diff options
Diffstat (limited to 'include/asm-generic')
| -rw-r--r-- | include/asm-generic/io.h | 29 |
1 files changed, 8 insertions, 21 deletions
diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h index bf8204de3a48..ed74d2e9af75 100644 --- a/include/asm-generic/io.h +++ b/include/asm-generic/io.h @@ -922,28 +922,16 @@ static inline void *phys_to_virt(unsigned long address) /** * DOC: ioremap() and ioremap_*() variants * - * If you have an IOMMU your architecture is expected to have both ioremap() - * and iounmap() implemented otherwise the asm-generic helpers will provide a - * direct mapping. + * Architectures with an MMU are expected to provide ioremap() and iounmap() + * themselves. For NOMMU architectures we provide a default nop-op + * implementation that expect that the physical address used for MMIO are + * already marked as uncached, and can be used as kernel virtual addresses. * - * There are ioremap_*() call variants, if you have no IOMMU we naturally will - * default to direct mapping for all of them, you can override these defaults. - * If you have an IOMMU you are highly encouraged to provide your own - * ioremap variant implementation as there currently is no safe architecture - * agnostic default. To avoid possible improper behaviour default asm-generic - * ioremap_*() variants all return NULL when an IOMMU is available. If you've - * defined your own ioremap_*() variant you must then declare your own - * ioremap_*() variant as defined to itself to avoid the default NULL return. + * 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. */ #ifndef CONFIG_MMU - -/* - * Change "struct page" to physical address. - * - * This implementation is for the no-MMU case only... if you have an MMU - * you'll need to provide your own definitions. - */ - #ifndef ioremap #define ioremap ioremap static inline void __iomem *ioremap(phys_addr_t offset, size_t size) @@ -954,14 +942,13 @@ static inline void __iomem *ioremap(phys_addr_t offset, size_t size) #ifndef iounmap #define iounmap iounmap - static inline void iounmap(void __iomem *addr) { } #endif #endif /* CONFIG_MMU */ + #ifndef ioremap_nocache -void __iomem *ioremap(phys_addr_t phys_addr, size_t size); #define ioremap_nocache ioremap_nocache static inline void __iomem *ioremap_nocache(phys_addr_t offset, size_t size) { |