1 /* SPDX-License-Identifier: GPL-2.0+ */
3 * Generic I/O functions.
5 * Copyright (c) 2016 Imagination Technologies Ltd.
8 #ifndef __ASM_GENERIC_IO_H__
9 #define __ASM_GENERIC_IO_H__
12 * This file should be included at the end of each architecture-specific
13 * asm/io.h such that we may provide generic implementations without
14 * conflicting with architecture-specific code.
20 * phys_to_virt() - Return a virtual address mapped to a given physical address
21 * @paddr: the physical address
23 * Returns a virtual address which the CPU can access that maps to the physical
24 * address @paddr. This should only be used where it is known that no dynamic
25 * mapping is required. In general, map_physmem should be used instead.
27 * Returns: a virtual address which maps to @paddr
30 static inline void *phys_to_virt(phys_addr_t paddr)
32 return (void *)(unsigned long)paddr;
37 * virt_to_phys() - Return the physical address that a virtual address maps to
38 * @vaddr: the virtual address
40 * Returns the physical address which the CPU-accessible virtual address @vaddr
43 * Returns: the physical address which @vaddr maps to
46 static inline phys_addr_t virt_to_phys(void *vaddr)
48 return (phys_addr_t)((unsigned long)vaddr);
53 * Flags for use with map_physmem() & unmap_physmem(). Architectures need not
54 * support all of these, in which case they will be defined as zero here &
55 * ignored. Callers that may run on multiple architectures should therefore
56 * treat them as hints rather than requirements.
59 # define MAP_NOCACHE 0 /* Produce an uncached mapping */
62 # define MAP_WRCOMBINE 0 /* Allow write-combining on the mapping */
65 # define MAP_WRBACK 0 /* Map using write-back caching */
68 # define MAP_WRTHROUGH 0 /* Map using write-through caching */
72 * map_physmem() - Return a virtual address mapped to a given physical address
73 * @paddr: the physical address
74 * @len: the length of the required mapping
75 * @flags: flags affecting the type of mapping
77 * Return a virtual address through which the CPU may access the memory at
78 * physical address @paddr. The mapping will be valid for at least @len bytes,
79 * and may be affected by flags passed to the @flags argument. This function
80 * may create new mappings, so should generally be paired with a matching call
81 * to unmap_physmem once the caller is finished with the memory in question.
83 * Returns: a virtual address suitably mapped to @paddr
86 static inline void *map_physmem(phys_addr_t paddr, unsigned long len,
89 return phys_to_virt(paddr);
94 * unmap_physmem() - Remove mappings created by a prior call to map_physmem()
95 * @vaddr: the virtual address which map_physmem() previously returned
96 * @flags: flags matching those originally passed to map_physmem()
98 * Unmap memory which was previously mapped by a call to map_physmem(). If
99 * map_physmem() dynamically created a mapping for the memory in question then
100 * unmap_physmem() will remove that mapping.
102 #ifndef unmap_physmem
103 static inline void unmap_physmem(void *vaddr, unsigned long flags)
108 #endif /* !__ASSEMBLY__ */
109 #endif /* __ASM_GENERIC_IO_H__ */