From 7a1aedba7061948eee4d188740e24ffb20ff7ab7 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Horia=20Geant=C4=83?= Date: Thu, 19 May 2016 18:10:43 +0300 Subject: [PATCH] asm-generic/io.h: allow barriers in io{read,write}{16,32}be MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit While reviewing the addition of io{read,write}64be accessors, Arnd -finds a potential problem: "If an architecture overrides readq/writeq to have barriers but does not override ioread64be/iowrite64be, this will lack the barriers and behave differently from the little-endian version. I think the only affected architecture is ARC, since ARM and ARM64 both override the big-endian accessors to have the correct barriers, and all others don't use barriers at all." -suggests a fix for the same problem in existing code (16/32-bit accessors); the fix leads "to a double-swap on architectures that don't override the io{read,write}{16,32}be accessors, but it will work correctly on all architectures without them having to override these accessors." Suggested-by: Arnd Bergmann Acked-by: Arnd Bergmann Signed-off-by: Horia Geantă Signed-off-by: Herbert Xu --- include/asm-generic/io.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h index 002b81f6f2bc..325c8908f6de 100644 --- a/include/asm-generic/io.h +++ b/include/asm-generic/io.h @@ -613,7 +613,7 @@ static inline void iowrite32(u32 value, volatile void __iomem *addr) #define ioread16be ioread16be static inline u16 ioread16be(const volatile void __iomem *addr) { - return __be16_to_cpu(__raw_readw(addr)); + return swab16(readw(addr)); } #endif @@ -621,7 +621,7 @@ static inline u16 ioread16be(const volatile void __iomem *addr) #define ioread32be ioread32be static inline u32 ioread32be(const volatile void __iomem *addr) { - return __be32_to_cpu(__raw_readl(addr)); + return swab32(readl(addr)); } #endif @@ -629,7 +629,7 @@ static inline u32 ioread32be(const volatile void __iomem *addr) #define iowrite16be iowrite16be static inline void iowrite16be(u16 value, void volatile __iomem *addr) { - __raw_writew(__cpu_to_be16(value), addr); + writew(swab16(value), addr); } #endif @@ -637,7 +637,7 @@ static inline void iowrite16be(u16 value, void volatile __iomem *addr) #define iowrite32be iowrite32be static inline void iowrite32be(u32 value, volatile void __iomem *addr) { - __raw_writel(__cpu_to_be32(value), addr); + writel(swab32(value), addr); } #endif -- 2.11.0