Commit 9439eb3a authored by Will Deacon's avatar Will Deacon
Browse files

asm-generic: io: implement relaxed accessor macros as conditional wrappers 



{read,write}{b,w,l,q}_relaxed are implemented by some architectures in
order to permit memory-mapped I/O accesses with weaker barrier semantics
than the non-relaxed variants.

This patch adds wrappers to asm-generic so that drivers can rely on the
relaxed accessors being available, even if they don't always provide
weaker ordering guarantees. Since some architectures both include
asm-generic/io.h and define some relaxed accessors, the definitions here
are conditional for the time being.

Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent f114040e

include/asm-generic/io.h

+26 −0
Original line number Diff line number Diff line
@@ -53,18 +53,27 @@ static inline u32 __raw_readl(const volatile void __iomem *addr) 
#endif



#define readb __raw_readb

#ifndef readb_relaxed

#define readb_relaxed readb

#endif



#define readw readw

static inline u16 readw(const volatile void __iomem *addr)

{

	return __le16_to_cpu(__raw_readw(addr));

}

#ifndef readw_relaxed

#define readw_relaxed readw

#endif



#define readl readl

static inline u32 readl(const volatile void __iomem *addr)

{

	return __le32_to_cpu(__raw_readl(addr));

}

#ifndef readl_relaxed

#define readl_relaxed readl

#endif



#ifndef __raw_writeb

static inline void __raw_writeb(u8 b, volatile void __iomem *addr)
@@ -88,8 +97,19 @@ static inline void __raw_writel(u32 b, volatile void __iomem *addr) 
#endif



#define writeb __raw_writeb

#ifndef writeb_relaxed

#define writeb_relaxed writeb

#endif



#define writew(b,addr) __raw_writew(__cpu_to_le16(b),addr)

#ifndef writew_relaxed

#define writew_relaxed writew

#endif



#define writel(b,addr) __raw_writel(__cpu_to_le32(b),addr)

#ifndef writel_relaxed

#define writel_relaxed writel

#endif



#ifdef CONFIG_64BIT

#ifndef __raw_readq
@@ -104,6 +124,9 @@ static inline u64 readq(const volatile void __iomem *addr) 
{

	return __le64_to_cpu(__raw_readq(addr));

}

#ifndef readq_relaxed

#define readq_relaxed readq

#endif



#ifndef __raw_writeq

static inline void __raw_writeq(u64 b, volatile void __iomem *addr)
@@ -113,6 +136,9 @@ static inline void __raw_writeq(u64 b, volatile void __iomem *addr) 
#endif



#define writeq(b, addr) __raw_writeq(__cpu_to_le64(b), addr)

#ifndef writeq_relaxed

#define writeq_relaxed writeq

#endif

#endif /* CONFIG_64BIT */



#ifndef PCI_IOBASE

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