddr)76 io_mapping_unmap_atomic(void __iomem *vaddr)
77 {
78 iounmap_atomic(vaddr);
79 }
80
81 static inline void __iomem *
io_mapping_map_wc(struct io_mapping * mapping,unsigned long offset,unsigned long size)82 io_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
94 static inline void
io_mapping_unmap(void __iomem * vaddr)95 io_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*/
105 static inline struct io_mapping *
io_mapping_init_wc(struct io_mapping * iomap,resource_size_t base,unsigned long size)106 io_mapping_init_wc(struct io_mapping *iomap,
107 resource_size_t base,
108 unsigned long size)
109 {
110 iomap->iomem = ioremap_wc(base, size);
111 if (!iomap->iomem)
112 return NULL;
113
114 iomap->base = base;
115 iomap->size = size;
116 #if defined(pgprot_noncached_wc) /* archs can't agree on a name ... */
117 iomap->prot = pgprot_noncached_wc(PAGE_KERNEL);
118 #elif defined(pgprot_writecombine)
119 iomap->prot = pgprot_writecombine(PAGE_KERNEL);
120 #else
121 iomap->prot = pgprot_noncached(PAGE_KERNEL);
122 #endif
123
124 return iomap;
125 }
126
127 static inline void
io_mapping_fini(struct io_mapping * mapping)128 io_mapping_fini(struct io_mapping *mapping)
129 {
130 iounmap(mapping->iomem);
131 }
132
133 /* Non-atomic map/unmap */
134 static inline void __iomem *
io_mapping_map_wc(struct io_mapping * mapping,unsigned long offset,unsigned long size)135 io_mapping_map_wc(struct io_mapping *mapping,
136 unsigned long offset,
137 unsigned long size)
138 {
139 return mapping->iomem + offset;
140 }
141
142 static inline void
io_mapping_unmap(void __iomem * vaddr)143 io_mapping_unmap(void __iomem *vaddr)
144 {
145 }
146
147 /* Atomic map/unmap */
148 static inline void __iomem *
io_mapping_map_atomic_wc(struct io_mapping * mapping,unsigned long offset)149 io_mapping_map_atomic_wc(struct io_mapping *mapping,
150 unsigned long offset)
151 {
152 preempt_disable();
153 pagefault_disable();
154 return io_mapping_map_wc(mapping, offset, PAGE_SIZE);
155 }
156
157 static inline void
io_mapping_unmap_atomic(void __iomem * vaddr)158 io_mapping_unmap_atomic(void __iomem *vaddr)
159 {
160 io_mapping_unmap(vaddr);
161 pagefault_enable();
162 preempt_enable();
163 }
164
165 #endif /* HAVE_ATOMIC_IOMAP */
166
167 static inline struct io_mapping *
io_mapping_create_wc(resource_size_t base,unsigned long size)168 io_mapping_create_wc(resource_size_t base,
169 unsigned long size)
170 {
171 struct io_mapping *iomap;
172
173 iomap = kmalloc(sizeof(*iomap), GFP_KERNEL);
174 if (!iomap)
175 return NULL;
176
177 if (!io_mapping_init_wc(iomap, base, size)) {
178 kfree(iomap);
179 return NULL;
180 }
181
182 return iomap;
183 }
184
185 static inline void
io_mapping_free(struct io_mapping * iomap)186 io_mapping_free(struct io_mapping *iomap)
187 {
188 io_mapping_fini(iomap);
189 kfree(iomap);
190 }
191
192 #endif /* _LINUX_IO_MAPPING_H */
193