1 /* SPDX-License-Identifier: GPL-2.0+ */ 2 /* 3 * Generic I/O functions. 4 * 5 * Copyright (c) 2016 Imagination Technologies Ltd. 6 */ 7 8 #ifndef __ASM_GENERIC_IO_H__ 9 #define __ASM_GENERIC_IO_H__ 10 11 /* 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. 15 */ 16 17 #ifndef __ASSEMBLY__ 18 19 /** 20 * phys_to_virt() - Return a virtual address mapped to a given physical address 21 * @paddr: the physical address 22 * 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. 26 * 27 * Returns: a virtual address which maps to @paddr 28 */ 29 #ifndef phys_to_virt 30 static inline void *phys_to_virt(phys_addr_t paddr) 31 { 32 return (void *)(unsigned long)paddr; 33 } 34 #endif 35 36 /** 37 * virt_to_phys() - Return the physical address that a virtual address maps to 38 * @vaddr: the virtual address 39 * 40 * Returns the physical address which the CPU-accessible virtual address @vaddr 41 * maps to. 42 * 43 * Returns: the physical address which @vaddr maps to 44 */ 45 #ifndef virt_to_phys 46 static inline phys_addr_t virt_to_phys(void *vaddr) 47 { 48 return (phys_addr_t)((unsigned long)vaddr); 49 } 50 #endif 51 52 /* 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. 57 */ 58 #ifndef MAP_NOCACHE 59 # define MAP_NOCACHE 0 /* Produce an uncached mapping */ 60 #endif 61 #ifndef MAP_WRCOMBINE 62 # define MAP_WRCOMBINE 0 /* Allow write-combining on the mapping */ 63 #endif 64 #ifndef MAP_WRBACK 65 # define MAP_WRBACK 0 /* Map using write-back caching */ 66 #endif 67 #ifndef MAP_WRTHROUGH 68 # define MAP_WRTHROUGH 0 /* Map using write-through caching */ 69 #endif 70 71 /** 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 76 * 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. 82 * 83 * Returns: a virtual address suitably mapped to @paddr 84 */ 85 #ifndef map_physmem 86 static inline void *map_physmem(phys_addr_t paddr, unsigned long len, 87 unsigned long flags) 88 { 89 return phys_to_virt(paddr); 90 } 91 #endif 92 93 /** 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() 97 * 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. 101 */ 102 #ifndef unmap_physmem 103 static inline void unmap_physmem(void *vaddr, unsigned long flags) 104 { 105 } 106 #endif 107 108 #endif /* !__ASSEMBLY__ */ 109 #endif /* __ASM_GENERIC_IO_H__ */ 110