The inX() and readX() I/O accessors must enforce ordering against subsequent calls to the delay() routines, so that a read-back from a device can be used to postpone a subsequent write to the same device. On some architectures, including arm64, this ordering can only be achieved by creating a dependency on the value returned by the I/O accessor operation, so we need to pass the value we read to the __io_par() and __io_ar() macros in these cases. Acked-by: Arnd Bergmann <arnd@xxxxxxxx> Reported-by: Andrew Murray <andrew.murray@xxxxxxx> Signed-off-by: Will Deacon <will.deacon@xxxxxxx> --- include/asm-generic/io.h | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h index d356f802945a..303871651f8a 100644 --- a/include/asm-generic/io.h +++ b/include/asm-generic/io.h @@ -32,9 +32,9 @@ /* prevent prefetching of coherent DMA data ahead of a dma-complete */ #ifndef __io_ar #ifdef rmb -#define __io_ar() rmb() +#define __io_ar(v) rmb() #else -#define __io_ar() barrier() +#define __io_ar(v) barrier() #endif #endif @@ -65,7 +65,7 @@ #endif #ifndef __io_par -#define __io_par() __io_ar() +#define __io_par(v) __io_ar(v) #endif @@ -158,7 +158,7 @@ static inline u8 readb(const volatile void __iomem *addr) __io_br(); val = __raw_readb(addr); - __io_ar(); + __io_ar(val); return val; } #endif @@ -171,7 +171,7 @@ static inline u16 readw(const volatile void __iomem *addr) __io_br(); val = __le16_to_cpu(__raw_readw(addr)); - __io_ar(); + __io_ar(val); return val; } #endif @@ -184,7 +184,7 @@ static inline u32 readl(const volatile void __iomem *addr) __io_br(); val = __le32_to_cpu(__raw_readl(addr)); - __io_ar(); + __io_ar(val); return val; } #endif @@ -198,7 +198,7 @@ static inline u64 readq(const volatile void __iomem *addr) __io_br(); val = __le64_to_cpu(__raw_readq(addr)); - __io_ar(); + __io_ar(val); return val; } #endif @@ -471,7 +471,7 @@ static inline u8 inb(unsigned long addr) __io_pbr(); val = __raw_readb(PCI_IOBASE + addr); - __io_par(); + __io_par(val); return val; } #endif @@ -484,7 +484,7 @@ static inline u16 inw(unsigned long addr) __io_pbr(); val = __le16_to_cpu(__raw_readw(PCI_IOBASE + addr)); - __io_par(); + __io_par(val); return val; } #endif @@ -497,7 +497,7 @@ static inline u32 inl(unsigned long addr) __io_pbr(); val = __le32_to_cpu(__raw_readl(PCI_IOBASE + addr)); - __io_par(); + __io_par(val); return val; } #endif -- 2.11.0
