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

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{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: Will Deacon <will.deacon@arm.com>
This commit is contained in:
Will Deacon 2013-09-03 10:44:00 +01:00
parent f114040e3e
commit 9439eb3ab9
1 changed files with 26 additions and 0 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

26
include/asm-generic/io.h
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@ -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