diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h new file mode 100644 index 0000000..0f5160c --- /dev/null +++ b/include/asm-generic/io.h @@ -0,0 +1,110 @@ +/* + * Generic I/O functions. + * + * Copyright (c) 2016 Imagination Technologies Ltd. + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +#ifndef __ASM_GENERIC_IO_H__ +#define __ASM_GENERIC_IO_H__ + +/* + * This file should be included at the end of each architecture-specific + * asm/io.h such that we may provide generic implementations without + * conflicting with architecture-specific code. + */ + +#ifndef __ASSEMBLY__ + +/** + * phys_to_virt() - Return a virtual address mapped to a given physical address + * @paddr: the physical address + * + * Returns a virtual address which the CPU can access that maps to the physical + * address @paddr. This should only be used where it is known that no dynamic + * mapping is required. In general, map_physmem should be used instead. + * + * Returns: a virtual address which maps to @paddr + */ +#ifndef phys_to_virt +static inline void *phys_to_virt(phys_addr_t paddr) +{ + return (void *)(unsigned long)paddr; +} +#endif + +/** + * virt_to_phys() - Return the physical address that a virtual address maps to + * @vaddr: the virtual address + * + * Returns the physical address which the CPU-accessible virtual address @vaddr + * maps to. + * + * Returns: the physical address which @vaddr maps to + */ +#ifndef virt_to_phys +static inline phys_addr_t virt_to_phys(void *vaddr) +{ + return (phys_addr_t)((unsigned long)vaddr); +} +#endif + +/* + * Flags for use with map_physmem() & unmap_physmem(). Architectures need not + * support all of these, in which case they will be defined as zero here & + * ignored. Callers that may run on multiple architectures should therefore + * treat them as hints rather than requirements. + */ +#ifndef MAP_NOCACHE +# define MAP_NOCACHE 0 /* Produce an uncached mapping */ +#endif +#ifndef MAP_WRCOMBINE +# define MAP_WRCOMBINE 0 /* Allow write-combining on the mapping */ +#endif +#ifndef MAP_WRBACK +# define MAP_WRBACK 0 /* Map using write-back caching */ +#endif +#ifndef MAP_WRTHROUGH +# define MAP_WRTHROUGH 0 /* Map using write-through caching */ +#endif + +/** + * map_physmem() - Return a virtual address mapped to a given physical address + * @paddr: the physical address + * @len: the length of the required mapping + * @flags: flags affecting the type of mapping + * + * Return a virtual address through which the CPU may access the memory at + * physical address @paddr. The mapping will be valid for at least @len bytes, + * and may be affected by flags passed to the @flags argument. This function + * may create new mappings, so should generally be paired with a matching call + * to unmap_physmem once the caller is finished with the memory in question. + * + * Returns: a virtual address suitably mapped to @paddr + */ +#ifndef map_physmem +static inline void *map_physmem(phys_addr_t paddr, unsigned long len, + unsigned long flags) +{ + return phys_to_virt(paddr); +} +#endif + +/** + * unmap_physmem() - Remove mappings created by a prior call to map_physmem() + * @vaddr: the virtual address which map_physmem() previously returned + * @flags: flags matching those originally passed to map_physmem() + * + * Unmap memory which was previously mapped by a call to map_physmem(). If + * map_physmem() dynamically created a mapping for the memory in question then + * unmap_physmem() will remove that mapping. + */ +#ifndef unmap_physmem +static inline void unmap_physmem(void *vaddr, unsigned long flags) +{ +} +#endif + +#endif /* !__ASSEMBLY__ */ +#endif /* __ASM_GENERIC_IO_H__ */