110 lines
3.3 KiB
C
110 lines
3.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0+ */
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/*
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* Generic I/O functions.
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*
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* Copyright (c) 2016 Imagination Technologies Ltd.
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*/
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#ifndef __ASM_GENERIC_IO_H__
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#define __ASM_GENERIC_IO_H__
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/*
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* This file should be included at the end of each architecture-specific
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* asm/io.h such that we may provide generic implementations without
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* conflicting with architecture-specific code.
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*/
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#ifndef __ASSEMBLY__
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/**
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* phys_to_virt() - Return a virtual address mapped to a given physical address
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* @paddr: the physical address
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*
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* Returns a virtual address which the CPU can access that maps to the physical
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* address @paddr. This should only be used where it is known that no dynamic
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* mapping is required. In general, map_physmem should be used instead.
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*
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* Returns: a virtual address which maps to @paddr
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*/
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#ifndef phys_to_virt
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static inline void *phys_to_virt(phys_addr_t paddr)
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{
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return (void *)(unsigned long)paddr;
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}
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#endif
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/**
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* virt_to_phys() - Return the physical address that a virtual address maps to
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* @vaddr: the virtual address
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*
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* Returns the physical address which the CPU-accessible virtual address @vaddr
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* maps to.
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*
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* Returns: the physical address which @vaddr maps to
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*/
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#ifndef virt_to_phys
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static inline phys_addr_t virt_to_phys(void *vaddr)
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{
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return (phys_addr_t)((unsigned long)vaddr);
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}
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#endif
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/*
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* Flags for use with map_physmem() & unmap_physmem(). Architectures need not
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* support all of these, in which case they will be defined as zero here &
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* ignored. Callers that may run on multiple architectures should therefore
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* treat them as hints rather than requirements.
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*/
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#ifndef MAP_NOCACHE
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# define MAP_NOCACHE 0 /* Produce an uncached mapping */
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#endif
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#ifndef MAP_WRCOMBINE
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# define MAP_WRCOMBINE 0 /* Allow write-combining on the mapping */
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#endif
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#ifndef MAP_WRBACK
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# define MAP_WRBACK 0 /* Map using write-back caching */
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#endif
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#ifndef MAP_WRTHROUGH
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# define MAP_WRTHROUGH 0 /* Map using write-through caching */
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#endif
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/**
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* map_physmem() - Return a virtual address mapped to a given physical address
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* @paddr: the physical address
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* @len: the length of the required mapping
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* @flags: flags affecting the type of mapping
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*
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* Return a virtual address through which the CPU may access the memory at
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* physical address @paddr. The mapping will be valid for at least @len bytes,
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* and may be affected by flags passed to the @flags argument. This function
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* may create new mappings, so should generally be paired with a matching call
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* to unmap_physmem once the caller is finished with the memory in question.
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*
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* Returns: a virtual address suitably mapped to @paddr
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*/
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#ifndef map_physmem
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static inline void *map_physmem(phys_addr_t paddr, unsigned long len,
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unsigned long flags)
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{
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return phys_to_virt(paddr);
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}
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#endif
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/**
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* unmap_physmem() - Remove mappings created by a prior call to map_physmem()
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* @vaddr: the virtual address which map_physmem() previously returned
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* @flags: flags matching those originally passed to map_physmem()
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*
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* Unmap memory which was previously mapped by a call to map_physmem(). If
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* map_physmem() dynamically created a mapping for the memory in question then
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* unmap_physmem() will remove that mapping.
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*/
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#ifndef unmap_physmem
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static inline void unmap_physmem(void *vaddr, unsigned long flags)
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{
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}
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#endif
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#endif /* !__ASSEMBLY__ */
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#endif /* __ASM_GENERIC_IO_H__ */
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