2 * Generic I/O functions.
4 * Copyright (c) 2016 Imagination Technologies Ltd.
6 * SPDX-License-Identifier: GPL-2.0+
9 #ifndef __ASM_GENERIC_IO_H__
10 #define __ASM_GENERIC_IO_H__
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.
21 * phys_to_virt() - Return a virtual address mapped to a given physical address
22 * @paddr: the physical address
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.
28 * Returns: a virtual address which maps to @paddr
31 static inline void *phys_to_virt(phys_addr_t paddr)
33 return (void *)(unsigned long)paddr;
38 * virt_to_phys() - Return the physical address that a virtual address maps to
39 * @vaddr: the virtual address
41 * Returns the physical address which the CPU-accessible virtual address @vaddr
44 * Returns: the physical address which @vaddr maps to
47 static inline phys_addr_t virt_to_phys(void *vaddr)
49 return (phys_addr_t)((unsigned long)vaddr);
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.
60 # define MAP_NOCACHE 0 /* Produce an uncached mapping */
63 # define MAP_WRCOMBINE 0 /* Allow write-combining on the mapping */
66 # define MAP_WRBACK 0 /* Map using write-back caching */
69 # define MAP_WRTHROUGH 0 /* Map using write-through caching */
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
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.
84 * Returns: a virtual address suitably mapped to @paddr
87 static inline void *map_physmem(phys_addr_t paddr, unsigned long len,
90 return phys_to_virt(paddr);
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()
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.
103 #ifndef unmap_physmem
104 static inline void unmap_physmem(void *vaddr, unsigned long flags)
109 #endif /* !__ASSEMBLY__ */
110 #endif /* __ASM_GENERIC_IO_H__ */