diff options
Diffstat (limited to 'include/asm-generic/io.h')
| -rw-r--r-- | include/asm-generic/io.h | 21 |
1 files changed, 20 insertions, 1 deletions
diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h index c6af40ce03be..76d456c516a1 100644 --- a/include/asm-generic/io.h +++ b/include/asm-generic/io.h @@ -942,7 +942,9 @@ static inline void *phys_to_virt(unsigned long address) * * ioremap_wc() and ioremap_wt() can provide more relaxed caching attributes * for specific drivers if the architecture choses to implement them. If they - * are not implemented we fall back to plain ioremap. + * are not implemented we fall back to plain ioremap. Conversely, ioremap_np() + * can provide stricter non-posted write semantics if the architecture + * implements them. */ #ifndef CONFIG_MMU #ifndef ioremap @@ -995,6 +997,23 @@ static inline void __iomem *ioremap_uc(phys_addr_t offset, size_t size) } #endif +/* + * ioremap_np needs an explicit architecture implementation, as it + * requests stronger semantics than regular ioremap(). Portable drivers + * should instead use one of the higher-level abstractions, like + * devm_ioremap_resource(), to choose the correct variant for any given + * device and bus. Portable drivers with a good reason to want non-posted + * write semantics should always provide an ioremap() fallback in case + * ioremap_np() is not available. + */ +#ifndef ioremap_np +#define ioremap_np ioremap_np +static inline void __iomem *ioremap_np(phys_addr_t offset, size_t size) +{ + return NULL; +} +#endif + #ifdef CONFIG_HAS_IOPORT_MAP #ifndef CONFIG_GENERIC_IOMAP #ifndef ioport_map |