From e97133959ad2942ae43c81a08858bef01bc0ec18 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 13 Aug 2019 07:53:05 +0200 Subject: asm-generic: ioremap_uc should behave the same with and without MMU Whatever reason there is for the existence of ioremap_uc, and the fact that it returns NULL by default on architectures with an MMU applies equally to nommu architectures, so don't provide different defaults. In practice the difference is meaningless as the only portable driver that uses ioremap_uc is atyfb which probably doesn't show up on nommu devices. Signed-off-by: Christoph Hellwig Reviewed-by: Arnd Bergmann Reviewed-by: Palmer Dabbelt --- include/asm-generic/io.h | 36 ++++++++++++++++-------------------- 1 file changed, 16 insertions(+), 20 deletions(-) (limited to 'include/asm-generic') diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h index d02806513670..bf8204de3a48 100644 --- a/include/asm-generic/io.h +++ b/include/asm-generic/io.h @@ -935,18 +935,7 @@ static inline void *phys_to_virt(unsigned long address) * defined your own ioremap_*() variant you must then declare your own * ioremap_*() variant as defined to itself to avoid the default NULL return. */ - -#ifdef CONFIG_MMU - -#ifndef ioremap_uc -#define ioremap_uc ioremap_uc -static inline void __iomem *ioremap_uc(phys_addr_t offset, size_t size) -{ - return NULL; -} -#endif - -#else /* !CONFIG_MMU */ +#ifndef CONFIG_MMU /* * Change "struct page" to physical address. @@ -980,14 +969,6 @@ static inline void __iomem *ioremap_nocache(phys_addr_t offset, size_t size) } #endif -#ifndef ioremap_uc -#define ioremap_uc ioremap_uc -static inline void __iomem *ioremap_uc(phys_addr_t offset, size_t size) -{ - return ioremap_nocache(offset, size); -} -#endif - #ifndef ioremap_wc #define ioremap_wc ioremap_wc static inline void __iomem *ioremap_wc(phys_addr_t offset, size_t size) @@ -1004,6 +985,21 @@ static inline void __iomem *ioremap_wt(phys_addr_t offset, size_t size) } #endif +/* + * ioremap_uc is special in that we do require an explicit architecture + * implementation. In general you do not want to use this function in a + * driver and use plain ioremap, which is uncached by default. Similarly + * architectures should not implement it unless they have a very good + * reason. + */ +#ifndef ioremap_uc +#define ioremap_uc ioremap_uc +static inline void __iomem *ioremap_uc(phys_addr_t offset, size_t size) +{ + return NULL; +} +#endif + #ifdef CONFIG_HAS_IOPORT_MAP #ifndef CONFIG_GENERIC_IOMAP #ifndef ioport_map -- cgit From 97c9801a15e5b0c9a20e495b2ccabf010894e74b Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Sun, 11 Aug 2019 14:53:20 +0200 Subject: asm-generic: don't provide ioremap for CONFIG_MMU All MMU-enabled ports have a non-trivial ioremap and should thus provide the prototype for their implementation instead of providing a generic one unless a different symbol is not defined. Note that this only affects sparc32 nds32 as all others do provide their own version. Also update the kerneldoc comments in asm-generic/io.h to explain the situation around the default ioremap* implementations correctly. Signed-off-by: Christoph Hellwig Reviewed-by: Arnd Bergmann --- include/asm-generic/io.h | 29 ++++++++--------------------- 1 file changed, 8 insertions(+), 21 deletions(-) (limited to 'include/asm-generic') 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) { -- cgit From d092a87073269677b7ff09e71a8d91912b7f969a Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Wed, 16 Oct 2019 08:09:38 +0200 Subject: arch: rely on asm-generic/io.h for default ioremap_* definitions Various architectures that use asm-generic/io.h still defined their own default versions of ioremap_nocache, ioremap_wt and ioremap_wc that point back to plain ioremap directly or indirectly. Remove these definitions and rely on asm-generic/io.h instead. For this to work the backup ioremap_* defintions needs to be changed to purely cpp macros instea of inlines to cover for architectures like openrisc that only define ioremap after including . Signed-off-by: Christoph Hellwig Reviewed-by: Arnd Bergmann Reviewed-by: Palmer Dabbelt --- include/asm-generic/io.h | 18 +++--------------- 1 file changed, 3 insertions(+), 15 deletions(-) (limited to 'include/asm-generic') diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h index ed74d2e9af75..bd676f21b5bd 100644 --- a/include/asm-generic/io.h +++ b/include/asm-generic/io.h @@ -949,27 +949,15 @@ static inline void iounmap(void __iomem *addr) #endif /* CONFIG_MMU */ #ifndef ioremap_nocache -#define ioremap_nocache ioremap_nocache -static inline void __iomem *ioremap_nocache(phys_addr_t offset, size_t size) -{ - return ioremap(offset, size); -} +#define ioremap_nocache ioremap #endif #ifndef ioremap_wc -#define ioremap_wc ioremap_wc -static inline void __iomem *ioremap_wc(phys_addr_t offset, size_t size) -{ - return ioremap_nocache(offset, size); -} +#define ioremap_wc ioremap #endif #ifndef ioremap_wt -#define ioremap_wt ioremap_wt -static inline void __iomem *ioremap_wt(phys_addr_t offset, size_t size) -{ - return ioremap_nocache(offset, size); -} +#define ioremap_wt ioremap #endif /* -- cgit From 80b0ca98f91ddbc09828aff5a00af1c73837713e Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 13 Aug 2019 11:24:04 +0200 Subject: lib: provide a simple generic ioremap implementation A lot of architectures reuse the same simple ioremap implementation, so start lifting the most simple variant to lib/ioremap.c. It provides ioremap_prot and iounmap, plus a default ioremap that uses prot_noncached, although that can be overridden by asm/io.h. Signed-off-by: Christoph Hellwig Reviewed-by: Arnd Bergmann Reviewed-by: Palmer Dabbelt --- include/asm-generic/io.h | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-) (limited to 'include/asm-generic') diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h index bd676f21b5bd..325fc98cc9ff 100644 --- a/include/asm-generic/io.h +++ b/include/asm-generic/io.h @@ -923,9 +923,10 @@ static inline void *phys_to_virt(unsigned long address) * DOC: ioremap() and ioremap_*() variants * * 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. + * themselves or rely on GENERIC_IOREMAP. 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. * * ioremap_wc() and ioremap_wt() can provide more relaxed caching attributes * for specific drivers if the architecture choses to implement them. If they @@ -946,7 +947,18 @@ static inline void iounmap(void __iomem *addr) { } #endif -#endif /* CONFIG_MMU */ +#elif defined(CONFIG_GENERIC_IOREMAP) +#include + +void __iomem *ioremap_prot(phys_addr_t addr, size_t size, unsigned long prot); +void iounmap(volatile void __iomem *addr); + +static inline void __iomem *ioremap(phys_addr_t addr, size_t size) +{ + /* _PAGE_IOREMAP needs to be supplied by the architecture */ + return ioremap_prot(addr, size, _PAGE_IOREMAP); +} +#endif /* !CONFIG_MMU || CONFIG_GENERIC_IOREMAP */ #ifndef ioremap_nocache #define ioremap_nocache ioremap -- cgit