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Paul Burtond4150ca2017-09-14 15:05:01 -07001/*
2 * Generic I/O functions.
3 *
4 * Copyright (c) 2016 Imagination Technologies Ltd.
5 *
6 * SPDX-License-Identifier: GPL-2.0+
7 */
8
9#ifndef __ASM_GENERIC_IO_H__
10#define __ASM_GENERIC_IO_H__
11
12/*
13 * This file should be included at the end of each architecture-specific
14 * asm/io.h such that we may provide generic implementations without
15 * conflicting with architecture-specific code.
16 */
17
18#ifndef __ASSEMBLY__
19
20/**
21 * phys_to_virt() - Return a virtual address mapped to a given physical address
22 * @paddr: the physical address
23 *
24 * Returns a virtual address which the CPU can access that maps to the physical
25 * address @paddr. This should only be used where it is known that no dynamic
26 * mapping is required. In general, map_physmem should be used instead.
27 *
28 * Returns: a virtual address which maps to @paddr
29 */
30#ifndef phys_to_virt
31static inline void *phys_to_virt(phys_addr_t paddr)
32{
33 return (void *)(unsigned long)paddr;
34}
35#endif
36
37/**
38 * virt_to_phys() - Return the physical address that a virtual address maps to
39 * @vaddr: the virtual address
40 *
41 * Returns the physical address which the CPU-accessible virtual address @vaddr
42 * maps to.
43 *
44 * Returns: the physical address which @vaddr maps to
45 */
46#ifndef virt_to_phys
47static inline phys_addr_t virt_to_phys(void *vaddr)
48{
49 return (phys_addr_t)((unsigned long)vaddr);
50}
51#endif
52
53/*
54 * Flags for use with map_physmem() & unmap_physmem(). Architectures need not
55 * support all of these, in which case they will be defined as zero here &
56 * ignored. Callers that may run on multiple architectures should therefore
57 * treat them as hints rather than requirements.
58 */
59#ifndef MAP_NOCACHE
60# define MAP_NOCACHE 0 /* Produce an uncached mapping */
61#endif
62#ifndef MAP_WRCOMBINE
63# define MAP_WRCOMBINE 0 /* Allow write-combining on the mapping */
64#endif
65#ifndef MAP_WRBACK
66# define MAP_WRBACK 0 /* Map using write-back caching */
67#endif
68#ifndef MAP_WRTHROUGH
69# define MAP_WRTHROUGH 0 /* Map using write-through caching */
70#endif
71
72/**
73 * map_physmem() - Return a virtual address mapped to a given physical address
74 * @paddr: the physical address
75 * @len: the length of the required mapping
76 * @flags: flags affecting the type of mapping
77 *
78 * Return a virtual address through which the CPU may access the memory at
79 * physical address @paddr. The mapping will be valid for at least @len bytes,
80 * and may be affected by flags passed to the @flags argument. This function
81 * may create new mappings, so should generally be paired with a matching call
82 * to unmap_physmem once the caller is finished with the memory in question.
83 *
84 * Returns: a virtual address suitably mapped to @paddr
85 */
86#ifndef map_physmem
87static inline void *map_physmem(phys_addr_t paddr, unsigned long len,
88 unsigned long flags)
89{
90 return phys_to_virt(paddr);
91}
92#endif
93
94/**
95 * unmap_physmem() - Remove mappings created by a prior call to map_physmem()
96 * @vaddr: the virtual address which map_physmem() previously returned
97 * @flags: flags matching those originally passed to map_physmem()
98 *
99 * Unmap memory which was previously mapped by a call to map_physmem(). If
100 * map_physmem() dynamically created a mapping for the memory in question then
101 * unmap_physmem() will remove that mapping.
102 */
103#ifndef unmap_physmem
104static inline void unmap_physmem(void *vaddr, unsigned long flags)
105{
106}
107#endif
108
109#endif /* !__ASSEMBLY__ */
110#endif /* __ASM_GENERIC_IO_H__ */